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A&P - Ch 23

Digestive System

Question	Answer
alimentary canal; digests and absorbs food; mouth, pharynx, esophagus, stomach, small intestine, large intestine	digestive system
teeth, tongue, salivary glands, liver, gallbladder & pancreas	accessory digestive organs
taking food into the digestive tract	ingestion
moving of food through gut	propulsion
propulsion includes	swallowing & peristalsis
alternate waves of contraction & relaxation	peristalsis
chewing, mixing food with saliva by tongue, peristalsis in stomach	mechanical digestion
more/less stationary alternate contractions & relaxations	segmentation
in peristalsis, adjacent segments of alimentary tract organs	alternately contract & relax, which moves food along tract distally
in segmentation, nonadjacent segments of alimentary tract organs alternately contract and relax	moving food forward then backward
food mixing & slow food propulsion occurs	during segmentation
complex food molecules are broken down into simpler ones by enzymes	chemical digestion
passage of digested end products along w/water from lumen of gut into blood/lymph	absorption
elimination of indigestible substances from body as feces	defecation
serous membrane of abdominal cavity	peritoneum
located on external surface of most digestive organs	visceral peritoneum
lines the body wall	parietal peritoneum
located btwn two peritoneums; fluid lubricates mobile organs	peritoneal cavity
double layer of peritoneum	mesentery
travel in the mesentery	blood vessels, lymphatics, & nerves
functions of the mesentery include	holding organs in place & storing fat
lies posterior to peritoneum	retroperitoneal organs
are surrounded by peritoneum	intraperitoneal organs
mucous membrane layer of alimentary canal	mucosa
connective tissue layer of alimentary canal	submucosa
inner circular, outer longitudinal muscle layers of alimentary canal	muscularis externa
visceral peritoneum layer of alimentary canal	serosa
arterial supply that supports hepatic, splenic, & gastric, and inferior & superior mesenteric	abdominal aorta
drains nutrient-rich blood from digestive organs & delivers it to liver first	hepatic portal vein
alimentary canal has its own __ __ neurons	intrinsic enteric
in alimentary canal, this regulates glands & smooth muscle in mucosa	submucosal nerve plexus
in alimentary canal, this is located btwn muscle layers & controls GI tract motility	myenteric nerve plexus
sympathetic & parasympathetic nerves are the __ __ of alimentary canal nervous system	extrinsic control
in alimentary canal, this inhibits secretion & motility	sympathetic nerves
in alimentary canal, this stimulates secretion & motility	parasympathetic nerves
oral/buccal cavity is lined with	stratified squamous epithelium
area btwn lips & cheeks, then teeth & gums	vestibule
area that lies within teeth & gums	oral cavity proper
area of median attachment of each lip to gums	labial frenulum
palatine bones & palatine processes of maxillae	hard palate
fold formed mostly of skeletal muscle, within oral cavity	soft palate
closes off nasopharynx during swallowing	function of soft palate
uvula __ __ from soft palate free edge	projects downward
taste, mixing food during chewing, formation of bolus, helps in swallowing & speech	functions of tongue
has intrinsic & extrinsic muscles	tongue
attachment of lips to the gums	lingual frenulum
surface of tongue shows	papillae
whitish, provide friction; located on surface of tongue	filiform papillae
reddish, scattered over tongue surface	fungiform
V-shaped row in back of tongue surface	circumvallate/vallate
papillae that are associated w/taste buds	fungiform & circumvallate
arterial supply from abdominal aorta & hepatic portal vein make up	splanchnic circulation
gland located anterior to ear	parotid
open into vestibule next to 2nd upper molar	parotid duct
gland medial to body of mandible	submandibular gland
each submandibular gland duct opens	on each side of lingual frenulum
gland located under tongue	sublingual gland
sublingual gland ducts open	into floor of mouth
contains electrolytes, salivary amylase, lipase & mucin and also lysozyme, defensins	saliva
part of saliva that protects against bacteria	lysozyme & defensins
continuously keep mouth moist	intrinsic glands
parotid, submandibular, & sublingual glands are	extrinsic
produce secretions when ingested food increases salivation	stimulates receptors in mouth & parasympathetic stimulation
sympathetic stimulation inhibits	salivation causing dry mouth
