A&P Exam 3

chewing, mixing, churning, and segmentation

Mechanical digestion

Segmentation

mixes food with digestive jucies by moving back and forth, makes absorption more efficient

Peristalsis

propels food forward only

carbs, proteins, fats, and nucleic acids

4 digestive enzymes (macromolecules)

vitamins, free amino acids, minerals, cholesterol, and water

Nutrients that are absorbed without being digested**

mouth, pharynx, esophagus, stomach, small and large intestine

Digestive tract organs (digestion and absorption)

liver, gallbladder, and pancreas

Accessory organs (digestion)

mucosa, submucosa, muscularis externa, and serosa

Digestive tract histology (lumen to outside, smooth muscle)

submucosa

GI tract blood supply

inner circular and outer longitudinal (smooth muscle), motility (segmentation and peristalsis)

Muscularis externa layers and function

autonomic nervous system, regulates digestive motility, secretion, and blood flow, has sensory neurons, can function independently of CNS, 2 nerve plexuses

Enteric nervous system

submucosal and myenteric

ENS Nerve plexuses (2)

parasympathetic fibers and ganglia lie between circular and longitudinal muscle layers of the muscularis externa

ENS: Myenteric/Auerbach’s nerve plexus location

salivary amylase

Enzyme for digestion of carbs

lingual lipase

Enzyme for digestion of fat

mouth/oral cavoty

Where do we begin chemcial digestion of carbs and fats?

parotid, submandibular, and sublingual

3 major salivary glands

parotid glands

Salivary glands affected by mumps

connects oral cavity to esophagus and nasal cavity to larynx, where GI and respiratory tracts intersect

The pharynx

propulsion of bolus into esophagus

Pharynx function

begins between C6 and cricoid cartilage, passes through mediastinum, enters diaphragm through esophageal hiatis, meets at stomach at lvel T7

Esophagus pathway

gastroesophageal sphincter and cardiac sphincter, opens for bolus, prevents stomach from regurgitating into esophagus

Esophagus: LES other names and function

oral, pharyngeal, and esophaheal

Swallowing (deglutition): 3 phases

voluntary, tongue forms bolus and pushes it into laryngopharynx

Swallowing: oral phase

involuntary, pharyngeal contrictors (skeletal muscle) push bolus into esophagus, palate, tongue, vocal cords, and epiglottis other paths

Swallowing: pharyngeal phase

involuntary, peristalsis drives bolus down, LES relaxes and allows into stomach

Swallowing: esophageal phase

the stomach

Where does chemical digestion of protein begin

food storage, contains rugae

stomach function

bicarbonate mucus, tight junctions, and damaged cells are shed and replaced quickly

Stomach protection: Mucosal Barrier

internal mucosal folds present when stomach if empty

stomach: gastric rugae

cardia, fundus, body corpus, and pyloric region

4 regions of the stomach

controls stomach emptying of chyme into small intestine

pyloric (gastroduodenal) sphincher

oblique layer for twisting and churning

Stomach: additional muscularis externa layer (3)

mucous, parietal, chief, and enteroendocrine cells

4 gland cells found within stomach (gastric glands)

HCL, ghrelin, and intrinsic factor (b12)

Gastric cells: Parietal cells

pepsinogen and gastric lipases

Gastric cells: chief cells

gastrin

Gastric cells: Enteroendocrine cells (G cells)

omeprazole and lansoprazole, blocks parietal cells

Propton pump inhibitors

emetic center of medulla oblongata, CTZ

vomiting controlled by …

erosions of stomach wall, perforation leads to peritonitis, caused by H pylori

Gastric ulcers

cephalic, gastric. and intestinal

3 overlapping stages of gastic secretion

stomach responds to mere sight, smell, taste, or throught of food

Gastric secretion phase: Cephalic

stomach detects food and short proteins

Gastric secretion phase: Gastric

duodenum responds to arriving chyme, inhibits stomach activity and upstream, activates downstream

Gastric secretion phase: Intestinal

duodenum, jejunum, and illeum

3 divisions of the small intestine

retropertioneal, bile and pancreatic jucie, secretes CCK

SI: Duodenum

stimulates release of bile from gallbladder (on deman bile release)

