endocrine systems and receptors

Question 1

what is the definition of a hormone?

Answer 1

Any substance elaborated by one cell to regulate another cell. May be delivered by autocrine, paracrine, or endocrine routes.

Question 2

what is the general biological response of a hormone pathway?

Answer 2

an amplification of a signal transduction cascade

Question 3

how long can the action of hormones last?

Answer 3

from seconds to days.

Question 4

which body part provides the highest level of endocrine control?

Answer 4

the hypothalamus
(the endocrine director)

Question 5

what does hypothalamic control do?

Answer 5

it integrates the activities of nervous and endocrine systems through the secretion of regulatory hormones, the synthesis of hormones and direct neural control

Question 6

can hormones have an antagonistic action?

Answer 6

yes

Question 7

can hormones have complementary actions?

Answer 7

yes

Question 8

what are the three classes of hormones?

Answer 8

steroids
amine-derived
peptides

Question 9

what is an example of a steroid hormone?

Answer 9

oestrogen

Question 10

what is an example of an amine derived hormone?

Answer 10

adrenaline/epinephrine

Question 11

what is an example of a peptide hormone?

Answer 11

oxytocin
ADH
insulin

Question 12

are steroids hydrophobic or hydrophilic?

Answer 12

hydrophobic

Question 13

how are steroids transported?

Answer 13

in blood plasma by binding to carrier proteins (~90%).

Question 14

true or false- unbound steroids are biologically inactive

Answer 14

FALSE
biologically active

Question 15

name a stress hormone

Answer 15

cortisol

Question 16

when steroids pass through the plasma membrane, what process do they initiate?

Answer 16

1)Activated hormone-receptor complex forms within the cell
2) The complex binds to DNA & activates specific genes, leading to Gene activation leads to production of key proteins

Question 17

are amine hormones hydrophobic or hydrophilic?

Answer 17

Hydrophilic

Question 18

are amine hormones transported unbound or bound?

Answer 18

unbound

Question 19

which type of amine hormones are bound to carrier proteins?

Answer 19

thyroid amine hormones

Question 20

where are amine hormones secreted from?

Answer 20

the thyroid and the medulla

Question 21

where is adrenaline stored until needed?

Answer 21

as vesicles in the cytoplasm

Question 22

are peptide hormones hydrophilic or hydrophobic?

Answer 22

hydrophilic

Question 23

how are peptide hormones transported?

Answer 23

unbound in blood plasma

Question 24

where are peptide hormones secreted from?

Answer 24

pituitary
parathyroid
heart
stomach
liver
kidneys

Question 25

are peptide hormones synthesized as precursor molecules?

Answer 25

yes

Question 26

where are peptide hormones stored once synthesised?

Answer 26

secretory vesicles

Question 27

what is the structure of the peptide hormone somatostatin?

Answer 27

a ring due to disulfide bonds

Question 28

what is the structure of the peptide hormone insulin?

Answer 28

2 chains held together by disulfide bonds

Question 29

what kind of hormones are insoluble in plasma?

Answer 29

steroid and thyroid hormones

Question 30

what does binding to a carrier protein lead to?

Answer 30

Facilitation of hormone transport
Increased half-life of the hormone (half life is the amount if time it takes a hormone to lose 50% of its physiological activity)
A reservoir for the hormone

Question 31

which carrier protein binds cortisol?

Answer 31

Cortisol-binding globulin (CBG)
binds in a selective manner

Question 32

which carrier protein binds thyroxine?

Answer 32

Thyroxine-binding globulin (TBG)
binds T4 selectively
also binds some T3

Question 33

which carrier protein binds testosterone and oestradiol?

Answer 33

sex steroid binding globulin (SSBG)