• Ribonucleotide reductase
• Ribonucleotide reductase (RR)
• process begins with the reduction of rNDPs
• he phosphorylation of dNDPs to dNTPs is catalyzed by the same nucleoside diphosphate kinases that phosphorylates rNDPs to rNTPs, using ATP as the phosphate donor.
• Leukopenia i
• severe anemia caused by hypochromic erythrocytes and megaloblastic bone marrow
• orotic aciduria that causes retarded growth
• olism >. Two inherited disorders affecting pyrimidine biosynthesis are the result of deficiencies in the bifunctional enzyme catalyzing the last two steps of UMP synthesis, orotate phosphoribosyl transferase and OMP decarboxyla
• Because the products of pyrimidine catabolism are soluble, few disorders result from excess levels of their synthesis or catabolism
• salvage of pyrimidine bases has less clinical significance than that of the purines, owing to the solubility of the by-products of pyrimidine catabolism.
• (when CMP and UMP are degraded) or b-aminoisobutyrate (when dTMP is degraded) and NH₃ and CO₂.
• leads ultimately to b-alanine 
• OMP decarboxylase
• PS-I of the urea cycle is localized in the mitochondria and utilizes ammonia
• refers glutamine as a substr
• localized to the cytoplasm
• carbamoyl synthetase activity of this complex is termed carbamoyl phosphate synthetase II (CPS-II) as opposed to CPS-I, which is involved in the urea cycle.
• t the first step which is catalyzed by aspartate transcarbamoylase, ATCase
• analog of folic acid.
• dihydrofolate reductase (DHFR),
• suicide substrate
• dTTP is utilized only in DNA, it is therapeutically possible to target rapidly proliferating cells over non-proliferating cells through the inhibition of thymidylate synthase. Many anti-cancer drugs act directly to inhibit thymidylate synthase, or indirectly, by inhibiting DHFR.
• ollowing completion of UMP synthesis it can be phosphorylated  to UTP and utilized as a substrate for CTP synthase for the synthesis of CTP.  Uridine nucleotides are also the precursors for de novo synthesis of  the thymine nucleotides.
• aspartate  transcarbamoylase (ATCase) which is the rate limiting step in pyrimidine  biosynthesis
• action is catalyzed by carbamoyl phosphate synthetase II  (CPS-II)
• ynthesized from glutamine instead of ammonia and is synthesized in the  cytosol
• UTP is aminated by the action of CTP synthase, generating CTP.
• ridylate kinase
• UMP is phosphorylated twice to yield UTP (ATP is the phosphate donor
• no branch in the pyrimidine synthesis
• decarboxylated to UMP
• rotate monophosphate (OMP
• irst fully formed pyrimidine base (orotic acid)
• not built upon PRPP
• n a reaction catalyzed by the rate limiting enzyme of pyrimidine nucleotide biosynthesis,  aspartate transcarbamoylase >  (ATCase). >
• Carbamoyl phosphate is then condensed with aspartate
• aspartate transcarbamoylase (ATCase).
• pyrimidine nucleotide precursor is synthesized by CPS-II.
• carbamoyl phosphate used for pyrimidine nucleotide synthesis is derived from glutamine and bicarbonate, within the cytosol, as opposed to the urea cycle
• carbamoyl phosphate derived from ammonia and bicarbonate in the mitochondrion
• dditional mole of glutamine and ATP are required in the conversion of UTP to CTP
• aspartate
• irst completed base is derived from 1 mole of glutamine, one mole of ATP and one mole of CO₂ (which form carbamoyl phosphate

• ncreased availability of glucose-6-phosphate increases the rate of flux through the pentose phosphate pathway, yielding an elevation in the level of ribose-5-phosphate and consequently PRPP. The increases in PRPP then result in excess purine biosynthesis.

    
• deficiency in glucose 6-phosphatase activity
• glycogen storage diseases von Gierke's disease also leads to excessive uric acid production
• purine-degradative enzyme.
• ack of purine nucleoside phosphorylase (PNP)
• net effect is to inhibit DNA synthesis. Since lymphocytes must be able to proliferate dramatically in response to antigenic challenge, the inability to synthesize DNA seriously impairs the immune responses
• igh concentrations of dATP inhibit ribonucleotide reductase (see below), thereby preventing other dNTPs from being produced
• ield levels of dATP that are 50-fold higher than normal
• destruction of B and T lymphocytes,
• nzyme responsible for converting adenosine to inosine in the catabolism of the purines.
• deficiency in the enzyme adenosine deaminase (ADA)
• SCID is
• self-mutilation
• severe symptoms of gout but also a severe malfunction of the nervous system
• disorder is inherited as a sex-linked trait,
• loss of a functional HGPRT gene
• Lesch-Nyhan syndrome
• treated by administering the antimetabolite: allopurinol. This compound is a structural analog of hypoxanthine that strongly inhibits xanthine oxidase
• Most forms of gout are the result of excess purine production and consequent catabolism or to a partial deficiency in the salvage enzyme, HGPRT
• precipitation of urate as monosodium urate (MSU) or calcium pyrophosphate dihydrate (CPPD) crystals, in the synovial fluid of the joints, leading to severe inflammation and arthritis
• linical manifestations of abnormal purine catabolism arise from the insolubility of the degradation byproduct, uric acid
• muscle lacks most of the enzymes of the major anapleurotic reactions. Muscle replenishes TCA-cycle intermediates in the form of fumarate generated by the purine nucleotide cycle.
• in muscle cells
• purine nucleotide cycle
• hypoxanthine-guanine phosphoribosyltransferase (HGPRT
• adenosine phosphoribosyltransferase (APRT)
• insoluble and is excreted in the urine as sodium urate crystals
• Catabolism of the purine nucleotides leads ultimately to the production of uric acid
• feed-back inhibited by purine-5'-nucleotides (predominantly AMP and GMP).
• he essential rate limiting steps in purine bio synthesis > occur at the first two steps of the pathway.
• The accumulation of excess ATP leads to accelerated synthesis of GMP, and excess GTP leads to accelerated synthesis of AMP.
• synthesis of PRPP by PRPP synthetase
• synthesis of IMP require
• five moles of ATP
• IMP represents a branch point for purine biosynthesis, because it can be converted into either AMP or GMP through two distinct reaction pathways
• inosine 5'-monophosphate (IMP)
• begins with PRPP
• liver
• 2 high energy phosphate
• the salvage and de novo synthesis pathways of purine and pyrimidine biosynthesis lead to production of nucleoside-5'-phosphates
• PRPP synthetase and requires energy in the form of ATP as shown:
• ctivated sugar used is 5-phosphoribosyl-1-pyrophosphate
• nucleosides and/or bases are not re-utilized the purine bases are further degraded to uric acid and the pyrimidines to b-aminoiosobutyrate, NH₃ and CO₂
• bases are hydrolyzed from nucleosides by the action of phosphorylases that yield ribose-1-phosphate and free bases.
• Oligonucleotides are further digested by phosphodiesterases that act from the ends inward yielding free nucleosides
• Endonucleases degrade DNA and RNA at internal sites leading to the production of oligonucleotides
• not required in the diet
• ietary intake or synthesis de novo

89 more annotations...

