NameExampleDescriptionNotes

Cardiovascular System

CapillarySingle layer of endothelial cells with a basal laminaCan be encircled by pericytes; 3 kinds (continuous/somatic, fenestrated/visceral, discontinuous/sinusoidal)

Continuous/ Somatic CapillaryEndothelial cells are joined by tight junctions; continuous basal laminaHave pinocytic vesicles for transport; responsible for the BBB

Fenestrated/ Visceral CapillarySee fenestrae at the single arrows that are closed by diaphragms; at the double arrows you see continuous basal lamina on the outer surface of the endothelial cellFenestrations allow more exchange of materials; fenestrations are covered by a diaphragm, except in the kidney

Discontinuous/ Sinusoidal CapillaryHas central vein with cords of sinusoid that are lined by endothelium; discontinuous basal lamina; no tight junctionsAllows for greater exchange; see in the liver and spleen; find macrophages among or outside the endothelium

Tunica AdventitiaDense connective tissue; collagen type I fibers with few elastic fibersContains nerves (nervi vascularis), vasa vasorum, few lymphatics

External Elastic LaminaSeparates the tunica media from the tunica adventitia

ArterioleWell-defined t. media (1-5 layers of smooth muscle); IEL may be absentSmallest arteries; major determinants of bp; can tell the difference between this and a duct because this has smooth muscle around it; no EEL; t. adventitia is ill-defined and blends with surrounding CT

Muscular ArteryDistinct IEL; 6-40 layers of smooth muscle in t. media; distinct EELMost numerous kind of artery in our body; no elastic fibers; t. adventitia has dense CT with collagen and elastic fibers, vasa vasorum and nerves

Elastic ArteryCant really see t. intima; media has circularly arranged smooth muscle and sheets of elastin; indistinct IELElastin are fenestrated and imbricated to accommodate pressure changes; has vasa vasorum under the adventitita; elastic arteries maintain uniform and continuous mvmt of blood

Muscular VeinHas IEL, t. media has CT and circularly oriented smooth muscle, t. adventitia is thickest and contains longitudinal bundles of smooth muscleThis arrangement of smooth muscle in the t. adventitia and t. media helps strengthen the wall and propel the blood back to the heart; has valves which are folds of t. intima projecting into the lumen

Ex) vena cava

EndocardiumLined by simple squamous epithelium; see purkinje fibersNote that purkinje fibers do not have intercalated discs and are bound together via desmosomes and have gab junctions for electrical conduction

MyocardiumCardiac muscles ( intercalated discs

Urinary System

Renal CortexKnow you are in the cortex because you can see renal corpuscles (round, granular structures); striations are the pars recta (medullary rays)Contains renal corpuscles, convoluted and straight tubules, collecting tubules and collecting ducts; renal corpuscles contain the glomerulus

Renal MedullaKnow you are in the medulla because you see striations, which are the medullary rays, and no corpuscles; the red staining regions are the vasa rectaRays made of straight tubules and collecting ducts

Renal CorpusclesBowmans capsule is made of simple squamous epithelium in visceral and parietal layers; vascular poles present at the opening of the capsuleGlomerulus surrounded by Bowmans capsule; visceral layer has podocytes; urinary space is between visceral and parietal layers ; vascular pole is where afferent and efferent arterioles meet

Proximal Convoluted Tubule (PCT)Cuboidal epithelium; has microvilli which gives the lumen of the PCT its messy appearance (not clear); large cells that are cuboidal to high cuboidal; eosinophilic (bc lots of mitochondria in basal infoldings)Know you are in the cortex because you see the renal corpuscles; has tight junctions, plicae, interdigitations, Na+/K+ ATPase, aquaporins; 6:1 ratio of PCT:DCT (distal CT)

Thick Descending LimbSimilar epithelial lining to PCT except its more cuboidal; well developed microvilli gives a dirty lumenAka pars recta; not as specialized for absorption; most sensitive to mercury poisoning and affected most during acute renal failure

Thin Descending Limb/ Thin Ascending Limb (Loop of Henle)Simple squamous epithelium; nucleus bulges into the lumen; clear lumen (no microvilli); can see vasa recta (bright red spots) thin descending is permeable to H2O; thin ascending is permeable to solutes and not H2O ( countercurrent exchange; 4 types of epithelial cells (type I-IV), all simple squamous

Vasa RectaVasa recta at the loop of henle; see RBCs; know youre in the medulla because you see striationsCapillary network that works in the countercurrent exchange mechanism