20 primary teeth are called	deciduous
have deciduous teeth from	6-24 month of age
deciduous teeth include	2 incisors, 1 canine, 2 molars
permanent teeth develop, when roots are resorbed & teeth fall out at	6–12 years of age
there are 32 __ teeth	permanent
permanent teeth include	2 incisors, 1 canine, 2 premolars, 3 molars
oropharynx & laryngopharynx make up	pharynx
functions of oropharynx & laryngopharynx	allow passage of food & air
oropharynx & laryngopharynx are made up of	stratified squamous epithelium lining
oropharynx & laryngopharynx have __ muscle layer wall	skeletal
muscular wall of oropharynx & laryngopharynx serves to	contract & propel food into esophagus
is 10-inch muscular tube extends from pharynx to stomach	esophagus
esophagus pierces diaphragm at	esophageal hiatus
lined by stratified squamous epithelium	esophageal mucosa
glands in submucosa of esophagus, secrete mucus that	helps in bolus movement
made up of skeletal muscle superiorly & smooth muscle inferiorly	muscularis layer of esophagus
outermost connective tissue layer of esophagus	adventitia
ingestion of food; mechanical digestion; chemical digestion; propulsion are all	digestive processes of mouth
chewing is __ digestion	mechanical
salivary amylase breaks up polysaccharides during	chemical digestion in mouth
propulsion in mouth/swallowing is called	deglutition
voluntary contraction of tongue; 1st phase of deglutition	buccal phase
involuntary contraction of tongue; 2nd phase of deglutition	pharyngeal-esophageal phase
cardiac region of stomach surrounds	cardiac orifice
dome-shaped region of stomach	fundus
mid-portion of stomach	body
antrum, pyloric canal, & pylorus	pyloric region
convex; greater omentum hangs from it	greater curvature
concave; extends lesser omentum btwn it & the liver	lesser curvature
increase surface area of stomach	ruggae
omentum is __ that __ stomach	mesentery; surrounds
muscularis externa is made up of	inner circular, outer longitudinal, & oblique muscle layers
activates pepsin, & kills many bacteria	HCl acid
required for Vit. B12 absorption (lack of intrinsic factor → pernicious anemia	intrinsic factor
( inactive form of pepsin) for protein digestion	pepsinogen
gastrin is a(n)	hormone
prevents self digestion of stomach	mucosal barrier
mucosal barrier consists of layer of __ mucus	bicarbonate-rich
mucosal barrier consists of __ __ between epithelial cells	tight junctions
mucosal barrier consists of __ __ cells being quickly replaced by new cells	damaged epithelial
inflammation caused by anything that breaches mucosal barrier	gastritis
erosion of the stomach wall	gastric ulcer
important cause of gastritis & ulcers	Helicobacter pylori bacteria
__ of proteins by HCl is digestive process in stomach	denaturation
protein __ begins by pepsin in stomach	digestion
stomach delivers __ to small intestine	chyme
neural control of stomach is through	parasympathetic
hormonal control of stomach is through	gastrin
stimulation of gastric secretion is under	neural & hormonal controls
even before food enters stomach- by the site, smell & taste of food	cephalic (reflex) phase
in cephalic (reflex) phase, signals from smell & taste receptors reach brain, resulting in	vagus nerve stimulating the stomach
once food reaches the stomach; phase lasts for 3–4 hours provides most of gastric juice	gastric phase
neural stimulation & gastrin involved in __ of gastric secretion	regulation
intestinal gastrin as partially digested food enters duodenum (brief); increase gastric secretion	stimulatory effect
decreases gastric secretion	inhibitory effects
inhibitory effects work through neural pathway of	enterogastric reflux
inhibitory effects work through neural pathway of	intestinal hormones of CCK, secretin
also causes increase in HCl secretion	histamine
stomach stretches in __ of food	anticipation
stomach stretches to __ food as it enters without greatly increasing tension	accommodate
stomach pressure __ __ until 1.5L of food is ingested	remains constant
increased by distension of stomach by food & gastrin	peristalsis
stretching & peristalsis are involved in	gastric motility & emptying
peristaltic waves move from the fundus toward the pylorus	propulsion
most vigorous peristalsis & mixing action occur close to pylorus	grinding
pyloric end of stomach acts as pump that delivers small amounts of chyme into duodenum, simultaneously forcing most of contained material backward into stomach	retropulsion
pyloric valve opens slightly	during retropulsion
