Body Water Homeostasis Flashcards
1
Q
In a 70kg man, what is the bodily water content?
A
42 litres
2
Q
How is the 42 litres of water in the body divided?
A
- Intracellular (2/3 ~ 28l )
- Extracellular- interstitial fluid (~11l)
- Extracellular- blood plasma (~3l)
* blood volume=5l because there are 2l of red cells
3
Q
How is osmotic pressure of blood plasma monitored?
A
Osmoreceptors in the supraoptic and paraventriuclar nuclei of the hypothalamus
4
Q
How do the osmoreceptor cells control osmolality and sodium ion conc of the blood?
A
Influence feeling of thirst and also release anti-duirectic hormone (ADH)/ vasopressin
5
Q
Where is ADH/vasopressin released from?
A
The posterior pituitary gland.
6
Q
What is the effect of ADh/vasopressin ?
A
Works on kidneys, causing an increase in the permeability of the collecting ducts to water. Thus increasing the reabsorption of water from the urging into the blood.
