Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Endocrinology > Endo 1 - Hypothalamo-hypophysial axis > Flashcards

Endo 1 - Hypothalamo-hypophysial axis Flashcards

1
Q

Where is the pituitary gland ?

A

It lies at the base of the brain in a dip of the sphenoid bone - the sella turcica

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

What is the other name for the pituitary gland?

A

Hypophysis

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

How many lobes compose the pituitary? What are they called?

A

2 - anterior and posterior
anterior = adenohypophysis
posterior = neurohypophysis

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

How does the pituitary gland develop?

A

5th week gestation
Upward growth from the buccal cavity and downward growth from base of the brain
secretory part derived from buccal - adenohypophysis
neural part (made up of nerve axons) from brain - neurohypophysis

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

Where do hypothalamic neurons terminate/secrete ?

A

At the median eminence - region between hypothalamus and pituitary
And at the posterior pituitary - longer axons

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

What is the pars distalis?

A

The body of the anterior pituitary

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

What is the pars tuberalis?

A

The part of the anterior pituitary which wraps around the pituitary stalk (often called infundibum)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe the pathway that blood has in anterior pituitary

A

Superior hypophysial artery –> primary capillary plexus –> long portal veins –> secondary capillary plexus –> cavernous sinus –> internal jugular veins
Posterior pituitary has different blood supply by inferior hypophysial artery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe the hypothalamo-adenohypophysial axis

A
  1. Hypothalamus nuclei send neurons to median eminence –> hypothalamic neurosecretion released into rich capillary network - primary capillary plexus - which connects hypothalmus to padenohypophysis
  2. These travel to adenohypophysial cells via long portal vein
  3. These inhibit/stimulate the cells which results in the secretion of hormone into general circulation
    The vessels are fenestrated = leaky so that content can reach cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

List the adenohypophysial hormones, their class (protein, glycoprotein, polypeptide) and by which cells they are produced

A
  1. Somatotrophs –> GH (somatotrophin) - protein, 191 aa
  2. Lactotrophs –> prolactin - protein, 199 aaa
  3. Thyrotrophs –> TSH - glycoprotein alpha 92aa, beta 110 aa
  4. Gonadotrophs –> LH and FSH - glycoproteins, both 92 aa alpha and 115 aa beta
  5. Corticotrophs –>ACTH (corticotrophin) -polypeptide 39 aa
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which hypothalamic hormone stimulates/inhibits which adenohypophysial hormone?

A

GHRH (stim.) + somatostatin (inhib.) –> GH

Dopamine (inhib, MAIN SIGNAL = exception) + Thyrotrophin Releasing hormone (TRH; stim.)–> Prolactin

TRH (stim.) –> TSH

Gonadotrophin RH (stim)–> LH and FSH

Corticotrophin RH (Stim - main) + Vasopressin (stim)–> ACTH

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

How can you describe the way in which hypophysial hormones are released?

A

In a pulsatile fashion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Which hormone is an exception where the dominant signal for its release is inhibitory?

A

Prolactin - dominant signal is dopamine - more than TRH

You have to inhibit the inhibitory molecule (DA) to have PRL secreted

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

Where does GH mainly act ?

A

Liver - lots of GH receptors

binding of GH produces IGFI and IGF II which mediates the effects of GH in tissues

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

What are the stimulants to GH release? (7)

A

Some Students Only Eat Food And Grow

  1. Sleep
  2. Stress (acute)
  3. Oestrogen
  4. Exercise
  5. Fasting
  6. Amino acids
  7. Ghrelin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the effects of GH? (5)

A
  1. Stimulation of amino acid transport into cells
  2. Stimulation of protein synthesis
  3. Increased cartilaginous growth
  4. Stimulation of lipid metabolism
  5. Increased insulin resistance and therefore increased blood glucose
17
Q

What are the controls of prolactin?

A

Stimulants
1- Suckling –> stimulates the tactile receptors on nipples/breasts. This inhibits Dopamine (DA) and stimulates TRH via an afferent neural pathway, thus stimulating the release of prolactin.
2- Oestrogens and Iodothyronines also increase the production of prolactin via a direct and indirect pathway.

18
Q

What are the effects of prolactin? (4)

A
  1. Mainly: Lactogenesis in post partum women.
  2. Renal Na (and water) Reabsorption
  3. Immunological effects e.g. T-cell stimulation
  4. Hyperprolactinaemia is high level of prolactin inn the blood and has a contraceptive effect as prolactin inhibits LH/FSH.

Endocrinology (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions