Histo Block C

• mucosa: lamina propria (CT underlying the epithelium) + muscularis mucosa (smooth muscle)
• submucosa: dense irregular CT
• muscularis externa: inner circular & outer longitudinal layers of smooth muscle
• serosa: serous membrane

• varies by location
• epithelium
• lamina propria - CT layer that contains glands, vessels & components of the immune system
• muscularis mucosa - smooth muscle cells in two layers

• protection: from antigens, pathogens & other substances (esophagus)
• absorption: allows movement of digested nutrients, water & electrolytes into the blood and lymph (small intestine)
• secretion: provides lubrication & delivers enzymes, hormones and antibodies

• epithelium is protective
• stratified squamous nonkeratinized
• lamina propria is unspecialized
• muscularis mucosa consists of scattered bundles of longitudinal muscle fibers

• gastric mucosa specialized to produce digestive enzymes & acids
• simple columnar epithelium
• mucus-secreting cells protect against self-digestion

• specialized for absorption
• simple columnar epithelium
• absorptive cells (enterocytes) w/ scattered goblet cells
• surface area vastly increased via evaginating villi

mucosa similar to colon (absorptive & secretory simple columnar epithelium) w/ more lymphoid tissue

• absorptive & secretory epithelium
• simple columnar epithelium
• shaped into crypts (NO villi)

• epithelium is protective
• nonkeratinized stratified squamous
• transitions to epidermis (keratinized)

• contains most of the elements of ordinary CT
• generally not as fibrous as the deeper CT of submucosa
• has a relatively high proportion of lymphocytes & other immune cells
• has practically no fat cells
• includes a rich bed of capillaries

• consists of dense irregular CT
• contains blood vessels, lymphatic vessels & nerves (enteric nervous system)

• two layers of smooth muscle - inner circular & outer longitudinal
• myenteric plexus: Auerbach's plexus (postganglionic parasympathetic neurons) between the layers of smooth muscles

• forms sphincters
• pharyngoesophageal sphincter
• pyloric sphincter
• ileocecal valve
• internal anal sphincter

vomiting

contractions of the muscularis mix & propel the contents of the digestive tract - peristalsis

• serous membrane + small amount of CT
• large amound of adipose can develop here

thoracic portion of the esophagus, duodenum, ascending & descending colon, rectum & anal canal

• exists between the circular & longitudinal layers of muscularis externa
• provides motor innervation to both layers
• provides secretomotor innervation to the mucosa (postganglionic parasympathetic neurons)

• lies in the submucous coat of the intestine
• contains ganglia from which nerve fibers pass to the muscularis mucosa & the mucous membrane

• Auerbach's plexus
• Meissner's plexus

• connects the pharynx to the stomach
• epithelium: nonkeratinized stratified squamous epithelium
• lamina propria: lymphatic nodules
• submucosa: dense irregular CT; large blood & lymphatic vessels; Meissner's plexus & glands
• muscularis externa: upper 1/3 - striated muscle; middle 1/3 - mixed muscle; lower 1/3 - smooth muscle

• esophageal glands proper: occur in submucosa; secrete mucus
• esophageal cardiac glands: terminal portion of esophagus; neutral secretion

• occur in submucosa
• secrete mucus
• secretion is slightly acidic; functions to lubricate luminal wall
• small, compound tubuloalveolar glands
• scattered along length of esophagus, slightly more concentrated in upper 1/2

• similar to cardiac glands
• found in the terminal portion of the esophagus
• secretion is neutral & designed to protect the esophagus from acid reflux from the stomach

• a condition in which the lining of the esophagus changes from squamous to columnar epithelium
• result of chronic acid reflux into the esophagus
• pre-cancerous

abrupt change from stratified squamous epithelium to simple columnar epithelium

• rugae: longitudinal folds or ridges
• gastric pits: numerous openings in the mucosal surface
• mucous surface cells: secrete mucus & provide mechanical protection from components of chyme & stomach acid
• mucosa: simple columnar epithelium

• cardiac
• fundus
• pylorus

• simple branched tubular glands
• produce gastric juice (~2L/day)
• consists of a neck & the fundus (body)

• hydrochloric acid (parietal cells)
• pepsin (chief cells)
• mucus (mucus cells)
• intrinsic factor (enteroendocrine cells/parietal cells)

• pH 1.0-2.0
• produced by parietal cells
• initiates digestion of dietary proteins
• converts inactive pepsinogen to pepsin
• bacteriostatic

• proteolytic enzyme
• converted from pepsinogen (produced by chief cells) by HCl
• hydrolyzes proteins into peptides

• provides an acid protective coating
• provides a physical barrier between stomach cells & ingested material
• neutral pH
• secreted by mucous neck cells

• glycoprotein that binds to vitamin B12
• essential for absorption of B12 in ileum
• produced byparietal cells in humans

• pyloric glands - branched, coiled tubular glands
• mucous secreting cells
• enteroendocrine cells
• DEEP gastric pits

• mucous secreting cells - protect the epithelium of the esophagus
• shallow gastric pits

• fundic glands produce gastric juice
• fundic glands: simple branched tubular glands
• gastric juice contents: HCl, pepsin, mucus, intrinsic factor

• mucous neck cells
• chief cells
• parietal cells
• enteroendocrine cells

• located within the gastric glands
• have an extensive intracellular canalicular system
• produces hydrogen ions
• transports K and Cl ions
• forms HCl
• secretes intrinsic factor

• lack of intrinsic factor (can be autoimmune)
• intrinsic factor: glycoprotein secreted by the parietal cells; binds vitamin B12 allowing it to be absorbed in the ileum
• can be caused by gastritis, gastretomy
• symptoms: fatigue, shortness of breath, tingling sensations, difficulty walking and diarrhea, red tongue, abnormally large, misshapen RBCs

