Chemical Digestion

How many hours does it take for food to pass through the large intestine?

12-24

How many hours does it take for the stomach to empty?

4

Why is a highly acidic environment necessary in the stomach?

A highly acidic environment is necessary in the stomach because it activates pepsinogen to pepsin which is the active protein digesting enzyme

Tooth structure includes:

A thin periodontal ligament that holds the tooth in place

As the food in the stomach is repeatedly squeezed and mixed with gastric juice, it is converted into a semifluid consistency called _?_

Chyme

Both constipation and diarrhea involve an imbalance of water absorption. Explain how each condition occurs.

Diarrhea is when food residue rushes through the large intestine before it has enough time to absorb the water. Since fluids and ions are lost if diarrhea is prolonged it could lead to dehydration and if severe enough can be fatal. Constipation is when the food residue stays too long in the large intestine and too much water is absorbed.

Which of the following terms indicates the breakdown of food?

Digestion

pancreas

Ducts a variety of enzymes in an alkaline fluid into the duodenum

Many people have 2 - 3 bowel movements each day. Re-read the paragraph on the top of page 277 and explain why this occurs.

People have 2-3 bowel movements each day because of the mass movements that occur over large areas of the colon. Mass movements are long and slow but powerful contractile waves that push contents towards the rectum. Having fiber in your diet increases the strength of the contractions in the colon.

intestinal glands

Produce an enzyme-poor "juice" containing mucus; found in the submucosa of the small intestine.

gastric (stomach) glands

Produce hydrochloric acid, intrinsic factor and pepsin.

salivary glands

Secretion includes amylase, which begins starch digestion in the mouth.

The primary function of the small intestine is __?__.

absorption of nutrients

Name 2 substances that can be absorbed by the stomach

aspirin & alcohol

While the large intestine produces no enzymes, there are numerous "resident" __?__ present to metabolize any remaining nutrients.

bacteria

The combination of _?__ (produced by the liver) and lipase causes fats to be broken down.

bile

stomach

breakdown of food & begin protein digestion

mouth

breakdown of food & begin starch digestion

Which enzymes are produced by the cells of the small intestine?

brush border enzymes

The pressure exerted by food on the ______ valve cause it to open so that food can enter the stomach

cardioesophageal

sections of small intestine

duodenum, jejunum, ileum

small intestine

enzymatic breakdown of all types of organic molecules & absorption

The chief cells produce hydrochloric acid, which activates stomach enzymes.

false

What medical condition results from the gastric juices backing up into the esophagus?

heartburn

The chemical found within the stomach that is necessary to activate pepsinogen to pepsin is __?__.

hydrochloric acid

The anterior chisel-shaped teeth that are adapted for cutting are called __?__.

incisors

Which of the following is NOT characteristic of the large intestine?

it is the main site of digestion

Which one of the following represents the correct order through which food passes in the alimentary canal?

mouth, pharynx, esophagus, stomach, small intestine, large intestine

Which of the following lists the layers of the digestive tract from the lumen out in the correct order?

mucosa, submucosa, muscularis, serosa

Name one chemical essential for stopping a heart attack that can be absorbed in the mouth

nitroglycerine

What gland supplies the majority of the enzymes found in the small intestine?

pancreas

The digestive juice product contain enzymes capable of digesting all three major foodstuff categories is

pancreatic

Mumps is a common childhood disease that includes nflammation of the __?__.

parotid glands

What do you call the protein digesting enzymes found in the stomach?

pepsin

The tooth is anchored to alveolar bone by the

periodontal ligament

Liver

produces bile, which is transported into the duodenum via the bile duct

esophagus

propulsion of food

The sphincter between the stomach and duodenum is the _?_

pyloric sphincter

large intestine

reabsorption of water

Enzyme that begins the digestion of starch

salivary amylase

If an incision has to be made in the small intestine to remove an obstruction, the first layer of tissue to be cut is the __?__.

serosa

Most of the GI tract is composed of a __?__ epithelium, while the oral cavity through the esophagus and lower anal canal are composed of a __?__ epithelium.

simple columnar; nonkeratinized stratified squamous

Which food stuff is digested in the mouth?

starch

The portion of the large intestine closest to the liver is the

transverse colon

Food within the lumen of the alimentary canal is considered to be outside the body.

true

This structure closes off the nasopharynx when you swallow.

uvula