Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

ESA 2 - MEH > 8. The hypothalamic pituitary axis > Flashcards

8. The hypothalamic pituitary axis Flashcards

1
Q

Describe the location of the pituitary.

A

Beneath the hypothalamus in a socket of bone - the sella turcica.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the embryological origins of the anterior and posterior lobes of the pituitary.

A

anterior lobe: projection of ectoderm (Rathke’s pouch) growing upward from roof of mouth

posterior lobe: ectodermal tissue growing downwards from diencephalon of developing brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Which structure connects the hypothalamus and pituitary?

A

infandibulum (pituitary stalk)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What does the posterior pituitary consist of?

A
  1. axons and terminals that originate in hypothalamus

2. specialised glial cells - pituicytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Which 2 hormones are released from the posterior pituitary (and what hormone type are they)?

A
  1. oxytocin (peptide)

2. anti-diuretic hormone (peptide)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Where are oxytocin and ADH synthesised in the hypothalamus?

A
  • ADH: supraoptic nucleus

- oxytocin: paraventricular nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What stimulates oxytocin release from the posterior pituitary?

A
  1. suckling (milk let-down reflex) - stimulus is transmitted via neurons from the breast to the hypothalamus
  2. during childbirth: pressure on cervix and uterine wall
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the effect of oxytocin release?

A
  1. activates oxytocin Rs on myoepithelial cells surrounding mammary alveoli… contraction to squeeze milk into duct system
  2. during childbirth: activates oxytocin Rs on uterine SM cells… powerful uterine contractions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Why is synthetic oxytocin (pitocin) often administered after birth?

A

increase uterine tone and control bleeding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the effect of ADH release?

A

reduction in urine production:
activates Rs on distal tubular epithelium of collecting ducts in kidneys… translocation of aquaporin water channels in plasma membrane of collecting duct cells (increased permeability)… reabsorption of water into blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Why does drinking alcohol increase urination and lead to dehydration?

A

inhibits ADH release from posterior pituitary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How is blood osmolality regulated?

A

OsmoRs in hypothalamus detect changes in plasma osmolality…

  1. If high: stimulates ADH release from posterior pituitary (and stimulates thirst)… increased H2O reabsorption from collecting ducts
  2. If low: inhibits ADH release from posterior pituitary (and inhibits thirst)… decreased H2O reabsorption from collecting ducts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How is hypothalamus control of anterior pit. different to control of posterior pit.?

A
  • posterior pit.: neuronal control

- anterior pit.: tropic hormone control

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Where are hypothalamus hormones destined for AP stored?

A

median eminence just above AP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are hormones stored in median eminence released into?

A

hypophyseal portal system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What type of R do hypothalamic tropic hormones bind to in the AP?

A

hormone-specific GPCRs

17
Q

Name the 7 hypothalamic tropic hormones.

A
  1. thyrotropin-releasing hormone (TRH)
  2. corticotropin-releasing hormone (CRH)
  3. gonadotropin-releasing hormone (GnRH)
  4. prolactin-releasing hormone (PRH)
  5. prolactin release-inhibiting hormone (PIH)
  6. growth hormone-releasing hormone (GHRH)
  7. growth hormone inhibitory hormone (GHIH) / somatostatin
18
Q

Describe the downstream effects of TRH release.

A

i. TRH binds R on AP thyrotropes…
ii. release of TSH (thyroid stimulating hormone)…
iii. binds R on thyroid follicular cells…
iv. T3 and T4 release

19
Q

Describe the downstream effects of CRH release.

A

i. CRH binds R on AP corticotropes…
ii. release of ACTH (adrenocorticotropin hormone)…
iii. binds R on adrenal cortex cells…
iv. glucorticoid (mainly cortisol) release

20
Q

Describe the downstream effects of GnRH release.

A

i. GnRH binds R on AP gonadotropes…
ii. release of LH (luteinising hormone) and FSH (follicle stimulating hormone)…
iii. bind Rs on gonad cells…
iv. LH: stimulates progesterone and oestrogen production and ovulation (females) or testosterone production (males)
FSH: stimulates gamete production (eggs or sperm)

21
Q

What system regulates hormone release in the HPA?

A

negative feedback loops:

  1. ultra-short loop: hypothalamic tropic hormone limits own production in autocrine/paracrine fashion within hypothalamus
  2. short loop: AP hormone inhibits production of hypothalamic releasing hormone or stimulates production of hypothalamic inhibiting hormone
  3. direct long loop: peripheral effector hormone inhibits production of AP hormone
    indirect long loop: peripheral effector hormone inhibits production of hypothalamic tropic hormone

ESA 2 - MEH (42 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions