The Digestive System Flashcards
function of digestion system
- ingestion and motility
- secretion
- digestion
- absorption
- storage and elimination
- immune barrier
what is ingestion and motility
movement of food through digestive tract
what is secretion
released of substances into GI tract
what is digestion
breakdown of food molecules into small subunits
what is absorption
passage of digested end products into blood or lymph
what is storage and elimination
temporary storage before elimination of indigestible food
what is an immune barrier
the intestinal lining is the physical barrier to pathogens and toxins
purpose of inegstion
entrance of food into our bodies by mouth
purpose of mastication
chewing food and mixing with saliva
what is propolsion
movement of food along the ddigestive tract
what deglutition
“swallowing” tounge pushed masticated food from mouth to oralpharynx
what is peristalsis
involuntary contraction and relaxation of muscle of Gi tracts
purpose of churning
vigorous mechanical movement by the stomach to grind and break ingested foods
purpose of segmentation
contractions of circular muscles of chyme thru gi tract as chyme moves in both directions and is mixed
purpose of digestion
breakdown of foodstuff into smaller parts
uses both mechanical and chemical
purpose of absorption
movement of monosaccharides, aa, fats into blood or lymph
purpose of defication
expulsion of indigestible material out of the body thru the anus
main players of digestive system
alimentary canal
accessory organs
function of alimentary canal
ingest
digest
absorbs
defecate
Is the alimentary canal one continuous hallow tube from mouth to anus? T/F
true
what does the alimentary canal include
mouth
pharynx
esophagus
stomach
small intestine
large intestine
anus
function of accessory organs
assist the process of digestive breakdown
what are the accessory organs
teeth
tongue
salivary glands
pancreas
liver/ gallbladder
what are the layers of the alimentary canal
mucosa
submucosa
serosa
muscularis
tissue type in the rest of gi tract
simple columnar ET
muscle types in muscularis externae
circular and longitudinal
what tissues are in the mouth, pharynx, esophagus, and anus
non keratinized stratified squamous ET
purpose of circular muscle
when contracted presses food stuff
purpose of longitudinal muscle
when contracted, moves food along canal
what is the alimentar canal inervated by
The ANS with enteric plexus
what do the submucosal nerve plexus do
gland secretion
what do the myenteric nerve plexus do
contractions
mouth
oral cavity. beginning of alimentary canal
what is mechanical breakdown in mouth
mastications from teeth
what is the chemical breakdown in mouth
alpha anylase that breaks down CHO into polysaccharide
what is the touge
an accessory organ of the mouth. mixed and initiates swallowing
3 parts of pharynx
Nasopahryx
oroparynx
laryngoparhynx
____pharynx reviced bolus and sends to _______pharyx
oro to laryngo
what divides the pro.. and laryngo…
epiglottis
esophagus
extends from laryngo… to stomach
25cm
fx on esophagus
carry food to stomach via perstailsis
in esophagus lower 2/3rds
involuntary smooth muscle
in esophagus what is the upper 1/3rd
voluntary skeletal muscle
what is the gastroesophageal spinchter
the gateway from esophagus to stomach
what is heart burn
“acid reflux” where acid from the stomach is regurgitated into the esophagus
a burning sensation
what is GERD
gastroesophageal reflux disease
function of stomach
in mechanical and chemical breakdown of food
what shape is the stomach
c shapped
where is the stomach located
upper left quadrant of abdominal cavity
length of stomach
6 to 10 inches
what does the stomach produce to protect itself
an alkaline mucus
what is the stomach between in
between the esophagus and small intestine
why is the stomach an active structure
does strong contractions that aid in breakdown of food
size of stomach when empty
size of fist
how does the stomach help in chemical secretion
aid in breakdown of food into smaller subunits
size of stomach when really full
4L of food/fluid
the stomach serves as a ______ until we ingest
holding tank
what is chyme
food mixed with secretions that leave stomach little by little
what does the inner oblique do in the stomach
mechanical use to grind n churn
what is Ruage
the wrinkly impression when the stomach is empty
4 regions of the stomach
cardia
fundus
body
pyloric
sig. of cardia
where esophagus connects to stomach
sig. of fundus
dome shaped superior region of stomach
sig. of pyloris
connects stomach to small intestine
sig. of body
majority of stomach
what is the pyloric sphincter
doorway to small intestine. controls stomach emptying
what is the greater curvature
