Brainscape's Knowledge GenomeTM

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


See full index

MEH 2023 > Session 11 ILOs - Hypothalamic pituitary axis and pituitary disorders > Flashcards

Session 11 ILOs - Hypothalamic pituitary axis and pituitary disorders Flashcards

1
Q

What do the hypothalamus and pituitary gland form?

A
  • a complex functional unit
  • that serves as the major link between the endocrine and nervous systems.
  • This is the hypothalamic pituitary axis.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Where does the pituitary gland sit in relation to the hypothalamus?

A
  • The pituitary gland sits beneath the hypothalamus in a socket of bone called the sella turcica
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Give 8 functions that are controlled by the hypothalamic pituitary axis

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

How many parts does the pituitary gland consist of?
Name them

A

2 - anterior pituitary gland and posterior pituitary.

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

Describe the technicalities of the posterior pituitary

A
  • Technically not a gland
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Why is the posterior pituitary technically not a gland?
What is it really?

A

Because it doesn’t produce the 2 hormones that it releases.

It is a site of release for oxytocin and Anti diuretic hormone

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

Give a functional link between the hypothalamus and the anterior pituitary gland

A
  • The hypothalamus secretes tropic hormones which have direct effects on the release of anterior pituitary hormones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe a physical relationship between the hypothalamus and posterior pituitary

A
  • The posterior pituitary is physically connected to the hypothalamus, since the hypothalamus drops down through the infundibulum to form the posterior pituitary
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What produces oxytocin and ADH?

A
  • Neurosecretory cells
  • In the supraoptic and paraventricular nuclei
  • Of the hypothalamus.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe what happens to the oxytocin and ADH produced by the hypothalamus

A
  • Transported down nerve cell axons to the posterior pituitary.
  • The posterior pituitary stores and releases the hormones into the general circulation to act on distant target tissues
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Hormones produced by nerve cells in the hypothalamus act via…

A

2 distinct neurocrine pathways

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

Describe the 2 ways that hormones produced by nerve cells in the hypothalamus act

A

1) ADH and oxytocin are released from the posterior pituitary and have direct effects on distant target tissues

2) Hormones secreated exclusivley into hypophyseal portal system that regulate production of the anterior pituitary gland hormones

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

Name the 2 hormones produced in the hypothalamus for release from the posterior pituitary and give their abbreviations and alternative names

A
  • Oxytocin (OT)
  • Antidiuretic hormone (ADH) Also called vasopressin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What do tropic hormones of the hypothalamus do?

A

Have direct effects on the release of anterior pituitary hormones

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

Name the 6 Tropic hormones produced by the hypothalamus and state their abbreviations

A
  1. CRH - corticotropin releasing hormone
  2. GHRH - growth hormone releasing hormone
  3. GHIH/Somatostatin - growth hormone inhibiting hormone
  4. GnRH - gonadotropin releasing hormone
  5. PIH - prolactin release-inhibiting hormone
  6. TRH - thyrotropin releasing hormone

You need to C a GGGP Today

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

What is dopamine also known as?

A

Prolactin release-inhibiting hormone

17
Q

What is somatostatin also known as?

A

Growth hormone-inhibiting hormone

18
Q

What is oxytocin responsible for? (2)

A
  • Milk let down
  • Uterus contractions during birth
19
Q

What is ADH responsible for?

A

Regulation of body water volume

20
Q

What is the actual name of TRH and what is it responsible for? (2)

A
  • Thyrotropin releasing hormone
  • Stimulates thyroid stimulating hormone release
  • Has minor +ve control on prolactin
21
Q

What is the actual name for PIH and What is PIH responsible for? (1)

A
  • Prolactin release-inhibiting hormone (Dopamine)
  • Inhibits the release of prolactin
22
Q

What is the actual name for CRH and what is it responsible for? (1)

A
  • Corticotropin releasing hormone
  • Regulates adrenocorticotropic hormone
23
Q

What is the actual name for GnRH and what is it responsible for? (1)

A
  • Gonadotropin releasing hormone
  • Causes LH and FSH release
24
Q

What is the actual name for GHRH and what is it responsible for? (1)

A
  • Growth hormone releasing hormone
  • Releases growth hormone
25
Q

What is the actual name for GHIH and what is it responsible for? (1)

A
  • Somatostatin - growth hormone inhibiting hormone
  • Inhibits growth hormone
26
Q

Name the hormones produced by the anterior pituitary gland and give their abbreviations (6)

A
  1. ACTH - adrenocorticotropic hormone
  2. GH - Growth hormone
  3. FSH - follicle stimulating hormone
  4. LH - luteinising hormone
  5. PRL - prolactin
  6. TSH - thyroid stimulating hormone

(All girls flirt like the prosper)

27
Q

What does TSH stand for and describe it’s roles (1)

A
  • Thyroid stimulating hormone
  • Stimulates secretion of thyroid hormones from thyroid gland
28
Q

What does ATCH stand for and describe it’s roles (1)

A
  • Adrenocorticotropic hormone
  • Secretion of hormones from adrenal cortex - mainly cortisol
29
Q

What does FSH stand for and describe its functions

A
  • Follicle stimulating hormone
  • Stimulates development of sperm and egg
30
Q

