Homeostasis

Question 1

describe the distribution of water in the body.(assuming healthy 70Kg male)

Answer 1

• 42L of water altogether
• 28L intracellular
• 10L interstitial
• 3L intravascular
• 1L transcellularly ie CSF, digestive juices and mucus

Question 2

what is the most common intracellular ion?

Answer 2

K+ - potassium

Question 3

what is the most common extra cellular ion?

Answer 3

Na+ - sodium
Cl- - chlorine
HCO3- - bicarbonate

Question 4

what is homeostasis?

Answer 4

the property of a system in which variables are maintained so that internal conditions remain stable and relatively constant

Question 5

define osmosis.

Answer 5

the net movement of solvent molecules through a semipermeable membrane down a concentration gradient to a higher solute concentration

Question 6

define osmolality.

Answer 6

the measure of the number of dissolved particles per Kg of fluid.

Question 7

define osmolarity.

Answer 7

measure of the number of dissolved particles perL of fluif

Question 8

define osmotic pressure.

Answer 8

pressure applied to a solution bby a pure solvent required to prevent inwards osmosis

Question 9

define oncotic pressure.

Answer 9

form of osmotic pressure exerted by proteins that tends to pull fluid into it’s solution.

Question 10

what are the 4 causes of odema?

Answer 10

• inflammatory leakage
• increased venous pressure
• blocked lymphatics
• hypoalbuminaemic

Question 11

what causes odema by inflammatory leakage?

Answer 11

• increased vascular permeability due to inflammation
• proteins leak out
• H2O follows to dilute toxins

Question 12

what causes odema due to increased venous pressure?

Answer 12

• increased venous pressure causes H2O to leak out into tissues
• due to thrombosis or hypertension

Question 13

what causes odema due to being hypoalbuminaemic?

Answer 13

• albumin exerts the main oncotic pressure on the blood

- lack of this causes fluid to leave into the tissue