RE: Help with VTCT A & P - Please!!!!!

LOTS of information can be found here

Here's some pointers -

The deposition / breakdown of fat in body -
Fat molecules are a rich source of energy for the body. The first step in digestion of a fat such as butter is to dissolve it into the watery content of the intestinal cavity. The bile acids produced by the liver act as natural detergents to dissolve fat in water and allow the enzymes to break the large fat molecules into smaller molecules, some of which are fatty acids and cholesterol. The bile acids combine with the fatty acids and cholesterol and help these molecules to move into the cells of the mucosa. In these cells the small molecules are formed back into large molecules, most of which pass into vessels (called lymphatics) near the intestine. These small vessels carry the reformed fat to the veins of the chest, and the blood carries the fat to storage depots in different parts of the body.

Lipases break down fat. Along with bile salts, they also help the absorption of the fat-soluble vitamins, such as A, D, E, and K, and essential fatty acids.

The absorption / elimination of water in digestive system -
In the colon (also called the large intestine), the cells are arranged to absorb water from the intestinal contents, so that fecal elimination can occur at a convenient time and in a convenient form.
Water absorbed in the stomach too.
Water mixes with emulsified fats in order that lipase can act on them.
95% of water absorption also occurs in the small intestine.
haustra - puches in the colon which increase surface area for water absorption.
The colon absorbs the remaining water and produces the feces. The process takes about 12 hours. Liquid chyle enters the colon through the ileocecal sphincter, whose pursed lips protrude into the cecum to help prevent backflow of chyme under pressure. This valve relaxes only when peristalsis arrives from the ileum. Muscle movements in the colon consist of: 1) minor peristaltic waves, 2) haustral churning, and 3) mass peristalsis.
Haustral churning is produced by segmentation contractions which serve to mix the contents to enhance absorption. Mass peristalsis consists of large movements which occur at intervals, usually associated with meals. These movements are often initiated by the gastrocolic reflex (or gastroileal or duodenocolic reflexes) which stimulates the colon in response to food entering the stomach. This reflex is especially active after fasting and when the food is hot or cold. It causes mass peristalsis in about 15 minutes which continues for about 30 minutes. These movements cause the chyme to move in several large steps through the colon, stopping at each step to be further concentrated and converted into feces. The chyme turns from a liquid into a slush and then into firm feces. In the process some vitamins such as vitamin K and certain B vitamins are produced and absorbed, along with water and electrolytes

Importance of excretory system in healthy body -
The excretory system removes harmful materials from the body
While urine and feces are both waste material of body processes, they are in completely different categories. Urine is a waste product of the urinary system process while feces are waste products of the digestive system. Feces may contain about one-third bacteria, most of which are harmless, even beneficial while in the gut, but dangerous to others and they may also contain virulent and even deadly pathogens in the form of bacteria, viruses, amoebae, and various parasitic worms. Urine, on the other hand, contains excess water, salt, and protein waste in the form of urea as uric acid, and seldom any pathogens; should a person be in a situation of insufficient water and in danger of overheating due to lack of perspiration, urine may be safely used to dampen clothing to aid cooling. It is futile to attempt to drink it (or salty ocean water), as it requires more water from the body to excrete the salt than is available in the fluid.

Function of large intestine a

RE: Help with VTCT A & P - Please!!!!!

Thank you so so much, I really appreciate this, at least i may be able to get my portfolio finished nw, when have you got your a & p exam, Monday

RE: Help with VTCT A & P - Please!!!!!

Yep, monday [:o]

Good luck!

Sam x