HPA

Question 1

What is the function of the hypothalamus?

Answer 1

• Control of metabolism
• mediation of stress
• control of the reproductive system
• control of temperature
• integration of autonomic and endocrine functions.

Question 2

On the wall of which ventricle does the hypothalamus sit?

Answer 2

The wall of the third ventricle.

Question 3

What part of the hypothalamus has a leaky blood-brain barrier?

Answer 3

The median eminence due to fenestrations (pores)

Question 4

What connects the hypothalamus and the pituitary gland?

Answer 4

The infundibulum- stalk comprised of nerve fibres and specialised portal vessels.

Question 5

What is the pathway of signal produced by the paraventricular nucleus?

Answer 5

Neurosecretory cells in the paraventricular nucleus release secreting factors (neuro-hormones).
These leave the median eminence and enter the infundibulum.
They travel through the the portal vessels to enter the pituitary gland.
There they cause the release of specific hormones.

Question 6

What cell types produce each of the following:

• Follicle stimulating hormone and luteinising hormone (gonads/ reproduction)
• Thyroid stimulating hormone (thyroid/energy expenditure)
• Adrenocorticotropic hormone (adrenal/stress)
• Growth hormone (widespread anabolic actions)

Answer 6

• Gonadotrophs
• Thyrotrophs
• Corticotrophs
• Somatotrophs

Question 7

What is the pathway of stress?

Answer 7

Hypothalamus detects stress, leading to the release of corticotropin releasing hormone (CRH) from neurosecretory cells of the paraventricular nucleus.
It then travels to the anterior pituitary gland where it acts on corticotrophs to release ACTH
ACTH acts on the adrenal cortex.
Cortisol then travels through the blood initiating the stress response.

Question 8

What is the posterior pituitary gland responsible for?

Answer 8

Control of vasopressin (dehydration) and oxytocin (love, breast milk production and contractions during birth)

Question 9

What is the vasopressin?

Answer 9

Antidiuretic hormone- prevents dehydration by preventing urine dilution.

Question 10

What is the difference in how signalling molecules travel from the magnocellular cells of the neurosecretory cells to the posterior pituitary gland and from the paraventricular nucleus to the anterior pituitary gland?

Answer 10

When travelling from the paraventricular nucleus signal go through the portal vessels.
When travelling from the magnocellular nucleus, signals do not travels through the portal vessels.