Thick Ascending LimbCuboidal cells with apical position because of basal membrane infoldings; nuclei are close to each other; different from PCT because no microvilli and no columnar cells; clear lumenIncludes both medullary and cortical portions; impermeable to H2O

Macula DensaFound at the vascular pole; cells are narrowed, tall, closely packed together; lies adjacent to the afferent arteriole; forms a row of nuclei that show up as a dense spotMarks the beginning of the distal convoluted tubule; osmoreceptor of fluid and sends info to juxaglomerulus apparatus via gap junctions in the mesangial cells

Distal Convoluted Tubule(Marked with d); nuclei are apical in position; small, basophilic cells; very few microvilli (clear lumen)Aka pars convoluta; has compartmentalized mitochondria in basal infoldings; active transport of Na+ from the filtrate into the interstitium

Juxta-glomerular ApparatusMade of the macula densa, juxtaglomerular cells, and extraglomerular mesangial cells; smooth muscle cells of the afferent arteriole; contains secretory granulesRenin-angiotensin-aldosterone system; sensor of blood volume and renal fluid composition

Collecting Tubules and Ducts2cs and 3bs: cuboidal, clear lumen, basophilic, beaded, borders (between cells)

Cant differentiate between collecting tubule and duct; has light and dark cells

Minor CalyxSee change in epithelium: from cuboidal to transitionalCollecting ducts empty into the papillary ducts (duct of Bellini), which opens into the area of the cribosa (on apex of renal papilla) and material from here goes to minor calyx

UreterHas stellate shaped lumen; transitional epithelium; connective tissue on outside; upper 2/3 have inner longitudinal and outer circular layer of smooth mucle; lower 1/3 is a longitudinal layerBetween the renal pelvis and bladder; long, muscular tube; contraction of smooth muscle layers is peristalsis

Difference between ureter and vas deferens: in VD have clearly delineated smooth muscle layers but in ureter its hard to see the differences

Urinary BladderTransitional epith several layers thick; scalloped-looking when relaxed; thin basal lamina with fibroelastic CT; inner longitudinal, middle circular, outer longitudinal muscularis layerVesicles in epith creates a membrane that can open and stretch the epith; tight junctions between cells; hemidesmosomes in basement mb

Respiratory

Trachea- Cartilaginous LayerOuter purple staining region is hyaline cartilage and deep to that have blood vesselsC-shaped hyaline cartilage; prevents collapse of the lumen; trachealis sm. muscle bridges the gap btwn free ends of cartilage; dense fibroelastic CT btwn rings to help in elongation of trachea

Trachea- EpitheliumRespiratory epith lining lumen; ciliated cells; mucous cells; goblet cells; brush cells; short basal cells; APUD cells; very thick basal lamina; longitudinal elastic lamina; mucosa and submucosaCiliated cells protect and remove inhaled particles; basal cells are stem cells for pseudostrat epith; APUD cells makes polypeptide H and has basal granules; submucosa has seromucus glands

Trachea- Submucosal GlandsSee respiratory epith with goblet cells; notice submucous glands with trichrome stain; also note the hyaline cartilage to the right of the slide (perichondrium)Seromucus glands are important in trapping particles

Secondary/ Intrapulmonary BronchusCan see alveoli around it (marked as A); respiratory epith lines the lumen; lamina propria separated from submucosa by spiraling layers of smooth muscle; seromucus glands in submucosaAppearance of smooth muscle instead of external elastic lamina; less need for cilia and goblet cells (bc dont have to condition air as much)

See lots of seromucus glands under the epithelium; dark basophilic staining

3 features of intrapulmonary bronchus: alveoli, cartilage forms plates, smooth muscle is under the epitheliumSame epithelium as the trachea except the number of goblet cells decreases, and there is less cilia

BronchiolesNo more goblet cells; epith transitions from respiratory to simple ciliated columnar; no cartilage in walls; smooth muscle; no submucsal glandsHas Clara cells (secretes a surface-active agent to keep bronchiole walls from collapsing)

Very thick muscular wall, so you know this is the bronchiole

Terminal BronchiolesSimple cuboidal epithelium; no goblet cells; lots of smooth muscle with alveolar tissue on the outside; serrated appearance of epithelium; complete smooth muscle ringalveolar out pouchings make muscles look like plates in between

Respiratory Bronchiole (RB)Terminal bronchiole (TB) has smooth muscle around it; alveoli starts out pouching from it as you get closer to the RB; RB has no smooth muscle; RB has simple cuboidal epith

