digestive system Flashcards
what are the 2 main groups in digestive system? and give examples for each
GI tract:
- tube from the mouth to anus
- includes: mouth, pharynx, esophagus,S/L intestine
Accessory digestive organs:
- need help from other substances to break down food
- teeth
- tongue
- pancreas
- liver
- gallbladder
what is the difference between mechanical and chemical digestion?
mechanical:
- physical breakdown of food like chewing/churning
chemical:
- uses enzymes to break down food
- stomach acid (chyme)
what is the role of esophagus and what is the function of the upper/lower esophageal sphincters?
esophagus= tube that passes bolus down to the stomach
upper sphincters= esophagus= stops air coming in and food going up
lower sphincters=stomach=stops stomach acid from going up and prevent acid reflux
name the 4 layers of the GI wall and point their features
mucosa=iner layer
- has musuc secreting cells to protect the GI tract
submucosa=Connective tissue, blood vessel, lymphatics ; help with nutrients absorbtion and nerve signaling
muscularis= circular/longitudinal layers with smooth muscles responsible for peristaltic movements of bolus
serosa= made of connective tissues covered by epithelial cells
- outer layer
name some functions/features of the stomach
- mixing chamber and a holding reservoir
- has chyme inside
- HCI= kills bacteria
- within the stomach the gastric glands release: pepsinogen which starts the chemical digestion of proteins only if activated by HCI will then turn to pepsin which breaks down large proteins
gastric juice is a mixture of what 3 cells (gastric/stomach pits)? and state their function also define gastric juice
parietal= make HCI and instrinsic factor which helps with absorbing vitamin B12
chief= make pepsinogen that only activated by HCI and secretes gastric lipase
neck mucus= makes mucus
gastric juice= HCI +enzymes,mucus and IF that is all released by gastric glands within the stomach
what are the 2 enzymes within the pancreas and what 2 chemicals are mostly in the pancrease?
- has mostly salt and water
has 2 enzymes: lipase and amylase
lipase= starch digesting
amylase= fat digesting
which enzymes break down protein in small intestine?
trypsinogen
is only released when protein digestion is needed when its active it turns to trypsin in lumen and activates other proteases(these break down protein also)
in the liver what do hepatocytes make?
Bile
where is bile stored and what is its function?
stored in gallbladder
function= emulsification (break down fat so they’re more digestible)
what are the 3 main function/metabolism of liver and describe each
carb metabolism= stores glucose to glycogen then back to glucose to keep blood glucose levels normal
lipid metabolism= makes bile for fat digestion and absorption
protein metabolism= converts amino acid to ammonia then to urea
what is the main function of the small intestines?
absorb and digest for water,proteins,lipids
3 regions in SI and their functions
duodenum= top part wherre food mixes with juices from pancreas to break down food into smaller bits
jejunum= absorbs nutrients
illeum= absorbs water to keep body hydrated and any other remaining nutrients
what are the 3 types of digestion in the small intestines and give examples ?
mechanical= peristalsis (movement)
chemical= chyme is less acidic due to the pancreas releasing bicarbonate and alkaline mucus
enzyme= 2 enzymes are produced by villi:
- peptidases= break down peptides
- Disaccharidases=. break down double sugar molecules into simple sugars
examples of double sugar= sucrase and lactase
what is the process of absorption in small intestines when chyme enters
when chyme enters with some digested carbs/proteins the intestinal glands excrete juice to help with absorption and brush along microvilli which are found on the surface to further help with the break down of food