• most common site in cardiac region of stomaach
• caused by acid damaging the epithelium or by a Heliobacter pylori infection

• principal site for digestion & absorption
• duodenum, jejunem & ileum
• contains plicae circulares, villi with lacteals, crypts of Lieberkuhn, GALT, paneth cells

• fingerlike projections covered with simple columnar epithelium & goblet cells
• absorptive cells have microvilli on apical surfaces
• in small intestine
• increased surface area to maximize absorption of nutrients

• intestinal glands: simple tubular glands
• occur between the villi
• extend from the muscularis mucosa through to the lumen

• found in the base of the crypts
• produce antibacterial enzymes
• regulate normal bacterial flora of the small intestine
• have intensely pink staining granules

break up molecules & transport them into the tissues

• plicae circulares
• villi - leaflike
• crypts of Lieerkuhn between the villi
• Brunner's glands: found in the submucosa; secrete alkaline mucus that neutralizes acids from the stomach

• principal site of nutrient absorption
• villi are fingerlike
• intestinal glands (Paneth cells)
• NO brunner's glands

• site of water & electrolyte resorption
• similar histology to the jejunum
• contains Peyer's patches
• fingerlike villi

located on the side of the ileum opposite the mesentery

• function: resorption of electrolytes & water; elimination of undigested food
• NO plicae
• NO villi
• LOTS of goblet cells
• teniae coli

• NO villi
• submucosa
• mucosa + TONS of goblet cells (increasing toward the distal end of the colon)
• taenia coli
• crypts of Lieberkuhn are deeper than those in the small intestine
• site of most water & mineral resorption

• increaase in volume of stool OR frequency of defecation
• one of the most common clinical signs of gastrointestinal disease
• may reflect primary disorders outside of the digestive system
• caused by viruses, bacteria, parasites or drugs

• developmental disorder of the enteric nervous system
• both myenteric (Auerbach) and submucosal (Meissner) plexi are absent
• sometimes called "mega-colon"
• results in functional obstruction of the bowel

• numerous lymphatic nodules around the entire structure
• mucosa similar to the colon

• symptoms
• low-grade fever accompanies rigor, nausea & vomiting
• tenderness & firm swelling can be felt on palpation over right lower abdomen
• pain is aggravated w/ touch, pressure, moving, cough, sneeze, deep breath, straining, etc.
• loss of appetite with diarrhea or constipation
• elevated WBC count due to inflammation

• transition from simple columnar epithelium (intestinal mucosa) to keratinized stratified squamous epithelium
• muscularis externa thickens to form the internal anal sphincter
• external anal sphincter is striated muscle

• largest internal organ
• divided into two lobes
• within lobes are lobules
• produces most of the body's plasma proteins (albumins, lipoproteins, glycoproteins, prothrombin)
• stores & converts vitamins & iron (A,D,K)
• degrades drugs & toxins
• produces bile

• Vitamin A: precursor of retinal
• Vitamin D: important for Ca & K metabolism
• Vitamin K: important for prothrombin synthesis

• albumins: regulates plasma volume & colloid osmotic pressure
• lipoproteins: VDLs (transport triglycerides)
• glycoproteins: proteins involved in iron transport (haptoglobin, transferrin, etc.)
• prothrombin & fibrinogen: blood clotting

• parenchyma
• connective tissue stroma (reticular fibers)
• sinusoidal capillaries
• perisinusoidal spaces (space of Disse)

• dual blood supply
• venous (portal) system via the hepatic portal vein
• arterial supply via the hepatic artery

• hepatic artery & portal vein dump into sinusoids then central vein
• central vein empties into the sublobular veins then the inferior vena cava

• functional unit drained by a central vein
• six-sided prism with each corner being a portal triad
• afferent blood supply & bile drainage

• hepatic artery & portal vein supply the sinusoidal capillaries
• lined with simple squamous epithelium
• sinusoidal blood "bathes" the hepatocytes
• intimate contact with hepatocytes
• provide exchange of substances between blood & hepatocytes
• empty into central vein

• large polygonal liver cells
• about 80% of cells in the liver
• make up the cell plates of the parenchyma
• many are binucleate
• capable of division & regeneration
• store glycogen & lipids
• numerous peroxisomes (involved in detoxifying, particularly alcohol)
• metabolic, endocrine & secretory function

• arise from monocytes
• form part of lining of the sinusoids
• tissue macrophages
• phagocytic
• involved in the breakdown of old or damaged RBCs

composed of simple cuboidal or columnar epithelium

• thin tubes that collect bile secreted by hepatocytes
• merge to form bile ductules which eventually become common hepatic duct

• branch of hepatic artery
• branch of portal vein
• branch of bile duct

• excessive alcohol consumption causes a variety of digestive system disorders
• alcoholic liver disease, fatty liver, liver fibrosis, liver cirrhosis, alcoholic hepatitis, pancreatitis

• decrease in detoxification & hepatocyte function, barrier dysfunction & permeability
• increase in Kupffer cell activation, LPS sensitization, bacterial overgrowth & microbial translocation

• STORAGE OF BILE DUCT
• bile exits liver through common hepatic duct
• bile is shunted through cystic duct into gallbladder
• storage capacity of 40-70mL
• expulsion of bile upon relaxation of sphincter of Oddi
• smooth muscle cells in wall of gallbladder contract to expel bile through the cystic & common hepatic duct into duodenum

invaginations of the mucosa extending into the muscularis externa

• emulsifies lipids
• aids in digestion & absorption of lipids from gut
• contains organic components (lecithin, cholesterol, bilirubin)
• contains inorganic components (bile salts)

• gall stones
• cholesterol stones: usually yellow-green & made primarily of hardened cholesterol
• pigment stones: small, dark stones made of bilirubin

• pain in right upper or middle upper abdomen
• pain may be constant, sharp, cramping or dull
• pain may spread to the back or below the right shoulder blade
• fever
• yellowing of skin & whites of eyes (jaundice)
• clay-colored stools
• nausea & vomiting

• during cephalic & gastric phases, stimulation by vagal nerve fibers causes release of pancreatic juices
• acidic chyme entering duodenum causes the enteroendocrine cells of the duodenal wall to release secretin
• fatty protein rich chyme induces release of cholecystokinin
• CCK & secretin enter bloodstream
• upon reaching the pancreas, CCK induces the secretion of enzyme-rich pancreatic juice
• secretin causes copious secretion of bicarbonate-rich pancreatic juice

• centroacinar: secrete biocarbonate ions
• acinar: secrete pancreatic amylase, pancreatic lipase, trypsinogen, chymotrypsinogen, etc.

