HP Final Exam Part 1

What are the major organs in the digestive system that food goes through?

Mouth, esophagus, stomach, small intestine, and large intestine

What are the organs that food does not go through?

Salivary glands, pancreas, liver, and gallbladder

Peristalsis is

progressive waves of contraction that move from one section of the GI tract to the next. Muscles contract behind the bolus

Segmental contractions

responsible for mixing food

Peristalitic contractions

responsible for forward movement

What are the components in the reflex arc of the vomiting reflex?

Efferent signals from vomiting center initiates a wave of reverse peristalsis that begins in the small intestine and moves upward.

What are their major functions of digestive organs?

Secretion, digestion, absorption, and mobility

What is the metabolic pathway of alcohol in the body?

Alcohol dehydrogenase oxidizes alcohol into acetaldehyde. ALDH2 then converts acetaldehyde into acetate

Why is the deficiency of ALDH2 related to cancer risk?

Deficiency causes a buildup of acetaldehyde in the salvia, which increases the risk of esophageal cancer.

What are the three leading modifiable cancer risk factors?

smoking, obesity, and alcohol

What are heartburn and its cause?

If the lower esophageal sphincter relaxes abnormally or weakens, stomach acid may back up into your esophagus, called acid reflux. Frequent acid reflux can irritate and inflame the lining of your esophagus, causing heartburn

What is the pH change through the GI tract? What cells are responsible for acid secretion?

pH of 2 in gastric juice and pH 7 at the cell surface. Parietal cells and pepsin

Parietal cells secretes

HCl

Chief cells secrete

inactive pepsinogen, which is activated to pepsin when mixed with HCl acid

Mucous cells secretes

mucus and bicarbonate as barriers to protect the stomach from HCl

Pepsin is a

protease that cleaves proteins into smaller peptides

What are the protein-digesting enzymes in the stomach and small intestine, and produced bywhich cells/organs?

Trypsin and chymotrypsin, which produce more enzymes

Why does heavy drinking cause fatty liver?

alcohol shifts liver metabolism away from burning toward fat production. This leads to accumulation of triglycerides in liver cells

What is the role of Na+ in the absorption of glucose and amino acids?

acting as a co-transporter, provides the energy needed to move glucose and amino acids into the cell

Where is bile made and stored?

liver and gallbladder

What are the functions of bacteria in the colon?

digesting cellulose, formation of vitamin K, producing fatty acid and causing the odor of the feces

What is the cause of lactose intolerance?

the small intestine does not make enough of an enzyme called lactase to digest lactose and causes bloating, cramps, and diarrhea

How is fat digested and absorbed?

Pancreatic lipase breaks the fatty acids off the 1st and 3rd carbons of glycerol, producing 2 free fatty acids and 1 monoglyceride. These products diffuse into intestinal epithelial cells, where they are rebuilt into triglycerides and then packaged and released by exocytosis into lacteals.

What are the two general effects of local hormonal control in the intestine?

GI hormones and appetite control

Where is the control center of satiety?

Hypothalamus

What is the mechanism of GLP-1 agonist being used as weight loss drugs?

tirzepatide (zepbound)

Which organ secrete the following hormone and their effect on appetite: ghrelin

stomach (when empty) and increases

Which organ secrete the following hormone and their effect on appetite: leptin

adipose tissue and decreases

Which organ secrete the following hormone and their effect on appetite: CCK and PYY

Small intestine (when full) and decreases

Which organ secrete the following hormone and their effect on appetite: GLP-1

Intestine and decreases

Which organ secrete the following hormone and their effect on appetite: Asprosin

Adipose tissue (when fasting) and increases

Where are the places of digestion of carbohydrate and what is it digested to before absorption?

Mouth, stomach and small Intestine. Monosaccharides

Where are the places of digestion of protein, and what is it digested to before absorption?

Stomach and Small Intestine. Amino acids

Where are the places of digestion of nucleic acid and what is it digested to before absorption?

Small intestine. Sugars, nitrogenous bases, and phosphates

Where is the place of digestion of fat, and what is it digested to before absorption?

Small intestine. Fatty acids and monoglycerides

What is the function of bile salt?

emulsify fats, breaking them into smaller droplets to aid in digestion and absorption