Pituitary Gland Flashcards

1
Q

What synthesizes vasopressin and oxytocin?

A

PVN (paraventricular nucleus)

SON (supraoptic nucleus)

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

What does vasopressin do?

A

Enhance water retention of the kidney via aquaporin water channels
Direct pressor effect via constraction of the smooth muscle in vascular system

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

Whar are the parts of the vasopressin gene?

A
  • SP
  • VP
  • NPII
  • Copeptin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is copeptin?

A

related to vasopressin. Vasopressin is bound to receptors on platelets (extends half life)
Can assay for vasopressin levels

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

What are the vasopressin receptor in the kidneys?

A

AVPR2

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

What is the receptors for vasopressin in vascular system?

A

AVPR1a

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

What kind of hormone is vasopressin?

A

Peptide (9 aa with disulfide bond)

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

What provides feedback regulation to the vasopressin effect?

A

Volume and pressor receptors

to see pressor effect, must mask the baroreceptors

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

How is vasopressin released?

A

Made in hypothalamic MNC, Packaged into vesicle and sent to posterior pituitary where it is stored. It is released when stimuli acts on hypothalamus and calcium influx

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

What causes the release of vasopressin?

A
  • High plasma osmolality (MNC in hypothalamus)
  • Low blood volume or pressure (IX and X)
  • increase plasma angiotensin II (SFO)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What hormone has a permissive effect on vasopressin?

A

Aldosterone

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

What is the ultimate result from increased vasopressin?

A

Anti-diuresis (concentrated urine)

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

What counteracts vasopressin and aldosterone?

A

Atrial natriuretic peptide

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

What is the action of increased vasopressin?

A
Increase permeability to water
-aquaporin insertion
-Water flow out of tubule/duct in kidney
Increase thirst
Smooth muscle contraction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What happens when MNCs sense high osmolality?

A

Increase action potentials to release more vasopressin

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

What is the stimulus of the regulation of vasopressin?

A
  • Osmotic difference
  • Hypovolemia
  • blood pressure in jeopardy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the receptors involved in the regulation of Vasopressin?

A
  • NTS

- SFO

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are compensatory reaction from vasopressin signaling?

A

Salt and water intake

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is a disease that relates to loss of vasopressin?

A

Diabetes insipidus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the signs of diabetes insipidus?

A

Polyuria, polydipsia, urine of low specific gravity, dehydration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What does pathognomic mean?

A

A sign specifically characteristic of a particular disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are some causes of diabetes insipidus?

A
  • Central DI
  • Nephrogenic DI
  • Psychosomatic polydipsea
  • Inappropriate ADH secretion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How can you rule out central DI?

A

Determine whether endogenous ADH can occur and if it is increased and so does concentration of urine it is not central DI

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How can you rule out nephrogenic DI?

