Metabolism

Question 1

What four organs play a role in fuel metabolism?

Answer 1

Liver, brain, muscle, adipose

Question 2

How do the four organs communicate?

Answer 2

Communicate via the nervous system, circulating substrates, concentration of hormones

Question 3

How do the organs function as a network?

Answer 3

Provide substrates to another and process compounds from another

Question 4

What are the coordinators of the metabolism?

Answer 4

Primary: 2 peptide hormones (insulin and glucagon)
Supporting: 2 catecholamines (epinephrine and norepinephrine)

Question 5

Function of circulating hormones

Answer 5

1. Coordinate energy storage when food is abundant and available
2. Make stored energy available during “survival crisis”

Question 6

3 purposes of enzymes

Answer 6

1. Storage
2. Use
3. Generation of specific fuels

Question 7

Insulin

Answer 7

1. Water soluble protein hormone
2. Produced in beta cells (in the islets of langerhans) in the pancreas
3. Stored in secretory granules
4. Anabolic effector
5. Promotes production of glycogen, triaglycerols, and protein
6. Held together by disulfide bonds

Question 8

Regulation of insulin secretion

Answer 8

• Beta cell secretion of insulin is coordinated with alpha cell secretion of glucagon
• rate of glucose use by peripheral tissues as a result of insulin secretion is counter balanced by glucagon release and glucose production in the liver

Question 9

Insulin secretion from glucose stimuli

Answer 9

Increase in blood glucose levels coordinates with increase of insulin release and insulin production

Question 10

Negative effectors of insulin

Answer 10

1. Scarcity of dietary fuels (glucose and amino acids)

2. Increase in levels of epinephrine

Question 11

Epinephrine

Answer 11

1. Secreted by adrenal medulla in response to stress, trauma, extreme exercise
2. Directly mobilizes glucose from the liver and fatty acid from adipose tissue
3. Can override the normal glucose stimulated release of insulin