Alveolar DuctWhere the arrow is pointing it shows the RB; as you go further in epith becomes squamous; see tiny drumsticks of smooth muscle making up the alveolar sacs between the ducts ---------------->

Interalveloar SeptumSmooth muscle separating the sacs; highly attenuated simple squamous epithCells of septum covered with surfactant (made by Type II pneumocytes); makes up blood-gas barrier

PneumocytesCircular cells (low cuboidal) = great alveolar cells (Type II pneumocyte); Type I are on either side of septum; arrows pointing to fibroblasts; crescent-shaped cells are RBCsEndothelium coming in contact with Type I is place where gas exchange takes place. @ capillary you have Type I cells

Dust CellLarge cell in the middle of the lumen; arrow pointing to continuous capillaryDust cell phagocytoses particles, then travels through the lymph to get into blood, or through respiratory tract to be spit out; not found in the septum- only in lumen!

Integument

Stratum CorneumOutermost layer of epidermis; flatted, scale-like dead cells; entirely filled with keratin filaments; arrows pointing to ductsMajor constituent of the water barrier of the epidermis; stratum disjunctum is where the cells are shed off (only in thin skin)

Stratum LucidumAbove the stratum granulosum; has lost its cell organelles and is only composed of filaments and eleidinOnly present in thick skin; eleidin is the breakdown product of keratohyalin

Stratum GranulosumSquamous cells; keratinized; last layer where you see live cells (nucleated); many keratohyalin granules (strongly basophilic); mb-coating lamellar granules2-5 layers in thick skin; granules produce substance that acts like cement in the intercellular space as a water-proofing barrier

Stratum BasalisMost basal layer; attached to basal lamina with hemidesmosomes (ruffled appearance- where arrow is); cuboidal-columnar cells; basophilic3 kinds of cells (MMM): mitotically active cells, Merkel cells, melanocytes

Thick SkinCan see the stratum lucidum, has a thick corneum, and has larger dermal ridges (interdigitations of epidermis and dermis)Hairless; found on palms of hands, soles of feet

Thin SkinNo lucidum; corneum looks like its splitting offHas hair

DermisHas more cells than fibers; loose CT with thick collagen fibers (type I), fibroblasts & elastic fibers decreasing as you go closer to the epidermis; below this have reticular CTTwo layers: papillary layer (has blood supply), reticular layer; in loose CT have mast cells, macrophages, lymphocytes, eosinophils, fibroblasts

Meissners CorpusclesIn the papillary layer of dermis; capillary loops that looks like a stack of coinsFine-touch receptors

Pancinian corpusclesOnion-shaped corpuscle in bottom right; around it you see sweat glandsDeep touch and pressure receptor; present in reticular layer of dermis; has a nerve in the center

Hair FollicleInvagination of the epidermis; within the hair follicle is the arrector pilli muscles which are the pink strands inside the dermis, connecting the reticular and papillary layersRoot of hair embedded in dermal papilla

Eccrine Sweat GlandsSecretory units have stratified cuboidal epith; with keratin filaments w/terminal web; sweat glands found in reticular dermis and duct goes through epidermis to outsideSecretory units have dark and light cells with myoepithelial cells around it for contraction

Myoepithelial CellsSurrounds light and dark cells; these cells are darker staining than secretory epitheliumContractile function for secretions of eccrine glands; protoplasmic extensions around secretory endpiece

Eccrine DuctCoiled structure that goes all the way through epidermisWater secretions; cholinergic innervation

Apocrine Sweat GlandsFound in the reticular dermis; large dilated structure; coiled secretory unit enveloped by myoepithelial cells and simple cuboidal epithResponds to hormones; found only in the axilla, areola, perianal skin around the anus, and external genitalia; viscous secretions; adrenergic innervation

Sebaceous GlandsAcinar cells surrounded by myoepith cells; arrector pilli muscles go thru; pale-staining because stores fat; in reticular dermis (see more fibers, less cells)

Oily secretion (sebum); holocrine secretion (no ducts); in thin skin; sacs (alveoli) empty into the neck of the hair follicle

Eye

EyeSclera on outside (to the right), then middle vascular layer (choroid) with dark-staining melanocytes and more cells than fibers (loose CT), then have layers of the retinaChoroid lies between the sclera and retina and has choriocapillary layer and Bruchs mb