• acini comprise 80% of pancrease
• composed of columnar to pyramidal epithelial cells with minimal stroma
• centroacinar cells: in center of acini; occasionally in clusters; pale cytoplasm & oval nuclei
• intercalated duct: drains acini via interlobular ducts (cuboidal epithelium) to interlobular ducts lined by mucin secreting columnar cells

• secretin: stimulates water & bicarbonate secretion by duct cells; is stimulated by acid from stomach and luminal fatty acids
• cholecystokinin: promotes discharge of digestive enzymes by acinar cells; released from duodenum in response to fatty acids, peptides & amino acids
• pancreatic enzymes: trypsin, chymotrypsin, aminopeptidases, elastase, amylases, lipase, phospholipases, nucleases

packaging of most proteins as inactive proenzymes

• stimulates water & bicarbonate secretion by duct cells
• stimulated by acid from stomach & luminal fatty acids

• promotes discharge of digestive enzymes by acinar cells
• released from duodenum in response to fatty acids, peptides & amino acids

• trypsin
• chymotrypsin
• aminopeptidases
• elastase
• amylases
• lipase
• phospholipases
• nucleases

• acini
• intercalated ducts: extends into acinus
• intralobular ducts: form a complex branching network; striated ducts
• interlobular ducts: lined with low columnar epithelium
• main pancreatic duct

• paired kidneys - left slightly higher than right
• paired ureters - exit hilum; insert into trigone (posterior aspect of urinary bladder)
• single urinary bladder
• single urethra

• waste excretion/ water conservation
• acid/base regulation
• endocrine function - erythropoietin & renin
• hydroxylation of vitamin D

• outer layer of capsule: collagen & associated fibroblasts
• inner layer of capsule: mostly myofibroblasts, few collagen fibers

straight tubules (striations) in the cortex, some of which are continuous with collecting tubules of the medulla

• medullary ray at center
• one half adjacent cortical labyrinth
• duct of Bellini: single medullary duct
• all nephrons associated with the duct

• juxtamedullary nephron: long loops of Henle
• midcortical nephron: short loops of Henle

• outer stipe: only thick tubular segments, outer medullary collecting ducts
• inner stripe: thick & thin tubular segments; outer medullary collecting ducts
• inner medulla: thin segments; inner medullary collecting ducts

• renal corpuscle: glomerulus + Bowman's capsule
• proximal convoluted tubule
• proximal straight tubule
• descending thin limb of loop of Henle
• ascending thin limb of loop of Henle
• ascending thick limb of loop of Henle (Distal staight tubule)
• macula densa
• distal convoluted tubule

• renal corpuscle: glomerulus + Bowman's capsule
• proximal convoluted tubule
• proximal straight tubule
• descending thin limb of loop of Henle
• ascending thin limb of loop of Henle
• ascending thick limb of loop of Henle (Distal staight tubule)
• macula densa
• distal convoluted tubule
• connecting/collecting tubule
• outer medullary collecting duct
• inner medullary collecting duct
• papillary ducts of Bellini

• glomerular capullary tuft
• visceral layer of Bowman's capsule
• parietal layer of Bowman's capsule

• afferent arteriole
• juxtaglomerular cells
• glomerular capillaries
• efferent arteriole
• distal staight tubule w/ macula densa
• extraglomerular mesangial cells
• mesangial cells

• proximal convoluted tubule
• parietal layer of Bowman's capsule
• podocytes
• basal lamina/basement membrane
• urinary space

• lamina rara externa - associated with podocyte layer
• lamina densa
• lamina rara interna - associated with capillary layer

• podocyte pedicels
• glomerular basement membrane - lamina rara externa, lamina densa, lamina rara interna
• capillary endothelium

• endothelium pores: retain formed elements of the blood & repel anionic molecules
• GBM: physical & charge dependent repulsion of molecules
• pedicels: limit molecular passage by slit size & anionic charge

• type IV collagen
• laminin
• fibronectin
• heparan sulfate

limits protein loss: mechanical barrier & anionic charge

cell adhesion molecule that links adjacent pedicels & forms diaphragm of filtration slit

• nephrin: cell adhesion molecule, links adjacent pedicels, forms the diaphragm
• neph1 & 2: linking proteins supporting the nephrin sheet
• FAT1,2 & P-cadherin: cell adhesion molecules

• mesangial cells (pericytes)
• mesangial matrix

• contractile
• phagocytic
• proliferate
• synthesize matrix collagen
• secrete prostoglandins & endothelins (very potent vasoconstrictors)

• provide mechanical support
• control glomerular barrier membrane material turnover
• regulate blood flow
• secrete vasoactive substances
• respond to angiotensin II

• major site of reabsorption (80% of ultrafiltrate)
• glycocalyx: ATPases, peptidases
• transcellular pathway: ATP dependent transport of glucose, peptides, proteins & water
• paracellular pathway: for small ions (calcium, potassium, water)

• exclusively water reabsorption due to osmotic gradient
• cell types I, II, III (mostly squamous cells)

