Endocrine system Questions

Question 1

How do the actions of the endocrine system and the nervous system control body function?

Answer 1

Regulates body

Question 2

How is an endocrine organ different from an exocrine organ?

Answer 2

Endocrine glands secrete into duct system

Exocrine secretes into blood

Question 3

What is the difference between a target cell, target tissue and target organ?

Answer 3

Target cells- cells w/ receptors from hormones

Target tissue-

Target organ- organ most affected by specific substance

Question 4

What are the three factors that determine target cell activation?

Answer 4

• Hormone blood levels
• number of receptors on /in the target cell
• binding between receptor and hormone

Question 5

Define hormone?

Answer 5

made by endocrine glands to control and communicate with other cell bodies

Question 6

What is the difference between a circulating hormone and local hormone?

Answer 6

Circulating hormones-
- endocrine signaling, passes from
-secretory cells making them into interstitial fluid then into blood/ lymph

Local hormones
-Autocrine signaling
- local hormones mess w/ close cells or the same cell that secreted them w/o entering the blood

Question 7

Define paracrine

Answer 7

acts on neighboring cells

Question 8

Define autocrine

Answer 8

acts on same cell that secreted it

Question 9

Define half-life

Answer 9

time it takes for hormones blood level to decrease by half

Question 11

What is the difference between up regulation and down-regulation?

Answer 11

Up-Regulation
- low hormone circulation causes target cells to increase receptors for the hormone

Down-Regulation
- high hormone circulation causes target cells to decrease the number of receptors for hormone

Question 12

What is the difference between a water soluble and lipid soluble hormone?

Answer 12

Water Soluble
- from amino acids
- hormone receptor on the plasma membrane
- hydrophilic hormones( cant diffuse through lipid bilayer)

Lipid Soluble
- from lipids
- hydrophobic
- hormone receptor in cell

Question 13

How do lipid soluble hormone work?

Answer 13

1. diffuse from blood
2. goes through interstitial fluid and the plasma membranes lipid bilayer into the cell
3. hormone binds to receptors on the nucleus/ cytosol
4. hormone receptor complex alters gene expression

Question 14

Name the lipid soluble hormones

Answer 14

Steroids
Thyroid
Nitric oxide
Eicosanoids

Question 15

How do water soluble hormones work?

Answer 15

1. Binding of Hormone to activate G protein which activates adenylate cyclase(first messenger)
2. activated adenylate cyclase converts ATP to cAMP
3. cAMP activates kinases
4. activated kinases phosphorylate celluar proteins
5. phosphorylated proteins cause reactions that make physiological responses

Question 16

Understand the messenger pathway in a water-soluble hormone.

Answer 16

first messenger binds hormones to cell membrane receptors on the cell to start signaling cascade carried out by the second messenger

Question 17

Define negative feedback

Answer 17

hormone output reverses stimulus

Question 18

Define positive feedback

Answer 18

hormone output encourages stimulus