• mucocutaneous junction is present where the lining meets the external integument of the body
• glands
• ined with stratified squamous epithelium
• rypts have sub-crypts, whose lining epithelium is secretory.
• surface is folded to form cervical crypts
• channel is lined
• simple cuboidal
• The wall consists of   little else but muscle and CT
• The height of the lamina propria, and the degree of coiling and proliferation of   the glands is greatest when the uterus is being prepared   for a Blessed Event
• many blood vessels in place among the fibers of the supporting lamina propria.
• imple tubular
• A consistent feature of the lamina propria is the presence of deep uterine glands
• imple to stratified cuboidal,
• he endometrium is a an epithelial covering over a rather extensive CT lamina propria.
• lamina propria is very deep, and   it's shot through with the profiles of the uterine gland
• imple to pseudostratified   columnar, and there are no ciliated cell
• cranial end
• visceral peritoneum, the perimetrium, which has probably been   lost on your slide.
• myometrium is the largest single piece of smooth muscle in the body,
• ndometrium to mean its lining of epithelium (and the associated connective tissue) and the myometrium to refer to its massive wall of smooth muscle.
• slide 708
• he uterus has an even thicker   wall than does the uterine tube, and the point of transition is marked by the   presence of glands in the lamina propria of the uterine part of this specimen.
• Slide 706 shows the final part of the isthmu

• longitudinal folds and an absence of obstructing convolutions.

   
• star-shape" of the lumen in cross section
• narrower in diameter
• mucosal folds are much less complex than   in the ampulla, and the muscular wall is greatly thickened.
• The isthmus of the uterine tube is seen on slide 209
• apillary beds in the lamina propria (seen in the image at right) provide for the cells' needs.
• mucosal epithelium in the ampulla (above, right) is a columnar ciliated sheet that may be pseudostratified in places
• permanent structures.
• can also see the CT investment of the tube,   which is a fold of the peritoneum (the mesosalpinx, from the Latin for a   trumpet).
• smooth muscle,
• ciliated epithelium resting on a lamina propria of connective tissue
• ampulla, into which the infundibulum leads, is the longest and largest region of the uterine tube
• finger-like fimbriae (left) that surround the infundibular opening.
• xtremely   convoluted
• uboidal   to columnar
• imple ciliated cells

•   infundibulum leads into the ampulla, the widest portion of the tube,   seen on slide 684.

   
• The vast majority of follicles never make it beyond the primordial stage in the first place, and 99% never get past being a primary follicle. Atresia can occur at any phase of follicle development, up to and including the stage of maturity
• corpus albicans" can really be applied to either situation, because after all, a scar is a scar.
• tell them apart by the presence of a small remnant of the zona pellucida in the corpus atreticum
• orpus atreticum" and a "corpus albicans
• he corpus atreticum is a follicle that never ovulated, the corpus albicans has
• CT invades the place where the follicle was, forming a   scar. This scar is a corpus atreticum
• ollicles which never develop, or whose development is arrested at   some point
• atretic follicle at lower right is in the process of degeneration and will produce a smaller and very similar scar when it's finished the process of degeneration.
• slide 154
• corpora albicantia (CA)
• In most domestic animals the CL lasts the entire pregnancy (if one results); in humans it does not. Eventually, whether or not pregnancy occurs, however, the CL will regress and disappear, leaving a scar.
• umulus   oophorus, and the theca interna)
• lide 678,
• The cells of the corpus luteum—derived   partly from the theca and partly from the zona granulosa—
• cells of the theca interna, together with those of the zona   granulosa, collapse inward and proliferate to fill the empty space that was once a mature follicle's antrum
• hours rather than days
• forming corpus luteum.
• slide 678
• irst stage after ovulation
• slide 678.
• tigmata (St)
• oocyte with its accompanying corona radiata is   cast loose
• necrotic plaque (the stigma) forms
• eaches this stage, the follicle is ready to ovulate.
• Graafian" follicle
• granulosa cells (GC)
• theca (TC)
• mature follicle
• all of these subdivisions are derived from the former population of follicular epithelial cells
• The "wall" of this follicle now consists of the membrana granulosa (G), around which theca is very well developed
• orona radiata (CR)
• mmediately adjacent to the oocyte and butting up against the ZP.
• isolated onto a mound of (former) follicular cells. This mound is the cumulus oophorus (CO)
• ou   may correctly term any follicle enclosing a fluid filled antrum a   tertiary follicle, whether you see an oocyte in it or   not
• antrum, the fluid-filled cavity that is the distinguishing   hallmark of the next stage is formed. This the tertiary or antral  follicle.
• llicular epithelial cells are secretory:
• corpus luteum
• "wall" around the outside of this follicle.
• "epithelioid" cells intermeshed with the stromal elements. These interstitial cells are forming the theca (from Greek, a "cup"
• econdary follicle: the oocyte is greatly enlarged, the stratification of the follicular epithelium is obvious, and most importantly, the zona pellucida has been formed.
• till a primary
• sort of basal lamina   to the first layer of these cells, pressed up against the egg. Follicles demonstrating a stratified follicular epithelium, and enclosing   oocytes with a distinct ZP are secondary follicles
• zona pellucida  (ZP)
• progression of follicular development is a continuum; there is a smooth transition from one stage to the next
• ransition, so we'll designate it as "1^o-2^o" to indicate its status.
• enlarge compared to the oocyte in primordial follicles
• low cuboidal
• primary oocyte
• surrounded by a single layer of squamous follicular epithelial cells.
• Primordial follicles will be located close up under the outer surface of the organ (i.e., right up near the   tunica albuginea) usually occurring   in clusters
• rimordial follicle is characterized by a single layer of thin, squamous follicular epithelium around its periphery. The primary follicle, the next stage, also has a single layer of epithelium, but it's cuboidal in shape.
• one in which all follicles are at birth,
• rimordial follicle is the earliest stage
• primordial (P) and primary (1°) follicles
• in all species only a minuscule fraction of those follicles will ever get past the primordial stage.
• the stem cells of eggs, the oogonia, are not present in mammals at the time of birth.
• most never do ovulate.
• ortex
• rregular CT
• Follicles are surrounded and enmeshed in a webwork of collagen fibers, with fibroblast
• e parenchyma is the "functional tissue,
• collagen fibers
• outer limit of the ovary is demarcated by a tough, dense connective tissue,   the tunica albuginea, or "white coat
• ortex is the outer portion, in which you'll find the   developing follicles
• CT core, which carries blood   vessels into the organ
• a cortex and a medulla
• slide 154.
• homas Caceci

106 more annotations...

