Hormones

Question 1

endocrine system

Answer 1

regulates our internal environment by secreting hormones into the bloodstream. hormones travel to target cells/ tissues and stimulate a response

Question 2

homestasis

Answer 2

internal environment
energy metabolism
growth
reproduction and development

Question 3

endocrine system consists of

Answer 3

endocrine glands that secrets hormones which are carried in the blood stream to the target cells upon which they act

Question 4

major endocrine glands

Answer 4

hypothalamus 
pituitary gland 
parathyroid gland
thyroid gland 
adrenal gland 
pancreas

Question 5

hormones

Answer 5

hormones are chemical messegers produced in one location and transported to a second location (target cells) where they cause a response in those cells

Question 6

specificity of hormone action

Answer 6

hormone can only generate a response if the cell has a receptor that binds to that hormone
cells generally have different receptors so they can respond to more than one hormone

Question 7

receptors

Answer 7

proteins in the cell membrane or inside the cell

Question 8

water soluble hormones

Answer 8

peptides
catecholamines - adrenaline and noradrenaline
made and stored until required (released by exocytosis)
travel in the blood

Question 9

lipid (fat) soluble hormones

Answer 9

steroids
thyroid hormones
steroids are made as required and not stored
they travel in the blood bound to carrier proteins as they would become non-functional if they weren’t.

Question 10

water soluble hormone receptors

Answer 10

these hormones cannot cross the cell membrane

so receptors are found in the target cell plasma membrane poking out of the cell slightly.

Question 11

lipid soluble hormone receptors

Answer 11

can diffuse across the cell membrane into target cell
so receptors are found in the cytoplasm or in the nucleus
when the hormone gets close to the target cell the carrier protein is released

Question 12

cellular response to WATER SOLUBLE hormones

Answer 12

1. water soluble hormone binds to receptor on the cell surface
2. hormone binding allows activation of associated protein
3. G- protein activates adenylyl cyclase
4. second messenger production e.g. cAMP
5. cAMP activates protein kinase
6. protein kinase activates specific enzyme
7. enzyme converts specific substrate to product

Question 13

cellular response to LIPID SOLUBLE hormones

Answer 13

1. lipid soluble hormone dissociates from the carrier protein
2. hormone diffuses across the cell membrane
3. hormone binds to intracellular receptor
4. hormone-receptor complex acts as a specific transcription factor
5. new mRNA is generated
6. new protein is generated by translation of mRNA
7. new protein mediates cells specific response (slow response)

Question 14

control of hormone secretion

Answer 14

amount of hormone in blood depends on
1- rate of hormone secretion
2. rate of removal from the blood
negative feedback loop controls secretion
enzymes in blood or cells control rate of removal