AP+Digestive+System+HW

1. Describe in you words the processes that occur in the digestive system (ingestion, digestion, movement, absorption, elimination) Ingestion is when the mouth chews the food. Once the food is chewed and swallowed it goes through a passage way called a pharynx. The esophagus then pushes the food to the stomach and then the next process of digestive process begins. Digestion is mechanical or chemical. Mechanical digestion is when the food is broken down into smaller pieces for our cells to absorb. But at this stage the food pieces are not small enough for the cells to take in. In Chemical digestion it begins in the mouth and is not completed until it reaches the small intestine. Movement of the GI tract moves along the digestive tract and is very important for the body to preform its other functions, such as food most be passed from organ to organ. Absorption is when the nutrients go into the cells that are lining the GI tract. Elimination is when the food has gone through all of the organs and the food that cant be digested needs to be eliminated from the body through the anus.
 * Chapter 8 Digestive System**
 * 8.1 Overview of Digestion**

1. Describe the MECHANICAL and CHEMICAL digestion that occurs in the mouth. Mechanical digestion is when the mouth chews the food into smaller pieces. Chemical digestion is when the stomach breaks down the food that is in the stomach.
 * 8.2 First Part of the Digestive Tract**

2. What is heartburn? Is due to acid reflex when the stomachs contents go into the esophagus.

3. What is a dental cavity? (What causes it?) Is when bacteria in the mouth metabolize sugar and give off acids. It is caused by sweets and the lack of brushing and flossing your teeth.

1. What are the functions of the stomach and how is the wall of the stomach modified to perform these functions? The functions of the stomach stores food, initiates the digestion of protein, and controls the movement of chyme into the small intestine. It doesn't absorb nutrients but ti does absorb alcohol because it is fat soluble. The wall of the stomach is mortified as four different layers. The muscularis contains three layers of smooth muscle. The circular and longitudinal layers also contain a layer of smooth muscle. The oblique layer helps the stomach stretch and mechanically break down the food.
 * 8.3 Stomach and Small Intestine**

2. What are the functions of the small intestine and how is the wall of the small intestine modified to perform these functions? The functions of the small intestine is when the food is broken down into smaller pieces. The enzymes are secreted by the pancreas and enters a duct at the duodenum. The duct then brings the bile from the liver and gallbladder into the duodenum. The bile emulsification causes fat droplets to disperse in to water. The fat is then mechanically broken down to fat droplets by the bile and is hydrolyzed to glycerol and fatty acids by lipase that is present in pancreatic juice. The pancreatic amylase begins and an intestinal enzyme finishes the digestion of carbohydrates to glucose.

3. What is lactose intolerance? What causes it and what are the symptoms? is when the body cant break down then lactose in milk or other diary products. Indigestible lactose causes fluid retention in the small intestine.

1. What are the three main accessory organs and how do they assist the digestive process? Pancreas: is a endocrine gland that secrets the hormone insulin into the blood. When the blood glucose level rises rapidly it produces an overload of insulin. liver: largest and a important metabolic gland in the body. It has 100,000 lobules that serve as a structural and functional units. It receives blood via the hepatic portal ten from the capillary bed of the GI tract and filters the blood in the capillaries of the lobules. The liver acts like a sewage because ti removes poisonous substances from the blood. It also removes iron and vitamins A,D,E,K and B from the blood and stores them. it combines amino groups with carbon dioxide to form urea. Finally it makes plasma protein ad helps regulate the quantity of cholesterol in the blood.
 * 8.4 Three accessory organs.**

2. What is a gallstone? Is when a liquid is stored in the gallbladder hardens into pieces of stone like material

3. What is hepatitis? inflammation of the liver

4. What is cirrhosis? is a chronic disease of the liver. The organs become fatty and then the liver tissue is replaced by inactive fibrous scard tissue. It is seen in alcoholics due to malnutrition and the liver is forced to break down. It has also been seen in obese and over weight people because their diet is high in fatty foods.

1. What is the function of the large intestine? It absorbs water and does not produce any digestive enzymes and doesnt absorb any nutrients. It does absorb vitamins produced by bacteria. the bacteria breaks down the indigestible material and produce B complex vitamins and most of vitamin K. It forms feces, which are 3/4 water and 1/4 soild. Defecation rids the body of feces. Peristalis occurs whent eh feces are forced into the rectum. feces collect in the rectum until it is time to defecate.
 * 8.5 Large Intestine**

2. Briefly describe the disorders of the large intestine: diarrhea, constipation, diverticulosis, hemorrhoids, IBS, IBD, polyps, cancer. Diarrhea: is an infection if the lower intestinal tract and nervous stimulation. It can be caused by food poisoning by eating contaminated food, and then the intestinal walls become irritated and peristalsis increases.

Constipation: the feces are hard and dry. An intake of water and fiber can help regulate defcation.

Diverticulosis: is the occurrence of little pouches of mucosa that have pushed out through weak spots in the muscularies.

hemorrhoids: is chronic constipation when the englarged and inflammed blood vessels at the anus.

IBS: irritable bowl syndrome is when your mucles contract each other powerfully without its normal coordination. and example is cramps, gas, constipation

IBD: inflammatory bowl disease Ulcerative colitis affects the large intestine and rectum. Crohns disease is when ulcers can spread deeper and can casue diarrhea, recal bleeding, and abdominal cramps and urgency.

Polyps: is small growths arising from the epithelial lining

Cancer: dietary fat causes increase in bile secretion. Intestinal bacteria convert bile salts to substances that promote development of cancer. Regular elmination reduces the time that the colon wall is exposed ti any cancer promotes agents in feces.