• Usually the lumen of this tube is filled with sperm
• aberrant ducts (left)
• receives input of sperm from the efferent ducts
• tereocilia" do not have the internal structure and they can't move at all. They're filled with cytoplasm, and they're a structure for absorption, not movement of fluids.
• lined by a columnar epithelium
• urethra, the opening in the center, is the major landmark by which to recognize this gland.
• most important to clinicians is the   prostate gland, shown here in cross section
• In histological sections, most of these look much alike.
• Horses have sperm with heads shaped like broadhead arrows, as do humans. Dogs   have paddle shaped sperm heads.
• perm smear from a rat
• scimitar shaped
• Slide 934
• principal piece
• ext part of the tail is the midpiece. This   portion is covered by the mitochondrial sheath, and is noticeably thicker than   the rest of the tail.
• large microvilli.
• arying in height
• one very long, monstrously coiled tubule
• efferent ducts. These relatively short and highly coiled   ducts are lined by a pseudostratified columnar epithelium of peculiar   appearance
• scalloped" or "festooned" appearance
• Many (but not all) of the epithelial cells lining the duct,   especially the taller ones, are ciliate
• unused ones degenerate with the rest of the mesonephros
• connecting piece of the tail is the region immediately behind the   head, and is very short
• perm smears on slides 212 and 934
• This triangular shaped bone is located   dorsal to the urethra, and ventral to the corpus cavernosum
• slide 707
• lined with simple squamous epithelium,
• corpus cavernosum, also filled with blood
• Immediately surrounding the urethra are the blood sinuses of the corpus spongiosum, which in this slide are still filled with blood
• Slide 751 and 707
• ductus deferens carries sperm to the urethra, and the sperm are discharged   through that portion of the urethra which passes through the penis
• cremaster   muscle, a
• keletal muscle (left) as part of the spermatic cord
• carries the principal artery supplying blood to the organ, an d the veins that drain it (see below); as well as the nervous supply and the ductus   deferens; the whole is bound together with CT.
• spermatic cord, the suspensory structure of   the testis
• Slides 211 and 709
• surrounded by a CT   envelope
• lining epithelium is, as before, a stereociliated   pseudostratified columnar type
• hickness of the wall in proportion to the cross section is clearly   visible
• slide 704
• t left is the ductus deferens, and its supporting CT structure, a fold of the peritoneum, the mesoductus deferens
• epididymis' overall diameter enlarges and the passage through the tubule becomes more open as you progress to the "tail" portion: simultaneously the wall becomes thicker and more muscular.
• very large and easily-seen Golgi apparatus profiles in the cells
• lining epithelium
• produces glycoprotein material that coats the sperm
• pididymis is an absorptive and secretory organ:
• "stereocilia,"
• resemble the cilia
• epithelial lining from the low cuboidal of the rete to the rather elaborate lining of the efferent ducts at the junction.
• ortion of the  intra-testicular rete testis in the lower right portion of this field
• rete, where it emerges from the mediastinum to lead into the adjacent efferent ducts
• lined by simple cuboidal epithelium.
• The exit from each seminiferous tubule is "guarded" by Sertoli cells, where the ends of the tubules join the rete
• lide 241
• efferent ducts
• rete testis
• This duct fills the extra-testicular organ, the epididymis.
• ductus epididymidis
• ow cuboidal epithelium
• he tunica albuginea has a thickened region in its centerline, the mediastinum testis
• uclei have the vesicular staining pattern and the prominent nucleolus typical of other secretory cell types.
• estosterone is a steroid hormone, so these cells have a good deal of smooth endoplasmic reticulum
• pituitary hormone ICSH (Interstitial Cell Stimulating Hormone)
• slide 51. e
• cuboidal in shape and present in groups of 2-20 cells
• interstitial cells (or Leydig   cells
• n the regions between the seminiferous tubules
• produce the male   steroid hormone testosterone
• forest of tails waves above them, and the accumulated cast off cytoplasmic droplets are below
• tailed spermatid" is a fairly common sight.
• thers more advanced will have tails beginning to   develop
• chunky and squarish-looking cells with nuclei beginning to get   quite dense, as at left.
• much closer to the lume
• spermatids
• large cells with a round nucleus filled with   clumped chromatin materia
• Primary spermatocytes are the initial product of spermatogonial   maturation
• their densely stained,   round nuclei
• Spermatogonia are basally located (i.e., at   the periphery of the tubule)
• undergo meiosis, become haploid spermatocytes, which then complete morphological differentiation into spermatozoa.
• permatogonium, the stem cell from which the rest of the cell types are derived
• blood-testis barrier is created by the occluding junctions of adjacent Sertoli cells
• e basal compartment has access to the blood stream and all the immune system components it carries.
• transfers the haploid cells to the luminal side and prevents the diploid ones from being exposed to it.
• basal compartment, are located the diploid spermatogonia
• occluding junctions
• basal compartment, near the periphery, is sealed off from the luminal compartment
• A major role of the Sertoli cell is to define two separate and physiologically different compartments in the seminiferous tubule.
• permatids,
• spermatocytes
• ertoli cell's overall shape is somewhat like a tree
• ertoli cell's nucleus, with its rhomboid inclusion and vesicular nucleoplasm, is clearly eviden
• Sertoli cells are really the only true "resident cells" of the seminiferous tubules.
• nucleus will be slightly separated from the tube border, pale-staining, with an oval to pyramidal shape, and one or two   prominent nucleoli
• outermost portion of the tubule, right up against   the boundary layer
• nurse" cell that sustains the proper environment   for spermatozoa to develop
• easily identifiable in H&E preparations by its   nucleus
• Sertoli cell or sustentacular cell
• ning cells of the tubules comprise the seminiferous epithelium.
• Sertoli or Sustentacular Cell
• interstitial region—you   will also find blood vessels of the peritubular capillary network, and the interstitial   cells, discussed below.
• butted edge to edge to form the wall of the tube
• squamous epithelium,
• outer wall of each seminiferous tubule   is a single layer of boundary tissue cells
• myoid cells or peritubular   contractile cells,
• bulk of the testicular tissue is the seminiferous tubules
• bulk of the volume of the testis is filled with the seminiferous tubules:
• few small incursions of CT off the tunica albuginea
• small septa subdivide the   cavity
• eptation is usually incomplete
• many blood vessels running through it,
• hick   band of dense collagenous connective tissue, the tunica albuginea.
• outer border of the testis
• slide 51
• cytocrine" (i.e., cell-secreting)
• testes are both "exocrine" and endocrine in nature
• Thomas Caceci

113 more annotations...

• nd of penile urethra has a lining of stratified squamous epithelium; farther   up in the pelvic urethra, nearer the bladder, the lining is still urinary   epithelium.
• Slide 707 has on it a cross section of a canine penis
• scalloped free border   is visible, and the inclusion bodies that are characteristic of   the urinary epithelial cells are evident
• urinary epithelium,
• a fair amount of elastic connective tissue in the wall to provide   for elasticity and distensibility.
• hree layers of smooth muscle: inner and outer layers are longitudinal, and   the middle more or less circular
• wall of the bladder is similar to that of the ureter
• lide 723 is the urinary bladder
• muscular wall very thick
• wo   layers of muscle in the wall: an inner longitudinal one, and an outer circular   one
• Slide 657
• thin muscular outer tunic, a CT lamina propria, and a lining of urinary epithelium.
• Masson's method
• ureter at left is from slide 152,
• rine has been coagulated and trapped in the specimen (Ur)
• enal pelvis (RP) a
• ined with a high cuboidal to columnar epithelium
• openings you see in it are the ends of the large collecting ducts (D)
• This is the tip of the renal crest from a preparation of fetal cat kidney
• slide 152
• PCT, typically only one or two nuclei of the wall cells will be visible; more than that are usually seen in a DT profile. Capillaries of the vasa recta (Cap) are also visible
• ell the PCT and DT apart in the medullary region by their size (the DT is larger in diameter
• CD) is the largest of these, and it has a wall of distinctly high cuboidal to columnar epithelium
• ypical field from the renal medulla
• ells themselves are rather pale staining   compared to those of the other tubules.
• quite large, with walls formed of cuboidal   epithelium. They're larger than the DT and the nuclei of their mural cells   bulge somewhat into the lumen.
• fall in systemic blood pressure triggers a response in the juxtaglomerular cells, which causes renin release into the blood. The macula densa cells may function as chemoreceptors, sensing a drop in sodium concentration of the DT, to trigger renin release

• polarized towards the blood vessel, because as it true of all hormones, renin is secreted into the blood.

