Hypothalamus and Pituitary Gland Content support revision basis

Question 1

what is the relationship between hypothalamus and pituitary

Answer 1

Interaction of the endocrine and nervous systems in the regulation of homeostasis

Question 2

What do neurons in the supra and paraventricular nuclei of hypothalamus project into and do

Answer 2

Neurons with cell bodies in the supra and paraventricular nuclei of hypothalamus project into posterior pituitary gland, directly releasing hormones into venous drainage

Question 3

What do neurons with cell bodies in medial hypothalamic nuclei project into and do

Answer 3

Neurons with cell bodies in medial hypothalamic nuclei project into median eminence, releasing tropic hormones into pituitary portal veins

Question 4

What do tropic hormones influence

Answer 4

Tropic hormones influence cells in anterior pituitary gland to produce hormones circulating in the body

Question 5

Give 2 examples of gonadotropins

Answer 5

FSH and LH

Question 6

Where do gonadotropes play integral roles

Answer 6

hypothalamus-pituitary-testis axisand thehypothalamus-pituitary-ovary axis

Question 7

What hypothalamic releasing hormone is FSH and LH secretion regulated by

Answer 7

gonadotropin-releasing hormone (GnRH)

Question 8

Where is GnRH released from

Answer 8

released from neurons of the arcuate and preoptic nuclei of the hypothalamus.

Question 9

What are 2 types of GnRH secretion and what 3 factors can influence GnRH secretion

Answer 9

2 types of secretion: pulsatile or episodic

3 factors that can influence GnRH secretion: stress, exercise and diet.

Question 10

What is the frequency of GnRH secretion that increases LH secretion

Answer 10

At a frequency of 1 pulse per hour, GnRH preferentially increases LH secretion

Question 11

What is the frequency of GnRH secretion that increases FSH secretion

Answer 11

at a frequency of 1 pulse per 3 hours, GnRH preferentially increases FSH secretion.

Question 12

What does LH stimulate in males and from where does this come from

Answer 12

LH stimulates testosterone production from the Leydig cells of the testes

Question 13

What is the main male androgen

Answer 13

Testosterone is the main male androgen

Question 14

What does testosterone feed back to the hypothalamus to do? What does it do when it reaches the level of the pituitary gland

Answer 14

Testosterone feeds back on the hypothalamus to inhibit GnRH secretion and at the level of the pituitary to inhibit LH secretion

Question 15

What is the most important role of HPG axis in female reproduction

Answer 15

to control the uterine (menstrual) and ovarian cycles​

Question 16

What are the spheres of follicles in the thyroid composed of

Answer 16

Spheres of follicles composed of follicular cells and parafollicular cells

Question 17

What do follicular cells produce and where is this thing stored?

Answer 17

Follicular cells produce thyroid hormone, stored in colloid lumen

Question 18

What do parafollicular cells (C cells) produce

Answer 18

Parafollicular cells (C cells) make calcitonin

Question 19

What do principal (chief) cells do?

Answer 19

they are Predominant and secrete PTH

Question 20

How many iodines does T3 and T4 have respectively

Answer 20

T4 = 4 iodides
T3 = 3 iodides

Question 21

What does T4 act as

Answer 21

acts as a plasma reserve

Question 22

What does T3 act as

Answer 22

acts as the active form of T4

Question 23

Which 3 locations is T4 converted to active T3?

Answer 23

T4 is converted to active T3 in peripheral tissues, brain and pituitary gland

Question 24

What is the production of T4 and T3 catalyzed by

Answer 24

Catalysed by Thyroid Peroxidase (TPO)

Question 25

What are the 2 stages of T4/T3 production

Answer 25

Stage 1. Iodination

Stage 2. Coupling

Question 26

What 3 molecules make T4

Answer 26

2 x DIT with Tgb

Question 27

What 3 molecules make T3

Answer 27

1x DIT, 1x MIT and Tgb