Powerpoint 6 Flashcards
What 6 hormones are released from the anterior pituitary and where do they do?
- TSH –> thyroid
- ACTH –> arenal cortex
- FSH & LH –> testes and ovaries
- GH –> Entire body
- Prolactin (PRL) –> mammary lands
- Endorphins –> pain receptors in brain
What two hormones are released from the posterior pituitary and where do they go?
- Oxytocin –> Uterine muscles, mammary glands
2. ADH –> kidney tubules
Which hypothalamic nuclei whose axon connects to the posterior pituitary produce vasopressin? Oxytocin?
- Supraoptic (ADH)
2. Paraventricular (OT)
What type of peptide hormones come from the posterior pituitary?
nonapeptides - 9 amino acids
What are characteristics of nonapeptides that are released from the posterior pituitary?
- 9 a.a.
2. formation of ring via disulphide bridge
How does the vasopressin nonapeptide differ from the oxytocin nonapeptide?
ADH: Phe (top left), Arg (chain)
Oxytocin: Ile (top left), Leu (chain)
How is pig vasopressin different from human vasopressin?
Pigs have lysine-vasopressin instead of arginine-vasopressin
What does oxytocin do?
Contracts smooth muscle cells
- Myoepithelial cells of the alveoli
- Smooth muscle cells of the uterus during labour
What does vasopressin do?
- H2O retention by the kidney
- Contraction of blood vessels (arteriole)
If you could describe vasopressin in one word what would it be?
antidiuretic
What two systems does vasopressin affect?
- osmotic
- pressure-volume
What 3 receptors does vasopressin pair with and where are they located?
- V1a
- V1b
- V2
What is the function vasopressin?
water retention, thirst as the primary regulator of osmolarity
In terms of vasopressin osmolarity regulation, is the control/conservation of water or the regulation of Na concentrations in plasma more complicated?
Regulation of [Na] in plasma
What 2 systems are involved the regulation of [Na] in plasma via vasopressin?
- RAS (renin-angiotensin system)
2. aldosterone
Regulation of osmolarity: Osmoreceptors located in _______ detect osmotic changes in _________: osmostat responds to as little as ___% change in osmolarity. i.e. Cell ______ when blood too dilute or ______ when blood too concentrated – contraction sends neural signals to _________ nuclei to release _________.
- hypothalamus
- blood plasma
- 1%
- expands
- contract
- Supraoptic
- vasopressin
Vanilloid Receptor-Related Osmolarity Activated Channel
??????????
What 4 signals can be sent to the pituitary gland from the body indicating low blood pressure? What is released as a result and how does this control blood pressure in the body?
- Angiotensin 2
- hyperosmolarity
- decreased atrial receptor firing
- sympathetic stimulation
Vasopressin release from pituitary –> causes vasoconstriction & renal fluid reabsorption
- Vasoconstriction leads to increased arterial pressure
- Renal fluid reabsorption leads to increased blood volume
How many nephrons per kidney?
1 million
What is thirst triggered by?
Changes in osmolarity or volume - strongly triggered by hypovolemia (decreased blood volume)
Changes in osmolarity are usually too _____ to trigger thirst.
small - 1 to 2%
In dehydration plasma osmolarity _____ and blood volume ______ resulting in ________ release to ______ water and produce more ________ urine.
- increases
- decreases
- vasopressin
- retain
- concentrated
If water is excess (usual condition) then there is a small ________ in osmolarity and thus ______ vasopressin resulting in _______ urine.
- decrease
- less
- diluted
What happens to osmostat and vol/pressure during pregnancy?
reset - less sensitive
total body water volume/pressure increase as a result of vasodilation
Vasopressin now responds to the reset point
What does the placenta produce during pregnancy and how does this affect vasopressin?
Placenta produces enzymes to degrade vasopressin
The total body water of elderly declines to as low as ___% of young adults by the age of 80.
50%
What physiologies in elderly are decreased? Causing elderly to be susceptible to what two things?
- decrease kidney filtration rate + collecting duct less responsive to vasopressin
- decreased response to dehydration and decrease ability to excrete water load
Susceptible to HYPO and HYPERatremia (low/high sodium ion level in the blood)
What is characteristic of the urine of people with diabetes?
- large volume
- hypotonic
- dilute
- tasteless (insipid)
What are the 4 main causes of diabetes insipidus urine?
- lack of AVT (released by pineal gland) (trauma, tumour, etc)
- lack or response to AVT in kidney (receptor defect, aquaporin defect)
- rapid metabolism of AVT - less available especially during pregnancy i.e. transient diabetes insipidus
- polydipsea - individual drinks too much and excess urine is normal response
How is diabetes insipidus diagnosed?
by water deprivation test — normal people will end up with concentrated urine while people with diabetes insipidus will not
