exam 4 digestive system Flashcards
what is the gastrointestinal tract
tube that extends from mouth to anus
what organs compose the GI tract
mouth pharynx esophagus stomach small intestine anus
what is peristalsis
contraction waves in esophagus
digestion definition
process of breaking down food into small fragments
- mechanical digestion
- chemical digestion
absorption definition
water and food molecules pass through GI lymphatics and blood vessels
functions of the digestive system
digestion
absorption
eliminates waste
what are the accessory digestive organs
tongue teeth salivary glands liver gallbladder pancreas
describe the components of the peritoneum
parietal peritoneum: lines abdominal wall
visceral peritoneum: covers abdominal organs
peritoneal cavity
how is the digestive system controlled
autonomic nervous system
- parasympathetic
- sympathetic
how does the parasympathetic NS interact with GI tract
stimulates/increases GI tract
“rest and digest”
how does the sympathetic NS interact with the GI tract
inhibits/decreases GI tract
“fight or flight”
oral cavity contains what type of cell tissue
nonkeratinized stratified squamous epithelium
describe and number the teeth in each quadrant
total of 32 Incisors (2) Canines (1) Premolars (2) Molars (3)
how does the number of adult teeth differ from the number of kids teeth
32 vs 20 teeth
0 premolars and only 1 molar in each quadrant
the tongue is is covered by what tissue?
skeletal muscle covered with stratified squamous epithelium
CN IX innervates what part of the tongue
posterior taste and sensory
CN VII innervates what part of the tongue
anterior taste
CN V innervates what part of the tongue
anterior sensory
what exactly is the hard palate
anterior 2/3 of palate, bony
composed of maxilla and palatine bones
what exactly is the soft palate
posterior 1/3 of palate, formed from skeletal muscle
uvula is attached
function of the soft palate
rises to close off nasopharynx when we swallow
the parotid gland is innervated by
CN IX
sublingual and submandibular glands are innervated by
CN VII
what are the 3 pairs of salivary glands
parotid
submandicular
sublingual
functions of saliva
- dissolves food molecules so they can be tasted
- aids in compacting a bolus
- cleanses mouth
- chemical digestion of carbohydrates
- lysozymes and antibodies in saliva inhibit bacterial growth
what is the pharynx
muscular tube that connects nasal cavity and mouth, to larynx and esophagus
funciton of the pharynx
skeletal muscle helps us “voluntarily” propel stuff from the mouth to the esophagus
which parts of the pharynx conducts both air and food
oropharynx and larynopharynx
what type of cells line the nasopharynx
pseudostratified ciliated columnar epithelium
what type of cells line the oro-/laryngopharynx
nonkeratinized squamous epithelium
list the order of the layers in the pharynx from inner
lumen mucosa submucosa muscularis externa advetitia and serosa
describe the mucosa of the pharynx
- innermost tunic
- epithelium
- lamina propria
- muscularis mucosae: think layer of smooth muscle
describe the submucosa of the pharynx
- CT
- contains major blood vessels
describe the muscularis of the pharynx
- typically contains 2 layers of smooth muscle tissue
+ inner circular layer
+ outer longitudinal layer - responsible for peristalsis
describe the serosa or adventitia of the pharynx
- outermost layer
- serosa= visceral peritoneum and areolar CT
- adventitia= areolar CT only
function of the esophagus
propel food to the stomach
describe the anatomy of the esophagus
muscular tube that connects pharynx to stomach
describe the mucosa of the esophagus
nonkeratinized stratified squamous epithelium
describe the muscularis of the esophagus
2 layers of muscle
- upper 1/3: skeletal only
- middle 1/3: skeletal and smooth
- lower 1/3: smooth only
function of the stomach
churns food and mixes it with gastric juices to break it down into chyme
location of the stomach
connects esophagus and duodenum in the upper left part of abdomen
describe the mucosa of the stomach
simple columnar epithelium
- contains gastric pits
- contains gastric glands, branching off
describe the muscularis of the stomach
3 layers of smooth muscle
- innermost oblique
- inner circular
- outer longitudinal
function of small intestine
- finishes the chemical digestion process
- absorbs most of all nutrients
describe the 3 portions of the small intestine
duodenum:
- receives chyme from stomach
jejunum:
- 2nd part
ileum:
- connects to cecum of large intestine
describe the duodenum
- c-shaped
- receives bile and enzymes from liver and pancreas through duodenal papilla
describe the jejunum
- 3/5 of remaining small intestine
- huge surface area
describe the ileum
- last 2/5 of small intestine
- still some folds but MALT (lymphatic structure)
what type of tissue is the SI mucosa composed of
simple columnar epithelium with goblet cells
why is there circular fold in the mucosa and submucosa in the SI
- increase surface area of SI through which nutrients can be absorbed
- slow down chyme and allow it to mix intestinal juices, allowing time for full nutrient absorption
where can villi be found within the SI
circular folds of the mucosa
function of the villi
- help increase surface area
- provide greater distance for materials to be ingested and absorbed
what are within the centers of the villus
blood vessels and a lacteal, which absorbs lipids
function of large intestine
absorption of water and electrolytes
- storage of undigested materials until it can be expelled from the body
describe the cecum
connects to ileum
- lower right part of abdomen
- vermiform appendices attach here
describe the ascending colon
right side of the body
describe the transverse colon
runs from the right to left side of body
describe the descending colon
left side of body
describe the sigmoid colon
in pelvic cavity, s-shaped
describe the rectum and anal canal
terminal portion of large intestine
- feces leave anal canal through anus
describe the mucosa of the LI
simple columnar epithelium with goblet cells
describe the muscularis of the LI
2 layers of smooth muscle
- outer longitudinal layers consists of teniae coli
- results in haustra: bubble/pouches
function of the liver
- produces and secretes bile (aids lipid digestion)
- processes products of digestion (+alcohol and drugs)
describe the anatomy of the liver
right lobe
left lobe
quadrate lobe
caudate lobe
what are the portal triads
- branch of hepatic portal vein
- branch of hepatic artery
- branch of bile duct
describe the blood flow in the liver
- veins bring nutrients to liver
- artery brings oxygen to liver
- flow from corners to central vein
what is the direction of bile production in the liver
bile produced goes away from central vein
function of gallbladder
stores bile secretion by liver
location of gallbladder
underneath liver
location of pancreas
behind stomach
function of acinar cells
secrete pancreatic juice, which leaves via pancreatic duct
what is the biliary apparatus
network of “tubes” that transports bile and pancreatic juices to duodenum
left and right hepatic ducts come together to form the ?
common hepatic duct
cystic duct and common hepatic duct unite to for the?
common bile duct
what is the arterial supply to GI tract
- celiac trunk
- superior mesenteric artery
- inferior mesenteric artery
main 4 veins of GI tract
- splenic vein
- superior mesenteric vein
- inferior mesenteric vein
- hepatic portal vein
function of hepatic portal system
veins that drain blood from GI tract directly to liver
function of hepatocytes
processes blood from hepatic portal vein in the liver, which leaves via hepatic veins to the inferior vena cava
