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
