Gastrointestinal Absorption and Ruminant GI Physiology

These flashcards cover key concepts related to gastrointestinal absorption and digestion for better understanding and exam preparation.

Sucrose

The most common plant sugar, a disaccharide composed of glucose and fructose.

Alpha-amylase

An enzyme secreted by the pancreas that breaks down starch into maltose and maltotriose.

Chylomicrons

Lipoproteins that surround triglyceride molecules, facilitating the transport of lipids through the lymphatic system.

Aquaporin channels

Protein channels that allow water to move across cell membranes following osmotic gradients.

Basolateral Membrane

The membrane of a cell that faces the bloodstream, involved in the transport of nutrients like hexoses and pentoses.

Micelles

Structures formed by bile salts surrounding fatty acids and monoglycerides, facilitating their absorption.

Triglycerides

Fats composed of glycerol and three fatty acids, which are the main form of fat storage in the body.

Lacteal vessels

Lymphatic vessels in the intestines that transport chylomicrons away from the gastrointestinal tract into the lymphatic system.

Insulin-independent transporters

Transport means like SGLT-1, GLUT-2, and GLUT-5 that do not require insulin to function.

VLDL

Very Low-Density Lipoproteins, which transport triglycerides from the liver to peripheral tissues.

Hydrostatic pressure

Pressure exerted by fluids within vessels, important in the absorption of water.

Osmolarity

A measure of solute concentration; a higher osmolarity draws water across membranes.

Hydrophilic and hydrophobic ends

Refers to the dual properties of lipoproteins that enable them to interact with both water and lipids.

Tight junctions

Connections between adjacent cells that control the flow of substances through the spaces between those cells.

Osmolarity change due to starch in duodenum activates

vagal parasympathetic stimulation of pancreatic secretion

Digestion starts in mouth with

salivary lipase breaking it down to fatty acids, monoglycerides, and diglycerides

What must bind to pancreatic lipase before it is fully active?

colipase

Bile salts surround

freed fatty acids, monoglycerides, cholesterol, and fat-soluble vitamins to form small micelles

When released from enterocyte, main lipoprotein on surface is

apoplioprotein B48

Liver uses remaining triglycerides for

energy and can store vitamins A, D, and E that were in chylomicron

VLDL can deliver triglycerides to

peripheral tissues

2 forces needed to move water

osmotic pressure and hydrostatic pressure

Tight junctions offer more resistance to flow than

fenestrated endothelial basement membrane

Countercurrent movement of solute from vein to arteriole in lamina propria of villus helps

with water absorption