Chapter 17 - Endocrine Function

Question 1

What is a gland?

Answer 1

Organ of secretion

Question 2

What is a exocrine gland?

Answer 2

Glands that secrete substances onto the bodies external surface

Question 3

What is an endocrine gland?

Answer 3

Glands that secrete chemical signals or hormones into the circulatory system.

Question 4

What is a ligand?

Answer 4

The general term for chemical signals

Question 5

Describe the regulation of signal release for both the endocrine system and the nervous system.

Answer 5

Endocrine: Amplitude modulated signals. Amount of hormone determines strength of signal.

Nervous: Frequency modulated signal. Frequency of AP determine strength.

Question 6

Name the 5 types of chemical signals?

Answer 6

Hormones

Autocrine

Paracrine

Pheromones

Neurohormones

Question 7

What is a hormone?

Answer 7

Type of intercellular signal, between cells, that are produced by endocrine glands, enter circulatory system and affect distant cells.

Question 8

What is Autocrine?

Answer 8

Released by cells and have an affect only on the same cell type from which the chemical signal was released.

Question 9

What is Paracrine?

Answer 9

Released by cells and affect other cell types locally. Does not get transported through blood.

Question 10

What is Pheromones?

Answer 10

Secreted into environment and modify behaviior and physiology of the other organism.

Question 11

What are neurohormones?

Answer 11

Produced by neurons and function like hormones.

Question 12

What are the three ways secretion is regulated?

Answer 12

1. When a non hormone effects the endocrine gland.
2. Nervous system triggers endocrine system.
3. When another hormone produced by another gland effects a different hormone of a different gland in a chain reaction.

Question 13

Describe positive feedback?

Answer 13

When the body increases the deviation from the norm.

Question 14

Describe negative feedback?

Answer 14

When the body works against positive feedback to keep the body at homeostasis

Question 15

Describe the three ways Hormone Secretion changes through time

Answer 15

Chronic: Maintenance of relatively constant concentration of hormone. Long run and constant amount.

Acute: A sudden change in amount of hormone secretion.

Cyclic:Hormone amount and rate comes in waves during cycles.

Question 16

What are the two types of hormones based on how they are transported?

Answer 16

Unbound (free) hormones

Hormones bound to plasma proteins

Question 17

Describe the composition and movement of free hormones.

Answer 17

They are lipid soluble and can diffuse into the fluid in tissues. They are very quick and mobile

Question 18

Describe the composition and movement of bound hormones.

Answer 18

They are water soluble and they need pores in the walls of capillaries in order to transfer information. They move slow and are larger units and tend to stay in the blood for longer periods of time.

Question 19

What is half-life?

Answer 19

The length of time it takes for half a dose of a substance to be eliminated from the circulatory system.

Question 20

Which types of hormones have long and which have short half-lifes?

Answer 20

Usually lipid soluble bound proteins have a long half-life because they stay in the blood stream longer.

Water-soluble free hormones have short half-lives because they are fast.

Question 21

What is down-regulation?

Answer 21

When receptor molecules are degraded and rapidly decrease.

Question 22

What is up-regulation?

Answer 22

Increase of receptors. Thus increasing the sensitivity to that hormones.

Question 23

Describe the receptor and hormones of the Membrane-Bound Receptors

Answer 23

Interacts with hormones at the extracellular surface.

Interacts with hormones that cannot pass through the plasma membrane such as water-soluble or large hormones.

Question 24

Describe the receptor and hormones of the Intra-Cellular Receptors.

Answer 24

The receptor is found in the cytoplasm of the nucleus.

Interacts with lipid soluble hormones and small molecules that can pass through the plasma membrane.