Exam IV

• Mucosa: stratified squamous non-keratinizing epithelium; changes to simple columnar at the stomach
• Lamina propia: dense elastic connective tissue with a few defensive cells and maybe some mucous glands
• Muscularis mucosa: a thick band of longitudinally arranged smooth muscle
• Submucosa: contains mucous glands
• Muscularis Externa: inner is circular layer, and outer is a longitudinal layer; in the upper 1/3 it is striated for voluntary motion; the middle 1/3 is smooth mixed with striated for peristalsis; and the lowest 1/3 is purely smooth muscle
• NOTE: the mucosa technically includes the epithelium, the lamina propia, and the muscularis mucosa

a nerve that lies between and innervates the two layers of the muscularis externa

• stratified squamous changes to simple columnar
• change from serous glands to simple tubular glands

• Caridac region: entrance ot the stomach, nearest the heart
• Body or corpus: large central portion; cheif region of muscular grinding and production of chemicals necessary for digestion
• Anteroom: from the antrum to the pyloris; important regulatory region bc it produces hormones such as gastrin
• Pyloris: portion nearest the duodenum; has many layers of thick smooth muscle

• Mucosa: simple columnar epithelium; short pits with tubular glands; surface cells are mucous cells
• Muscularis Mucosa
• Submucosa
• Muscularis Externa: three layers (outer longitudinal, middle circular, and inner oblique)
• Serosa: outermost layer with a simple squamous mesothelium

• surface mucosal cells: covers the surface and pits; basal nucleus
• parietal cells: large with central nucleus; transport H and Cl and make instrinsic factor; present in the tubular fundic glands
• mucous neck cells: associated with parietal cells at the neck of the glands; not seen in H&E
• chief cells: at the bas eof hte gastric glands; cuboidal or low columnar; basophili; secrete pepsinogen and other zymogens
• enteroendocrine cells: scattered throughout the glands; flask-shaped with a narrow neck; dense membrane-bound granules that secrete different hormones such as gastrin, glucagon, seratonin

• mucosa changes from gastric pits to villi; made of columnar cells for absorption and goblet cells that secrete mucous
• Brunner's glands: in the submucosa of the duodenum; produce secretions that neutralize the acid and a mucous that protects the small intestine
• organization into shrot tubular glands called crypts
• paneth cells are at the base of the crypts; they have secretory granules that stain bright red; secrete lysozyme and other antibacterial substances
• enteroendocrine cells

Peyer's patches and Plicae circularis

• no more villie, but still has columnar epithelium with microvilli
• deep crypts and glands
• lots of lymphatic tissue
• three thick bands of muscle in the muscularis externa, called the taenia coli

• Exocrine: acini of serous-type cells are filled with granules of mixed enzymes for secretion; makes tryosinogen, chymotrypsinogen, carboxypeptidases, elastase, amylase, lipase, lecithinase, ribonuclease, and deoxyribonuclease
• Endocrine: islets of Langerhans; alpha cells make glucagon; beta cells make insulin; delta cells make somatostatin

• exocrine secretion via bile ducts
• maintenance of optimal concentrations of various components of blood and filtering of the blood

phagocytic cell in the liver

• maintain water and electrolyte homeostasis
• regulate blood pressure
• endocrine function: production of erythropoetin for RBC formation, renin for BP control, and modification of Vit D to its active form

• Renal corpuscle: glomeruli + Bowman's capsule
• Nephron: renal corpuscle + tubule
• Uriniferous tubule: nephron + collecting duct

• receives the gomerular filtrate
• primary site for resorption of useful sugars, small proteins and salts
• cuboidal cells with brush border and mitochondira rich infoldings
• active movement into the cells but passive movement from cells to nearby peritubular capillaries

• cuboidal cells with diminished brush border
• clear cytoplasm
• sodium and water resorption
• sensitive to ADH

• between the PCT and DCT
• responsible for osmotic gradient in the interstitium of the medulla necessary for the resorption of water
• surrounded by interstitial tissue and collecting ducts

• receive the urine from the DCT
• clumped to form medullary rays
• impermeable to water in the absense of ADH

• Somatotrophs: Growth Hormone
• Thyrotrophs: thyroid stimulating hormone
• Gonadotrophs: FSH and LH
• Lactotrophs: prolactin
• Corticotrophs: adrenocorticotropic hormone and melanocyte stimulating hormone
• Folliculostellate cells: may be stem cells

• Antidiuretic hormone (ADH) and oxytocin
• both are made by the hypothalamus and transported down into the posterior pituitary and stored there until they are released into the blood stream

• 1. follicular: single layer of cuboidla cells forma bag full of colloid; make inactive thyroglobulin and recruit iodine
• 2. parafollicular: aka clear/c cells; make calcinonin to lower blood calcium

• 1. Chief/principal cells: majority of cells; synthesize and secrete parathyroid hormone; their cytoplasm stains
• 2. Oxyphil cells: function unclear; smaler dark nucleus and clear cytoplasm

• Crotex:
• 1. zona glomerulosa: clumps or bakks of cells right underneath the capsule; secrete the mineralocorticoids, mostly aldosterone
• 2. zona fasiculata: bubbly appearance because of lipids; secretes the glucocorticoids, like cortisol
• 3. zona reticularis: dense layer of cells; secretes the andrgens

Medulla: chromaffin cells; store the catecholamines such as epinephrine and norepinephrine; controlled by neurons and secrete their contents when sense acetylcholine

• Pinealocytes: synthesize and release melatonin which regulaes circadian rhythms and scavenges hydroxyl radicals
• NOTE: Brain sand is dark and function unknown; can't see brain dust