Chapter 24 A&PII

the digestive tract in humans includes the structures for — of food, — of food into —, — of nutrients, and removal of —

consumption, breakdown, nutrients, absorption, wastes

function of oral cavity

ingestion and mastication

function of pharynx

swallowing

function of esophagus

swallowing

function of stomach

storage, mixing, digestion

function of small intestine

mixing, digestion, absorption

function of large intestine

storage and elimination

histology there are — tunics

four

layers of tunics from most internal to most external

mucosa, submucosa, muscularis, serosa

mucous epithelium: nonkertinized — epithelium in mouth, oropharynx, esophagus, anal canal. — epithelium in —

stratified squamous, simple columnar

mucosa: lamina propria: loose —

CT

mucosa: muscularis mucosae: —

smooth muscle

submucosa: thick layer of —, nerves, blood vessels, —. Meissner’s plexus is important for

connective tissue, small glands, secretion

muscularis: 2 or 3 layer of —, contains Myenteric plexus that is important for —

smooth muscle, motility of GI tract

serosa or adventita: — tissue, visceral —- is present called serosa, outer layer is derived from adjacent —- called adventita

connective tissue, peritoneum, connective tissue

sensory neurons that connect the — to —

digestive tract to CNS

ANS motor neurons that connect — to —

CNS to digestive tract

enteric neurons that are confined to —

enteric plexuses

sensory enteric neuron: detect chemical composition of — and degree of — of digestive tract wall

digestive content, stretch

motor enteric neurons: stimulate or inhibit —- contraction and — secretion

smooth muscle, glandular secretion

interneurons enteric neurons: directly connect — to —

sensory to motor

local nervous regulation: —- nervous system

enteric

enteric nervous system: local reflexes to control —, — and —

peristalsis, mixing, blood flow

general nervous regulation: coordination with the —. Stimuli originate within GI tract at — or in CNS —. parasympathetic response through — nerve. sympathetic response inhibits muscle —, —, and decrease in blood flow to the —

CNS, sensory neurons, sight/smell/taste, vagus, contraction, secretion, digestive tract

major ENS neurotransmitters are — which stimulates and — which inhibits

acetylcholine, norepinephrine

serotonin: stimulates —, 95% of the body’s serotonin is found in the —

digestive motility, digestive tract

production of paracrine chemicals like —. help local reflexes in ENS control the conditions of the internal environment of the digestive tract such as —

histamine, pH levels

abdominal cavity walls and organs lined with —

serous membranes

organs covered by —

visceral peritoneum

interior surface of the abdominal cavity is lined by —

parietal peritoneum

mesenteries: extensions of the — that have fused into —. routes by which vessels and nerve pass from — to —.

peritoneum, connective tissue sheets, body wall to organs

retroperitoneal: organs that have no —

mesenteries

omentum is —. connects — to other organs. stores fat and provides — and —

double larger of peritoneum, stomach, support and protection

lesser omentum connects lesser curvature of stomach to —, greater omentum connects greater curvature of stomach like an apron to —

liver, transverse colon

oral cavity has — and oral cavity proper

vestibule

lips and cheeks are responsible for muscles of —, —, and speech

facial expressions, mastication

hard palate is — and bony. soft palate is — and made of muscle and connective tissue

anterior, posterior

the tonsils are also part of the —

oral cavity

the tongue is responsible for speech, taste, moving —, and —

food, swallowing

teeth and salivary glands are also part of the —

oral cavity

teeth are involved in — and speech.

there are — sets

primary, deciduous, milk are in — and there are —

permanent or secondary are in — and there are

mastication, two, childhood, 20, adults, 32

types of teeth: —, canines, molars, and —

incisors, premolars

parotid glands: largest, and just anterior to the —

ear

submandibular glands: along inferior border of the —-

posterior mandible

sublingual: smallest, in the floor of the —

oral cavity

salivary amylase: breaks down —

starch

lingual lipase: — digestion

lipid

saliva: prevents — in the mouth by continually washing the oral surface.

bacterial infections

saliva: bicarbonate ions: buffer to neutralize the — produced by oral bacteria

acids

proteins lysozyme and immunoglobulin A have — actions

antibacterial

saliva mucous: prevent —- and — digestion

physical irritation, enzymatic

swallowing is also called

deglutition

pharynx is swallowing: posterior walls of oropharynx and laryngopharynx contains —. — covers the larynx opening to keep food and drink from entering

pharyngeal constrictors muscle, epiglottis

esophagus is swallowing: transports food from — to —. has — and — sphincters

pharynx to stomach, upper and lower

voluntary phase of swallowing: bolus of food is moved by — from the oral cavity to the —

tongue, pharynx

pharyngeal phase of swallowing: reflex initiated by stimulation of — in the pharynx.

