Lecture 30- Endocrine System

Question 1

Endocrinology

Answer 1

Study of hormones and endocrine organs

Question 2

Hormones

Answer 2

Chemical messengers that are released into blood and elicit target cell effects

Question 3

Autocrines

Answer 3

Local chemical messengers, act on same cell that secrete them

Question 4

Paracrines

Answer 4

Local messengers, act on neighbouring cells

Question 5

What does chemical structure of hormone determine?

Answer 5

Solubility in water, how it’s transported, how long it lasts and what receptor it can act upon

Question 6

Water soluble hormones

Answer 6

Bind to exterior surface of target cell and circulate freely in plasma

Question 7

Lipid soluble hormone

Answer 7

Can diffuse through plasma membrane and bind to receptors within target cells

Question 8

Amine hormones

Answer 8

Made by modifying amino acids

EX. Histamine derived from histidine
Serotonin derived from tryptophan

Question 9

Peptide hormones

Answer 9

Chains of less than 50 amino acids

EX. Oxytocin

Question 10

Protein hormones

Answer 10

Up to 200 amino acids long

EX. Insulin

Question 11

Glycoproteins

Answer 11

Proteins with attached carbohydrate

Question 12

Eicosanoids

Answer 12

Derived from polyunsaturated fatty acids

EX. Prostaglandins

Question 13

Cyclic AMP signalling mechanism

Answer 13

Involves hormone binding to receptor, activating G protein, generates cAMP, activates enzymes

Question 14

Gonadal and adrenocortical hormones

Answer 14

Lipid soluble

Steroids, derived from cholesterol

Question 15

Thyroid hormones

Answer 15

Thyroxine and triiodothyronine Mae from amino acid tyrosine

Lipid soluble because of two benzene rings

Question 16

Direct gene activation

Answer 16

Occurs when a lipid soluble hormone bonds tried intracellular receptor , activating a specific region of DNA causing production of mRNA and initiation of protein synthesis

Question 17

Endocrine gland stimuli

Answer 17

Signals that encourage synthesizer and release of hormones

May be humoral, neural or hormonal

Question 18

Three factors the magnitude of target cell response depends on….

Answer 18

1. Blood levels of hormone
2. Relative numbers of target cell receptors
3. Affinity of receptor for hormone

Question 19

Permissiveness

Answer 19

Occurs when one hormone cannot exert full effect without another hormone present

Question 20

Synergism

Answer 20

occurs when more than one hormone produces the same effects in a target cell, and their combined effects are amplified.

Question 21

Antagonism

Answer 21

occurs when one hormone opposes the action of another hormone.