   
• granules are very noticeable
• juxtaglomerular cells that
• juxtaglomerular cells
• bright pink renin granules in their   cytoplasm
• slide 148 b
• modified smooth muscle cells,
• acula densa is only one part of the complete juxtaglomerular apparatus.
• Between the MD and the nearest Juxtaglomerular cells are a few lacis cells of uncertain function.
• region of the arteriole close up to the wall of the corpuscle has several cells in it that contain pink-stained granules of renin (see below). these are the juxtaglomerular cells.
• macula densa is polarized away from the lumen of the tubule, and towards the adjacent specialized cells in the wall of the afferent arteriole.
• structurally distinct region is always associated with the afferent arteriole of its own nephron.
• ery localized structure
• istinctly polarized towards the arteriole
• rea   near an afferent arteriole, in which nuclei are crammed tightly
• e macula densa (Latin for "dense spot
• lide 148.
• wall of the DT at the point where the tubule and the afferent arteriole   are in contact cells are taller than the normal and much more crowded together
• egulation   of systemic blood pressure, and hence indirectly controls glomerular blood   flow.
• here's one special region in the wall of the DT which is probably involved in   this coordination. Locating it will definitively identify the distal tubule.
• show 4 to 6 nuclei, rather than the 2 to 4 seen in the PCT
• DT's are usually quite a bit larger than PCT's,
• complete absence of microvilli on the free surface
• The cells are "sealed" at the top with an occluding junction
• ole is to pump sodium ions out of its lumen into the surrounding intracellular space. It does this by active   transport, using membrane bound pumps
• large open lumen, presence of urine, and most especially lack of a brush border identify these as distal tubules.
• arger in cross section than the PCT.
• walls of the DT, like   those of the PCT, are of simple cuboidal epithelium, but they lack a   brush bord
• iltrate passes from the loop of   Henle into the distal tubule (DT).
• loops are larger and lack erythrocytes.
• The loop of Henle is easy to spot by its wall of squamous epithelium
• slide 148
• blood vessels of the rete mirabile and the vasa recta surround these loops.
• imple squamous (loop)
• cuboidal with microvilli (PCT)
• identified on these slides fairly easily by its thin outer wall and empty lumen.
• The loop of Henle is made of simple squamous epithelium.
• Mammals and birds can make urine that is hypertonic to their body fluids.
• lide 689
• glycocalyx
• PAS stain makes the PCT's brush border more easily visible

• Since this tubule is a three dimensional structure, you will see microvilli of the brush border cut in all planes, from sagittal to transverse.

   
• he presence of a brush border is proof that you're looking at a proximal tubul
• proximal convoluted tubule, PCT).   Here at least 99% of what is present in the filtrate as it leaves Bowman's space is recovered.
• Only the PCT has such a brush border. The other kidney tubules don't
• slide 148
• Most of the cortical tissue around the renal corpuscles is proximal tubules
• distinct and prominent microvillous brush border
• proximal tubule has a wall of simple cuboidal epithelium
• elt-like layer of amorphous material lying between the podocyte processes and the capillary endothelium.
• thick basement membran
• stained with the PAS reaction.
• Slide 658
• mesangial cells shown are intra-corpuscular resident macrophages
• he processes cover the entire surface of the capillaries in   the glomerulus, except for slits between adjacent processes; these slits are   the actual site of filtration
• long,   extensively arborized foot processes which wrap around the capillaries   of the glomerulus
• of podocytes . > Po
• podocytes.
• isceral layer of the renal corpuscle
• If arterial pressure falls, obviously kidney function will be impaired.
• formed elements are unable to get out but the fluid phase of the blood (the plasma) can do so quite easily.
• From proximal (i.e. the   initial point of filtration into Bowman's space) to distal these are the renal corpuscle,
• make out veins accompanying the larger   arteries on slide 84.
• wonderful net
• orm long straight   segments, the vasa recta.
• rete mirabile
• e concentration of sodium is highest in the deep   medulla and lowest in the cortex
• se   post-glomerular capillaries are vital to maintaining a gradient of sodium concentration in   the kidney's interstitial spaces

• efferent arteriole breaks up into   the fine capillary networks which surround the loops of the nephrons, the rete mirabile.

   
• efferent arterioles are   somewhat smaller than the afferent ones
• important point: blood leaving the glomerulus does not do so in a vein, but in an artery.
• efferent arteriole
• single afferent arteriole is dedicated to one specific glomerulus and no other
• ne intralobular artery may (and usually will) serve several glomeruli.
• essels coming off the arcuate arteries are the intralobular arteries, giving rise in turn to the small afferent arterioles, each of which feeds blood into a single glomerulus
• e interlobar arteries,
• the renal artery  ,  > >
• renal artery , an >d
• renal artery, an
• renal artery,
• arcuate arteries
• pproximately at the corticomedullary junction
• short pieces located at the junction   and running parallel to the outer surface of the organ
• visceral layer which consists of the podocytes
• lomerulus" is just the capillaries
• supplying individual lobes of the organ
• Slide 84 is an "injected" preparation
• blood flow is the driving   force behind urine formation
• nephron
• renal corpuscle, the proximal tubule, the loop of Henle, and the distal tubule.
• urinary pole leads into the first of the nephron's passages, the proximal tubule.
• sealing off Bowman's space.
• he visceral layer is continuous with the parietal laye
• uboidal epithelium of the proximal tubule at the urinary pole
• arietal layer, the outside wall of the corpuscle, is a thin simple squamous type, resting on a basal lamina

• glomerulus is suspended inside Bowman's space.

   

  
• Bowman's space.
• ther end is the beginning of the process of modifying blood filtrate to urine (the urinary pole)
• ite of entry of blood into the capillary tuft (the vascular pole)
• a capillary complex, the glomerulus
• outer shell of epithelium
• two components
• medulla has no corpuscles, but the cortex does have tubules.
• cortex, the bulk of its substance is composed of the various types of renal tubules
• has no renal corpuscles, only tubules
• e medulla,
• medulla
• renal corpuscles are the actual site of blood filtration and the initial stage of urine production
• round structures containing small blood vessels
• cortex has large numbers of renal corpuscles
• ifferentiate between the cortex and the medulla
• slide 148.
• capsule of irregular CT is visible as the green-blue
• Masson's stain.
• Slide 152
• no CT scaffolding in the kidney's internal volume
• nlike the capsule of many other organs, this one doesn't send septa down into the parenchyma
• dense collagenous connective tissue envelope
• renal corpuscles and their glomeruli
• red regions in the cortex
• Thomas Caceci

146 more annotations...

• The thyroid   gland's principal product, thyroxin, effects an increase in metabolic   rate.
• ound nucleus and weakly stained cytoplasm.
• most numerous parathyroid cells are   the chief cells
• rincipal product is parathormone or parathyroid hormone
• cellular parenchyma of uniform appearance, cells with characteristics associated with secretion, and a high degree of vascularization
• mbedded in the substance of the thyroid gland (T) or set into a depression on its surface
• has its own distinct capsule (C) and blood supply from that of the thyroid,
• well   vascularized
• as is the thyroid gland
• not   lobulated
• has its own distinct capsule
• eparate   endocrine organs
• one of four   small oval bodies associated with the thyroid gland
• Slide 691 a
• present in all of the interfollicular areas, providing support for the   overall structure of the gland
• CT fibers are   stained green
• Masson's stain
• Slide 691
• steoblasts
• Calcitonin plays a major role in calcium metabolism. It has the effect of lowering circulating calcium levels by stimulating uptake into the bone
• The   C-cells do not produce colloid; they produce the hormone calcitonin instead.
• val shaped, larger,   and more lightly stained than the follicular cells
• part of the follicular wall are the C-cells or clear cells,   sometimes called parafollicular cells.
• apillary beds in all of the interfollicular spaces (these   can usually be identified by the presence of erythrocytes in the capillary   lumen, and/or by coagulated, stained blood plasma).
• The thyroid is unique in another way: it stores its secretory product extracellularly.
• store product in an inactive form
• nique to the thyroid among endocrine glands
• Colloid incorporates   the hormones thyroxin and tri-iodothyronine as part of a large (660,000 dalton) glycoprotein, thyroglobuli
• amorphous material present inside the follicles is colloid
• all composed of simple   cuboidal
• hollow balls of cells
• unmistakabl
• rganization of the gland into follicles is easily seen.
• a section   of parathyroid gland o
• thyroid gland
• slide 691. (Slide 691
• Nerve fibers from the sympathetic side of the autonomic nervous system synapse directly with the cells of the adrenal medulla, and when these neurons fire, the medullary cells respond. Instead of sending out a neural signal however, they respond by secretion—of the hormone epinephrine.
• rterial supplies are separated, the venous drainage isn't
• tained with silver to show the medullary cells as a distinct, positively-stained population.
• drenal medulla makes the catecholamine   hormones epinephrine and norepinephrine
• chromaffin   reaction
• ells of the adrenal   medulla are somewhat more basophilic than those of the cortex
• corticomedullary junction is quite easy to see.
• lose this regular   arrangement,
• eparating the rows and cords of cells are irregular   vascular channels, or sinusoids similar to those in the liver.
• bundle of sticks
• cords of cells run in   roughly the same direction.
• regular rows, radiating away from the center of the gland
• highlights the capsule and the stroma
• region of   little globes
• ivided into three zones:
• cortex is q
• cortex i
• cortex
• zona fasciculata, and zona reticularis.