outer curve of stomach
what is the lesser curvature
inner curve of stomach
what is the stomach lumen covered iwth
mucus cells
what is present in the musus cells to better protecting from self digestion
tight junctions
what are ulcers
breakdown of mucosal barriers
what can cause ulcers
excessive intake of NSAIDs or helicobacter pylori
what does an a perforated ulcer turn into
peritonitis
what are gastric pits
looks like lil dots that lead into the mucos cell and deep into gastric glands and secrete gastric juices
what are gastric juices
mix of digestive enzymes and fluid
what are gastric pits made of
mucous cells
what are gastric glands made of
parietal cell
chief cells
enteroendocrine cells
how much gastric juices does one produce daily
2-4L
Sig. of cheif cells
in lower region
make pepsinogen (inactive)
sig. of parietal cells
in middle region
produce HCI which activates pepsinogen into pepsin
aid in B12 absorption
purpose of pepsin
breakdowns proteins into polypeptides, peptides, + AA
Sig. of enter-endocrine cells
secrete hormoens: gastrin
ghrelin
histamine
somatostatin
what is the release of gastrin triggered from
released when proteins/AA enter the stomach
stretching of stomach
acetylcholine detection
what is gastrin produces from
g- cells
fx of gartrin
increase gland secretion
(HCI + histamine )
increase stomach emptying
promotes peristalsis at the small and large intestine
where is ghrelin released from
gastric gland when stomach is empty
Fx of grelin
stimulates hunger
when stomach is ____ grelin levels_____
and appetite ____
full, drop, drops,
where is histamine released from
ECL cells
enterochromaffin cells
fx of histamine
increase HCI
increase breakdown of proteins
where are somatostatin produced
in D cells in gastric glands
when is somatostatin released
in response to SNS Flight or fight
what does somatostatin do
restricts all gastric secretions
restricts blood flow to small intesting
3 phase of gastric secretions
cephalic phase
gastric phase
intestinal phase
what is the cephalic phase
when we see, smell or think of food and our mouth waters, stomach churns
what does the cephalic phase activate in brain
cerebral cortex
hypothalamus
medulla oblagata
what does the cephalic phase trigger
triggers release of actylcholine
what phase can depression and loss of appetite supress
cephalic phase
what triggers acetylcholine in the gastric phase
the stretch receptors
what initiates the gastric phase
when food enters the stomach
when does the intestinal phase start
when partially digested food enters the duodenum
what does the intestinal phase release
released intestinal gastrin into the blood which released more gastric juices
what happends after the presence of fatty, acidic or partially digested food in duodenum
enteropathic reflex
what does the enterogastric reflex do
closed the pyloric sphincter
increases intestinal hormones and enzyme
what is the body’s major digestive and absorptive organ
the small intestine
shape of small intestine
twisted muscular and sausage-like tube extending from the pyloric sphincter to the ileocecal valve
which part is the longest part of GI tract
the small intestine
all food absorption happens where
in small intestine
how do pancreatic juices and bile flow into duodenum
via major duodenal papilla
3 subdivisions of small intestine and %
duodenum 5%
jujunem 40%
illuem 55%
sig of duodenum
shortest regions
25cm
receives bile
essential part
where is the major duodenal papill a
hepatopancreatic spincter
or sphincter of Oddi
Sig of jujnum
3ft in lenght
b/w duodenum and illeum
Sig of illem
6ft in length
thick with greater mucosal folds
what connects item with large intestine
the ileocecal valve
small intestine layers additions
pilcae circualres
villi
microvilli
what are pilcae ciruclares
deep ridges to increase SA
curvy to slow down food
villi
fingerlike projections increase SA
Microvillli
extension of plasma membranes of cells
hairbrush type (brush border)
sig of intestinal crypt
produces alkaline intestinal juices
capillary network
absorbs sugars and AA
other name for intestinal crypt
lieberkum
what is runners trot
lack of blood flow to cells due to lack of nutrients and water absorption
leads to diarrhea
sig of peyers patches
prevent bacteria from entering blood
chemical digestion in Small intestine
brush border enzymes: embedded in the plasma membrane. come in contact with chyme in the lumen to finish digestion
Final part of digestive tract
large intestine
role of large intestine
finish of absorption of water + nutrients
synthesize vitamins and form feces
what does the large intestine range from
from appendix to anus
diameter of large intestine
3 in
how long is large Intest.