Cornea(L to R): corneal epith (strat squamous nonkerat); Bowmens mb (type I collagen); Stroma (lots of collagen fibers); Descmets mb (type IV collagen); endothelium (simple squamous)Corneal epith has microvilli under it to keep it moist and basal infoldings to keep stroma dry; bowmans mb for strength; stroma for transparency; endoth keeps stroma transparent and dry

Corneoscleral LimbusSclera is top right corner, composed of dense CT; between the two layers have canal of Schlemm;Sclera is attachment site for ocular muscles; 3 layers (episcleral layer, (Tenons space), substantia propria, suprachoroid lamina)

Anterior ChamberCornea is pink band to the right, brown is the iris with the ciliary body processes at the top. Anterior chamber is white between the cornea and lens (pink blob in bottom left)Ciliary processes are rich in loose CT and fenestrated capillaries for the production of aqueous humor that drains into the ant chamber

IrisAnterior border is to the right; has a layer of pigmented cells posteriorly (dilator pupillae muscles located here) which is a continuation of the pigmented layer of the retina; extends up to form the pupilHas 3 layers (anterior limiting mb, stroma, posterior epith); ant has pigment cells and fibroblasts; constriction done by stroma of iris (constrictor pupillae muscle); post has 2 layers of epith; inner (w/melanin granules) and outer (myofilaments to make dilator pupillae muscle);

Ciliary BodyContinuous thickened ring that lies at the anterior portion of the sclera; loose CT around ciliary muscle; zonule fibers attach to the lensFocus on close objects have relaxation of zonule fibers (aka suspensory lig of lens) and increase convexity of the lens; inn CN III PSNS

Canal of SchlemmInferior and to the right of the iris (white spot)Trabecular meshwork merges to make the canal; drains fluid from the anterior chamber

Sphincter PupillaePink spot at the apex of the irisConstricts eye

LensLens capsule on outside (glycoproteins and type IV collagen); subcapsular epith (cuboidal); lens fibers (elongated, thin, flattened)Lens fibers filled with crystalline and is supported by the zonule fibers (imp for accommodation)

*Subluxation of lens occurs when fibers dont form (Marfans)

*Cataract: accumulation of pigments gets in lens

RetinaChoroid to left; then retinal pigment layer, layer of rods and cones; external limiting membrane, outer nuclear layer, outer plexiform layer, inner nuclear layer, inner plexiform layer, ganglion cell layer, layer of optic nerve fibers, inner limiting membrane

Ear

CochleaVestibulocochlear nerve running through (pink stretch in middle); modiolus surrounds central nerve with scala vestibuli and scala tympaniHelicotrema- where scala tympani and vestibuli meet; filled with perilymph

ScalasBigger partition is scala vestibuli (right) and smaller is scala media (left); vestibular membrane separates them with squamous epith; opening at bottom is scala tympani separated with basilar mb (simple cuboidal)Vestibuli and tympani illed with perilymph; Media filled with endolymph; Outer wall of scala media has stria vascularis (makes endolymph); spiral ligaments from the basilar membrane surround scalas

Organ of CortiIn the center of the slide, lying on the basilar mb; see neuroepithelial hair cells; stereocilia in apical positionReceptor for hearing; tips of hair cells are in tectorial mb; pillar cells are supporting cells between inner and outer hair cells (sound transduction); inner and outer hair cells supported by phalangial hair cells

Spiral GanglionWithin the organ of Corti have spiral ganglion (pink dots at top of slide); fibers of ganglion transmitted down through big pink blob in slideMade of the cell bodies of organ of Cortis bipolar neurons

Male Reproductive System

TestesTunica albuginea on the outside, covering it; circles are seminiferous tubulesFunction: produce spermatozoa and testosterone

Leydig CellsCT surrounding seminiferous tubules is tunica propria; Leydig cells are in interstitium (central, large nucleus, lipid droplets, surrounded by mitochondria and smooth ER)Secrete testosterone; highly vascularized with tunica vasculosa; stimulated by LH

Sertoli CellsColumnar; irregular plasma membrane so you cant see cell boundary; spermatagonia in basal compartment and spermatocytes, spermatids, and spermatozoa in adluminal compartmentTight junctions for adluminal and basal compartments; est blood-testes barrier; fxns: support and nourish sperma-tagonia, secrete MIH, phagocytosis of excess cytoplasm, secrete fluid to transport sperma-tozoa, has FSH receptors to incr ABP, secretes inhibin

