3) muscularis mucosa- thin layer smooth muscle contains circular and longitudinal fibers which cause folds in muscularis layer which increases movement and absorption.
esophagus adventitia
esophagus epithelium (stratified squamous)
esophagus epithelium (stratified squamous)
Histology of submucosa and fxn?
Dense irregular connective tissue containing exocrine glands and lymphatic tissue.
controls vasoconstriction adn local movement by muscularis mucosa smooth muscle.
what is serosa? adventitia?
serosa- serous membrane covering all organs or walls of cavity not open to outside. secretes slippery fluid that is formed of simple squamous epithelium
adventitia- fibrous connective tissue
esophagus longitudinal muscle fiber
Digestion refers to:
chemical breakdown of food
functions of digestion?
mechanical processing
absorption
compaction
ingestion
intestinal hormone that stimulates secretion of duodenal glands?
enterocrinin
portion of small intestine attaching to large instestine?
ileum
what triggers gastric secretion of gastric phase?
entry of food into stomach
what does enteroendocrine cells of stomach secrete?
gastrin
if a decrease level of bile salt in bile what does it interfere with?
digestion of fat
which is greater?
pH of blood in gastric veins during digestion of large meal or following a fast?
during digestion of large meal. This is when pH is stimulated
if duodenal papilla blocked what would happen?
interfere with neutralization of chyme
decrease protien digestion
decrease carb digestion
impair fat digestion
what are plicae circulares?
transverse folds in mucosa and submucosa of sm intestine
what are gastric pits?
pockets in lining of stomach that contain secretory cells
what is myenteric plexus?
network of neurons
intestinal hormone stimulates pancreas to release watery secretion high in bicarbonate ion?
secretin
Intestinal phase of gastric digestion include?
conrol rate of gastric emptying
neural and endocrine reflexes involved
help ensure functions of sm intestine work with effeciency
begins when chyme enters sm intestine
when chyme reaches duodenum what happens?
blood levels of secretin increase
if parotid gland duct is blocked?
interferes with carb digestion in mouth.
what does pepsin enzyme digests?
protiens
where are sensory nerve cells, parasympathetic ganglia and sympathetic postganglionic fibers found?
submucosal plexus
the pancrease secretes what fluid in response to secretin?
rich in bicarbonate
intestine hormone stimulates gallbladder to release bile?
Cholecystokinin (CCK)
pancrease secretes fluid in response to cholecystokinin?
rich in enzymes
which cranial nerves control motor fibers responsible for digestion?
cranial nerve X
if muscularis mucosa is contracted what happens?
shape of intestinal lumen altered and epithelial pleats adn folds move.
what does gastroileal reflex do?
make room for more intestinal content by moving chyme to colon
modifcation of digestive epithelium that allows expansion of organ
presence of folds or pleats
proteinase produced in stomachs of babies so they can digest milk?
rennin
intestinal hormone stimulate release of insulin form pancreatic islet ?
gastric inhibitory peptide (GIP)
why is stomach able to distend as it recieves food?
1. loose tissue in form of rugae.
2. smooth muscle of stomach is elastic
3. increase of sympathetic stimulation druing filling of stomach to decrease tonus of gastric smooth muscle
4. mucosa of stomach is elastic
fxn of large intestine?
reabsorption of water and compaction of feces
if carbonic anhydrase in parietal cells are blocked?
high pH during gastric digestion
what do lacteals do?
carry product of digestion that wont pass through walls of blood capillaries
peristalsis?
waves of muscle contraction tha propel contents of digestive tract from one point to another
intestine hormone stimulates parietal cells and chief cells in stomach to secrete what fluid?
intestinal gastrin
if hormone cholecystokinin is blocked ?
composition of pancreatic secretion affected
where carb digestion begins?
mouth
disease that causes large portion of gastric mucosa to atrophy, resulting in less secretion by gastric glands.
anemia (intrinsic factor necessary for RBC production)
what regulates digestive system activities?
hormones
parasympathetic/sympathetic neurons
contents of digestive tract
plicae and intestinal villi do what?
increase surface area of mucosa of small intestine
which is false about the secretions from salivary glands?
D) contain enzymes for digestion of lipid
what does enterokinase do?
activates protien digesting enzymes
function of oral cavity?
1. analyze material before swallow
2. lubrication
3. mechanical processing of food
4. digest carb
what happens during deglutition?
soft palate elevates
upper esophageal sphincter opens
salivation d/t stimulation of tongue is a result of what ?
parasympathetic innervation
most products of fat digestion are absorbed by ?
lympghatic vessels
what enhances absorption effectiveness of small intestine?
1. plicae circulares
2. microvilli
3. intestinal movement
4. villi
what makes up exocrine portion of pancreas?
pancreatidc acini
when is pharyngeal phase initiated?
bolus comes in contact with pharyngeal arches
function of toungue?
1. mechanical processing food
2. manipulation of food
3. sensory analysis of food
4. aiding in speech
is pharyngeal phase voluntary or involuntary?
involuntary
what happens during deglutition?
breathing stops and airways open
vocal cords close
lower esophogeal sphincter contracts
soft palate lifts
what is responsible for primary water absorption?
large intestine
do salavary glands contain enzymes for digestion of simple sugar?
NO
portion of small intestine attached to pylorus of stomach?
duodenum
location of digestive organs?
pancrease extends from duodenum to spleen
gallbladder is on undersurface of right lobe of liver
middle part of small intestine is called jejunum
which teeth are blade shaped for cutting or chopping?
incisors
function of liver?
synthesis and secretion of bile
synthesis of plasma protien
inactivation of toxin
storage of glycogen adn lipid reserves
hormone NOT associated with small intestine?
intrinsic factor
function of digestive tract lining?
safeguard nearby tissue
digest swallowed bacteria
protect from digestive acid
protect from abrasion
which process is ENTIRELY under nervous control?
salivation
what happens during cephalic phase of gastric digestion?