MOD 9

Question 1

What percentage of total body weight is water?

Answer 1

~60%

Question 2

How does increased body fat affect TBW (total body water)?

Answer 2

decrease TBW because fat tissues contain less water

Question 3

Why do females generally have less TBW than males?

Answer 3

Higher body fat percentage

Question 4

Main compartments of body fluids?

Answer 4

Intracellular (55% TBW), Extracellular (45% TBW)

Question 5

How much water is lost insensibly per day?

Answer 5

~900 mL

Question 6

What conditions can increase water loss?

Answer 6

Diarrhoea, excessive sweating

Question 7

Main determinant of ECF osmolality?

Answer 7

Sodium (Na⁺)

Question 8

Normal range of osmolality in humans?

Answer 8

275–295 mOsM

Question 9

Osmolality formula?

Answer 9

2 × [Na⁺] + [urea] + [glucose]

Question 10

Difference between osmolarity and tonicity?

Answer 10

Osmolarity = solute concentration; Tonicity = effect on cell volume

Question 11

What happens to a cell in a hypotonic solution?

Answer 11

It swells

Question 12

What happens to a cell in a hypertonic solution?

Answer 12

It shrinks

Question 13

What hormone responds to high osmolarity?

Answer 13

ADH (vasopressin)

Question 14

Where does ADH increase water reabsorption?

Answer 14

Collecting duct (via aquaporins)

Question 15

What is the role of the renal medulla in water conservation?

Answer 15

Maintains a high osmotic gradient

Question 16

What hormones regulate Na⁺ reabsorption?

Answer 16

Aldosterone, RAAS, ADH, natriuretic peptides

Question 17

What triggers RAAS activation?

Answer 17

Low Na⁺, ECF volume, or BP

Question 18

Function of natriuretic peptides (ANP, BNP)?

Answer 18

Decrease sodium reabsorption

Question 19

Why is potassium regulation important?

Answer 19

Affects membrane potential and excitability

Question 20

Symptoms of hypokalaemia?

Answer 20

Muscle weakness, cardiac/respiratory effects

Question 21

Symptoms of hyperkalaemia?

Answer 21

Arrhythmias, weakness, diarrhoea

Question 22

Normal pH range of blood?

Answer 22

7.38–7.42

Question 23

Effects of acidosis on neurons?

Answer 23

Less excitable

Question 24

What is the primary buffer system?

Answer 24

Bicarbonate buffer system

Question 25

How does hypoventilation affect pH?

Answer 25

Decreases pH (more acidic)

Question 26

Common causes of fluid loss?

Answer 26

Vomiting, diarrhoea, sweating, haemorrhage

Question 27

How does dehydration affect osmolality?

Answer 27

Increases osmolarity

Question 28

Three compensatory mechanisms for dehydration?

Answer 28

Thirst, fluid conservation, increased BP

Question 29

Most accurate indicator of fluid status?

Answer 29

Daily weight

Question 30

Fluid deficit signs?

Answer 30

Sunken eyes, dry mucosa, lethargy, cold skin

Question 31

Fluid excess signs?

Answer 31

SOB, oedema, weight gain, crackles

Question 32

What does the presence of ketones in urine suggest?

Answer 32

Starvation or poorly controlled diabetes

Question 33

What does high specific gravity indicate?

Answer 33

Concentrated urine (dehydration)

Question 34

Symptoms of hyponatraemia?

Answer 34

Confusion, cramping

Question 35

Symptoms of hypocalcaemia?

Answer 35

Numb fingers, prolonged QT

Question 36

Symptoms of hypomagnesaemia?

Answer 36

Confusion, arrhythmias