Spermatogenic CellsSpermatagonia are large round structures at bottom; sertoli cells in middle; primary spermatocytes are above sertoli cells and are large with large nuclei; spermatids are round structures towards lumenSpermatagonia has Pale Type A, Dark Type A, and Type B cells; 1 sperma-tocytes are largest germ cells; will never see 2 spermatocytes; spermatid has heterochromatin, centrioles, Golgi granules

Tubuli Recti and Rete TestesLined with simple cuboidal epith and lots of microvilli and a single flagellaT. recti drains seminiferous tubules, which then leads into the rete testes, which then drains into the ductuli efferentes

Ductuli EfferentesHills and Valleys; alternating clusters of cuboidal cells and ciliated columnar cells; see smooth muscle surrounding it below epithelial layer (1st sign of smooth muscle in male genital tract) Cuboidal cells are for absorption; ciliated columnar cells are for the transport of spermatozoa

Ductus EpididymisRing shape of epithelium; pseudostratified columnar epith with sterocilia; basal cells (round, undifferentiated) at base of epith; spermatozoa in the lumenHas head, body and tail regions; Basal cells are stem cells for principle cells; principle cells reaborb excessive seminal fluid and secrete glycero-phosphocholine to inhibit early capacitation

Ductus DeferensStar-shaped lumen; pseudostratified epith with stereocilia; layer of lamina propria (w/CT); then have muscular layer (inner longitudinal, middle circular, outer longitudinal)Differences from ureter: ureter has transitional epith, well developed lamina propria, poorly developed muscular layers; epididymis has pseudostratified epith with stereocilia, poorly developed lamina propria, well developed muscular layers

Seminal VesiclesTortuous tubes separated by CT; false lumen; pseudostratified columnar and cuboidal cells; below the epith you can see lamina propria with inner circular and outer longitudinal layers of muscle (cant see muscle)

Unlamellated concretions in lumen (homogenous)glycoproteins

Prostate GlandLamillated concretions (can see layers); pseudostratified epithelium; fibromuscular stromaLamillated concretions because Ca2+ deposits in a concentric fasion; aka corpora amylacia; glandular tissue has 3 zones: central (benign prostatic hypertrophy), transitional zone, peripheral zone (cancer)

PenisLight-staining corpora cavernosa above; corpus spongiosum has urethra in center; separated by trabeculae (smooth muscle and elastic fibers); corporus spongiosum has less smooth muscle and more elastic fibers than cavernosaAt distal end it forms the glans penis, which is made of dense CT and smooth muscle, lined by stratified squamous nonkerat epith (prepuse epith)

Female Reproductive System

OvaryCortex is bottom portion with follicles; Medulla is top portion with blood vessels and lymphatics; surrounding it have tunica albuginea

Germinal epithelium at bottom (simple cuboidal); tunica albuginea comes after this (fibrous CT)Germinal epith is continuous with mesothelium and covers the mesovarium

Primordial FollicleSurrounded by simple squamous epitheliumArrested in prophase of 1st meiotic division until female is sexually mature (caused by FSH released by anterior pituitary)

Primary Follicle (unilaminar)Simple cuboidal epithelium; microvilli penetrates zona pellucida showing up as an intense stain; arrow points to basal lamina; theca interna shown as thicker cells @ follicleOutside basal lamina have theca interna (smooth ER and lipid droplets; secretes steroids; highly vascular; LH receptors) and theca externa (continuous with stroma)

Primary Follicle (multilaminar)Cuboidal epithelium; microvilli and penetrates zona pellucidaMore mature than unilaminar follicle

Secondary Follicle/ Graafian FollicleAntrum fills in; see theca interna and externa around follicleNow known as antral follicle; antrum contains hormone-rich fluid

Cumulus Oophorus and Corona Radiata/ tertiary follicleOocyte surrounded by granulosar cells (corona radiata); sits on a hill of granulosar cells (cumulus oophorus)Corona radiata sends microvilli to the zona pellucida to communicate with gap junctions

Atretic FollicleNuclei becomes dense; arrangement of granulosar cells not normal; zona pellucida is around itDegenerated follicle

Corpus LuteumGranulosar lutein cells fills in antrum; theca interna turns into theca lutein cells (retains linear characteristsics)

*progesterone maintains endometrium for implantationMaintained during fertilization via HCG; granular lutein cells convert androgens to estrogens and secretes progesterone; theca lutein cells secrete progesterone and androgens

Oviduct (Fallopian Tube)Epithelial lining of oviduct; ciliated columnar epithelium; between this have peg cellsFrom infundibulum to intramural region have decrease in ciliated columnar cells and increase in peg cells; cilia move secretions from peg cells to move ovum along tube; peg cells secrete fluid for nutrition to ovum and help in capacitation