What does LH stand for and describe its functions

A

LH - luteinising hormone

  • Stimulates ovulation
  • Stimulates secretion of sex hormones
31
Q

What does PRL stand for and describe its functions

A
  • Prolactin
  • Stimulates mammary gland development and milk secretion
32
Q

What does GH stand for and describe its functions (3)

A
  • Growth hormone
  • Stimulates growth
  • Stimulates energy metabolism
  • Stimulates IGF’s - insulin - like growth factors
33
Q

Describe the factors controlling GH secretion (long and short loop negative feedback)

A

Growth hormone is produced in the anterior pituitary
However, control is mediated by the hypothalamus by the following tropic hormone
- Stimulated by GHRH
- Inhibited by GHIH/somatostatin

Liver cells and skeletal muscle responds to GH and produce IGF (insulin-like growth factors)

GH controlled by short and long feedback mechanisms:

Short loop negative feedback = Mediated by GH itself by stimulating GHIH/somatostatin release

Long loop negative feedback = Mediated by IGFs:

  • Feeds back to the hypothalamus to inhibit GHRH release and stimulates GHIH/somatostatin release
  • Inhibits the release of GH from the anterior pituitary
34
Q

Describe how GH exerts its effects on cells both directly and indirectly through Insulin like growth factors

A

Direct effect:
- Growth hormone binds to its receptor on target cells to activate intracellular signaling cascades that promote growth and regulate cellular metabolism

Indirect effect:

  • Growth hormone stimulates (via the GH receptor) cells in the liver and skeletal muscle to secrete insulin like growth factors (IGFs/somatomedins)
  • IGFs (IGF-1 - Adult growth, IGF-2 - Fetal growth) are hormones that also act to stimulate body growth and regulate metabolism in target cell (by binding to and activating IGF receptors)
35
Q

Describe the clinical feature of disease states resulting from malfunction of the hypothalamic pituitary axis

A

Pituitary disorders:

Acromegaly (4)

  • Excess growth hormone in adults caused by a GH-secreting pituitary tumour
  • Results in large extremities - large hands and feet
  • Gradual changes in features over years
  • Can cause diabetes and high BP

Prolactinoma (4)

  • Prolactin secreting pituitary tumour
  • Bigger than 1cm = macro-adenoma
  • Smaller than 1cm = micro-adenoma
  • Can because menstrual disturbances, fertility issues, galactorrhea (milk production outside of pregnancy)

Non-functioning pituitary adenoma (4)

  • No secretion of biologically active hormones
  • May secrete inactive hormones
  • Clinical symptoms arise due to the lump or hypopituitarism
  • Hypopituitary bloods with disinhibition hyperprolactinaemia

Cushing’s disease

  • caused by a benign pituitary adenoma secreting ACTH
  • Can result classical moon face, purple striae, abdominal obesity, thin and weak arms and legs etc…

Diabetes Insipidus (3)

  • Excessive water loss due to insufficicent ADH release (so you are unable to reabsorb water back into the blood)
  • Can result in severe dehydration and hypernatremia
  • Large quantities of pale (insipid) urine

Pituitary apoplexy (5)

  • Apoplexy is old fashioned word for stroke
  • Sudden vascular event in a pituitary tumour which leads to reduced blood flow to the pituitary gland
  • You have either had a heamorrhage within the tumour (bleeding)
  • On an infarction within the tumour (blood supply cut off)
  • Sudden onset headache, double vision, cranial nerve palsy, hypopituitarism - cortisol deficiency is most dangerous
36
Q

Outline the endocrine tests use to asses pituitary function

A

3 Main test types: imaging, visual fields and biochemical assessment

Imaging:
- MRI to see tumours

Visual fields:
- Visual field tests to see if optic nerve is compressed

Biochemical assessment :

- Basal (one off) blood test for:
Thyroid axis - fT4, TSH
Gonadal axis - LH, FSH
testosterone - men 
oestradiol - women
Prolactin axis - serum prolactin
- Dynamic tests (adrenal/HPA and growth hormone) : 
Stimulation tests if suspect deficiency
Suppression tests if suspect excess
Adrenal - cortisol at 09:00am
Growth hormone - GH or IGF-1
Adrenal axis:
Deficiency/under active adrenal gland
• Synacthen test
• Insulin stress test
Excess
 • Dexamethasone suppression test
GH axis:
Deficiency
• Insulin stress test
Excess
• Glucose tolerance test
37
Q

Outline management and treatment options for pituitary disorders

A

Treatments for the pituitary disorders:
Acromegaly
- Can surgically remove GH secreting tumour (Trans-sphenoidal surgery)
- Radiotherapy
- Drugs (e.g. dopamine receptor agonist - Bromocriptine and somatostatin analogue - SSA)

Prolactinoma
- Treated with TABLETS (dopamine receptor agonist - Bromocriptine) - NOT OPERATION

Non-functioning pituitary adenoma
- Dopamine receptor agonist - Bromocriptine

Cushing’s disease

  • Depends on what’s causing it!
  • Caused by steroids: dose will be gradually reduced or stopped
  • Caused by a tumour: surgery, radiotherapy or medicine e.g. Ketoconazole

Diabetes Insipidus
- Synthetic vasopressin (nasal spray, tablet, injection)

Pituitary apoplexy
- Made on an individual basis, could be surgery

MEH 2023 (8 decks)

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