during cephalic phase of gastric motility,	signals from smell & taste receptors reach brain; results in vagus nerve increase stomach motility
during gastric phase of gastric motility,	distention of stomach w/food
both neural stimulation & gastrin increase	stomach motility
intestinal phase of gastric motility	distention of duodenum w/chyme decreased stomach motility
stomach __ 4 hours after a meal	empties
as chyme enters the duodenum, receptors	respond to stretch- neural reflex
fatty, acidic chyme- (by hormones & neural reflexes)	chyme contents
decrease stomach motility & gastric emptying (and further duodenal filling)	chyme
major organ of digestion/absorption; 20 ft long from pyloric sphincter- ileocecal valve	stomach
10"; ‘C’ shaped & is retroperitoneal; bile duct & pancreatic duct open here; entry is controlled by the sphincter of Oddi	duodenum
8" long; suspended from posterior abdominal wall by mesentery	jejunum
12"; joins large intestine at ileocecal valve; suspended from posterior abdominal wall by mesentery	ileum
structural modifications increase surface area for nutrient absorption	circular folds, villi, & microvilli
1cm tall; folds of mucosa & submucosa	circular folds
circular folds also called	plicae circulares
finger-like extensions of the mucosa	villi
projections of plasma membrane of absorptive cells ((brush border)	microvilli
microvilli contain __ __ enzymes, only found in small intestines; responsible for "fine-tuning"	brush border
largest gland in body; right, left, caudate, & quadrate lobes; contains falciform ligament	liver
separates the (larger) right & (smaller) left lobes	falciform ligament
falciform ligament attaches liver to	anterior abdominal wall
hexagonal units; composed of plates of liver cells	liver lobules
liver lobules filter & process	nutrient-rich blood
liver lobules contain __, which are leaky capillaries btwn plates of hepatocytes that contain macrophages	sinusoids
process nutrients reaching them through portal blood; store glucose as glycogen	hepatocytes
hepatocytes use __ __ to form plasma proteins	amino acids
hepatocytes store __ vitamins	fat-soluble
hepatocytes detoxify by	converting ammonia to urea
hepatocytes __ bile	secrete
liver produces 500- 1000 ml __ which is conveyed to the duodenum	bile/day
yellow-green solution; contains bile salts, bilirubin, & cholesterol	bile
cholesterol derivatives that function in fat emulsification & absorption	bile salts
pigment formed from destruction of red blood cells	bilirubin
triglycerides & phospholipids in bile	cholesterol
most bile salts are	reabsorbed & recycled
most of bilirubin is	lost in feces
stores & concentrates bile, by absorbing its water & ions	gall bladder
when gall bladder muscle wall contracts it	releases bile into its cystic duct, then flows into bile duct
acidic, fatty chyme causes duodenum to	release cholecystokinin (CCK)
cholecystokinin (CCK) causes __ of gall bladder	contraction
cholecystokinin (CCK) causes sphincter of Oddi to	relax
result of cholecystokinin (CCK) release by gall bladder, bile	enters into duodenum
pancreatic acini secretes pancreatic juice which breaks down all categories of foodstuff	exocrine function of pancreas
release of insulin & glucagon by cells in islets of Langerhans	endocrine function of pancreas
watery bicarbonate rich fluid containing enzymes (trypsinogen, chymotrypsin amylase, lipase)	pancreatic juice
activated in the duodenum to trypsin	trypsinogen
neutralizes acid chyme & provides optimal environment for pancreatic enzymes	HCO3
when fatty/acidic chyme enters duodenum secretin & CCK are released, which then	induce secretion of pancreatic juice
Vagal stimulation also stimulates release of __ & __ by duodenum	secretin & CCK
as chyme enters duodenum	carbohydrates & proteins are only partially digested
no fat digestion has taken place	as chyme enters duodenum
digestion is __ in small intestine	completed
all __ absorption takes place in small intestine	nutrient
most of __ __ takes place in small intestine	water absorption
delivered from liver & pancreas to small intestines	bile, enzymes, & bicarbonate ions
optimal pH required for __ activity in small intestines	enzyme
intestinal juice secreted by intestinal glands is __ __	enzyme poor
intestinal juice secreted by intestinal glands is __ __ with some mucous	mostly water
mix chyme w/bile, pancreatic & intestinal juices, & move food residues through ileocecal valve into large intestine	small intestine movements
most common motion of small intestine in which chyme moves backwards & forwards	segmentation