Oviduct- InfundibulumInfundibular region because mucosa is thrown into longitudinal folds (looks like seminal vesicles but no false lumen- can trace folds back to the base!); inner circular and outer longitudinal mucosal foldsMuscularis mucosa helps move ovum to uterus

Oviduct- AmpullaLess folds compared to infundibulumDilated portion of oviduct; where fertilization takes place

Oviduct- IsthmusEven less folds in center; prominent mucosal layers

Oviduct- Intramural SegmentSingle fold in the center

UterusAt bottom have myometrium (smooth muscle); above it have endometriumMyometrium reacts to oxytocin; endometrium made of decidua basalis (stem cells) and desidua functionalis (sloughed off during menstruation)

Proliferative PhaseStraight glands and straight arteries (stops at basalis)Aka follicular phase, or estrogenic phase; glands and blood vessels increase because of estrogen; straight glands accumulate glycogen

Secretory PhaseGlands become torturous and larger; arteries becoming spiral and go up to and supply decidua functionalisEndometrium reaches its greatest height; progesterone maintains thickness; corpus luteum stimulates gland to secrete glycogen, which enlarges the gland

Late Secretory PhaseDilated glands; cork-screw appearance

CervixSee ectocervix and endocervix; more collagen fibers, less smooth muscle; purple dots are cervical glandsSecretions from glands are variable to phase; during secretory phase its viscous so more sperm cant fertilize and disallows microorganisms to pass

Cervix- Transformation ZoneT-zone is the squamo-columnar junction between ectocervix and endocervix; ectocervix is top (stratified squamous nonkerat); endocervix (simple columnar)Common site for cervical cancer; take Pap test smears from here

VaginaStratified squamous nonkerat epith (satisfying squamous); small lamina propria with elastic fibers (for stretch during parturition)Differences from esophagus: no glands in vagina and light-staining epith cells because of glycogen (negative stain with H&E); need glycogen to be converted to lactic acid (makes vagina acidic)

Mammary Gland- InactiveMore connective tissue than ducts

Mammary Gland- ActiveTubuloalveolar glands that take milk to nipple; intense proliferation of alveoliSecretory cells have cuboidal epitheliumMyoepithelial cells contract in response to oxytocin, which is released in response to sucklingLactiferous cells have

Placenta- Chorionic VilliBetween each villi have the intervillus space, where you find maternal blood; in each villi have fetal RBCs; see syncytiotrophoblast (outer layer of cells with brush border), under which is the cytotrophoblast.Fetal portion of villi is simple squamous cells.Exchange of gas between villus and intervillus space

Lymphoid Tissue

Peyers PatchesFound in the ileum (fiery epith); peyers patches are the lymphatic nodules at the bottom of the slideSecondary nodules because there is a germinal center (B-lymphocytes, mitotic cells, plasma cells, dendritic reticular cells, macrophages); not diffuse lymphatic tissue; cells at the center are larger with more cytoplasm; dense lymphoid tissue

Palatine TonsilStratified squamous nonkerat epith; numerous crypts; GC = germinal center surrounded by lymphocytes; nodules located in loose, collagenous CTPart of GALT; secondary nodules (so has germinal center); capsulated with CT; crypts have live and dead lymphocytes and bacteria; debris accumulate in crypts and can become infected (tonsillitis)

Pharyngeal TonsilCiliated psuedostratified epith (respiratory); no crypts present; germinal centersLocated on the roof of the nasopharynx; can hypertrophy because of chronic inflammation (adenoids)

Lingual TonsilStratified squamous nonkerat epith; sublingual glands (mucus secreting); lymphoid nodules surround a single crypt; nodule has germinal center; no CT capsuleLocated in the posterior 2/3 of the tongue

ThymusBilobed organ where the outer cortex is dark staining (bc has more lymphocytes and are more dense) and inner medulla is light staining (mature lymphocytes and less dense); no lymphoid nodules Fxn: formation, potentiation and destruction of lymphocytes; primary lymph organ, so no germinal centers and no afferent lymphatic vessels; CT capsule divides thymus into lobes

Thymus- Hassalls CorpusclesMade of rings of degenerating epith reticular cells; the HC looks like an onion ring and the ERC is the smaller one above itERCs degenerate over age (hyalinize or calcify during thymic involution) and become Hassalls corpuscles