• Na, K ATPase pump drives creation of gradient due to impermeability of ascending limb to water
• type IV cells

• purpose: produce a hypertonic medullary interstitium
• method: descending & ascending loops of Henle differ in their respective permeability to water and ions; Na/K ATPase pump in thick ascending & distal tubule drives creation of gradient
• descending: thin descending is freely permeable to water; limited permeability to Na, Cl, urea
• ascending: thin ascending impermeable to water; freely permeable to Na, K, Cl
• long loops: greatest medullary hypertonicity

• low cuboidal cells
• reduced short microvilli
• no prominent brush border
• basal plasma membrane infoldings/mitochondria

contains Na sensitive macula densa cells at vascular pole

• distal tubule: reabsorption of about 7% of filtered water
• proximal pars recta: sensitive to aldosterone (Na reabsorption from urine)
• distal portion: sensitive to antidiuretic hormone (ADH/vasopressin = water reabsorption)
• basal infoldings: Na/K ATPase, mitochondria

• low cuboidal epithelium
• central nuclei
• lateral cell boundaries
• intercalated (dark) & principal (light) cells

• dark cells
• secrete either H+ or HCO3-
• reabsorb K+
• buffering system

• light cells
• respond to aldosterone from adrenal cortex
• resorb Na+ and water
• secrete K+

• columnar cells
• clear cytoplasm
• lateral cell boundaries

• serve as osmotic equilibrating device
• depends on ADH-dependent water channels (AQP-2)

• loop of Henle: thick descending, thin descending, thin ascending, thick ascending
• vasa recta: descending & ascending segments, both freely permeable to water & ions (passive exchange)
• hypertonic medullary interstitium: serves as osmotic equilibrating device; depends on ADH-dependent water channels (AQP-2)
• antidiuretic hormone: ADH dependent distal portion of distal tubule & water channels in ducts of Bellini (AQP-2)

simple columnar on surface

transitional epithelium

• G1 & G2 glomeruli: efferent arterioles give rise to peritubular capillaries
• G3 glomeruli: efferent arterioles give rise to vasa recta capillaries
• arcuate aa & vv: boundary between cortex & medulla
• interlobular aa & vv: give rise to stellate arteries & veins (afferent arterioles)

• purpose: restores isotonic plasma; maintains hypertonic medullary interstitium
• method: descending & ascending loops of vasa recta are freely permeable to water & ions (passive exchange); Na/K ATPase pump in thick ascending loop of Henle and distal tubule drives creation of gradient
• descending: plasma is in equilibrium with medullary hyperosmotic interstitium at bottom of loop
• ascending: hyperosmotic blood looses salt & gains water from interstitium

• juxtaglomerular cells of the afferent arteriole
• macula densa cells of the distal tubule
• extraglomerular mesangial cells (lacis cells)

• juxtaglomerular cells: secrete renin; react to decrease in stretch
• extraglomerular mesangial cells: modify activity of JG cells
• macula densa cells: sense changes in Na and regular JG cells

• length: ~25 cm
• lining: transitional epithelium
• muscular tunics: inner longitudinal, middle circular, outer longitudinal

• prostatisc urethra: transitional epithelium
• membranous urethra: stratified or pseudostratified columnar epithelium
• penile (spongy) urethra: pseudostratified columnar epithelium; navicular fossa lined by stratified squamous

• proximal: transitional epithelium
• terminal: stratified squamous epithelium

• glands: system of ductless glands
• hormones: blood borne - distant cells; paracrine secretion - adjacent cells; autocrine - producing cell
• function: physiological coordination, slow acting compared to rapidly acting nervous system

• discrete glands: have CT capsule & vascular supply; pituitary, thyroid, parathyroid, pineal, adrenal
• glands of mixed function: kidney, liver, pancreas, placenta, atrium
• diffuse endocrine tissue: diffuse neuroendocrine system; APUD - amine precursor uptake decarboxylation; GEP - gastroenterohepatic (gut & pancreas)

• steroid & fatty acid derivatives: originate from mesenchymal cells; often act intranuclearly (ovaries, testes, adrenal cortex)
• proteins & polypeptides: originate from endoderm (except anterior pituitary); cells often act on cell surface receptors (pituitary, thyroid, parathyroid, pancreas, gut, lung APUD cells)
• amino acid analogues: originate from neuroectoderm; often associated with neurotransmitters (thyroid parafollicular cells, adrenal medulla)

• body measures baseline levels & detects variations
• stimulus: low Ca+ ions
• response: parathyroid glands secrete PTH to increase blood calcium

• fast acting response to "flight or fright" stimulus
• response: pre-ganglionic sympathetic stimulation elicits release of epinephrine & norepinephrine via adrenal medulla

• slower response to certain developmental cues
• stimulus: homeostasis & growth
• response: pituitary gland stimulates other glands to release hormones

• systemic: into bloodstream; adrenal medulla - epinephrine
• paracrine: affect neighboring cells; Leydig cells of testes - testosterone (maturation of sperm)
• autocrine: cell that secretes hormone is affected by same hormone; supraoptic nucleus of thalamus - oxytocin

ligand/NT/hormone/drug + receptor/enzyme/protein

• ligand: usually peptide hormones or amino acid analogues
• physiological effects: second messengers, increase metabolism, cellular division, excretion/secretion, vasoconstriction/dilation, increased contractility

• ligand: usually lipid or protein bounded hormones
• physiological effects: changing the function of the cell by targeting DNA transcription & mRNA translation
• slow & lasting effects

• negative feedback: the response or product of the initial stimulus diminishes further stimulation (ex - thyroxine)
• positive feedback: the response or product of the initial stimulus enhances further stimuluation; magnifies response (ex - oxytocin)

• part of CNS
• the "general" in charge of maintaining homeostasis in the body
• controls most endocrine functions & the autonomic nervous system
• close association with the pituitary gland

