Digestive System

Question 1

Digestive system order (from food intake to excretion)

Answer 1

Oral cavity, pharynx, esophagus, stomach, small intestine, large intestine, rectum

Question 2

Enteric nervous system

Answer 2

collection of 100 million neurons that govern function of gastrointestinal system. Triggers peristalsis.

Question 3

Hormones that drive thirst, hunger, and satiety

Answer 3

1. Thirst: ADH, Aldosterone
2. Hunger: Glucagon, Ghrelin
3. Satiety: Leptin, Cholecystokinin

Question 4

Ptyalin

Answer 4

Salivary amylase. Breaks sugar into smaller sugars (maltose and dextrins)

Question 5

Esophagus: what muscles comprise it

Answer 5

1. Top: somatic (voluntary) control, mostly skeletal

2. Bottom: autonomic (involuntary) control, mostly smooth

Question 6

Swallowing: where initiated and where end

Answer 6

1. Initiated at upperesophageal sphincter (at oropharynx)

2. End with lower esophageal sphincter (cardiac sphincter)

Question 7

Emesis

Answer 7

Vomiting

Question 8

Gastric gland: 3 cells and their roles

Answer 8

1. Mucous cells: secrete mucus, bicarbonate. Protect muscular wall from acidic conditions
2. Chief cells: produce pepsinogen. Pepsin digests peptides near aromatic amino acids
3. Parietal cells: produce H+ that cleave pepsinogen to pepsin, produce intrinsic factor. Intrinsic factor helps absorb vitamin B12

Question 9

Gastric gland

Answer 9

Gland in fundus and body of stomach that respond to signals from vagus nerve (parasympathetic)

Question 10

Pylori glands

Answer 10

contain G-cells that secrete gastrin

Question 11

Gastrin

Answer 11

Induce parietal cells to secrete more HCl, signal stomach to mix contents

Question 12

Small intestine order

Answer 12

Duodenum, Jejunum, Ileum

Question 13

Enzymes and hormones in duodenum

Answer 13

Enzymes: brush-border enzymes, enteropeptidase
Hormones: secretin, Cholecystokinin

Question 14

Brush-border enzymes

Answer 14

In luminal surface.

1. Disaccharidases (maltase, isomaltase, lactase, sucrase)
2. Aminopeptidase: removes N-terminal AA. Di- and tripeptides can be absorbed back into the intestinal wall

Question 15

Enteropeptidase

Answer 15

Activation of other digestive enzymes from accessory organs.

1. Secretes hormones (secretin, CCK)
2. Critical for trypsinogen activation
3. Can activates procarboxypeptidases A and B

Question 16

Secretin

Answer 16

peptide hormone, causes pancreatic enzymes to be released into duodenum

1. Regulates pH of digestive tract by reducing HCl production (by parietal cells)
2. Increases bicarbonate secretion from pancreas

Enterogastrone - hormone that slows motility through digestive tract

Question 17

Cholecystokinin (CCK)

Answer 17

Stimulates bile & pancreatic juice secretion. Secreted with entry of chyme

Question 18

Bile

Answer 18

Fluid of bile salts, cholesterol, and pigments.

Question 19

Bile salts

Answer 19

Cholesterol derivatives that make lipids form micelles, easier for pancreatic lipase for digestion

Question 20

Pancreatic juice

Answer 20

complex mixture of several enzymes in bicarbonate-rich alkaline solution. Neutralizes acidic chyme, provides good environment that digests nutrients.

Question 21

Accessory organs of digestion

Answer 21

1. Pancreas
2. Liver
3. Gallbladder

Question 22

Pancreas role in digestion

Answer 22

1. Release insulin, glucagon, somatostatin
2. Made of acinar cells, producing pancreatic juices
3. Secrete products into ducts that enter duodenum

Question 23

Liver functions

Answer 23

1. Processing nutrients (glycogenesis and glycogenolysis)
2. Production of urea from ammonia
3. Detoxification of chemicals
4. Production of bile
5. Synthesis of albumin and clotting factors

Question 24

Albumin

Answer 24

Protein that maintains plasma oncotic pressure, carrier for drugs, and hormones

Question 25

Bile ducts

Answer 25

Connect liver w/ gallbladder and small intestine.

1. Bile produced in liver, stored in gallbladder
2. Bile pigment: bilirubin (byproduct of Hg breakdown). Bilirubin travels to liver - conjugated then secreted into bile for excretion
3. Jaundice when liver malfunctions

Question 26

Gallbladder role in digestion

Answer 26

Stores & concentrates bile.

1. Contracts and pushes bile out to biliary tree upon CCK
2. Common site of cholesterol or bilirubin stone formation

Question 27

Lacteal

Answer 27

lymphatic channel that takes up fats for transport into lymphatic system

Question 28

What is absorbed via 2ndary active transport and facilitated diffusion

Answer 28

Simple sugars (glucose, fructose, galactose), amino acids. Small fatty acids.

Question 29

Packaging larger fatty acids

Answer 29

Reformed into triglycerides, then packaged into chylomicrons. Enter circulation via lacteals.