during segmentation, chyme is mixed and brought it in contact with	intestinal epithelium for absorption
because segmentation allows slow movement of chyme towards ileocecal valve	it allows enough time for digestion & absorption
begins with each wave starting distal to previous; meal residue, bacteria, mucosal cells & debris are moved into large intestine via	peristalsis after digestion in small intestines
function is to absorb remaining water & some electrolytes from food residue & to eliminate residue as feces	large intestine
3 bands of longitudinal smooth muscle in large intestine muscularis	teniae coli
pocket-like sacs caused by tone of teniae coli	haustra
fat-filled pouches of visceral peritoneum	epiploic appendages
teniae coli, haustra, & epiploic appendages are	unique features of large intestines
large intestine is subdivided into	cecum, appendix, colon, rectum, & anal canal
ascending colon, hepatic flexure, transverse colon, splenic flexure, descending colon, & sigmoid colon	distinct regions of colon
portions of colon that are anchored via mesenteries called mesocolons	transverse & sigmoid
potion of colon that joins rectum	sigmoid
last segment of large intestine that opens to exterior at anus	anal canal
anal sphincter composed of smooth muscle	internal
anal sphincter composed of skeletal muscle	external
anal sphincters are __ except during defecation	closed
consist of bacteria surviving small intestine that enter cecum, & those entering via anus	bacterial flora of large intestine
bacterial flora of large intestine serve, without harming host, to __ __ __	ferment indigestible carbohydrates
bacterial flora of large intestine serve, without harming host, to release	irritating acids & gases (flatus)
bacterial flora of large intestine serve, without harming host, to	synthesize B complex vitamins & vitamin K
when __ __ is present colon becomes motile	food residue
slow short lived movements of haustra occur one after another that move contents of colon	segmentations
during segmentations __ & __ is absorbed	water; salt
stronger & occur after eating; presence of food in stomach initiates reflex	mass peristalsis
mass peristalsis force	feces toward rectum
feces are forced into rectum by	mass movements of colon
stretching of rectal walls by feces initiates	defecation reflex
defecation reflex stimulates	contraction of rectal walls
defecation reflex relaxes	internal anal sphincter
defecation reflex contracts	external sphincter initially
stimulate relaxation of external anal sphincter & defecation occurs under	voluntary signals/conscious controls
salivary amylase, pancreatic amylase, & intestinal brush border enzymes are used to	break down carbohydrates
chemical digestion of starch; begins in mouth; breaks it down into 2-8 glucose units	salivary amylase
continues starch digestion, after salivary amylase	pancreatic amylase
convert disaccharides to monosaccharides	brush border enzymes
digests protein into polypeptides & a small number of amino acids, in stomach	pepsin
break up proteins into smaller peptides, in small intestine; pancreatic enzyme	trypsin & chymotrypsin
release free amino acids	brush border peptidases
small intestine is sole site of fat digestion brought about by	pancreatic lipases
emulsify large fat globules into tiny small droplets of fat which can easily be acted upon by lipases	bile salts
bile salts convert triglycerides to	free fatty acids & monoglycerides
most absorption is complete by time chyme	reaches ileum
amino acids & glucose are absorbed through mucosa of	intestinal villi by active transport
amino acids & glucose enter __ __ in intestinal villus & are ultimately transported to __ __ blood	capillary blood; hepatic portal
fats digestion products are absorbed by __ & enter blood through __	diffusion; lacteals
lymphatic capillaries	lacteals
bile salts are also needed for	fat absorption
products of fat digestion associate w/bile salts to form very small __ which can come into close contact with epithelial cell surfaces	micelles
lipid substances leave micelles & enter intestinal cells	via diffusion
microscopic particles of emulsified fat found in the blood and lymph and formed during the digestion of fats	chylomicrons
chylomicrons leave epithelial cells, in small intestines, enter __, & are transported to circulation via __	lacteals; lymph
chief cell is digestive system cell that	produces an inactive enzyme
islet cell is digestive system cell that	makes hormones