CCK (Cholescystokinin)

where most digestion and nutrient absorption occurs, B12 and IF complex

SI: Jejunum

joins large intestine at ileocecal valve, recyles bile salts

SI: Ileum

plicae circulares, vili, and microvili

Small intestine: 3 associated anatomy

forces chyme to spiral through lumen

SI: plicae circulares (circular folds)

brush border enzymes

SI: microvili

enterocytes, goblet, enteroendocrine, and paneth cells

Small intestine cells (4)

absorbs nutrients and electrolytes

SI cells: Enterocytes

secrete mucus

SI cells: Goblet cells

releases antimicrobial agents, defensins and lysozymes

SI cells: Paneth cells

produce secretin and CCK

SI cells: Enteroendocrine cells

stimulates pancreas and liver to secreate bicarbonate

Secretin

absorbs remaining water, stores residues temporarily, eliminates as stool, reclaims sodium and chlorine

Large intestine

Cecum, appendix, colon, rectum, anal canal, and anus

Large intestine structures

lymphatic tissue, hangs from cecum, part of MALT, bacterial storehouse

LI: Appendix (vermiform appendix)

ascending, transverse, descending, and sigmoid

LI: Colon (right to left)

teniae coli, haustra, and epiploic appendages

LI: associated anatomy

ileocecal valve, cecum, ascending colon, right colic (hepatic) flexure, transverse colon, left colic (splenic) flexure, descending colon, sigmoid colon, rectum

LI pathway

fermentation and vitamin synthesis (K&B)

LI: Metabolic functions

bile production, fat digestion, produces plasma proteins (globulins), destroys old RBCs, and glycogen storage

Liver functions

Kupffer cells (macrophages) and hepatocytes

Liver cells

hexagon, shape with portal triad (bile duct, portal vein, and hepatic artery)

Liver shape

right, left, caudate, and quadrate

Liver lobes (4)

falciform ligament

Liver: seperates larger right and smaller left lobes

common hepatic, cystic, and bile ducts

Liver: ducts (3)

leaves liver

Liver: common hepatic duct

connects gallbladder

Liver: cystic duct

formed by union of common hepatic and cystic ducts

Liver: bile ducts

alkaline solution prodcted by the liver, salts aid in lipid digestion and absorption

Bile (& Bile salts)

found in hollow fossa of liver, stores and concentrates bile

Gallbladder

bile and pancreatic duct unite, smooth muscle control of bile and enzyme entry into SI

Hepatopancreatic ampulla

excessive bile in blood, sclera eye

Jaundice

caused by obesity and increased insulin resistance

Non-alcoholic fatty liver disease

chronic inflammation of the liver, non-functional scar tissue

Cirrhosis

crystallized cholesterol that obstructs the flow of bile from gallbladder, sharp crystals cause agonizing pain that radiates into right thoracic region

Gallstones

trypsin, chymotrypsin, carboxypeptidase, amylase, lipase, and nucleases

Pancreas: Enzymes

actives chymotrypsin and carboxypeptidase to digest proteins

Pancreatic enzyme: Trypsin

MALT, GALT, peyer’s patches, and paneth cells

GI immunity

salivary amylase, pancreatic amylase, oligosaccharides/disaccharides, brush borde enzymes, monosaccharide

Flow of digestion/absorption of CARBS w/ enzymes

pepsin, trypsin, chymotryypsin, carboxypeptidase, brush border enzymes

Flow of digestion/absorption of PROTEINS w/ enzymes

fats, micelles, fattyacids/monoglycerides, triglycerides, chylomicrons, enter lymphatic lacteals

Fat emulsification process

pancreatic nucleases, brush border enzymes

Flow of digestion/absorption of NUCLEIC ACIDS w/ enzymes

ADEK

fat soluble vitamins

retinol, visual pigment

Fat: Vitamin A

calciferol, calcium absorption

Fat: Vitamin D

tocopherol, antioxidant

Fat: Vitamin E

phylloquinone, blood clotting

Fat: Vitamin K

thiamine

Water: Vitamin B1

riboflavin

Water: Vitamin B2

niacin

Water: Vitamin B3

pantothenic acid

Water: Vitamin B5

pyridoxine

Water: Vitamin B6

biotin

Water: Vitamin B7

folic acid, prevents birth defects during pregnancy

Water: Vitamin B9