E N D O C R I N E

Question 1

hormone definition

Answer 1

chemical substances secreted by cells into the extracellular fluids

Question 2

autocrine signaling definition

Answer 2

chemicals that exert effects on the same cells that secrete them

Question 3

paracrine signaling definition

Answer 3

locally acting chemicals that affect cells other than those that secrete them

Question 4

humoral stimulus definiton

Answer 4

hormone release caused by altered levels of certain critical ions or nutrients

Question 5

neural stimulus definition

Answer 5

hormone release caused by neural input

Question 6

hormonal stimulus

Answer 6

hormone release caused by another hormone (a trophic hormone)

Question 7

what 3 conditions determine the efficiency of a hormone action?

Answer 7

1. presence of a receptor for the hormone
2. blood levels of the hormone
3. affinity of the receptor for the hormone
4. relative numbers of receptors for the hormone on or in target cells

Question 8

permissiveness definition

Answer 8

one hormone cannot exert its full effect without the presence of another hormone

Question 9

synergism definiton

Answer 9

more than one hormone exerts the same effect at the target cell, and their combined effects are multiplied

Question 10

antagonism definition

Answer 10

one hormone opposes the action of another

Question 11

protein hormone action details

Answer 11

indirect

1. hormone (1st messenger) binds to receptor
2. receptor activates g protein (Gs)
3. g protein activates adenylate cyclase
4. adenylate cyclase converts ATP to cAMP (2nd messenger)
5. cAMP activates protein kinases

this triggers response of target cell (activates enzymes, stimulates cellular secretion, opens ion channels, etc.)

Question 12

steroid hormone action details

Answer 12

direct

1. steroid hormone diffuses through membrane lipids
2. hormone binds to cytoplasmic or nuclear receptors
3. hormone-receptor complex binds to DNA
4. gene activation
5. transcription and mRNA production
6. translation and protein synthesis

alteration of cellular structure or activity

target cell response

Question 13

hypothalamic connection with adenohypophysis

Answer 13

(anterior)

1. stimulation, hypothalamic neurons secrete hormones into primary capillary plexus
2. hypothalamic hormones travel through portal veins to the anterior pituitary where they stimulate or inhibit the release of hormones made in the anterior pituitary
3. in response to releasing hormones, the anterior pituitary secretes hormones into the secondary capillary plexus. this, in turn, empties into the general circulation

Question 14

hypothalamic connection with the neurohypophysis

Answer 14

(posterior)

1. hypothalamic neurons synthesize oxytocin of ADH
2. oxytocin and ADH are transported down the axons of the hypothalamic-hypophyseal tract to the posterior pituitary
3. oxytocin and ADH are stored in the axon terminals in the posterior pituitary
4. when associated hypothalamic neurons fire, action potentials arriving at the axon terminals cause oxytocin or ADH to be released into the blood

Question 15

ADH (antidiuretic hormone)

Answer 15

source: made in hypothalamus, released by posterior pituitary
function: tells kidneys to absorb water

target cell: kidneys

Question 16

Aldosterone

Answer 16

source: adrenal cortex
function: absorb Na+ (water follows)

target cell: kidney

Question 17

anterior pituitary hormones

Answer 17

hormone - releasing hormone - target

1. ACTH - CRH - adrenal glands
2. TSH - TRH - thyroid gland
3. GH - GH-RH & GH-IH - liver (somatomedin)
4. PRL - PRH & PIH - mammary glands
5. FSH & LH - GnRH - testes (inhibin & testosterone)
   - ovaries (estrogen, progesterone, inhibin)

Question 18

use TSH to illustrate negative feedback for hormones

Answer 18

hypothalamus > TRH > anterior pituitary > TSH > thyroid > T3 & T4 (TH)

negatively inhibits hypothalamus and secretion of TRH

Question 19

tropic hormones definition

Answer 19

hormones that regulate other endocrine glands and the secretion of their hormones

Question 20

which of the anterior pituitary hormones are trophic hormones?

Answer 20

1. TSH
2. ACTH
3. FSH
4. LH

Question 21

what 2 antagonistic hormones help regulate calcium?

Answer 21

1. calcitonin

2. parathyroid hormone (PTH)

Question 22

calcitonin

Answer 22

lowers blood calcium levels

source: thyroid gland

actions:
1. increased excretion of calcium by kidneys
2. calcium deposition in bones

Question 23

parathyroid hormone (PTH)

Answer 23

raises blood calcium levels

source: parathyroid glands

actions:

1. increased reabsorption of calcium by kidneys
2. calcium release from bones
3. increased calcitrol production causes calcium absorption by intestinal tract

Question 24

what 2 hormones are secreted by the pancreatic islet cells work antagonistically to regulate plasma glucose levels?

Answer 24

1. glucagon

2. insulin

Question 25

glucagon

Answer 25

source: beta cells

actions:
enhances glucose transport into body cells (out of blood), increases rate of glucose use and ATP generation, converts glucose into glycogen, and counters metabolic activity that would enhance blood glucose levels

Question 26

insulin

Answer 26

potent hyperglycemic agent

source: alpha cells

actions:
targets liver and promotes glucose breakdown and synthesis and fat to fatty acid conversion

Question 27

diabetes mellitus

Answer 27

results from hypo section of insulin (type 1 & 2)

Question 28

diabetes insipidus

Answer 28

results from hypo secretion of ADH