— closes nasopharynx

— and — close the opening into larynx

— and — move bolus to esophagus

stretch, soft palate, epiglottis and vestibular folds, pharyngeal constrictor and esophageal sphincter muscle

esophageal phase of swallowing: reflex initiated by the stimulation of — receptors in the esophagus

— plexus stimulates to peristaltic contractions to help move the food to the stomach

stretch, Myenteric

stomach regions: cardia: — opens into this part

esophagus

stomach regions fundus: to the left and above the —

cardia

stomach regions: body: largest part with — and — curvatures

greater and lesser

stomach regions: pylorus: between — and —

stomach and small intestines

sphincters in stomach: — and —

cardiac and pyloric

histology of stomach: has all — layers

four

serosa histology of stomach

outermost layer

muscularis histology of stomach: 3 layers of —

smooth muscle

submucosa and mucosa of stomach fold into — when the stomach is empty which disappear when filled

rugae

mucosa of stomach: — epithelium with gastric — and gastric —

simple columnar, pits, glands

gastric pits: openings for —

gastric glands

cells of stomach: surface mucus secrete

mucus

cells of stomach: mucous neck secrete

mucus

cells of stomach: parietal secrete — and —

hydrochloric acid and intrinsic factor

cells of stomach: chief cells secrete — and —

pepsinogen and lipase

cells of stomach: endocrine secrete — and —

regulatory hormones such as gastrin and histamine

secretions of stomach: mucus: — and — mucous cells. protect from — chyme and enzyme —

surface and neck, acidic, pepsin

secretion of stomach: intrinsic factor: made in —, required for absorption of —-, which is required for — synthesis

parietal, B12, DNA

secretions of stomach: Pepsinogen: secreted by —-, converted to — and digests —

chief cells, pepsin, proteins

secretions of the stomach: gastric lipase: secreted by — and digests —

chief cells, lipids

secretions of stomach: HCl secreted by —, kills —, denatures —, helps convert pepsinogen to —

parietal cells, bacteria, proteins, pepsin

regulation of stomach secretions

Cephalic phase: signals from — stimulates the medulla oblongata which stimulates parasympathetic signals to the — via the —

hypothalamus, stomach, vagus nerve

cephalic phase also stimulates the enteric nervous system of stomach stimulating —

gastric secretion

regulation of stomach secretions

gastric phase: ingested food stimulates gastric activity in two ways: by — the stomach, activating reflexes from — plexus and from the —-

stretching, myenteric, vagus nerve/brainstem

gastric phase stimulated by —, histamine, and —

ACh, gastrin

gastric phase has a — feed back mechanism. — secretion is inhibited by pH less than 2

negative, gastrin

intestinal phase of regulation of stomach secretions

chyme in the — with pH less than 2 containing — inhibits gastric secretions.

acids and fats initiate — reflex during gastric secretions

duodenum, lipids, enterogastric

intestinal phase

inhibit — and stimulate — neurons

— and — inhibits gastric secretion and stimulates pancreas and gallbladder

vagal activity, sympathetic, secretin and cholecystokinin

movements of the stomach 1: relatively weak contractions result in —, which thorougly mix ingested food with stomach secretions to form —

mixing waves, chyme

movements of the stomach 2: in the mixing wave, the more fluid part of the chyme is pushed toward the —, whereas the more solid center moves back toward the —

pyloric sphincter, body of the stomach

movements of the stomach 3: stronger contractions results in —-, which force the chyme toward and through the —. The pyloric sphincter usually remains closed because of mild —

peristaltic waves, pyloric sphincter, tonic contraction

movements of the stomach 4: again, the more fluid part of the chyme is pushed toward the — region, whereas the more solid center of the chyme squeezes past the — back toward the stomach of the body

pyloric region, peristaltic constriction

movements of the stomach 5: each peristaltic contraction is sufficiently strong to cause partial relaxation of the —- and the pump a few milliliters of chyme through the — opening and into the —-. increase motility leads to increased —

pyloric sphincter, pyloric opening, duodenum, emptying

three parts of small intestine

duodenum, jejunum, ileum

accessory glands associated with the dueodenum

liver, gall bladder, and pancreas

small intestine: most — and — takes place here

digestion and absorption

surface area increased by —, —, and —

mucosal folds, villi, microvilli

small intestines: absorptive, — and — cells

goblet and endocrine

duodenum: openings to ducts from — and —

liver and pancreas

jejunum: major area of —

nutrient absorption

ileum: — which is a type of MALT

Peyer’s patches

mucus of small intestine: protects small intestine — from — and —

lining, digestive enzymes and acidity

digestive enzymes called — enzymes.

disaccharidases: break down disaccharides to —

peptidases: hydrolyze —

brush border, monosaccharides, peptide bonds