the endocrine system

Question 1

glands

Answer 1

organs of the endocrine system that secrete hormones

Question 2

hormones

Answer 2

signaling molecules secreted directly into the bloodstream to distant target tissues. hormones bind to receptors in target tissues to induce a change in gene expression or cellular functioning.

Question 3

peptide hormones

Answer 3

made up of amino acids, hydrophilic / lipid insoluble, can travel freely in blood. bind to extracellular receptors. have rapid but short lived effects due to transient nature of secondary hormones.

Question 4

peptide hormone synthesis

Answer 4

derived from larger precursor polypeptides that are cleaved during post-translational modification. transported to golgi apparatus to be activated and directed to be released by exocytosis after being packaged into vesicles.

Question 5

first and second messengers in endocrine system

Answer 5

first messenger: hormone once it binds to receptor and triggers the transmission of a second signal.
second messenger: transmission is triggered by first messenger binding to recptor.

Question 6

signaling cascade

Answer 6

the connection between the hormone at the surface and the effect brought about by secondary messengers

Question 7

amplification

Answer 7

when one hormone molecule may bind to multiple receptors before it is degraded. OR
when one receptor activates multiple enzymes to produce large quantities of secondary messengers.

Question 8

examples of secondary messengers

Answer 8

cAMP cyclic adenosine monophosphate
IP3, inositol triphosphate
Ca2+, calcium

Question 9

steroid hormones

Answer 9

derived from nonpolar / lipiphilic molecules, must be carried by proteins in blood. can easily cross the cell membrane. bind to intracellular / intranuclear receptors. have slower but long lived effects. (can participate in gene regulation, altering amount of mRNA and proteins present in cell).

Question 10

steroid hormone receptors

Answer 10

intracellular / intranuclear. steroid hormone-receptors undergo conformational changes upon binding. receptor can bind directly to DNA to increase or decrease gene transcription.

Question 11

dimerization

Answer 11

example of conformational change of steroid hormone. pairing of two receptor-hormone complexes.

Question 12

steroid hormone carrier proteins examples

Answer 12

1. specific: sex hormone-binding globulin
2. non-specific: albumin
   hormones are generally inactive when bound to carrier protein

Question 13

amino-acid derivative hormones

Answer 13

include norepinephrine, epinephrine, triiodothyronine and thyroxine. derived from one or two amino acids and subsequent modifications.

Question 14

catecholamines

Answer 14

norepinephrine and epinephrine, bind to GPCRs. amino-acid derivative hormones

Question 15

thyroid hormones

Answer 15

triiodothyronine and thyroxine, bind to intracellular receptors. amino-acid derivative hormones

Question 16

direct hormones

Answer 16

secreted and then act directly on a target tissue (ex: insulin)

Question 17

tropic hormones

Answer 17

require an intermediary to have an effect on target tissue (ex: GnRH stimulates LH and FSH release)