paneth cell is digestive system cells that	produces lysozyme
parietal cell is digestive system cells that	makes intrinsic factor
Kupffer cell is digestive system cells that	is phagocytic
ingestion is	taking food into the digestive system
mechanical digestion is	chewing, mixing, churning, & segmentation of food
chemical digestion is	enzymatic degradation of foodstuffs into simpler molecules
absorption is	passage of digested materials from lumen of GI tract into blood/lymph
defecation is	elimination of indigestible food stuffs
mucosa is in __ __ w/ingested food	direct contact
submucosa is __ __ with many elastic fibers	dense CT
muscularis is composed of longitudinal & circular layer of __ __	smooth muscle
serosa is same structure as __ __	visceral peritoneum
paratoid gland is large salivary gland	lying behind ear
sublingual gland is salivary gland	below tongue
submandibular gland is smaller salivary gland	located under jaw
lingual frenulum	secures tongue to floor of oral cavity
rugae are	folds of mucosal layer
pyloric sphincter is located at	inferior end & controls stomach emptying
gastroesophogeal sphincter	lies at superior end & regulated movement of food from esophagus
body of stomach is	able to stretch & hold large amounts of food
cephalic phase is stimulated by	sight/smell of food
gastric phase is stimulated by	distention of stomach & low acidity
intestinal phase is stimulate by	partially digested proteins & fats
inhibits gastric gland secretions	secretin
increases the secretions of enzyme rich pancreatic juice	CCK
stimulated by partially digested proteins in the stomach and increases gastric gland secretions	gastrin
inhibits gastric gland secretions; released in response to presence of fatty chyme in the small intestine	GIP
contains openings for bile and pancreatic ducts	duodenum
deep permanent folds of the mucosa and submucosa	plicae circulars
contains valve that connects to large intestines	ileum
finger-like projections of the mucosa	villi
AKA brush border	microvilli
most is ingested in the form of starch	carbohydrates
triglycerides are the most common in diet	lipids
built of long chains of amino acids	proteins
made up of ribose/deoxyribose sugars & nitrogenous bases	nucleic acids
begins carbohydrate digestion in the mouth	salivary amylase
digests proteins in small intestines	trypsin
emulsifies fats for digestion	bile
brush border enzyme that act on disaccharides	sucrase, lactase, maltase
in order to prevent self-digestion of the pancreas, activation of pancreatic proteases	occurs in duodenum
during deglutition, bolus passes into stomach from esophagus through	gastroesophageal sphincter
during the intestinal phase of gastric regulation	stomach is initially stimulated and later inhibited
protective collections of lymphocytes and macrophages occur in	Peyer's patches
proteins are	main organic molecule digested in the stomach
peristalsis	propulsive function that occurs in the esophagus
characteristic of the large intestine	contains a large number of bacteria
gastrin	regulatory chemical stimulates gastric gland activity and motility
layering of the wall of the GI tract, starting from the layer next to the lumen	mucosa, submucosa, muscularis externa, serosa
hepatopancreatic ampulla is formed from the union of	bile duct and main pancreatic duct
effect of stripping the small intestines of their villi	decreased surface area for absorption would cause weight loss to occur
stomach produces	HCl & intrinsic factor
final product of carbohydrate digestion	monosaccharides
short reflexes in the digestive system are stimulated by	enteric plexus
most common cause of peritonitis	burst appendix
myxovirus causes	mumps
increased activity of anaerobic bacterial activity at the back of the tongue causes	halitosis
condition directly associated with an increased risk for heart disease and stroke	periodontitis
only stomach function that is essential to life is	secretion of intrinsic factor
phase of gastric secretion is considered a conditioned reflex	cephalic
hollow organs, like the stomach, that act as reservoirs exhibit	plasticity
many of the early food allergies seen in infants are caused by	absorption of whole proteins
condition that affects the large bowel and has no physiological or anatomical cause	irritable bowel
bile is a(n)	emulsifying agent
defecation is mediated by	sympathetic spinal cord reflex
three excitatory gastric hormones	gastrin, serotonin, histamine
stomach produces serotonin and histamine to __ smooth muscle contraction	regulate