• anterior pituitary
• pars distalis
• pars intermedia
• pars tuberalis

• posterior pituitary
• infundibulum
• pars nervosa
• median eminence

• oral ectoderm (Rathke's pouch): pars distalis, pars intermedia, pars tuberals (anterior pituitary)
• neuroectoderm: infundibulum, pars nervosa (posterior pituitary)

• pars distalis: largely vasomotor
• pars nervosa: neurohumoral

• inferior hypophyseal artery: pars nervosa
• superior hypophyseal artery: infundibulum, median eminence
• primary capillary plexus: infundibulum, median eminence
• secondary plexus: pars distalis

proximal end: site where hypothalamic releasing factors enter blood to influence pituitary gland hormone release

• basophils: corticotropes (ACTH cells), gonadotropes (FSH & LH cells), thyrotropes (TSH cells)
• acidophils: somatotropes (GH cells), lactotropes (PRL cells, mammotropes)
• chromophobes: acidophil or basophil that has released its hormones

• basophils: alpha & beta-endorphin cells that secrete MSH (melanocyte stimulating hormone)
• chromophobes
• colloid
• folliculostellate cells: cells that border colloid

• pituicytes: support cells
• Herring bodies: swelled axon terminals from the supraoptic & paraventricular nuclei of the hypothalamus (oxytocin & ADH secreting cells)

• oxytocin: targets uterus, mammary glands & CNS
• ADH: antidiuretic hormone stimulates aquaporin insertion into the apical & basolateral domains of cells in the DCT & CD

• Detection of low blood pressure
• Response: secretion of ADH (gets into bloodstream quickly)
• Two targets: DCT & collecting ducts in kidney - increased water absorption (aquaporin proteins) & Vasoconstriction
• Effect: RAISE BP (increasing amount of fluid in vessels)
• Feedback (negative) to inhibitADH secretion

• downward projection of the diencephalon
• epiphysis cerebri
• meninges invade, create connective tissue septa

• triangular (pine cone) shaped
• located at the anatomical midline of the brain
• postganglionic fibers from the superior cervical ganglion (SCG) supply innervation
• corpora arenacea: accumulation of calcium deposits
• pineal recess: continuation of third ventricle
• gland consists of anastomosing cords of cells, separated by CT septa

• pinealocytes: small neuronal-like cells, short processes which terminate on blood vessels; secrete melatonin
• neural glial cells: small nuclei, many slender processes; filled with intermediate filaments & resemble astrocytes

• secrete melatonin in response to decreased light via retinohypothalamic pathway
• melatonin may regulate circadian cycle, sleep induction, inhibit gonadal development & mood

light - retina - suprachiasmatic nucleus - intermediolateral cell column - superior cervical ganglion - postganglionic fibers - pineal gland

• neural crest: adrenal medulla
• intermediate mesoderm: adrenal cortex

• capsule: zona glomerulosa, zona fasciculata, zona reticularis
• medulla

• superior, middle & inferior suprarenal arteries
• capsular arteriole
• fenestrated cortical sinusoidal capillaries: supply cortex, drain into fenestrated medullary sinusoidal capillaries
• medullary arterioles: direct blood supply from the capsular artery to the medullary capillary sinusoids
• fenestrated medullary capillary sinusoids: drain hormone rich blood into adrenomedullary collecting veins
• central adrenomedullary vein (left & right suprarenal vein): drains either into the IVC (right) or left renal vein (left)

• zona glomerulosa: mineralocorticoids (aldosterone)
• zona fasciculata: glucocorticoids (cortisol)
• zona reticularis: gonadocorticoids (cortisol, weak androgens)
• medulla: epinephrine & norepinephrine

• short term: neural control stimulates release of catecholamines (epinephrine & norepinephrine)
• long term: stimulation of hypothalamic-pituitary-adrenal axis allows release of glucocorticoids & androgens

• secrete mineralocorticoids (aldosterone & deoxycorticosterone)
• effects water and electrolyte balance in renal tubules
• controlled by renin-angiontensin-aldosterone system

• columnar cells, ovoid groups
• sER, modest amount of lipids

• broadest zone
• 1-2 cell thick radial cords
• lots of lipids

• secrete glucocorticoids (cortisol & corticosterone)
• influences carbohydrate metabolism
• suppresses immune system
• elevated in stress
• controlled by ACTH

• small cells
• anastomosing cords of cells
• sources of cells for all zones of adrenal cortex

• secrete weak androgens - DHEA (dehydroepiandrosterone)
• controlled by CRH-ACTH (adrendocorticotropic releasing hormone)

• large cells
• anastomosing cords of cells
• secretes into venules

• secretes catecholamines (epinephrine & norepinephrine)
• functions as modified sympathetic ganglion
• innervated by preganglionic sympathetic fibers
• functions in "fight or flight"

• Enzymatic activity induced by glucocorticoids
• Medullary capillary percolated cortisol down from cortex to medulla
• PNMT (phenylethanolamine N-methyltransferase) converts NE to E
• Preganglionic sympathetic neuron stimulated cells to release hormones

• Macula densa detects low sodium; send signals to JG cells
• JG cells detect low pressure (decreased stretch)
• JG cells secrete renin
• Renin converts angiotensinogen to angiotensin I
• ACE (from lungs) converts angiotensin I to angiotensin II
• Angiotensin II stimulates zona glomerulosa to secrete aldosterone
• Aldosterone helps increase BP through reabsorbing salts & water at collecting ducts
• Increase in BP inhibits JG cells from releasing renin

• Long term stress to system causes hypothalmus to release CRH
• Corticotropes in anterior pituitary release ACTH
• Adrenal cortex (z. fasciculata & z. reticularis) release glucocorticoids & androgens
• Glucocorticoids & androgens inhibit release of CRH & ACTH

pharyngeal endoderm

• follicular cells/ "P" cells
• parafollicular cells/ "C" cells

• make up the follicular epithelium; line follicles
• range from simple squamous (inactive) to columnar (active) depending on functional state of gland
• apex of cells are joined by junctional complexes and project toward lumen of the follicle
• base of cells rest on basal lamina
• follicle is filled with colloid consisting of thyroglobulin & surrounded by fenestrated capillaries
• synthesize, store & release thyroid hormones

• lightly staining large cells ("clear cells")
• between the plasma membrane & basal lamina of the follicular cells
• apical border does NOT reach the follicular lumen
• secrete calcitonin into pericapillary space surrounded by fenestrated capillaries

• inactive glycoprotein secreted by follicular cells
• stored as colloid in follicular lumen

• triiodothyronine: T3, most active form
• tetraiodothyronin: T4, most prevalent form in circulation

• regulate growth & development
• regulate activity of the nervous system, alertness
• controls basal metabolic rate, regulating carbohydrate metabolism

• hypothyroidism: in children, leads to cretinism; in adults, myxedema
• hyperthryoidism: leads to hyperactivity, weight loss, agitation (ex. Graves disease)
• goiters: develop in both hypo- & hyperthryoidism

• thyroid stimulating hormone binds to receptor, stimulates second messenger system
• thyroglobulin synthesized in rER, stored as colloid in the follicle lumen
• thyroid peroxidase also stored in vesicle & lumen (helps to iodize thyroglobulin)
• ATP dependent pump sends iodide from blood to cell
• Iodide diffuses into lumen
• Iodide oxidized to iodine by thyroid peroxidase in lumen
• thyroglobulin is iodinated in lumen

• lysosomal pathway
• iodothyroglobin is endocytosed when thyroid stimulating hormone binds
• lysosomes fuse with colloid vesicle
• proteolysis of TG-I yields T3 & T4
• T3&T4 are secreted basolaterally and enter circulation

• excessive, unregulated synthesis of iodothyroglobulin
• principal cause: autoimmune thyroid-stimulating antibodies
• clinical characteristics: elevated T4, increased uptake of radioiodine, suppressed serum TSH levels, palpitations & tachycardia, exophthalmia, increased appetite, weight loss, increased sympathetic nerve tone

• protruding globes associated with retracted eyelids
• retrobulbar edema & increased CT matrix; leads to diplopia
• symptom of Graves disease (hyperthyroidism)

• suppresses bone resorption (inhibits osteoclast activity)
• lowers blood calcium level
• NOT essential for life
• regulated by blood calcium levels
• rapid, acute homeostatic effect
• opposes PTH secreted by chief cells of parathyroid gland

• 3rd pharyngeal pouches: inferior parathyroid glands
• 4th pharyngeal pouches: superior parathyroid glands

• anastomosing cords of cells
• chief/principal cells: small pale cells, contain secretory granules (PTH)
• oxyphil cells: large cells/cytoplasm, no granules, rich in mitochondria, very eosinophilic

• increases blood calcium level
• bone resorption: induces osteoblasts to release M-CSF (binds to monocytes, converst into osteoclasts); anabolic effect increased bone density
• increased reabsorption of calcium by the kidney: phosphate is excreted
• increased absorption of calcium by the gut

• essential for live
• slow, long-term homeostatic action
• raises blood calcium level

• osteitis fibrosa cystica: over-activity of PTH results in osteoporosis & fractures
• tetany: under-activity can lead to death

• cuboidal cells in endocrine pancreas containing a number of cell specific secretory granules
• beta cells: 70%; found in core; secrete insulin (lower blood glucose)
• alpha cell: 15%; secrete glucagon (raise blood glucose)
• delta cells: 10%; secrete somatostatin & gastrin
• PP/F cells: 5%; synthesize pancreatic polypeptide
• D1 cells: secrete vasoactive intestinal peptide (VIP)
• EC cells: release secretin, motilin (opposite effects of F cells)
• Epsilon cells: secrete ghrelin (stimulates appetite)

• synthesize insulin
• insulin decreases blood glucose by increasing glyconeogenesis (glycogen formation in liver), storage (fat in adipocytes) & utilization (skeletal muscle)

• synthesize glucagon
• glucagon increases blood glucose by increasing gluconeogenesis, glycogenolysis, proteolysis, hepatic lipase & fat mobilization

• synthesize somatostatin & gastrin
• somatostatin inhibits secretion of: insulin (paracrine), glucagon (paracrine) & HCl (parietal cells)

• synthesize pancreatic polypeptide
• stimulates gastric chief cells
• inhibits release of somatostatin
• decreases bile secretion, gut motility, acinar pancreas bicarbonate secretion

• preproinsulin: synthesized in rER; signal sequence removed
• proinsulin: transferred to Golgi apparatus; C peptide bound to A and B chains held together by disulfide bonds
• mature insulin: produced after cleavage of C peptide from proinsulin in secretory vesicle

energy & calcium dependent fusion of secretory vesicle (containing mature insulin & C peptide fragments) with plasma membrane allows release of insulin into bloodstream

• increase in blood glucose above 120 mg/dl
• causes release of insulin from beta cells
• increase glucose storage in liver, skeletal muscle & gate
• decreases blood glucose
• inhibits further insulin release

• decrease in blood glucose below 70 mg/dl
• stimulates release of glucagon from alpha cells
• mobilize glucose stores in liver, skeletal muscle & fat
• increases blood glucose
• inhibits further glucagon release

• insulin binds to alpha subunit of insulin receptor to activate autophosphorylation of beta subunit of receptor
• activated insulin receptor recruits GLUT-4  (insulin dependent glucose transporter protein) to plasma membrane
• GLUT-4 translocation facilitates uptake of glucose into tissue, out of blood

