Hypothalamus + Pituitary Gland

Question 1

Where is the hypothalamus?

Answer 1

Region of brain outside of blood-brain barrier

Question 2

What does the hypothalamus receive?

Answer 2

Sensory input from other regions of brain & periphery

Question 3

What does the hypothalamus output?

Answer 3

Sends efferent output via autonomic NS & pituitary gland

Question 4

What 2 parts is the pituitary divided into?

Answer 4

• posterior pituitary/lobe
• anterior pituitary/lobe

Question 5

What is the posterior pituitary/lobe composed of?

Answer 5

nervous tissue

Question 6

What is the anterior pituitary composed of?

Answer 6

epithelial tissue (type of glandular tissue)

Question 7

What hormones does the posterior pituitary gland store and release?

Answer 7

• antidiuretic hormone (ADH / vasopressin)
• oxytocin

NOTE: posterior lobe does not produce hormones

Question 8

When is ADH secreted?

Answer 8

• increased blood osmolarity (dehydration)
• decreased blood volume

Question 9

What does ADH act to stimulate?

Answer 9

• water reabsorption (increase BV)
• vasoconstriction (increase BP)

Question 10

What ADH disorders are there?

Answer 10

Diabetes insipidus:
- excess urine
- neurogenic
- nephrogenic

Question 11

What is neurogenic?

Answer 11

ADH deficiency due to damage to hypothalamus or posterior pituitary gland

Question 12

What is nephrogenic?

Answer 12

Defective ADH receptors in kidneys
(unable to respond to ADH)

Question 13

Why is oxytocin secreted?

Answer 13

• cervical stretch
• suckling
• sex

Question 14

What does oxytocin act to stimulate?

Answer 14

• contraction of smooth muscle in uterus
• milk ejection from mammary glands
• changes in behaviour (maternal bonding, social interactions)

Question 15

What hormones does the anterior pituitary gland produce?

Answer 15

• adrenocorticotropic (ACTH)
• thyroid-stimulating hormone (TSH)
• growth hormone (GH)
• gonadotropins (LH + FSH)
• prolactin (PRL)
• melanocyte-stimulating hormone (MSH)

Question 16

What type of molecule is ACTH?

Answer 16

Peptide derived from precursor POMC

Question 17

What is ACTH produced from?

Answer 17

Corticotrophs (specialised cells) in anterior lobe

Question 18

What stimulates the secretion of ACTH?

Answer 18

Stimulated by:
- corticotrophin-releasing hormone (CRH)
- AVP

Question 19

What does the secretion of ACTH promote?

Answer 19

• growth
• activity of adrenal cortex

Question 20

What type of molecule is TSH?

Answer 20

glycoprotein

Question 21

What stimulates the secretion of TSH?

Answer 21

thyrotrophin-releasing hormone (TRH) from hypothalamus

Question 22

What does TSH promote?

Answer 22

• growth
• activity of thyroid gland
• secretion of thyroid hormones

Question 23

What stimulates the secretion of GH?

Answer 23

growth hormone-releasing hormone (GHRH)

Question 24

What inhibits GH?

Answer 24

somatostatin

Question 25

What are the direct actions of GH?

Answer 25

• amino acid uptake & protein synthesis in cells
• lipolysis
• glycogenolysis
• secretion of insulin-like growth factors (IGFs)

Question 26

What are the indirect actions, via IGFs, of GH?

Answer 26

• protein synthesis
• chondrogenesis in cartilage
• bone growth

Question 27

What are the disorders of GH?

Answer 27

GH excess - acromegaly (gigantism)
GH deficiency - dwarfism

Question 28

What type of molecules are gonadotrophins?

Answer 28

glycoproteins

Question 29

What are gonadotrophins stimulated by?

Answer 29

gonadotrophin-releasing hormone (GnRH)

Question 30

What does gonadotrophins promote?

Answer 30

• growth
• activity of gonads (ovary & testis)

Question 31

What are the disorders of gonadotrophins?

Answer 31

• precocious (delayed puberty)
• infertility

Question 32

What produces prolactin in the anterior lobe?

Answer 32

lactotrophs (specialised cells)

Question 33

What is prolactin inhibited by?

Answer 33

dopamine

Question 34

What does prolaction promote?

Answer 34

• growth
• milk production in mammary glands

Question 35

What disorders are related to prolactin?

Answer 35

infertility