digestive system

Question 1

describe the digestive system

Answer 1

• aka the gastrointestinal system

- responsible for changing food & nutrients into waste

Question 2

digestive enzymes

Answer 2

chemicals that break down food and nutrients into smaller forms so they can be absorbed by the body

Question 3

list the 4 functions of the digestive system

Answer 3

1. ingestion
2. digestion
3. absorption
4. elimination

Question 4

describe ingestion

Answer 4

the process of taking in food, chewing, and dissolving it in the mouth

-process forms a soft ball of food called a bolus in preparation for digestion

Question 5

describe digestion

Answer 5

mechanical digestion: mechanical breakdown of food by the teeth or stomach muscles

chemical digestion: The brain sends messages to the gastric glands in the stomach wall stimulating them to secrete gastric juices such as Pepsin

Question 6

describe absorption

Answer 6

glucose & amino acids:

• absorbed by active transport after combining with a carrier molecule
• enter the blood through capillaries in the villi and transported to the liver

fatty acids & monoglycerides:
-absorbed into the epithelial cells of the intestinal lining where they are reassembled into triglycerides & pass into the villi

Question 7

describe elimination

Answer 7

the removal of indigestible foods and other waste materials through fecal matter from the body

*defecation is stimulated peristalsis

Question 8

peristalsis

Answer 8

a series of wave-like muscle contractions that allows food to move through the digestive system

Question 9

name the 4 primary organs of the digestive system

Answer 9

1. Mouth
2. Stomach
3. Small Intestine
4. Large Intestine

Question 10

mouth (mastication and deglution)

Answer 10

Food enters the system at the mouth and is chewed by the teeth to break it up into smaller amounts so that it can be swallowed and digested.

• The salivary glands produce saliva which contains enzymes that start to break down the food.
• The food then is swallowed and moves down into the esophagus (throat).
• The epiglottis is a small flap of tissue that covers the trachea (windpipe) to prevent food from entering and going into the lungs

Question 11

stomach (gastric digestion)

Answer 11

located in the left upper quadrant of the abdominal cavity.

• Food reservoir and the first major site of digestion.
• Food leaves the esophagus and enters the stomach via the cardioesophagal sphincter
• Digestive glands in the stomach produce pepsin and hydrochloric acid which turn the food into a semi-liquid called chyme.
• Food leaves the stomach and enters into the small intestine via the pyloric sphincter

Question 12

small intestine

Answer 12

a coiled, 20ft long tube consisting of 3 parts:

1. duodenum
2. jejunum
3. ileum

• Villi, which line the intestines and contain capillaries, absorb the nutrients
• about 90% of absorption of nutrients occurs here
• The walls of the intestine contract and relax to create segmental waves that push the food through the intestines (peristalsis)

Question 13

accessory organs of digestion

Answer 13

1. liver
2. gallbladder
3. pancreas

Question 14

liver

Answer 14

• lies in the upper right side of the abdomen just under the diaphragm
• one of the most complex visceral organs in the body

functions of the liver:
• Secretes bile, which is important in the digestion of fat.
• Converts excess glucose to glycogen and stores it; then, when glucose is needed, it releases glucose into the blood.
• Stores iron and certain vitamins.
• Converts excess amino acids to fatty acids and urea.
• Cholesterol is synthesized and stored in the liver.
• Vitamin D is synthesized and stored in the liver.
• Performs many important functions in the metabolism of proteins, fats, and carbohydrates.
• Manufactures many of the plasma proteins found in the blood (clotting factor).
• Detoxifies many drugs and poisons that enter the body.
• Breaks down bacteria and filters worn-out red blood cells.

Question 15

gallbladder

Answer 15

a pear-shaped organ of the digestive system that is situated under the liver and anterior to the duodenum

-stores and concentrates bile ready for transport to the duodenum via cystic and bile ducts

Question 16

pancreas

Answer 16

a large elongated gland the lies in the abdomen below the stomach with its head nestled in the curve of the duodenum

exocrine function: secretes pancreatic juices that chemically digest proteins, fats and carbs
*secretion of digestive juices is stimulated by the presence of chyme and by hormones

endocrine function: secretion of hormones insulin and glucagon

Question 17

trypsin, amylase, lipase

Answer 17

enzymes secreted by the pancreas

trypsin = breaks down protein 
amylase = breaks down starch/carbs
lipase = breaks down fats

Question 18

anorexia

Answer 18

loss of appetite

Question 19

nausea

Answer 19

an unpleasant sensation often accompanied by pallor, sweating and rapid heart beat

Question 20

vomiting

Answer 20

aka emesis, the sudden and forceful oral expulsion of the contents of the stomach

Question 21

esophageal reflux disease

Answer 21

refers to the backward movement of stomach contents into the esophagus, a condition that causes heartburn

Question 22

gastritis

Answer 22

inflammation of the mucosa of the stomach

a. Acute gastritis is usually caused by local irritants such as bacteria, alcohol, caffeine and aspirin. It may cause vomiting, and possibly bleeding.
b. Chronic gastritis is an ongoing problem usually resulting from alcohol abuse, cigarette smoking, or chronic use of anti-inflammatory medication (NSAIDS).

Question 23

ulcers

Answer 23

Peptic ulcer is a term used to describe ulcerative disorders that occur in the upper digestive tract (stomach and small intestine), the area exposed to acid-pepsin secretions

-causes pain and discomfort described as burning, gnawing or cramp-like and often occurs when the stomach is empty, complications include bleeding and perforation

Question 24

irritable bowel syndrome

Answer 24

a disorder characterized by recurrent intestinal symptoms not explained by structural abnormalities

symptoms: persistent/recurrent abdominal pain, gas, alternating diarrhea and constipation over a period of 3 or more months

Question 25

inflammatory bowel disease

Answer 25

a. Crohn’s Disease: can affect any area of the digestive tract from the mouth to the anus It consists of granulomatous lesions that are surrounded by normal-appearing tissue.
symptoms: are diarrhea, cramping pain, usually in the lower right quadrant, weight loss, fluid and electrolyte disorders and low-grade fever. The intestine may not be able to absorb nutrients and deficiencies may occur. There are often periods when the symptoms decrease and then flare up.
b. Ulcerative Colitis is inflammation of the colon only. The main symptom is diarrhea, which may occur many times a day. Lack of appetite, weakness and fatigue are common. The symptoms may decrease and flare up.

Question 26

appendicitis

Answer 26

condition in which the appendix becomes inflamed, swollen and gangrenous and eventually perforates

*if the appendix is not removed complications can occur which can be life-threatening

Question 27

diarrhea

Answer 27

excessively frequent passage of stools

Question 28

constipation

Answer 28

infrequent passage of stools

Question 29

celiac disease

Answer 29

gluten intolerance

symptoms: diarrhea, bloating, flatulence and abdominal pain. If intake of gluten is continued there may be weakness, muscle wasting and fatigue due
to lack of absorption of nutrients

Question 30

hemorrhoids

Answer 30

swollen, tortuous veins in the rectum or anus, may be internal or external

symptoms: itching and bleeding bright red blood

Question 31

large intestine

Answer 31

aka the bowels, extends from the small intestine, joining at the ileocecal valve, to the anus

-large intestine starts at the right lower quadrant, runs superiorly as the ascending colon, crosses the
abdominal cavity as the transverse colon and then runs inferiorly down the left side of the
abdominal cavity as the descending colon

-Food is stored in the large intestine until it is expelled by defecation

• defecation is controlled by:
  a. internal sphincter (autonomic/involuntary)

b. external sphincter (somatic/voluntary)