• Venous outflow from the cortex is mixed with   that of the medulla, and carries secretions from both parts.

   
• which   run straight through the cortex, bypassing it completely, and ramify into the   sinusoids of the medulla.
• medullary arteries
• adrenal cortex and the medulla have separate and distinct arterial supplies
• The cells of the   adrenal cortex all synthesize steroid hormones, and have a "foamy" appearance in some sections. This is due to the extensive lipid material in   them, and to the numerous SER and Golgi profiles in their cytoplasm.
• xtensive vascularization of both parts of   this organ
• eparate arterial supplies, but share a common venous drainage.
• Each has its own capsule (visible here as wisps of CT at the edges) and blood supply
• They arise from different embryonic rudiments, have vastly different functions, and respond to different signals,
• cortex and medulla
• cells of the islets are not easily distinguished from one another in H&E
• B cells make insulin
• A cells make glucagon
• A and B cells;
• Four type
• mmunostaining using the peroxidase reaction
• slets are more or less set off from the surrounding exocrine tissue by a thin "capsule" of CT
• of lighter staining material
• islands
• slide 34
• steroid-secreting cells, they don't show the basophilic reaction you would expect from protein making ones.
• Here's a cluster of interstitial cells wedged into the space between three seminiferous tubules (ST).
• Interstitial cells produce the "guy hormone" testosterone.
• slide consists of seminiferous   tubules, easily identified by their circular profile and characteristic   cell types
• testis is seen on slide 51
• amphibia and in many reptiles, the pineal body is directly light sensitive; it's sometimes been called the "third eye" or "parietal eye."
• the nervous system as responding rapidly to "short term" phenomena:
• It "resets" the internal clock on a daily basis by its cyclic response to light.
• linical significance as a radiographic"marker" for   the midline of the brain
• radio-opaque
• bvious aspect of the histology of the pineal gland is the presence of   the acervuli cerebri
• astrocytes
• large and lightly stained in H&E, with a rounded nucleus

• ineal hormone melatonin (5-methoxy-N-acetyl-tryptamine).

   
• pinealocytes,
• nondescript lump of uniformly stained tissue. There's a capsule of sorts and some internal stroma, and that's about it.
• slide 618
• epiphysis cerebri
• points of physical and physiological convergence between the nervous and endocrine systems,
• Master gland
• Thus the brain is acting as an endocrine organ, and releasing its products at a dependent site.
• oxytocin and vasopressin
• The pars nervosa is a place of storage and release of hormones made in the brain
• axons
• consists of well vascularized fiber tracts.
• The pars nervosa is neural tissue.
• filled with cerebrospinal fluid.
• third ventricle
• retains its connection with the brain
• ining cells
• ependymal cells
• cuff" or "sleeve" around the stalk of the pars nervosa   itself.
• pars tuberalis
• the adenohypophysis arises from embryonic ectoderm
• thin strip of somewhat basophilic cells.
• ressed closely up against the pars nervosa
• grades into the pars tuberalis without a definite boundary
• no acidophilic cells visible
• hypothalamus produces hormones, and the target organs of these hypothalamic releasing factors are specifically the cells of the adenohypohysis
• adenohypophysis
• hypothalamic releasing factors—target the cells of the pituitary and no others
• the hypothalamus itself produces hormones.
• median eminence of the hypothalamus, i.e., up in the actual brain, arteries end in capillary beds. The venous drainage from these capillaries in turn is sent through the sinusoids of the adenohypophysis, including most especially those in the pars distalis
• basophils produce thyroid stimulating hormone,   adrenocorticotropic hormone, and gonadotropic hormones.
• ac idophils produce growth hormon >e and   prolactin
• idophils produce growth hormon
• Each type produces different hormones
• chromophobes are the unstained cells
• basophils a more subdued color, resulting from their taking up hematoxylin
• cidophils are brightly stained with the eosin dye,
• acidophils and basophils, which stain pink or purple respectively.
• hromophils are those which have taken up stain
• ells in the cords are of several type
• adenohypophysis and the neurohypophysis,
• pars tuberalis
• The pituitary gland arises from two different embryonic rudiments: one is a   depression in the floor of the forming brain and the other is an evagination of   the dorsal surface of the forming gut
• ord-and-sinus architecture is found in the rest of the adenohypophysis, i.e., the pars intermedia and the pars tuberalis.
• channels are lined with fenestrated capillary endothelium
• cord and sinus arrangement of the pars distalis
• cord-and-sinus architecture

• meningeal covering of the brain (M).

   
• ypothalamus (H)
• homogeneous mass of cells (which it most decidedly isn't)
• pars distalis (PD)
• cranial pars distalis,   the pars intermedia
• three distinctly discernible subdivisions
• not every organ that could be considered "endocrine" in its function is necessarily "epithelial" in nature
• glandular epithelium, not "covering and lining
• uniform mass of relatively basophilic   cells,
• most prominent area
• lined with ependymal cells and filled with cerebrospinal fluid
• pars nervosa.
• communicates with the
• hird ventricle of the brain
• stalk is hollow,
• sphenoid bone and surrounded by a CT capsule which serves as the route for blood vessels
• hypothalamus of the brain is at the top of the image.
• cranial portion, consisting mostly of the pars distalis, is to the right
• pituitary gland from a cat
• slide 155
• onsists   mainly of nerve fibers with associated glial elements
• lumen of the   neurohypophysis, like the ventricles of the brain, is lined by ependymal cells
• secretions have as their target   organs other endocrine glands
• The endocrine system is supposedly concerned with seasonal or even yearly adaptations to environmental change.
• retains its connection to the tissue of   origin,
• integrated and coordinated
• umen that's continuous with the lumen of the brain's third ventricle.
• derived from the brain
• portion of the gland that comes from the gut:   it is epithelial in nature.
• "neuroendocrine system" or "neuroendocrine axis" has been coined to reflect the situation.
• epithelial organs
• haven't got the   elaborate duct system of exocrine glands: basically they're masses of cells with blood vessels running through   them
• medulla comes from an entirely different embryonic rudiment than   does the cortex
• zona glomerulosa

  • Cx by ACTH<br>
• Slide 1202
• pars intermedia secretes MSH, or "intermedin," which has   some similarities to ACTH in structure and in activity

  • Melanocyte secreting hormone<br>
• Histology

170 more annotations...

