Lecture 1 - Bodily Fluids And Oedema

Question 1

Define: Homeostasis

Answer 1

The state of dynamic equilibrium and is characterised by variable responses to changes in external environment

Question 2

Recall the percentage of water in a “standard” 70kg male

State the comparison in water between males and females

Answer 2

60% water

1/3 extracellular

80% interstitial
20% plasma

Males have a higher balance of water

Question 3

Explain negative and positive feedback loops

Answer 3

Negative feedback is a response that reduces the effect of the change that led to response.

Positive feedback is when a response increases the effect causing a greater response to occur

Question 4

Explain the importance of the acid-base balance for humans.

How are respiratory and metabolic pH changes controlled?

Answer 4

Fluctuations of pH from optimal can lead to cells dying as proteins will denature.

Respiratory is controlled by breathing.
Acidosis = breathe into bag with an increased breathing rate.
Alkalosis = reduce breathing rate

Metabolic is controlled by the Kidneys.
Acidosis = more H+ ions are secreted.
Alkalosis = more HCO3 - are secreted

Question 5

What is the normal range for pH and temperature?

Answer 5

pH = 7.40 +- 0.5

Temperature = 37.0 +- 0.5

Question 6

How does body regulate temperature.

Answer 6

• Vasoconstriction/dilation
• Piloerection/relaxation
• shivering
• sweating

Question 7

Describe Oedema

Answer 7

High hydrostatic pressure causes fluid in blood plasma to move out into the tissue fluid. Albumin proteins within the blood plasma attract water back into the blood. Excess tissue fluid is drained by the lymphatic system and secreted back into the blood stream.

Oedema is the build up of this excess tissue fluid is oedema.