S1) Intro To Body Systems Continued

Question 1

Below which temperature is a person severely hypothermic?

Answer 1

32 degrees

Question 2

At PH 7.4 what is the H+ conc? What is it at PH 7.1 and PH 7.7 (change of 0.3)?

Answer 2

40nM for PH 7.4
80nM for PH 7.1
20nM for PH 7.7

Question 3

Recall the mechanisms in broad terms that regulate PH and body temp:

Answer 3

Body temp: vasodilation/vasoconstriction, sweat secretion, shivering, hairs stand up/lay flat.

PH: buffer systems - e.g. sodium phosphate buffering system.

Question 4

Why is aluminium hydroxide a good acid neutraliser?

Answer 4

• it is insoluble and mildly alkaline.

Question 5

What are the terms given when there is too much and not enough water and what are the consequences of this?

Answer 5

• not enough = dehydration
• too much = toxicity
• lead to cell/tissue/organism death

Question 6

How many litres of fluid is needed each day to maintain a healthy adult?

Answer 6

2.5L

Question 7

Compare and contrast water balance in males and females and in early life and in older populations:

Answer 7

• Infants - highest % of TBW.
• males more than females (more body fat = less TBW).
• lean people have a higher % TBW than obese people.
• elderly have less TBW. (50%)
• adult male = 60%
• adult female = 50%
• infant = 70%

Question 8

What does hypotonic mean?

Answer 8

• less water inside cell
• solute conc inside cell is higher
• water transported into cell
• cell inflates and eventually bursts

Question 9

What does hypertonic mean?

Answer 9

• less water outside cell (so more water inside cell).
• solute conc inside cell is lower
• water is transported outside cell
• cell shrinks

Question 10

What does isotonic mean?

Answer 10

• same amount of water on both sides of plasma membrane

- solute conc in equal

Question 11

What is the difference between osmolality and osmolarity? What are their units?

Answer 11

• osmolality - conc of a solution expressed as total number of solute particles per kg. Osmol/L
• osmolarity - conc of a solution expressed as osomoles of solute particles per L of solution. Mol/L

Question 12

What is oedema and what causes it?

Answer 12

• fluid retention
• when hydrostatic pressure is higher than oncotic pressure.
• as a result of the presence of plasma proteins in interstitial space.
• lymphatics blocked.