A

If there is a response to exogenous ADH it is not nephrogenic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
How can you treat hypothalamic DI?
- Nothing if it is getting adequate water | - Exogenous ADH
26
What could cause inappropriate ADH secretion?
Release ADH with no osmotic or volume stimulation. Usually from neoplastic processes
27
How can you treat nephrogenic DI?
- Thiazide diuretics - Chlorothiazide - Hydrochlorothiazide - Dietary potassium
28
What does Oxytocin stimulate?
- Contraction of myometrium | - Milk letdown reflex
29
What is different about the regulation of oxytocin?
Positive or open loop regulation
30
What stimulates Oxytocin release?
Sight, smell, sounds, or nursing of young
31
What is the events of milk letdown?
Oxytocin causes secretory alveoli to contract-> milk flows into intralobular duct->goes into lobular duct-> gland cistern-> teat cistern-> teat canal-> milk ejected
32
Describe the positive feedback loop of oxytocin?
Mechanical stimulation of cervix-> oxytocin release-> relaxes cervix and contracts uterus-> more oxytocin
33
What are the different oxytocin effects?
- Glucocorticoid receptor: reduce cortisol - Alpha 2 receptor: blocks norepinephrine stress effects - Opiodergic activity: Reward and pain free - 5-HT synthesis: happiness - Cholinergic activity: Calm and sleep
34
Describe the oxytocin receptors.
There is only one receptor but there are different polymorphisms that can give it different functions
35
What are the four main hypophysiotrophins of the anterior pituitary?
- Growth hormone (GH) - Somatostatin (GHIH) - Corticotropin (ACTH) - Thyroid-stimulating hormone (TSH)
36
How are anterior pituitary hormones controlled?
Releasing factors that are made in the hypothalamus and released at the median eminence into portal blood and then acts on the anterior pituitary
37
What is the TRH?
Thyrotropin releasing hormone. Half life is 2-6 min.
38
What are the effects of TRH?
Release of TRH into portal system and causes thyrotropes to produce TSH from the thyroid and then T3 and T4 are secreted
39
Do TRH and TSH impact calcitonin
No
40
What hormones does TRH effect?
GH, ADH, Prolactin, cortisol (horses)
41
What is CRH?
Corticotropin releasing hormone. 41 AA peptide. Secreted by median eminiece and PVN neurons
42
What are the effects of CRH?
Released into portal system and stimulates the release of ACTH
43
What is POMC?
Pro-opiomelanocortin.
44
What is the N terminal of POMC?
Produces a strong proliferation in adrenal cortex as well as ACTH
45
What is the Prohormone Convertase I?
Made in pars intermedia and cleaves the POMC and makes alpha MSH and ACTH
46
What is GH?
Growth hormone. Polypeptide 191 AA. Made in somatotrophs in response to GHRH
47
What are some effects of GH?
Production if IGFs in the liver, muscle, and bone. Lipolytic effect
48
What are somatomedins?
IGFs that mediate GH effects. Provides feedback to shut off GH and stimulate GHIH
49
What increases GH release?
- Sleep - Hypoglycemia - incr Plasma aa (Arg) - Ghrelin (hunger stimulating peptide hormone from the stomach) - Exercise
50
What decreases GH release?
- Hyperglycemia - Glucocorticoids - Somatomedins - Somatostatin
51
Which hormone has the lowest species homology?
Growth hormone
52
What is Homeorhesis
Shift in metabolism associated with lactation
53
What is the effects of GH on bones?
- Promote chondrogenesis in epiphyseal plate | - Promote production of bone matrix
54
What is the metabolic effect of GH?
- Promotes aa uptake (per insulin) - Promotes lipolysis in adipocytes - Improve nutrient utilization - Diary cows: increase milk production
55
What is Pituitary Dwarfism?
Fairly rare. Deficiency of GH. Seen in dogs most common in German Sheperd's. Due to a cystic Rathke's pouch
56
What are some clinical signs of young animals with pituitary dwarfism?
- Proportional dwarfism - Delayed dentition - Delayed closure of growth plates - Haircoat abnormalities - Reduced exercise performance
57
What is the clinical signs of adults with pituitary dwarfism?
- Abnormal weight gain - Reduced lean mass - Reduced exercise performance - Osteopenia
58
What are some diagnosis of pituitary dwarfism?
-Insulin growth factor -Relaxation -Sedation Should see increase of GH with these
59
What is acromegaly?
Hypersomatotropism. Excess GH post puberty. Rare in dogs | and sometimes seen in older male cats. Get growth of membranous bones
60
What are some causes of acromegaly?
- Pituitary adenomas | - Pituitary hyperplasia
61
What are signs of acromegaly?
- Weight gain - Lean body in animals with diabetes mellitus - Enlarged jaw, tongue, forehead and extremities - Failure to shed
62
How can you diagnose acromegaly?
Glucose suppression test
63
What does the intermediate lobe produce?
alpha-MSH POMC convertase 1 POMC convertase 2
64
What regulates the pars intermedia?
regulated by dopamine which inhibits release
65
What can cause and PPID parkinson's?
Dopamine insufficiency
66
What is PPID?
Pituitary pars intermedia disfunction. Looks like Cushing's disease but it is from a loss of dopamine