Lecture 24- Digestive Secretions

Question 1

Enteroendocrine G cells

Answer 1

Produce gastric to stimulate gastric secretion and promote movement of food along GI tract

Question 2

What can stimulate production of HCL? What can stimulate stomach muscle contraction?

Answer 2

Histamine can stimulate parietal cells to produce HCL
Serotonin an stimulate stomach muscle contraction

Question 3

Gherlin

Answer 3

Hunger hormone

Released by stomach mucosa, highest levels just before meal, stimulates hunger, affects metabolism, muscle and bone maintenance and brain reward pathways

Question 4

Three phases of gastric secretion

Answer 4

1. Cephalic phase- conditioned reflex triggers by aroma, taste, sight or thought
2. Gastric phase- lasts 3-4 hours, provides 2/3 of gastric juices released, triggered by stretch and chemical stimuli
3. Intestinal phase- begins with brief stimulation of gastric secretions followed by inhibition when intestines become too acidic or stretched

Question 5

When does gastric secretion occur?

Answer 5

When HCL is formed by parietal cells

Protons (H+) secreted into stomach lumen by proton pumps as bicarbonate, then pumped into blood via Cl- and HCO3- anti porters

Cl ions pumped out to lumen to join with protons (H+) , forming HCL

Question 6

Gastric accommodation

Answer 6

Allows stomach to expand with food and maintain internal pressure

Question 7

Enteric pacemaker cells

Answer 7

In smooth muscle, establish stomachs electrical rhythm of peristaltic waves

Question 8

Liver

Answer 8

Largest glans in body, only organ that can regenerate

Composed of four lobes, made of plates of liver cells (hepatocytes) that surround centeral vein and meet at portal triads

Question 9

Portal triad

Answer 9

Composed o hepatic artery, hepatic portal vein and bile duct

Question 10

Hepatocytes

Answer 10

Secrete bile, process nutrients from blood, store fat soluble vitamins and play important roles in detoxification

Question 11

Hepatitis

Answer 11

Inflammation of liver, most commonly caused by viral infection

Question 12

Cirrhosis

Answer 12

Occurs when repeated damage causes scar tissue fibrosis to replace hepatocytes, reducing liver functions

Question 13

Non alcohol fatty liver disease

Answer 13

Build up of fat in liver

Question 14

Kwashiorkor

Answer 14

Enlarged fatty liver and eye a caused by protein deficient diet

Question 15

Gallbladder

Answer 15

Stores bile that is not needed immediately for digestion and concentrates it by absorbing water and ions

Question 16

Pancreas

Answer 16

Secretes pancreatic juice, containing enzymes and bicarbonate into small intestine

Question 17

How is bile and pancreatic juices delivered to intestine?

Answer 17

The bile duct and pancreatic duct join and duodenal wall