Lecture 4- Hypothalamus And The Pituitary

Question 1

What structure connects the hypothalamus and the pituitary gland?

Answer 1

Infundibulum

Question 2

What is the name of the depression in the sphenoid bone where the pituitary gland sits?

Answer 2

Sella turcica

Question 3

What is the name of the vessel network connecting the hypothalamus and the pituitary?

Answer 3

Hypothalamus hypophyseal portal system

Question 4

What are the 2 lobes of the pituitary?

Answer 4

Anterior and posterior pituitary

Question 5

Where does the anterior pituitary develop from, embryologically?

Answer 5

Ectoderm of Rathke’s pouch

Question 6

Where does the posterior pituitary develop from, embryologically?

Answer 6

Downward extension of neural ectoderm from the floor of the diencephalon

Question 7

What are the 3 parts do the anterior pituitary?

Answer 7

1. Pars tuberalis
2. Pars intermedia
3. Pars distalis

Question 8

What are the 2 parts of the posterior pituitary?

Answer 8

1. Infundibular stalk

2. Pars nervosa

Question 9

What are the 5 subtypes of anterior pituitary cells?

Answer 9

1. Lactotroph
2. Somatotroph
3. Thyrotroph
4. Gonadotroph
5. Corticotroph

Question 10

What causes an increase in growth hormone-releasing hormone secretion from the hypothalamus?

Answer 10

Low blood glucose and stress

Question 11

What is the result of growth hormone-releasing hormone secretion?

Answer 11

Human growth hormone secretion from the anterior pituitary

Question 12

What are the 4 functions of human growth hormone in the target tissues?

Answer 12

1. Increase protein synthesis
2. Increase tissue growth
3. Increase fat breakdown
4. Spares glucose usage

Question 13

What causes the release of corticotropin-releasing hormone ?

Answer 13

Stress and hypoglycaemia

Question 14

What is the result of corticotropin-releasing hormone?

Answer 14

Adrenocorticotropin hormone is released from the anterior pituitary

Question 15

What is the target tissue of adrenocorticotropin hormone?

Answer 15

Adrenal cortex

Question 16

What hormone is released from the adrenal cortex in response to adrenocorticotropin hormone?

Answer 16

Cortisol

Question 17

What part of the adrenal cortex is cortisol released from?

Answer 17

Zona fasciculata

Question 18

What are the 3 effects of cortisol?

Answer 18

1. Increase fat and protein breakdown
2. Increase blood and glucose levels
3. Anti-inflammatory effects

Question 19

What feedback effect does cortisol have?

Answer 19

Negative feedback to the hypothalamus to inhibit corticotropin-releasing hormone release

Question 20

What hormone from the hypothalamus is released to increase thyroid hormone production?

Answer 20

Thyrotropin-releasing hormone

Question 21

What is the effect of thyrotropin-releasing hormone on the anterior pituitary?

Answer 21

Causes the release of thyroid stimulating hormone

Question 22

What is the effect of thyroid stimulating hormone on the thyroid gland?

Answer 22

Causes the release of T3 and T4 from the thyroid gland

Question 23

What feedback effects do T3 and T4 have?

Answer 23

Negative feedback on both the hypothalamus and anterior pituitary, inhibiting thyrotropin releasing hormone and thyroid stimulating hormone release

Question 24

What are the cardiovascular effects of T3?

Answer 24

Increased heart rate and cardiac output

Question 25

What are the effects of T3 on bone?

Answer 25

Increased bone resorption

Question 26

What are the GI effects of T3?

Answer 26

Increased gut motility

Question 27

What effect does T3 have on lipids?

Answer 27

Increased lipolysis

Question 28

What effect does T3 have on the sympathetic nervous system?

Answer 28

Increased catecholamine sensitivity

Question 29

Is T3 or T4 more potent?

Answer 29

T3

Question 30

Which thyroid hormone is converted into the other that is released?

Answer 30

T3 is converted into T4

Question 31

How do hypothalamic hormones reach the anterior pituitary?

Answer 31

Through the hypothalamus-hypophyseal portal system

Question 32

How do hypothalamic hormones reach the posterior pituitary?

Answer 32

Through the hypothalamus-hypophyseal tract

Question 33

What 2 hormones are released from the posterior pituitary?

Answer 33

1. Oxytocin | 2. Anti-diuretic hormone

Question 34

Which 2 regions does oxytocin stimulate myoepithelial contractions?

Answer 34

1. Uterus | 2. Mammary glands

Question 35

What is the main function of anti-diuretic hormone?

Answer 35

Conserve body water and regulate tonicity* of body fluids * relative concentration of solutes dissolved in solution which determine the direction and extent of diffusion

Question 36

What increases the osmolality of plasma?

Answer 36

Water deprivation

Question 37

Increased osmolality of plasma activates which hypothalamic receptors?

Answer 37

Osmoreceptors

Question 38

Activation of hypothalamus osmoreceptors leads to what?

Answer 38

Release of anti-diuretic hormone