• insulin dependent diabetes mellitus (IDDM)
• lack of insulin due to destruction of beta cells: viruses, autoimmune, toxins
• generally found in children
• individuals require exogenous insulin to maintain life (no pancreatic insulin production)

• non-insulin dependent diabetes mellitus (NIDDM)
• insufficient insulin secretion relative to glucose levels
• fewer numbers of insulin receptors: decreased tissue response to insulin

• Cerebral infarcts (strokes), hemorrhages
• Myocardial infarcts
• Loss of beta cells
• Urinary bladder neuropathy
• Blindness (due to retinopathy, glaucoma, cataract)
• Glomerulosclerosis, pyelonephritis (due to thick basal lamina, proliferation of mesangial cells)
• Gangrene (due to arterosclerosis)
• Polydipsia: increased thirst
• Polyphagia: increased hunger
• Polyuria: increased urination

• ovaries, fallopian tubes, uterus, cervix & vagina
• undergoes regular cyclic changes from puberty to menopause
• primarily respondes to changes in levels of estrogens & progestogens

• produce gametes & steroid hormones
• medulla: central portion of ovary; contains loose CT and mass of large contorted blood vessels
• cortex: in periphery; contains the ovarian follicles (at different stages of development)
• blood-follicle barrier: to protect developing eggs; size & charge selective
• surrounded by tunica albuginea (dense CT layer between germinal epithelium & cortex)

• single layer of cuboidal epithelium covering surface of ovary
• originally though to be the site of germ cell formation
• continuous with the mesovarium

• primordial follicle: appear in ovary during 3rd month of fetal life
• primary follicle
• secondary follicle
• mature Graafian follicle
• corpus luteum: empty follicle after ovulation
• corpus albicans: regression of corpus luteum

• primordial follicle: has unilamellar structure; contains primary oocyte
• primary follicle: has multilamellar structure; zona pellucida; contains primary oocyte
• secondary follicle: has antrum; contains primary oocyte
• mature Graafian follicle: contains primary oocyte until hours before ovulation when meiosis I is completed; presence of first polar body indicates secondary oocyte

• FSH & LH stimulate the development of several primary follicles
• FSH stimulates granulose & thecal cells - begin to secrete estrogens
• later, progesterone levels begin to rise (LH peak) stimulating further development & growth of follicles
• ovulation occurs

• granulosa & thecal cells of the ruptured follicle form the corpus luteum
• corpus luteum secretes estrogens & progesterone
• no fertilization: corpus luteum degenerates
• fertilization: corpus luteum maintained by hCG; secretes estrogen & progesterone

• collapse follicle (after ovulation) becomes the corpus luteum
• secretes estrogen & progesterone
• these hormones stimulate growth of the lining of the uterus
• if fertlization does not occur, the corpus luteum degenerates into the corpus albicans

• normal ovary: one or two follicles at a time ready to ovulate
• polycystic ovary: endocrine imbalance leads to MANY follicles just below surface of ovary

• infertility
• infrequent, absent and/or irregular menstrual periods
• hirsutism - increased hair growth
• acne, oily skin, dandruff
• weight gain or obesity (due to excess insulin)
• skin tags
• pelvic pain
• anxiety or depression
• sleep apnea

• Graafian follicle cysts: most common; develop when an egg does not release properly during ovulation; will generally be reabsorbed
• corpus luteum cysts: egg fails to release; thin wall containing fluid (antrum) may rupture; will reabsorb
• hemorrhagic cysts: small ruptures in one of the blood vessels in the cyst wall

• ovarian torsion: ovary moves out of its usual position in pelvis; painful twisting of the ovary
• rupture: severe pain & internal bleeding

• infundibulum: funnel shaped segment adjacent to ovary
• ampulla: longest segment of the tube; site of fertilization
• isthmus: narrow segment adjacent to the uterus; mucosal folds are less complex than ampulla; muscularis is thickened

• ciliated simple columnar cells
• nonciliated secretory peg cells

• inner circular muscular layer
• outer longitudinal muscular layer

• transport is bidirectional (cilia & peristaltic contractions)
• fertilization occurs at the ampulla
• ovum stays in the fallopian tubes for 3 days
• estrogen stimulates ciliogenesis & progesterone increases the number of peg cells

• endometrium: mucosa of the uterus; proliferates & degenerates during the menstrual cycle
• myometrium: thick muscular layer; nondistinct muscular orientation
• perimetrium: visceral peritoneal covering of the uterus

• estrogenic/proliferative phase
• progestational/secretory phase
• menstrual phase

• begins after ovulation
• extends until the onset of the next menses
• under the influence of progesterone
• glands assume a corkscrew shape & have large irregular lumens

• uterine fibroids: thickening of uterine muscle
• occur in up to 50% of all women
• more common in African American women & obese women
• grow in response to estrogens

• birth control pills & IUDs stop growth by lowering estrogen levels
• gonadotropin-releasing hormone agonists shrink fibroids but cause menopause
• Rx: hysterectomy

• inner mucosa has numerous rugae
• lined with nonkeratinized stratified squamous epithelium
• muscular layer is 2 indistinct smooth layer muscles
• NO glands in walls (mucus is from cervical glands)

• endometrium contains large branched glands
• amount & thickness of cervical mucus changes throughout menstrual cycle
• mid-cycle: mucus is increased 10X and thinner (facilitates sperm travel)

• secrete mucus
• secretion changes during menstrual cycle

• used to diagnose infectious diseases (Candida albicans, Trichomonas vaginalis, Cornebacterium vaginale) and early cervical cancer & endometrial cancer
• effective & inexpensive screening tool

• human papillomavirus
• over 100 subtypes - 14 cause cervical cancer
• vaccines: Gardasil & Cervarix