triads have a branch of	hepatic artery & portal vein, and bile duct
begins in the stomach under the action of pepsin	protein digestion
pancreas does NOT have a serosa layer, making it	retroperitoneal
pyloric sphincter regulates passage of __ from the stomach into the duodenum	chyme
absorbed into lymphatic lacteals	digested fats
myenteric plexus controls	motility of digestive tract
continuous hollow tube extending from the mouth to the anus; its walls are constructed by the oral cavity, pharynx, esophagus, stomach, and small and large intestines	alimentary canal/GI tract
oblique layer allows stomach to churn/mix food, reducing into smaller pieces	modification of muscularis externa
muscularis externa differs from that of other GI organs in that	it has three layers of smooth muscle instead of two
nonkeratinized stratified squamous epithelium transitions to simple columnar epithelium at	gastroesophageal junction
non keratinized stratified squamous epithelium of esophagus relates to its function in that	it is abrasive resistant
simple columnar epithelium of stomach relates to its function in that it is	specialized for secretion
differentiation of colon from large intestine, is that colon is	where food exits after passing through large intestine
structure that suspends small intestine from posterior body	mesentery
villi are	finger-like extensions of intestinal mucosa that increase surface area for absorption
Peyer's patches are	large collections of lymphoid tissue found in submucosa of small intestine
circular folds are	deep folds of mucosa & submucosa that extend completely/partially around circumference of small intestine
stomach & oral cavity are	regions that break down foodstuffs mechanically
pharynx is	conduit for both air & food
lesser/greater omentum & mesentery are	structures continuous w/and representing modifications of peritoneum
esophagus/gullet	has no digestive/absorptive function
rugae are	folds of gastric mucosa
haustra are	sacculations of large intestine
microvilli are	projections of plasma membrane of a mucosal epithelial cell
ileocecal	valve at junction of small/large intestine
small intestine is	primary region of food/water absorption
frenulum is	membrane securing tongue to floor of mouth
large intestine	absorbs water & forms feces
vestibule is	area btwn teeth & lips/cheeks
appendix is	worm-like sac that out-pockets from cecum
stomach	initiates protein digestion
lesser omentum is	structure attached to lesser curvature of stomach
small intestine is	organ distal to stomach
pyloric	valve controlling food movement from stomach to duodenum
soft palate is	posterosuperior boundary of oral cavity
small intestine/duodenum is	location of hepatopancreatic sphincter through which pancreatic secretions & bile pass
parietal peritoneum is	serous lining of abdominal cavity wall
large intestine is	principal site for synthesis of Vit K by microorganisms
anus is	region containing 2 sphincters through which feces are expelled from body
hard palate is	bone-supported anterosuperior boundary of oral cavity
visible portion of tooth in situ	clinical crown
material covering tooth root	dentin
hardest substance in body	enamel
periodontal ligament	attaches tooth to bone & surrounding alveolar structures
root	portion of tooth embedded in bone
cementum	forms major portion of tooth structure; similar to bone
odontoblast	produces dentin
pulp	site of blood vessels, nerves, & lymphatics
anatomical crown	entire portion of tooth covered w/enamel
produces mucus; found in submucosa of small intestine	gastric glands
produces product containing amylase that begins starch breakdown in mouth	salivary glands
produces whole spectrum of enzymes & alkaline fluid that is secreted into duodenum	pancreas
produces bile that secrete into duodenum via bile duct	liver
produces HCl & pepsinogen	intestinal crypts
found in mucosa of small intestine; produces intestinal juice	duodenal glands
paratoid secretions are	mainly serous
role of gallbladder is to	store & concentrate bile
hepatic artery, portal vein, & common bile duct are three	structures always found in portal triad regions of liver
Kupffer cells are found on	lining of sinusoids in liver
Kupffer cells functions is to	remove debris from blood
liver is dark red in living animal because	this is where hemoglobin from dead RBCs are broken down & recycled
secretory cells of pancreas that serve digestive process	acinar cells

Created by: lfrancois

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A&P - Ch 23

Digestive System