S2M2 histo

• - epithelium
• - lamina propria (GALT)
• - muscularis mucosa (except in gallbladder)

• - DCT (GALT)
• -Meissners plexus

(glands present only in esophagus and duodenum)

• - 2-3 layers of SM
• - inner cirular and outer longintudinal
• -Myenteric plexus(PNS and ENS) (Auerbachs plexus) b/t 2 layers

• -serosa- covered by mesothelium
• -adventitia- no mesothelium

- with exception of enamel (ectodermal origin), all tooth associated structures are of neural crest cell origins

• - filiform- heavily keratinized, NO TASTE BUDS, scraping
• - fungiform- non/lightly keratinized, tasts bud present
• - vallate- largest, non keratinized, 250 TB/ papilla, Von Ebners glands (serous secretion into moat)
• - foliate- leaf-like and rudimentary

• - FA taste receptor on the surface of the tongue
• - people with large amounts of this will love the taste of fatty foods

- sour and salty- ion channels

- sweet, bitter and umami- G-protein linked receptors

- intercalated ducts(low cuboidal)-> striated ducts(actively transport Na from saliva to EC space)-> interlobular/excretory ducts

- parotid- purely serous, alpha amylase

- submandibular- predominantly serous, alpha amylase

- sublingual- predominantly mucous, lipase

• -shallow pits
• - deep glands: mucuous secreting, stem and enteroendocrine cells
• - few parietal cells (HCl) present

• - deep pits
• - short glands
• - predominantly mucous secreting
• -EEC- G cells (gastrin)

• - very shallow pits
• - deep glands
• -neck: lots of parietal cells(HCl)
• - base: Chief cells(pepsin)

• - only found in gastric glands
• - produce HCl and IF(intrinsic factor)
• - have fried egg appearance and intracellular canaliculi

• - only found in gastric glands and predominate in the base
• - produce pepsinogen and weak lipase
• - stimulated by gastrin
• - triangular shape, basal nuclei, strong basophilia
• - abundant RER on basal surface

• - pylorus
• - EEC (enteroendocrine cell)
• - secretes gastrin- induces HCl release from parietal cells and pepsin from chief cells

• - EEC
• - produce somatostatin
• - inhibit parietal and chief cell secretion

• - base of crypts
• - produce lysozyme
• - birds eye granules

• - I cells in SI produce
• - stimulates bile production and pancreatic enzyme secretion

• - S cells in SI
• - stimulate pancreatic and biliary HCO3 and H2O secretion

• - tubuloacinar glands in submucosa of the DUODENUM
• - secrete clear alkaline mucous
• - creates optimal pH for pancreatic enzymes

• - submucosa of ileum (more distally)
• - aggregations of lymphatic tissue
• - contain microfold cells that facilitate An and APC

• - describe liver as an exocrine gland
• - viewed as a triangle, with a central vein at each corner and a "central" bile duct
• - bile flows from corners to center

• - hexagonal shaped lobule
• - 6 portal triads (portal vein, hepatic artery and bile duct) at each corner
• - Central vein in the center

• - liver acinus perspective
• -diamond shape- short axis b/t 2 triads and long axis b/t 2 central veins
• -Zone 1- peritubular- center, first to recieve blood(and toxins)
• Zone 3- centrilobular- nearest to CV, last to recieve blood=> most vulnerable to anoxia

• -store Vit A and fat in normal liver
• - with repeated cell injury they turn into myofibrolblast and begin secreting Coll 1=> fibrosis of the liver
• -stellate cells in space of Disse(site of hematopoesis in 2 trimester)

- macrophage APCs in liver

• - made up of falciform ligament and lesser omentum
• - peritoneal connection between foregut and ventral body wall

• - splanchnic mesoderm that lies b/t thoracic cavity and stalk of yolk sac
• - ultimately becomes the central tendon of the diaphragm and the ventral mesentary

• - most common are bowel atresia and stenosis
• - most are caused by vascular accidents

• - 180 degree CLOCKWISE rotation as it reenters body cavity (= total of 90 degree CW rotation)
• - results in transverse colon passing BEHIND duodenum,
• therefore duodenum does not become secondary retroperitoneal and is mobile=> eventual strangulation

• - midgut fails to undergoe 180 degree CCW rotation as it reenters the body cavity
• - this results in the SI being on the right sde of the body
• - results in LI being on left side of the body

- macula densa- sense [Na+]

- JG cells- sense BP and produce renin

-lacis cells- specialized mesangial cells that release EPO

- cortical- intercalated cells(dark cells) that actively secrete H+ and principal cells(light cells) that respond to ADH and reabsorb H2O

-medullary- principal cells that respond to ADH and reabsorb H2O