Chemically digest food, absorb nutrients and transport undigested waste to the large intestine through peristalsis
what are the 3 parts of the small intestine?
the duodenum, the jejunum, The ilium
what is the ph of the small intestine
8
why is the small intestine and the large intestine called what they are?
small intestine is shorter in diameter then the large intestine. Even though the small intestine is longer.
what is the structrual unit of the small intestine and what do they contain?
the Villus is the structural unit. And each villi is covered in microvilli. They are full of blood vessels/have a capillary network. They increase surface area which increases chances of absorption
what increases the small intestines surface area?
the ridges in the small intestine, the villi on those ridges, and the microvilli on the villi
how do you know if an enzyme is active or not
If it ends in gen its inactive
what type of gland does the pancreas have and what does it secrete?
exocrine gland. The pancreas secretes bicarbonate ions when secretin is activated so it can neutralize the chyme from the stomach this deactivates pepsin into pepsinogen. it also secretes trypsinogen. It also secretes erepsin, amylase, and lipase.
what is amylase and lipase
amylase- carb digestion also occurs in mouth
lipase lipid chemical digestion
what are the 3 stages of protein break down and where do they occur
pepsin- digests proteins in stomach and breaks them down into smaller polypeptides (first stage)
trypsin- active version of trypsinogen it breaks polypeptides into peptides in the small intestine. 2nd
erepsin- third stage that chemically breaks down peptides into amino acids in the small intestine
what activates trypsinogen
enterokinase made in the small intestine creates trypsin
how are carbs digested and absorbed
initially polysaccharides are broken down by amylase in the mouth into smaller polysaccharides or disacharides. From there in the small intestine the remaining polysaccharides are broken down by amylase again into disaccharide and then the disaccharide are broken down further into monosaccharides using sucrase, lactase or maltase. They are then actively transported into the cells of the intestinal wall so it can be absorbed by the blood stream.
what are the 3 enzymes used to break down disaccharides
sucrase, maltase and lactase
where do bicarbonate neutralize chyme and deactivate pepsin?
duodenum
lipid digestion and absorption
fats enter the small intestine and are emulsified when bile is added to the fats. The emulsified fats are then broken down by lipase into glycerol and fatty acid molecules that can be diffused into the cells of the intestinal wall where they are reformed into triglycerides and coated with proteins to be transported through the lymph vessel
protein digestion and absorption
a bolus of food travels to the stomach where the proteins are broken down from pepsin produced by the gastric glands into smaller polypeptides, the protein then travels through the stomach to the duodenum as a chyme where the pepsin is deactivated into pepsinogen by bicarbonate and the chyme is neutralized. Further in the small intestine, the polypeptides is broken down further by trypsin into peptides. And then the peptides are broken down into amino acids by erepsin. They are then actively transported into the cells of the intestinal wall so it can be absorbed by the blood stream.
what does the liver produce and what do those things do
produces bile salts, which are stored in the gall bladder. Bile salts emulsify mechanically digest fats in the duodenum
what activates bile salts
CCK Cholecystokinin
what are some functions of the liver
detoxifies the blood by filtering poisonous substances
stores glycogen and some vitamins including A D and B12
recycles old rocs
what are gallstones and how are they formed
bile salts and cholesterol form large crystals that block the bile duct
what is jaundice
the yellowing of skin by bile salts produced in the liver but cannot get to the gallbladder because the bile duct is blocked
what is cirrhosis
when the liver tissue gets replaced by non functioning fat and conective tissue because of damage leading to lack of blood filtration
what are some functions of the large intestine
absorbs water salts and some vitamins and stores non digestible material until you can poop it out.
It also contains e.coli which synthesizes vitamin B and K
what stimulates gastrin hormone
presence of food in the stomach stimulates gastrin this causes parietal cells or stomach cells to produce HCL in the stomach
what stimulates gastric juice production
Presence of food in the mouth or stomach but also seeing or smelling or swelling food.
what stimulates the enterogastrone hormone and what does it cause
fats in the small intestine stimulate enterogastrone hormone. This causes peristaltic movement to slow down in the small intestine allowing food to remain there longer increasing nutrient absorption.
if food stays in my small intestine longer it won't be absorbed
False
the longer it stays more likely it will be absorbed
what adaptation in our intestines increases absorption
the microvillar surface
what is emulsification
breaking down something into smaller parts. For example the lipids in our small intestine are broken into smaller parts of that large lipid.
what substances need atp to be absorbed
protein and carbs.
what is lacteal
a small vessel within the villi that absorbs fatty acids into the lymphatic system
what are some evolutionary adaptations of animal involving digestion
