Hypothalamus and Pituitary

Question 1

what part of the pituitary releases neurohormones?

Answer 1

the posterior pituitary

Question 2

what is the infundibulum?

Answer 2

the stalk connecting the hypothalamus to the pituitary

Question 3

what two forms of hypothalamic neurohormones are there?

Answer 3

> tropic

> non-tropic

Question 4

what are tropic hormones?

Answer 4

Hormones which regulate the release of other hormones

Question 5

what are non-tropic hormones?

Answer 5

Hormones which act directly on tissue to cause a change in activity

Question 6

how is the anterior pituitary connected to the hypothalamus?

Answer 6

capillary portal system

Question 7

what is the origin of the anterior pituitary?

Answer 7

epithelial

Question 8

what is the origin of the posterior pituitary?

Answer 8

neural

Question 9

name 5 hypothalamic releasing hormones

Answer 9

> prolactin releasing hormones
> gonadotropin releasing hormones
> corticotropin releasing hormones
> thyrotropin releasing hormone
> growth hormones releasing hormone

Question 10

name 2 hypothalamic inhibiting hormones

Answer 10

> dopamine (prolactin inhibiting hormone)

> growth hormone inhibiting hormone (somatostatin)

Question 11

describe the hypothalamic-hypophyseal portal system

Answer 11

> network of tiny vessels
2 capillary beds connected in series
rapid due to short distance
small amount of neurosecretory neurons sufficient for control

Question 12

where do hormones from neurons enter the hypothalamic-hypophyseal portal system?

Answer 12

at the median eminence

Question 13

name 5 anterior pituitary hormones

Answer 13

> prolactin
> thyroid stimulating hormones
> adenocorticotropic hormone
> growth hormone
> follicle stimulating hormone (luteinising hormone)

Question 14

what is the action of prolactin?

Answer 14

targets the breasts and causes lactation

Question 15

what is the effect of adenocorticotropic hormone?

Answer 15

targets the adrenal cortex:

> triggers cortisol release

Question 16

what is the effect of growth hormone?

Answer 16

targets the liver:
> IGF-1 release
> tissue metabolism

Question 17

what are the effects of follicle stimulating hormone and luteinising hormones?

Answer 17

targets the gonads:
> sex hormone release
> regulates reproductive function

Question 18

name 3 integration centres in the anterior pituitary feedback control loop

Answer 18

> hypothalamus
ant. pituitary
target endocrine cells

Question 19

what is the long loop feedback in anterior pituitary control?

Answer 19

negative feedback from the endocrine target by hormones acting on the hypothalamus

Question 20

what is the short loop feedback in control of the anterior pituitary?

Answer 20

negative feedback loop: hormones released by the anterior pituitary act on the hypothalamus

Question 21

what is the function of the posterior pituitary?

Answer 21

stores and releases 2 neurohormones:
> vasopressin
> oxytocin

Question 22

where are oxytocin and vasopressin synthesised?

Answer 22

in the magnocellular neurons in the hypothalamus that run through the infundibulum and terminate on capillaries directly

Question 23

what triggers the release of vasopressin?

Answer 23

> increased plasma osmorality

> decreased plasma volume and blood pressure

Question 24

what are the effects of vasopressin?

Answer 24

regulates water balance:
> acts on kidney collecting ducts increasing water reabsorption
> constricts vascular smooth muscle causing increased blood pressure

Question 25

what is oxytocin release triggered by?

Answer 25

> babies head against the cervix

> suckling

Question 26

what are the effects of oxytocin?

Answer 26

> contraction of milk duct smooth muscle causing milk ejection
acts on uterine smooth muscle in childbirth

Question 27

describe a primary endocrine disorder

Answer 27

there is a defect in the cells that are secreting the hormone

Question 28

describe a secondary endocrine disorder

Answer 28

there is too little or too much trophic hormone from the pituitary

Question 29

describe a tertiary endocrine disorder

Answer 29

there is a defect in the hypothalamus