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ZOO 3115; Dr. Cherrington, GIT (05-06)
Study material for UW ZOO 3115, Exam 3
49
Physiology
Undergraduate 3
05/06/2015

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Cards

Term
(05-06) In the mouth, what begins carbohydrate digestion? What are the end products?
Definition
Amylase in the saliva breaks starch and glycogen into maltose or limit dextrins
Term
(05-06) In the stomach, what happens to amylase? What does this mean for carbohydrate digestion?
Definition
Amylase is denatured, leading to no further carbohydrate digestion
Term
(05-06) In the duodenum, what happens to carbohydrates?
Definition
Pancreatic amylase breaks down extra starch and glycogen into maltose and limit dextrins.
Term
(05-06) Can maltose be absorbed?
Definition
No
Term
(05-06) What finally breaks down maltose into absorbably molecules?
Definition
Brush border enzymes – specifically, maltase.
Term
(05-06) What are the brush border enzymes?
Definition
Sucrase, lactase, maltase, isomaltase.
Term
(05-06) What breaks down limit dextrins?
Definition
Isomaltase
Term
(05-06) How do glucose and galactose enter a cell? Why does this work?
Definition
A secondary active transport that moves two sodium for every one sugar. The sodium-potassium pump is constantly pumping sodium out of the cell, allowing the secondary active transport to move sodium along its concentration gradient.
Term
(05-06) How is fructose moved across the brush border into cells?
Definition
Facilitated transport
Term
(05-06) How do glucose and galactose exit a cell into the bloodstream?
Definition
Glut2 (carrier-mediated exit)
Term
(05-06) Glucose vs. fructose: Which requires ATP to move into and out of a cell?
Definition
Glucose
Term
(05-06) How does fructose exit a cell?
Definition
Facilitated transport through Glut4
Term
(05-06) In lactose intolerance, what enzyme is missing? Where is this enzyme normally found?
Definition
Lactase; brush-border enzyme
Term
(05-06) What is secreted in the stomach to encourage protein digestion? What is secreting it?
Definition
Pepsinogen; chief cells
Term
(05-06) On exposure to stomach acid, what happens to pepsinogen? What happens next?
Definition
A semi-active form of pepsinogen. This can then autocatalysis and remove 44 amino acids to become pepsin.
Term
(05-06) Why doesn’t pepsin eat your duodenum?
Definition
Pepsin is deactivated in alkaline conditions.
Term
(05-06) Are there proteases in the mouth?
Definition
No
Term
(05-06) What organ is the main area of protein digestion?
Definition
Pancreas
Term
(05-06) What are the pancreatic zymogen endopeptidases?
Definition
Trypsin and chymotrypsin
Term
(05-06) What are the pancreatic zymogen exopeptidases?
Definition
Carboxypeptidase and aminopeptidase
Term
(05-06) What are the limits to endopeptidases?
Definition
They are limited to certain amino acid internal bonds.
Term
(05-06) What is the function of exopeptidases?
Definition
They can cleave end bonds and finish digestion of proteins
Term
(05-06) What are polypeptides broken down into in the pancreas?
Definition
Amino acids and short peptidases
Term
(05-06) What activates trypsinogen?
Definition
Enterokinase to create trypsin
Term
(05-06) What does trypsin do?
Definition
It activates chrymotrypsin and carboxypeptidase.
Term
(05-06) What do fats begin as when eaten? What are they converted to?
Definition
Triglycerides, phospholipids, cholesterol are converted to fattyacids and monoglycerides
Term
(05-06) Define emulsification.
Definition
The combination of two immiscible liquids (oil and water – mayonaise!)
Term
(05-06) In the mouth, what begins lipid digestion?
Definition
Lipases beginthe process of breaking down fats
Term
(05-06) In the stomach, what enzyme works on lipids?
Definition
Lipases
Term
(05-06) Where are bile salts made?
Definition
The liver
Term
(05-06) Where do bile salts begin to work on lipids?
Definition
Duodenum
Term
(05-06) Are bile salts nonpolar, polar, or amphipathic? Why?
Definition
Amphipathic; the polar and nonpolar bits assist in the mixing of lipid and water
Term
(05-06) Emulsified fat can be acted on by _____ in the presence of _____.
Definition
Pancreated lipase and colipase
Term
(05-06) Why is colipase important?
Definition
Bile salts repel lipase unless colipase is present.
Term
(05-06) What does lipase break triglycerides into?
Definition
A monoglyceride and two fatty acids
Term
(05-06) How do we get lipids into the bloodstream?
Definition
Lipids diffuse into enterocytes and enter right into the endoplasmic reticulum. Next, triglycerides move to the Golgi apparatus to be packed into chylomiccrons. The chylomicrons are then spit out into interstitial fluid, where they move into lacteals of the lymphatic system and to the blood.
Term
(05-06) What’s important to remember when wondering how a lipid passes through a cell?
Definition
The membrane of cells is made out of lipids, so the lipid wanting to pass can just diffuse right across
Term
(05-06) Define chylomicrons
Definition
Lipids and proteins bound together – lipoproteins
Term
(05-06) Why do chylomicrons enter the lacteals instead of right into the bloodstream?
Definition
These molecules are too big to go straight into the bloodstream.
Term
(05-06) How are fat-soluble vitamins absorbed?
Definition
With lipids
Term
(05-06) How must B12 move into the blood?
Definition
B12 must bind to intrinsic factor (pernicious anemia is the malfunction disease)
Term
(05-06) Define enteric nervous system.
Definition
The gut’s “brain” that allows it to detect and respond to stimuli locally, without CAN input
Term
(05-06) What are the two main parts of the ENS?
Definition
Submucosal (secretion) and myenteric (motility)
Term
(05-06) What type of neurotransmitters does the enteric nervous system use?
Definition
All the normal ones – Ach, dopamine, etc.
Term
(05-06) What are the two pathways of the ENS?
Definition
Short reflex pathway and long reflex pathway
Term
(05-06) What are the three main receptors in the ENS?
Definition
Chemoreceptors, osmoreceptors, and mechanoreceptors
Term
(05-06) What does the short reflex pathway do?
Definition
Activates the ENS, which either stimulates effector cells or the release of hormones.
Term
(05-06) What does the long reflex pathway do?
Definition
Activates the CNS, which effects the ENS via the autonomic nervous system. ENS then either stimulates effector cells or the release of hormones.
Term
(05-06) What’s the overall product of the short reflex and long reflex pathways?
Definition
Increase in endocrine and exocrine secretion and/or increase in GI motility.
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