Lymph NodesDense CT capsule with trabeculae; outer cortex is darker staining; inner medulla has no nodules and is lighter staining; afferent vessels are invaginations of the capsule; hilum is below the medulla; no epithAfferent vessels carry lymph into the subcapsular sinus ( cortical sinus ( medulary sinus ( efferent lymphatics at the hilum ( exit; subcapsular sinus has lymph with antigens, lymphocytes, antigen-presented cells

Lymph Nodes- ParacortexParacortex is between cortex and medulla; stroma that supports the lymphocytes are made of reticular fibers; can see a secondary nodule in cortex with a pale-staining center (this is the germinal center)**note: primary nodules do not have a pale staining center (because no germinal centers!)

paracortex (i.e. deep cortex) has mainly T-cells and has High Endothelial Venules (HEV)

Lymph Nodes- HEVHEV have tall cuboidal cells; located in the paracortex; the other dark-staining cells are the lymphocytes that are enteringHEV allows for the transition of lymphocytes from the blood into lymph tissue, which is why you see lymphocytes here

Lymph Nodes- MedullaMedullary sinus is surrounded by cords (contains dark staining B-lymphocytes); afferent lymphatic vessels with valves drain into the medullary sinus; dark-staining cells in sinus are reticular cellsReticular cells slow down the lymph flow, allowing more time for macrophages to clean out antigens and debris; valves in the lymphatic vessels keep lymph flowing in proper direction (depending if aff/eff)

SpleenWhite pulp is large nodule, has germinal centers that decr with age; red pulp is between white pulp and contains sinusoids; covered with simple squamous epith; capsule sends in trabeculae

Spleen- White PulpEach nodule has PALS with densely-packed T-cells (highest concentration of T-cells in spleen found here) around central artery; PALS is darker-staining than central artery and white pulp; nodules have mainly B-cells which is why its darker staining; marginal zone is between white and red pulpThick accumulation of lymphocytes; PALS= periarterial lymphatic sheath; nodules have marginal zone to trap antigen from the circulation and present it to lymphocytes; lymphocytes of PALS + marginal zone = T cells; B cells are in germinal center

Spleen- Red PulpRed pulp has sinusoids and cords (splenic cords of Billroth)Cords are dense network of reticular fibers with erythrocytes, lymphocytes, plasma cells, macrophages; sinuses are between cords and are tall endoth cells with incomplete basal lamina of reticular fibers

Spleen- Theories of Circulation2 THEORIES of circulation 1) open- opens into the cords (humans) 2)closed (below)1.Splenic artery enters the spleen at the hilum and is distributed to the interior via TRABECULAE as TRABECULAR ARTERIES.

2 On leaving the Trabeculae, the vessel enters the parenchyma to be surrounded by periarterial lymphatic sheath (PALS) and occasional lymphatic nodules, this is now termed the CENTRAL ARTERY.

3. CENTRAL ARTERIOLES enter the red pulp by losing their periarterial lymphatic sheath and subdivide into numerous straight vessels-PENICILLAR ARTERIES.

4. Pencillar A. enter into the marginal sinus. Now in the white pulp. Pencillar arteries possess three regions: PULP ARTERIOLES, SHEATHED ARTERIOLES, and TERMINAL ARTERIAL CAPILLARIES (these are part of open circulation, this creates red pulp). Cords of Billroth (T and B lymphocytes, ERC, APC, macrophages, plasma cells).

5. These drain into the SINUSOIDS (closed circulation) or terminate as open-ended vessels in the PULP CORDS (open circulation).

6. SINUSOIDS are drained by PULP veins which lead to TRABECULAR veins and eventually join the SPLENIC Vein.

Endocrine

Pituitary Gland

Nervosa is on the left, distalis is on the right, intermedialis is between with colloid folliclesAka Hypophysis; source of peptide and glycoprotein hormones to influence growth, metabolism, reproduction; attached to hypothalamus via the infundibulum

Pituitary Gland- NeurohypophysisNuclei seen are from pituicytes (supporting cells); negative profiles are unmyelenated axons; blood vesselsAka Pars Nervosa; does not secrete hormones; supraoptic nuclei secretes ADH (vasopressin) and paraventricular nuclei secretes oxytocin (SAD POX); stores hormones in dilated portions called Herring Bodies

Pituitary Gland- Pars IntermediaPresence of colloids; neurohypophysis on right and distalis on leftSecretes alpha-melanocyte stimulated hormone