1.5 meters longs
regions of large intsetine
cecum
colon
recum
anus
sig of cecum
pouch like struct
loc of cecum
inferior to ileocecal valve
sig of appendix
fingerlike projection
bacterial reservoir to repop intesinal normal flora
4 parts of colon
ascending
transverse
descending
sigmoid
what does the sigmoid colon lead to
the rectum
what do the 3 lateral bends (rectal valve) help in
separate feces from gas
prevents SHARTS
the anal canal
where undigested food reaches ( 2in )
what do the Simple columnar et have in the large intest
houses enterocytes
tissues of Large intestine
simple columnar ET
what are enterocytes
an absorptive cell that absorbs water, salts, and vitamins
what are goblets cells
make mucus to ease movement of feces thru large intestine
what is the anus bordered by
the internal anal sphincter
and external anal sphincter
internal anal spincter
invoulnary or voluntary
involuntary smooth muscle
external anal spincter
invoulnary or voluntary
voluntary skeletal muscle
what does potty trainin help control
helps control external anal sphincter
what is the bacterial flora
700 species of bacteria
produces vit k and biotin
essential for chem digestion
uses fermentaion to breakdown CHO
what are farts made of
CO2 and methane
average water intake
2 liters
what % of water absorbed in large intestine
92%
what % of water absorbed in small intestine
7%
water % loss in feces
1%
what dose aldosterone promote
increase water reabsorption
what is diarrhea
3 or more loose stools a day
sever dehydration and electrolyte loss
what happens when water does not absorbs into intestine
diarrhea
what is constipation
to much water in reabsorbed which leads stool to become hard and dry. difficult to defecare
what is diverticul divertivulities
mucosa of the large intestine protrudes through colon wall
what caused diverticul diverticulities
a diet lacking in fiber
what are hemorrhoids
swollen inflamed veins in the rectum and anus
cause discomfort or bleeding
what can cause hemorrhoids
straining during bile movement
obesity
lack of fiber
pregnancy
what is chyme converted to
a semisolid feces
what is feces
undigested foodstuff
millions of bacteria
sloughed off cells
salts and water
what casues defecation
rise in rectal pressure
relaxtion of internal anal spincter
feces enters anus and urge happends
extenal anal spincter relaxes and defecation occurs
what muscles aid in defecation
abdominal and pelvic muscles
what are the accessory organs of digestive system
teeth, liver, gallbladder, pancreas,
what do the teeth do
assist in digestion by mastication
purpose of tounge
meat tentacle, mixing, tasting, and swallowing food
3 salivary glands
paratoid
sublingual
submandibular
what do salivory glands do
make saliva, and both mucus and serous secretions
what does the saliva help in
help form bolus and is anti bacterial
what enzyme is present in saliva
Alpha amylase to start breaking down CHO
fx of liver in relation to digestive system
MAKE BILE
bile producton
by hepatocyte
how much bile is made daily
250-1500mL of bile/day
what does bile consist off
bilrubin
bile salts
cholesterol
phospholipds
inorganic ion
what color is bile
greenish
what does bile break down
breaks down fat so lipase can further break it down more
gallbladder
a small thin-walled green sac that stores and concentrates bile from liver
when is bile released
when fatty foods enter duuodenum
hepatic duct
carries bile from liver joined with cystic duct
cycstic duct
carries bile gallbladder
common bile duct
brigs bile from other dicts to the duodenum
pancreas
long glandular organ behind stomach
fx on pancreas
both endo and exocrine fxs
undo-release insulin/glucagon islets
exo-digestive fins with acing cells that secrete pancreatic juices
pancreatic enzymes
bicarbonate
lipase
amylase
purpose of bicarbonate
neutralizes acids
increased pH so enzymes work better
purpose of lipase
digest triglycerides
purpose of amylase
digest starch/CHO and glucose