• modified apocrine sweat glands
• 15-20 lobes of branched tubuloalveolar glands
• lobes are subdivided into lobules
• initial development caused by estrogens/progesterones of puberty
• during pregnancy - estrogen & progesterone produced by the corpus luteum cause proliferation of ducts & growth of alveoli
• after delivery - estrogen & progesterone decrease, allowing prolactin to be released
• oxytocin is also released & stimulates contraction of myoepithelial cells (ejecting milk into ducts)

• consists of three parts - amnion, chorion, decidual tissue
• chorionic villi are of fetal origin
• decidual tissue is of maternal origin

• produces hCG for the first 2 months of pregnancy until the placenta can produce sufficient estrogen & progesterone to maintain itself & the uterine lining
• pituitary LH is shut down by high progesterone & estrogen from the corpus luteum

• testes
• seminal vesicles
• bulbourethral (Cowper's) glands
• prostate gland
• epididymis & vas deferens (system of ducts & conduits)

• head: nucleus & acrosomal cap
• neck: where flagellum connects to nucleus
• tail: middle, principle & end pieces
• middle piece - mitochondrial sheath (energy for motility)

• cell division that results in two daughter cells that are identical to parent cell
• before division, chromosomes duplication (2n to 4n)
• prophase - metaphase - anaphase - telophase

• series of two consective divisions in which chromosome number & DNA content is halved to form gametes
• unique to germ cells
• female: produce one ovum
• male: produce 4 spermatozoa

• reductional division (2n,4d to 1n,2d)
• S phase duplicates chromosomes
• prophase I: leptonene - zygotene - pachytene - diplotene - diakenesis
• metaphase I: homologous chromosomes line up on metaphase plate randomly (independent assortment ensures genetic diversity)
• anaphase I: chromosomes separate towards opposite poles of cell
• telophase I: cytokinesis occurs creating 2 genetically unique daughter cells

• leptotene: chromosome are straight & separate
• zygotene: homologous chromosomes pair up (tetrads)
• pachytene: "crossing over" occurs
• diplotene: chromosomes uncoil & separate a little
• diakinesis: nucleoli disappear; nuclear membrane disintegrate into vesicles

equatorial division; no replication (1n,2d to 1n,1d)

• spermatogonial phase: spermatogonia divide mitotically to increase in number; divide into primary spermatocytes
• spermocyte phase: primary spermatocytes undergo meiosis I to become secondary spermatocytes; crossing over & independent assortment occur
• spermatid phase: secondary spermatocytes undergo meiosis II to become spermatids

• golgi phase: coalescence of proacrosomal granules unti the acrosomal vesicle; centrioles initiate axoneme assembly
• cap phase: acrosomal vesicle spreads over anterior of nucleus (acrosomal cap)
• acrosome phase: nucleus flattens, elongates & moves next to cell membrane; cytoplasm displaced posterior; manchette forms; flagellum grows; mitochondrial wraps around axoneme
• maturation phase: reduction of excess cytoplasm around flagellum; sperm no longer attached to each other - released from Sertoli cells

crystalloid inclusion bodies of Sertoli cell

• supporting non-germinal cell
• secretes nutrients & provides support for developing sperm cells
• extend from lumen of seminiferous tubule to basement membrane
• tight junctions between cells divide compartments of seminiferous tubule
• contribute to formation of blood-testis barrier
• contain Chorcot-Boettcher crystalloid inclusion bodies

• protects developinig sperm cells in the lumen from antibodies & antigens in the blood
• primary spermatocytes are genetically unique cells - immune system would recognize them as foreign cells
• blood vessels are NOT in seminiferous tubules, but within interstitial spaces between seminiferous tuubules

• peritubular myoid cells
• sertoli cells
• leydig cells
• developing sperm cells

• stereogenic cells in interstitial spaces between seminiferous tubule
• secrete testosterone in response to LH from pituitary gland

seminiferous tubule - straight tubule - rete testis - efferent ductules - epididymis - vas deferens - ejaculatory duct - prostatic urethra - membranous urethra - penile spongy urethra

modifications of plasma membrane proteins of sperm due to exposure within female reproductive tract (allows fertilization)

• largest accessory gland; unpaired; epithelial lining variable (testosterone dependent)
• fibromuscular: contractions propell secretions into urethra
• concentric layers of mucosal & submucosal & main prostatic glands
• peripheral zone: most susceptible to prostate cancer
• transitional zone: susceptible to benign prostatic hyperplasia (BPH)

• prostatic acid phosphatase (PAP): can be detected in blood
• prostate-specific antigen (PSA): also produced in liver; high levels indicate prostate cancer (prostatic carcinoma)
• fibrinolysin & citric acid

• multifolded mucosa - pseudostratified columnar epithelium
• thin smooth muscle layer
• fibrous coat
• secretions - fructose, simple sugars, amino aacids, ascorbic acid, prostaglandins

• paired glands found in urogenital diaphragm
• compound tubuloalveolar glands with simple columnar epithelium
• secretes galactose, galactosamine, galacturonic acid, sialic acid & methylpentose
• preseminal fluid lubricates penile urethra - alkaline to neutralize environment of urethra & vagina

• supports sperm cell development
• responsible for maintaining duct & accessory glands
• promotes development of male secondary sex characteristics
• negative feedback inhibition of pituitary LH secretion

• pituitary secretes FSH - stimulating sertoli cells to secrete ABP
• pituitary secretes LH - stimulating Leydig cells to secrete testosterone
• sertoli cells secrete androgen binding protein into lumen of seminiferous tubules
• androgens (testosterone from Leydig cells) bind to androgen binding proteins, keeping testosterone levels high in the seminiferous tubule
• androgen binding protein signals pituitary to stop secreting FSH
• testosterone signals pituitary to stop secreting LH
• inhibin (from Sertoli cells) shuts off hypothalmus & pituitary stimulation