Pituitary Gland- Pars DistalisLots of nuclei staining differently; chromophobes (no stain) and chromophills (alpha cells are acidophils, beta cells are basophils)Cells arranged in clumps, between which are sinusoidal capillaries, blood vessels and thin CT

Pituitary Gland- Pars DistalisAcidophilic (alpha) cells in the pars distalisAcidophils divided into somatotrophs (secr growth hormone) and mammotrophs (sec prolactin) SAM

Pituitary Gland- Pars DistalisBeta cells are basophilic cells in the distalisTypes: corticotrophs (make ACTH), gonadotrophs (secretes FSH and LH), thyrotrophs (makes thyroid stimulating hormone to make thyroxin and triiodothyronin)

Adrenal GlandSurrounded by a CT capsule; zona glomerulosa under it, then zona fasciculate, then zona reticularis (very slight change in staining); medulla has a large vein (white) in itPaired and located at the superior poles of the kidneys; cortex has 3 zones (G, F, R) that rests under the capsule; under the cortex have the medulla with large vessels running through it

Adrenal CortexZona Glomerulosa because see rounded arch-like clusters under the capsuleSecretes minerlocorticoids (aldosterone) in response to the renin-angiotensin system activated in response to a reduction in blood pressure

Adrenal CortexZona fasciculata because has linearly arranged cells in cords 1-2 cells thick; cells have rounded nuclei, lipid droplets; separated by blood sinusoidsSecrete glucocorticoids, mainly cortisol (catabolism of aa to make glucose)

Adrenal CortexZona reticularis; forms an irregular network of branching cellular cords surrounded by blood vessels and CT; medulla is on top (see large blood vessels)Secretes weak androgens (DHEA)

Adrenal MedullaLarge blood vessel running through it; has larger cells and larger veins than zona reticularis; when stained with chronic salts the pheochromocytes take up a yellow/brown color; sometimes will see ganglion cellsPheochromocytes aka chromafin cells will secrete either epi or norepi; will sometimes have sympathetic neurons that have lost their axons and dendrites ( use vessels to transport secretions through the blood

PancreasKnow youre in the pancreas because see serous secreting units of the exocrine pancreas with central acinar cells in the middle Endocrine cells secrete insulin and glucagon; glucagon from alpha cells, insulin from beta cells, somatostatin from delta ells, pancreatic polypeptide (inhibit secr of exocrine enzymes) from F cells

Pancreas- Islets of Langerhans

Alpha cells are acidophilic; beta cells are basophilic; dont have to recognize other 2 cells typesWalled off from exocrine glands by reticular fibers

Pancreas- ExocrineSee islet of Langerhans (on left) with exocrine pancreas on right

Parathyroid GlandRow of adipocytes separate acidophilic Oxyphil cells (left), from basophilic chief cells (right)Increases blood calcium levels and activates osteoclasts; 3 cells types- principal/chief cells, Oxyphil cells, clear cells

Parathyroid Gland- Chief cellsBasophilic, small, large nucleus; clear cells are chief cells that have lost its acidophilia (dont have to recognize)Secrete parathyroid hormone (parathormone)

Parathyroid Gland- OxyphilsAcidophilic, larger than chief cells, small and dark centrally placed nuclei; occur in clustersUnknown function; eosinophilic because lots of mitochondria

Pineal GlandCan appreciate the lobulations with lots of nuclei (pinealocytes); basophlic bodies, corpora arenaea (acervuli) and brain sandAka epiphysis cerebri; evagination from posterior 3rd ventricle roof

Pineal Gland- Corpora ArenaceaConcretions that are unlamellated and basophilic (in prostate gland they are lamellated and acidophilic)Aka brain sand; accumulate with age

Pineal Gland- CellsAstrocytes have dark-staining nucleus; pinealocytes are pale-staining nucleus with prominent nucleoli; will find more pinealocytes than astrocytesAstrocytes are neuroglial cells; pinealocytes secrete melatonin and serotonin (night and day hormones) to promote cyclic changes in secretory activity of other organs (diurnal rhythms)

Thyroid GlandThyroid follicles make up parenchyma; stroma has blood vessels and CT; simple cuboidal epith around the follicles (high cuboidal means theres more activity; if squamous then not as active)Follicles are colloid-filled that have thyroglobulin that cells had made and secreted into the follicles; while under the influence of TSH the follicle picks up thyroglobulin

Thyroid Gland- Parafollicular cellsLocated in the stroma outside the follicle; large, pale-staining cellsSecretes calcitonin (decreases calcium in blood by increasing osteoblast activity and increasing calcium excretion in kidneys)