Purdue Anatomy 202/204 Lecture 21

Front 1

What two forms of movement are important for digestion?

Back 1

Mixing and propulsive.

Front 2

What are the four major activities of the digestive system?

Back 2

Motility, secretion, digestion, absorption.

Front 3

What are the various types of secretions carried out in the digestive system?

Back 3

Enzymes, mucus, inorganic salts, organic substances (like bile salts), excreted substances like cholesterol and bilirubin

Front 4

Why can't most proteins, fats, and carbohydrates immediately be absorbed by the digestive tract?

Back 4

They are too big, therefore they need to be further digested into smaller molecules first.

Front 5

What is the process of protein digestion?

Back 5

1. Begins in the stomach with pepsin.
2. Continues in small intestine with pancreatic trypsin, chmyotrypsin, carboxypeptidases A & B.
3. Next peptidases of brush border.
4. Finally, intracellular peptidases.

Front 6

What is the process of carbohydrate digestion?

Back 6

1. Begins in the mouth with salivary alpha amylase.
2. Continues in the small intestine with pancreatic salivary alpha amylase.
3. Finishes with enzymes in brush border

Front 7

What is the process of triglyceride digestion?

Back 7

1.Done primarily by pancreatic lipase.
2. Intracellular reconstruction into chylomicrons.

Front 8

How are carbohydrates absorbed?

Back 8

Must be absorbed as monosaccharides (ie. glucose) into the venules of intestinal villi. These villi then will run into the hepatic portal vein (remember hepatic portal artery supplies liver with oxygenated blood).

Front 9

How are proteins absorbed?

Back 9

Absorbed as amino acids, dipeptides, and tripeptides. They are all split into amino acids and pass into venues of intestinal villi. These villi will run into the hepatic portal vein.

Front 10

How are fats absorbed?

Back 10

Each triglyceride is broken into a monoglyceride and two fatty acids in the intestinal lumen. They are emulsified by a bile salt and then cross the brush border. They are reassembled into triglycerides which then complex into chylomicrons. Chylomicrons are too large to pass into venules so instead they pass into lacteals.

Front 11

What is the neural control of the digestive system?

Back 11

Sympathetic inhibit and parasympathetic stimulates action.

Front 12

What are the sympathetic actions on digestive system?

Back 12

Fibers are postganglionic and therefore adrenergic. These inhibit.

Front 13

What are the parasympathetic actions on digestive system?

Back 13

Mainly pre ganglion fibers which are cholinergic. Postganglionic neurons located within walls of the digestive tract which makes up enteric nervous system.

Front 14

What is a plexus?

Back 14

A network of intersecting nerves.

Front 15

What are the hormones of the digestive tract?

Back 15

1. Gastrin
2. Cholecystokinin
3. Secretin
4. Gastric inhibitory peptide
5. Somatostatin

Front 16

Describe gastrin and effects.

Back 16

From G-cells in the stomach which increase acid, pepsin, and gastric motility.

Front 17

Describe cholecystokin and effects

Back 17

From duodenum epithelial cells, causes gallbladder contractions and increase in pancreatic enzyme secretion.

Front 18

Describe secretin and its effects.

Back 18

From duodenum epithelial cells, causes bile duct and pancreas to release bicarbonate and slows gastric motility.

Front 19

Describe gastric inhibitory peptide and its actions.

Back 19

From the small intestine, it slows gastric secretions and motility.

Front 20

What stimulates release of gastrin?

Back 20

Peptides and amino acids (from protein digestion) and stomach distention.

Front 21

What stimulates release of cholecystokinin?

Back 21

Amino acids, peptides, fatty acids (digestive products).

Front 22

What stimulates the release of secretin?

Back 22

Acid from the stomach.

Front 23

What stimulates the release of gastric inhibitory peptide?

Back 23

Glucose and fat.

Front 24

What are the main products from carbohydrate digestion from salivary alpha amylase?

Back 24

Maltose (disaccharide) and oligosaccharides.

Front 25

What is receptive relaxation?

Back 25

The stomach relaxing to accomodate more food without increasing pressure appreciably.

Front 26

What prevents solid masses of food from entering the duodenum?

Back 26

The pyloric sphincter.

Front 27

What are the three influences on gastric secretions?

Back 27

1. Cephalic (thinking about food, or being afraid, etc).
2. Gastric-food and distention increases secretions and motility
3. Intestinal-Products reaching the duodenum inhibit stomach secretions and motility.

Front 28

What is the enterogastric reflex?

Back 28

A neural reflex that is initiated by products of digestion and acid which decreases motility.

Front 29

What two types of contractions are present in muscles of the digestive tract?

Back 29

1. Segmentation which acts to mix food and digestive juices.
2. Peristaltic which acts to move food through the tract.

Front 30

What controls flow from small intestine into large intestine?

Back 30

Ileocaecal valve.

Front 31

What types of contractions are present in the large intestine?

Back 31

Segmentation to mix, anti-peristalic and peristaltic for movement, and migrating for strip an area of it's contents.

Front 32

What is endotoxic shock?

Back 32

When bacteria and toxins invade the body they can cause serious infection and shock.

Front 33

What is one way the endotoxic shock can occur?

Back 33

After extreme hemorrhage, splanchnic circulation can be greatly reduced leading to ischemia. This increases permeability which allows bacteria in. With a blood transfusion, circulation is restored which can wash bacteria into general circulation. The bacteria then cause shock by massive nitric oxide induction into the system which is a vasodilator. This leads to a huge decrease in blood pressure.

Front 34

What is the neural control of defecation?

Back 34

Sympathetic is excitatory. Parasympathetic is inhibitory.

Front 35

What nerve supplies the anal sphincter?

Back 35

Pudendal nerve.