Homeostasis: Body Fluid Flashcards
1
Q
What is the compositon of urine?
A
- 95% water
- 2.8% dissolved salts and other ions
- 2% urea
- 0.2% creatinine, ammonia, and uric acid
2
Q
What are the three kinds of extracellular fluid?
A
- interstitial - fluid which bathes the cells;
- intravascular - fluid found inside blood vessels; and
- transcellular - fluid found in the ocular and CSF compartments.
3
Q
Define osmotic pressure (2 marks)
A
the capacity for a solution to take in a solvent via osmosis or the pressure needed to prevent osmosis.
4
Q
List two things that could cause osmotic pressure to increase and two things that could cause it to decrease. (3 marks)
A
Osmotic pressure can increase by:
- an increase in non-iodised water consumption;
- not-replenishing essential amounts of dissolved salts constantly; and
- sweating (loss of dissolved salts).
Osmotic pressure can decrease by:
- a lack in water consumption (dilution occurs);
- consuming high-salt foods; and
- never exercising.
5
Q
What substances are reabsorbed back into the blood during selective reabsorption?
A
Glucose, amino acids, K+, Na+, other ions…
6
Q
What substances are secreted back into the DCT via tubular secretion?
A
K+, creatinine, other ions and drugs.