Absorption In Digestion Flashcards
How is the sugar fructose transported?
It moves by facilitated diffusion down its concentration gradient from the lumen of the small intestine. It is then absorbed by the villis. Aka passive transport.
How are nutrients such as amino acids, small peptides, vitamins and most glucose molecules transported?
They are pumped against concentration gradients into the epithelial cells of the villus. Aka active transport.
How do many nutrients leave the villi of the small intestine?
Through the blood stream which goes to the liver for processing before entering other parts of the body.
How is water transported?
There is no mechanism for active transport of water instead water is reabsorbed by osmosis when sodium and other ions are pumped out of the lumen of the intestine.
What is the cecum?
A pouch next to the appendix that is important for fermenting ingested material especially in animals that eat large amounts.
When the blood glucose level rises above the normal range what happens?
Insulin is released and triggers the uptake of glucose into the body cells
When the blood glucose level is low what happens?
Glucagon is released which promotes the release of glucose into the blood from energy stores such as liver glycogen.
What is the key site of insulin and glucagon action?
The liver
Where are glucagon and insulin produced?
The pancreas
What is diabetes mellitus?
A disorder caused by a deficiency of insulin or a decreased response to insulin in target tissues. Therefore cells are unable to take up enough glucose to meet metabolic needs and instead fat becomes the main substrate for cellular respiration.