• ctions the respons
• ough endoplasmic reticulum
• centro-acinar cells.
• ancreas is a compound acinar gland.
• densely basophilic basal regions and bright eosinophilic secretory granules.
• blood vessel runs right through the "island." The pancreatic cells
• pancreatic tissue to the liver and to the blood vessels are clearly seen
• growing pancreas "invades" the liver during development but remains separated from it by CT. Pancreatic tissue (P) proliferates along branches of the hepatic artery (BV)
• slands" of pancreatic material scattered throughout the liver
• hile you're examining this slide, note the nucleated erythrocytes, and compare them to the ones in the exercise on blood!
• hepatocytes (which comprise most of its bulk) are reasonably similar in appearance
• he liver portion (Hp) lacks the distinct lobulation typical of mammals,
• fishes.
• Hepatopancreas
• pancreas combined with the liver.
• e isn't any ductwork associated with the islets.
• It's literally an "island" of endocrine tissue surrounded by an "ocean" of exocrine acinar pancreas.
• pancreatic islets of Langerhans (
• Since they aren't secretory, they'll be stained differently than the secretory cells. The classical histology term for these is the centro-acinar cells. They're just the first cells of the intercalated duct.
• simple columnar epithelium,
• medium sized ducts such as these have cuboidal to columnar epithelium in the wall. Very large ducts will show stratification.
• Blood vessels and ducts run through the septae
• capsule that surrounds it and CT septae subdivide it into lobes and lobules.
• e larger ducts in the system are easily
• pancreas
• extensively lobulated
• intercalated ducts
• The acinus is the basic secretory unit of the pancreas.
• zymogen granules are precursor forms of digestive enzyme
• The acinar cells have a deeply basophilic basal region and an eosinophilic apical area.
• ather uninteresting simple columnar form, containing no goblet cells
• canty lamina propria, and a thin and stringy tunica muscularis. There is no muscularis mucosae, and that's one of the "landmarks" for this organ
• tubular organ that fits the typical pattern. Its tunica mucosa is a very regular simple columnar epithelium, with no goblet cells or glands
• It's physically located in the sinusoid, separated by a small gap from underlying hepatocytes. This is the Space of Disse
• binucleated hepatocytes
• r lipofuscin or hemosiderin.
• on top of the hepatocytes and protruding into the sinusoids y
• lined by squamous endothelial
• left is a section of liver, stained to show glycogen
• lycogen is PAS positive:
• This is the beginning of the organ's venous outflow
• blood flow in the lobule is from the periphery to the  center.
• Each lobule is supplied by blood from two sources: a branch of the hepatic artery and a branch of the portal vein. These enter the lobule at its corners,
• Dr. Thomas Caceci

42 more annotations...

• etached
• ejunal villi are longer and more irregular than the short, blunt villi characteristic of the duodenum.
• only in the esophagus and in the duodenum are glands found in the submucosa, so the presence of these profiles definitively identifies this region for the histologist
• no change of epithelial type (it's stratified squamous on both sides) but the post-junctional epithelium is keratinized, as the lining of the anus makes a transition to the general integument.
• deep straight crypts of the rectum, and the absence of glands in the lamina propria.
• goblet cells in the sheet, it's the ano-rectal junction
• cardiac junction, where the esophageal epithelium (stratified squamous) abruptly transits to the epithelium of the stomach (simple columnar)
• immediate disappearance of the crypts and goblet cells.
• distinguished by the presence of an enormously enlarged tunica muscularis, forming the anal sphincter.
• large numbers of goblet cells ease the efforts of the tunica muscularis.
• aggregated lymphatic nodules (usually called Peyer's Patches
• he most prominent landmark in the ileum is the presence of large aggregations of lymphatic tissue in the submucosa.
• amina propria , the delicate CT that fills the cores of the villi and the spaces between the crypts, is demarcated from the more peripheral layers by the muscularis mucosae, a thin band of smooth muscle which runs all the way around the mucosal layer and which sends strands up into the villi
• hese structural variations serve as "landmarks" in the histological identification of different areas.
• with slide 40, a piece of duodenum
• presence of microvilli on the cells and crypts between villi increases the surface area available for absorption
• villi are not the only (or even the principal) adaptation to increase the surface area, the actual increase is vastly greater
• large intestine
• ecretions act as lubrication for the moving material.
• numerous goblet cells
• . between the protruding villi are deep intestinal crypts where new epithelial cells are generated by mitosis.
• The most visible and significant difference is the presence of villi in the small intestine, and their absence in the large intestine.
• verall the intestines have the normal form expected of tubular organs, including the four "tunics" discussed in Exercise 18, the tunica mucosa, tunica submucosa, tunica muscularis externa, and the tunica serosa
• parts of the digestive system responsible for the absorption of nutrients and water
• VM8054 Veterinary Histology

23 more annotations...

• carditis which manifests as congestive heart failure
• streptococcus pyogene
• ndividuals with positive cultures for strep throat should also be treated with antibiotics. Another important cornerstone in treating rheumatic fever includes the continuous use of low dose antibiotics (such as penicillin, sulfadiazine, or erythromycin) to prevent recurrence.
• e management of acute rheumatic fever is geared toward the reduction of inflammation with anti-inflammatory medications such as aspirin or corticosteroids. I
• RHD cause 99% of mitral stenosis often resulting in a “fish mouth” gross appearance
• Chronic rheumatic heart disease is characterized by repeated inflammation with fibrinous resolution.
• MacCallum plaques.
• acute RF, these lesions can be found in any layer of the heart and is hence called pancarditis

• Acute rheumatic valvular lesions may also involve a cell-mediated immunity reaction as these lesions predominantly contain T-helper cells and macrophages.^[6]

   
• antibodies which the immune system generates against the "M proteins" may cross react with cardiac myofiber sarcolemma and smooth muscle cells of arteries, inducing cytokine release and tissue destruction. This inflammation occurs through direct attachment of complement and Fc receptor-mediated recruitment of neutrophils and macrophages
• Characteristic Aschoff bodies, composed of swollen eosinophilic collagen surrounded by lymphocytes and macrophages can be seen on light microscopy
• Group A streptococcus pyogenes has a cell wall composed of branched polymers which sometimes contain "M proteins" that are highly antigenic. T
• Helper T cells subsequently activate B cells and induce the production of antibodies against the cell wall of Streptococcus. However the antibodies may also react against the myocardium and joints^[5], producing the symptoms of Rheumatic fever.
• This cross-reactivity is a Type II hypersensitivity reaction and is termed molecular mimicry
• caused by antibody cross-reactivity.
• Rheumatic fever is a systemic disease affecting the peri-arteriolar connective tissue and can occur after an untreated Group A streptococcal pharyngeal infection.
• Rheumatic fever is an inflammatory disease which may develop after a Group A streptococcal infection (such as strep throat or scarlet fever) and can involve the heart, joints, skin, and brain.

15 more annotations...

• Concrete flooring leads to foot lesions and shoulder lesions
• Economics drives the space allowance down while animal welfare considerations drive the space up.
• Once the decision is made to individually house sows to provide individual care, economics will determine the actual space that is provided
• If sow welfare was the only factor in designing the crate, then crates would be much larger (perhaps twice the area or more).

• Use of the gestation crate is driven by two primary factors:

   
   
  • Economics: The more sows per building one can have, the lower the building costs would be for the farm.  
   
  • Sow Welfare: The crate eliminates most social stress and allows for individual feeding of sows based on their individual needs.

4 more annotations...

• erous tubuloacinar gland
• One acinus, two acini.

