Digestive System Flashcards
bringing food and liquids into the mouth
ingestion
chewing, swallowing, churning
mechanical digestion
digestive/enzymatic breakdown of food into nutrient form
chemical digestion
enzymes, acids, buffers
secretion
movement of nutrients from small intestine to the bloodstream
absorption
involving compaction (dehydration of organic waste) and defecation (excretion/removal of feces)
elimination
Oral cavity function
mechanical digestion, moistening, mixing w salivary secretions
pharynx function
muscular propulsion of materials into the esophagus
esophagus function
muscular tube that transport materials from pharynx to stomach
stomach function
chemical and mechanical digestion (acids/enzymes and muscular contractions)
small intestine function
enzymatic digestion and absorption of water, organic substrates, vitamins, and ions
large intestine function
dehydration and compaction of indigestible materials to prepare for elimination (last chance to absorb water)
mucous membrane that lines the inside of the digestive tract
mucosa
what cells type lines the oral cavity, pharynx, and esophagus
stratified nonkeratinized squamous (wear and tear, resist stress + abrasion)
what cell type lines the stomach, small intestine and large intestine
simple columnar (secretion and absorption)
layer of the mucosa containing blood vessels, nerves, smooth muscle and lymphatic vessels
lamina propria
muscularis mucosae
narrow band of smooth muscle at the border of the mucosa
muscle contraction the propels a bolus through the tract in a series of circular contractions behind the food
peristalsis
muscular contraction where material is churned and fragmented as it is propelled by peristaltic contractions
segmentation
parietal peritoneum
lines the walls of the abdominopelvic cavity
visceral peritoneum
covers organs
intraperitoneal organs
organs that lie within the peritoneal cavity, surrounded by visceral peritoneum
ie. stomach, liver, jejunum, ileum
retroperitoneal organs
organs covered by visceral peritoneum on anterior surface, lie outside of visceral peritoneum
ie. kidneys, ureter, abdominal aorta
secondary retroperitoneal organs
organs form as intraperitoneal but become retroperitoneal (during embryonic development as visceral peritoneum fuses with opposing parietal peritoneum)
ie. pancreas, duodenum
fused double sheets of peritoneal (and their functions)
mesenteries
- stabilize organ position
- route of passage for blood vessels, nerves, and lymphatics
mesentery proper
sheet of mesentery that suspends small intestine (except duodenum)
Lesser omentum
lies between stomach and liver
greater omentum
from stomach and covers rest of abdominal organs on anterior surface
- w/thick layer of adipose
- energy reserve + insulation
space between cheeks, lips, and gums
oral vestibule
mastication
food moves between oral vestibule and occlusal surfaces of teeth
food is moistened w salivary secretions, processed mechanically
tongue muscles that alter the shape of the tongue
intrinsic tongue muscles
tongue muscles that affect the gross movement of the tongue
extrinsic tongue muscles
teeth types and numbers:
4 incisors, 2 canines, 4 premolars, 4-6 molars
pharyngeal muscles that push bolus toward the esophagus
pharyngeal constrictors
pharyngeal muscles that elevate the larynx
palatopharyngeus and stylopharyngeus
pharyngeal muscles that raise the soft palate
palatal muscles
esophagus passes through the ____________ and enters the abdominal cavity by passing through the _________ ________ of the diaphragm
mediastinum, esophageal hiatus
esophageal wall is made of:
mucosa (stratified nonkeratinized squamous epithelium)
submucosa (submucosal glands -> mucus)
muscularis externa (mixed skeletal and smooth muscle)
NO SEROSA LAYER
Gastric folds
relaxed stomach= mucosa forms many muscular ridges
- expand folds for larger stomach
smooth muscle layers of the stomach
circular, longitudinal, oblique
lining of the stomach:
________ leads to _________ which produce _________
gastric pits, gastric glands, gastric juice
produce alkaline mucus to protect stomach lining from autodigestion
mucous surface cells
in gastric pit, produce protective mucus
mucous neck cells
secrete intrinsic factor and hydrochloric acid
parietal cells
facilitates absorption of vitamin B12 from small intestine into bloodstream
intrinsic factor
kills microorganisms, denatures proteins, activates pepsinogen
hydrochloric acid
secrete pepsinogen. in newborns secrete rennin and gastric lipase to digest milk
chief cells in the stomach
converted to pepsin via hydrochloric acid to digest proteins
pepsinogen
produce hormones
enteroendocrine cells
secrete gastrin
G cells
- stimulates parietal and cheif cells
receives chyme from stomach, digestive enzymes from pancreas, bile from the liver and gallbladder
duodenum (retroperitoneal)
most of the digestion and absorption occurs here
jejunum (intraperitoneal)
last place of digestion and absorption in small intestine here, empties into large intestine
ilium (intraperitoneal)
Chyme is neutralized by ________ and _______ when it enters the small intestine from the stomach
alkaline secretions (pancreas)
alkaline mucus (brunner’s glands)
3 regions of the large intestine
cecum, colon, rectum
longitudinal bands of smooth muscle in the colonic wall
teniae coli
-aid in peristalsis
-define the haustra
sacs of fat attached to and extending from the large intestine
omental appendices
last portion of the rectum
anal canal
