intro to endo 2 W6

Question 1

endocrine reflex pathway stages?

Answer 1

stimulus
afferent signal
integration
efferent signal
physiological action
negative feedback

Question 2

simple endocrine reflex pathway - parathyroid hormone?

Answer 2

low plasma calcium stimulates parathyroid cells to release parathyroid hormone which acts on bone and kidneys to increase reabsorption, and increases intestinal absorption. this leads to increased plasma calcium which feeds back negatively.

Question 3

what are neurohormones

Answer 3

chemical signals released into the blood from a neuron

Question 4

3 groups of neurohormones produced by the nervous system?

Answer 4

catecholamines (adrenal medulla)
hypothalamic neurohormones (posterior pituitary gland)
hypothalamic neurohormones (anterior pituitary gland)

Question 5

endocrine structures incorporated into anatomy of the brain?

Answer 5

pineal and pituitary glands

Question 6

pituitary gland anatomy?

Answer 6

infundibulum - stalk connecting pituitary to brain
posterior pituitary - extension of neural tissue
anterior pituitary - true endocrine gland of epithelial origin

Question 7

other names for anterior/posterior pituitary?

Answer 7

anterior pituitary = adenohypophysis
posterior pituitary - neurohypophysis

Question 8

posterior pituitary hormones released and their functions?

Answer 8

vasopressin (ADH) - regulation of water balance
oxytocin - ejection of breast milk, uterine contractions

Question 9

how are posterior pituitary hormones released into circulation?

Answer 9

made and packaged in cell body of neuron in hypothalamus. vesicles transported down axon of cell into pituitary. vesicles stored in posterior pituitary and released into blood.

Question 10

6 hormones released by anterior pituitary gland?

Answer 10

prolactin
thyrotropin (thyroid stimulating hormone)
adrenocorticotropin
growth hormone
follicle stimulating hormone (FSH)
luteinizing hormone (LH)

Question 11

name for a hormone that controls the secretion of another hormone?

Answer 11

trophic hormone

Question 12

what hormones control the release of anterior pituitary hormones?

Answer 12

hypothalamic neurohormones
these are trophic hormones but they are called releasing or inhibiting hormones

Question 13

PRH causes what?

Answer 13

(PRH = prolactin-releasing hormone)
prolactin released from anterior pituitary targeting breast tissue (synthesise milk)

Question 14

TRH causes what?

Answer 14

(TRH = thyrotropin-releasing hormone)
causes release of prolactin and TSH (thyroid stimulating hormone)
TSH acts on thyroid gland to release thyroid hormones acting on many tissues

Question 15

CRH causes what?

Answer 15

(CRH = corticotropin-releasing hormone)
releases ACTH (adrenocorticotropic hormone)
ACTH acts on adrenal cortex to release cortisol which acts on many tissues

Question 16

GHRH causes what?

Answer 16

(GHRH = growth hormone releasing hormone)
releases GH which acts on liver and many tissues

Question 17

GnRH causes what?

Answer 17

(GnRH = gonadotropin-releasing hormone)
releases FSH and LH causing endocrine cells in gonads to release either androgens (males) or oestrogens and progesterone (females) which act on germ cells of gonads and many tissues

Question 18

what does PIH stand for? what is this also known as?

Answer 18

prolactin-inhibiting hormone
also known as dopamine

Question 19

GHIH stands for what?

Answer 19

growth hormone inhibiting hormone

Question 20

HPT axis?

Answer 20

hypothalamic pituitary thyroid axis

Question 21

HPA axis?

Answer 21

hypothalamic pituitary adrenal axis

Question 22

HPG axis?

Answer 22

hypothalamic pituitary gonadal axis

Question 23

3 levels of control - anterior pituitary?

Answer 23

hypothalamic stimulation (from CNS)
pituitary stimulation (from trophic hormones in hypothalamus)
endocrine gland stimulation (from trophic hormones in pituitary)

Question 24

2 types of negative feedback control?

Answer 24

long-loop feedback - hormone released from final target cell feeds back to suppress anterior pituitary and hypothalamic hormones
short-loop feedback - pituitary hormones feed back to suppress hypothalamic hormone

Question 25

negative control pathways for cortisol secretion?

Answer 25

short loop - ACTH inhibits hypothalamus
long loop - cortisol inhibits anterior pituitary and hypothalamus

Question 26

set of blood vessels transporting hypothalamic trophic hormones to pituitary?

Answer 26

hypothalamic-hypophyseal portal system

Question 27

what is a portal system?

Answer 27

specialized region of circulation consisting of two sets of capillaries directly connected by larger blood vessels

Question 28

advantage of hypothalamic-hypophyseal portal system?

Answer 28

less dilution of hormone
smaller amount of hormone needed to elicit a certain level of response
delivered directly to target
only small number of neurosecretory hormones can effectively control activity of anterior pituitary