• COMPOUND, TUBULOACINAR, MIXED SEROUS & MUCOUS 

   
• complete description of this gland would
• lachrymal gland of the eye
• acinar parts are shaped like grapes or eggs;
• tubuloacinar parts are shaped like...well, maybe a knobby banana
• compound gland
• The "tubulo-" section is the relatively straight part, and the bulbous termini are the "acinar" parts
• duct system is divided, and therefore compound
• Most of them are referred to as acinar or tubuloacinar, meaning that the secretory areas are round to oval shaped (acinar) or somewhat elongated, with bulbous ends (tubuloacinar)
• of the secretory regions.
• shape
• ductwork leading to the "moat" that surrounds the large tongue papillae
• open out via ducts onto the surface
• also be described by
• ongue. S
• tongue.
• left panel you see both serous and mucous secretory areas, in among the strands of skeletal muscle in the tongue. At right, a large serous gland is discharging via a duct (D) into the moat (M) around a vallate papilla.
• tongue.
• . Don't confuse them with the "sublingual salivary gland,
• Lingual glands may be of the serous or mucous or mixed type
• embedded in the tongue
• lingual salivary glands
• Whatever the structural arrangements of the gland,   the ductwork is the same for both types of secretion.
• common
• Another example of a mixed gland
• serous and mucous segments are clearly separated
• secretions   are mixed together
• The   serous acini can be entirely separated from the mucous acini
• serous demilune
• may   also form a sort of "cap" over the end of a mucous acinus
• mixed" glands
• bottom images
• wo secretory areas can be combined.
• produce both mucous   and serous secretions
• producing a mucous secretion the product is quite   viscous, and it tends to flatten the nuclei out and push them to the periphery   of the acinus
• isn't very responsive to an H&E stain, but it's   strongly PAS-positive
• middle set of images
• mucous   acini (MA)
• nuclei of serous acinar cells is round and centrally located
• serous acini (SA) tend to stain   fairly heavily with H&E, and to have a wedge-shaped appearance
• two top illustrations are   of a serous gland: the secretions of this type of gland are watery   and of low viscosity
• ue to the type of secretions   they make and the viscosity of the secretions
• ecretory regions differ in appearance.
• (above, left, about 100x).
• imple cuboidal epithelium (above, right, about 500x),
• he duct system is divided
• compound   exocrine glands;

47 more annotations...

• Slide 1203 will give you an opportunity to examine the structure of sinus hairs.
• Sinus hairs are very large hairs modified to act as mechanical sensors.
• Hair loss (alopecia)
• "whiskers" or vibrissa
• nutrition, age, health status, season of the year, sex, and many other factors
• Testosterone has just the opposite effect on hair follicles of the face.
• hormonal
• unstained melanocytes in among the keratinizing cells, and the pigment they're producing.
• relationship of the dermal papilla and the overlying epithelium.
• anagen
• ignals from the dermal papilla will continue to stimulate the germinal matrix epithelium, and the hair will elongate at the base. as it does so, the keratinization process occurs so that the bulk of the hair is dead; but division continues in the living cells of the germinal matrix.
• dermal papilla visible in the center of the bulb. The dermal papilla is not epithelia
• changeover back to the active anagen stage again
• n catagen m
• catagen
• ctive phase of production, anagen
• a hair doesn't grow "through" the skin, it grows from the skin. It's part of the skin's complete structure.
• wakens the follicle from its dormancy, and it enters into the transitional stage of telogen,
• Specialized keratinocytes at the base of the hair produce the hair
• club hair. Club hairs aren't anchored in so they fall out very easily.
• catagen, the stage of quiescence and cessation of new hair cell production.
• the hair, like the other adnexa of the skin, is epidermal in nature.
• hair in and of itself is dead material, but it's produced by living cells
• urrounded in its turn by the less   dense dermal sheath which is with the CT of the dermis.
• basement   membrane is the glassy membrane.
• epithelium of the follicle has to rest on a basement   membrane
• pigmentation in hair comes from melanocytes, just as the pigmentation of the skin does.
• catagen phase is characterized by a shrinkage and withdrawal of   the papilla away from the bulb. This removes the necessary induction and the   hair stops growing.
• contains melanocytes
• enclose a bit of the dermis.
• hickened amorphous structure right   outside the outer root sheath
• bottom of the follicle the epithelium swells to form a hair bulb
• growth of the hair and the inner root   sheath occur.
• triggering of hair growth by proximity of the dermal papilla is a classic   example of the phenomenon of induction
• dermal papilla itself isn't the source of the hair, the active epithelium lying over it   is
• he dermal papilla
• dermal papilla
• Some hairs are hollow
• glassy membrane" is the basement membrane of the follicle, separating it from the CT around it.
• hairs have no medulla; these are the curly "wool hairs"
• easy to tell apart
• slide 35.
• ortex in which the dead keratinized cells are very densely   packed,
• cuticle of the hair is so closely pressed against the   hair shaft and the adjoining cuticle of the root sheath (see below) that the two are indistinguishable in your sections.
• cuticle
• ross sections (see below)
• medulla, in which they aren't so densely packed.
• inner root sheath doesn't go all the way up the side of the hair follicle: it ends about halfway to the surface
• slide 35
• The outer root sheath, however, is continuous with the surface epidermis at the top of the follicle.
• left is from slide 11.
• sebaceous glands as a rough indicator of where you are with respect to the "deep" or "shallow" parts of the follicle
• nearly impossible to make out the cuticle, as it's very thin and applied closely to the hair.
• cells at the periphery of the gland are clearly healthy and alive,
• "foamy" appearance of the cells in the sebaceous gland,
• ee sebaceous gland
• e sebaceous gland
• sebaceous gland
• follicle on the left side of the field
• normal nuclei
• right is a follicle cut longitudinally, with a large array of sebaceous gland units
• pocrine glands, cytoplasm is pinched off and cast into the lumen, where it disintegrates and becomes the secretion.
• slide also the presence of sebaceous glands
• hairs usually emerge from the same opening on the surface.
• arge main guard hair and several smaller wool hairs with small or absent medullary regions (see below)
• left is a cross section through a compound follicle.
• ollicle from which more than one hair emerges
• piloerection
• smooth   muscle
• true dermal structure
• origin is in the fibrils of the dermis.
• grow from skin
• y grow from skin
• grow from skin
• separated from the underlying dermis and hypodermis by a basement membrane,
• he hair follicle and the hair it produces are part of the epidermal region of the skin
• hair grows from the hair follicle, not out of it
• ome sweat glands,   especially in thin integument, also open into the follicles, some don't.
• profiles of sweat   glands also visible near the base of the hair.
• ebaceous   gland opens into the follicle;
• principal parts
• slide 11, the nose of a dog
• hair bulb is that portion of the follicle which actively produces the hair;
• root sheath(s) surround the hair as it grows out
• is stuff is sebum
• high lipid content of the cells.
• outer root sheat
• catagen and its hair has fallen out.
• sebaceous gland is simple branched acinar in structure: all the pear-shaped secretory units discharge into a single short duct, that leads into the hair follicle about halfway towards the surface, just about at the level where the inner root sheath disappears.
• ebaceous glands are the only example in mammals of a holocrine gland, one in which the entire cell body of the glandular cells is sacrificed to become the secretory material.
• slide 35,
• ent tricohyaline granules of Huxley's layer a
• inner sheath has several layers
• most of the hairs are cut in cross section
• t Huxley's layer
• n slide 35
• nner sheath usually ends somewhere around the point of input of the sebaceous glands.
• never protrudes from the follicle openin
• inner sheath doesn't keratinize
• urface of the skin to one side of the hai
• bottom of the hair follicle the epithelium of the outer sheath fuses with that of the inner sheath
• upper part of the sheath is usually keratinized, although the lower part generally isn't.
• continuous with the surface epidermi
• structures that are part of the follicle are visible, including a sebaceous gland, a sweat gland, and the arrector pili muscle (APM)

102 more annotations...

• its own division of the peripheral nervous system
• enteric nervous system
• only one myenteric plexus that runs throughout the gut;
• fulfills the definition of a "ganglion,"
• myenteric plexus is a network of nerve fibers and neuron cell bodies
• myenteric plexus (and a coordinated submucosal plexus) is present throughout the entire length of the digestive tract from the esophagus to the anus
• ubmucosal plexus is much easier to see in the intestines, but it's present in the stomach as well.)
• n this image the stomach region is to the right, the duodenum to the left

• Unlike the "sphincter" of the esophageal-stomach junction, this is a true "valve" controlling flow.

   
• pyloric sphincte
• three layers.
• land profiles in the submucosa
• duodenum has goblet cells, as does the rest of the intestine
• epithelium in the stomach is simple columnar with no goblet cells
• different from those of the fundic region
• mucosal glands of the pyloric region are similar in appearance to the glands of the cardiac region
• very large and open gastric pits are characteristic of this part of the stomach.
• glands larger and more obvious
• gastric   pits tend to be deeper
• Structurally they closely resemble   the cardiac glands,
• Like the cardiac glands, pyloric glands produce a mucous secretion.
• hird category of gastric glands
• pyloric glands,

• "granularity" of the cytoplasm reflects both these features.

   
• Chief cells are shoved in among the parietal cells in groups of two or three
• Parietal cells are often binucleated:
• extensive infolding of its apical surface and an enormous number   of mitochondria
• rounded.
• parietal cells make hydrochloric   acid
• parietal cells are essentially ion pumps. They have no protein secretion function and hence little RNA in their cytoplasm
• show large amounts of RER
• strongly basophilic
• Chunky and angular in shap
• parietal cells are by contrast very eosinophilic
• arge numbers of secretory vesicles
• darkly stained cells are the chief cells
• parietal cells make the acid, and the chief cells make the proteases.
• undic glands are the source of the proteases of the stomach (trypsin and chymotrypsin) and the hydrochloric acid
• produced by two different cell types:
• continue to the deepest levels of the lamina propria and butt up against the muscularis mucosae. They do NOT extend into the submucosal layer.
• point indicated by the arrows, the gland bifurcates into two long, tube-shaped secretory region
• chief and parietal cells.
• tructural category
• simple branched tubular shape
• located in the deep parts of the tunica mucosa, surrounded by the connective tissue of the lamina propria
• undic portion of the stomach
• most numerous ones in mammalian stomachs
• open into the base of gastric pits. They   are deep, straight glands, with a mixed population of cell types
• most numerous type of gastric gland is the fundic gland.   These are found underlying the bulk of the gastric mucosa.
• slide 131.
• in the tunica mucosa
• similar glands can be found in the esophagus
• esophageal cardiac glands
• e limited in their   distribution to the stomach region immediately adjacent the esophagus
• Cardiac glands (CG)
• und in the most   proximal region of the stomach (i.e., that part closest to the input of   the esophagus, called the "cardiac region," because it's located   close to the heart)
• make a mucous secretion for protection of the epithelium from erosion
• glandular regions are wholly confined to the tunica   mucosa
• The gastric pits (GP) are lined with a simple columnar epithelium devoid of goblet cells.
• submucosal glands are not   found in the stomach at all.
• cardiac gland
• Note that in the stomach, in all its regions, the secretory glands are in the tunica mucosa, i.e., inside the muscularis mucosae
• the only two locations in which the glandular component of the digestive tract is outside the muscularis mucosae are the esophagus (see above) and the duodenum of the small intestin
• secretory structures, the various types of gastric mucosal   glands
• gastric pits or  foveolae,
• differs from the intestines
• simple columnar
• umen of the stomach
• slide 133,
• n the stomach the mucosal epithelium is secretory, and produces   products essential to the digestive process.
• here are no goblet   cells in it
• nside the actual stomach, the tunica mucosa differs in appearanc
• horse and rat
• t occurs actually inside the anatomic stomach.
• most species the epithelial transition from esophagus to stomach is right about at the point where the anatomic esophagus and the anatomic stomach meet
• muscularis mucosae (MM)
• very abrupt line that separates the two types of lining epithelia.
• There is no particularly thickened region of the tunica muscularis at this location
• ining of the stomach is a simple columnar type without goblet cells.
• tratified squamous cells of the esophagus have ridges
• differentiate between the two
• absence of goblet cells in the stomach
• simple columnar epithelium on the stomach side
• tratified squamous epithelium   on the esophageal
• margo plicatus
• esophageal-stomach junction
• Slide 133
• The stomach is a muscular bag whose principal function in most groups is   acidification and maceration of the food to the liquid state, and temporary   storage until it's passed to the intestines
• in dogs vomiti
• ability   to vomit voluntarily hasn't been lost.
• s > are exceptions to this statement. In these animals, the   tunica muscularis is entirely skeletal muscle for the entire length of the   esophagus, which facilitates vomiting
• n most species, skeletal muscle is replaced   by smooth muscle as one descends deeper into the organ; the tunica muscularis   near the junction with the stomach is wholly smooth muscle in most animals
• upper (cranial) esophagus and shows only the tunica muscularis.
• In the upper portion of the esophagus in most, if not all, mammals, the tunica   muscularis is composed of skeletal muscle arranged in two layers: inner   circular and outer longitudinal
• horses, cattle, and cats the cervical esophageal muscularis mucosae is it's discontinuous but present as scattered muscle bundles
• og and the pig, the muscularis mucosae is absent in the cervical part of the esophagus, but becomes evident in the distal portions
• slide 43

• muscularis mucosae is present and defines the two layers.

   
• like "islands" of smooth muscle
• n animals—unlike humans—the esophageal muscularis mucosae is discontinuous.
• parallel to the long axis of the organ.
• muscularis mucosae of the esophagus is composed of smooth muscle fibers
• (OTM)
• two layers, and inner (ITM)
• tunica muscularis
• The association of submucosal glands and a lining of stratified squamous epithelium is unique to the esophagus.
• ne of only two locations in the mammalian digestive tract where true glands are in the submucosa
• submucosal glands,
• esophageal glands proper (SG)
• Esophageal glands proper are outside the muscularis mucosae, and hence by definition in the submucosa
• esophageal glands proper,
• presence of glands in the submucosa
• One more clue to recognition of the esophagus
• keratinized.
• tratified squamous epithelium
• epithelial lining,
• small glands in the submucosal layer
• plicated nature of the tunica mucosa is obvious,
• landmarks to identify the organ and to determine where the section was taken.
• makes a transition from skeletal to smooth muscle about half-way down
• birds it is entirely smooth muscle
• unica muscularis externa (TM) contains both skeletal and smooth muscle fibers
• ome species (dogs, ruminants, horses) the entire tunica muscularis externa of the esophagus is composed of skeletal muscle
• keratinized,
• lining of the esophagus in all species is stratified squamous epithelium
• tunica mucosa (M)
• tunica submucosa (S) is seen here as a space between the tunica mucosa and the muscularis externa
• lide is the esophagus of a rat
• slide   113
• often lost in collecting samples of tissues
• "tunica adventitia" as a means to anchor it in place.
• overed by a fold of peritoneum, called here the tunica serosa.
• contractions are the propulsive mechanism for the food bolus
• large nervous complex between the layers
• tunica muscularis externa
• blood vessels, nerve fibers
• unica submucosa is another CT laye
• muscularis mucosae isn't always continuous, and it may send sprigs of muscle fibers up into the cores of villi where these are present
• ining epithelium; the underlying lamina propria (a loose, cellular CT that supports the epithelium); and the muscularis mucosae
• three parts
• tunica mucosa
• tunica   mucosa, the tunica submucosa, the tunica muscularis externa, and a tunica adventitia and/or tunica serosa
• enerally it includes four "tunics" or layers, a couple of which have subdivisions
• "non-glandular" and "glandular" regions of the stomach. In such situations the point of change is grossly visible, and the gross anatomist's term for it is the margo plicatus.
• sophageal-stomach junction
• Dogs and ruminants

  • Birds have smooth muscle all the way down<br>