Physiology - Body Fluid Compartments and Challenges to Homeostasis Flashcards Preview

The Renal System > Physiology - Body Fluid Compartments and Challenges to Homeostasis > Flashcards

Flashcards in Physiology - Body Fluid Compartments and Challenges to Homeostasis Deck (19)
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1
Q

What is osmolarity?

A

The concentration of osmotically active particles in solution

2
Q

How is osmolarity calculated?

A

Molar conc. x No. of osmotically active particles

(units osmol/l)

3
Q

Body fluids have an osmolarity of what value?

A

Around 300mosmol/l

4
Q

What is tonicity?

A

The effect a solution has on cell volume

5
Q

In terms of tonicity, what 3 things can a solution be?

A

Isotonic

Hypotonic (cell bursts)

Hypertonic (cell shrinks)

6
Q

What is the main difference between osmolarity and tonicity?

A

Tonicity takes into consideration the ability of solutes to cross the cell membrane

7
Q

What percentage of body weight is made up of water?

A

Males - 60%

Females - 50%

(Females have a higher average body fat percentage)

8
Q

What is the largest fluid compartment in the body?

A

Intracellular fluid

9
Q

How is the extracellular fluid split up?

A

Plasma

Interstitial fluid

Lymph and transcellular fluid (e.g. pleural fluid and CSF)

10
Q

What is the average input of fluid per day?

A

2500ml

(fluid intake- 1200ml, food intake - 1000ml, metabolism - 300ml)

11
Q

How can water be lost from the body?

A

Insensible (non alterable) loss from skin and lungs

Sensible (alterable) loss from sweat, faeces and urine

12
Q

In the extracellular fluid compartment, sodium and chloride ions are in ______ concentration and potassium is in ______ concentration

A

In the extracellular fluid compartment, sodium and chloride ions are in high concentration and potassium is in low concentration

13
Q

What is fluid shift?

A

Movement of water between fluid compartments in reponse to osmotic gradients

14
Q

In dehydration, the osmotic concentration of what increases?

A

ECF

15
Q

In which ways can fluid homeostasis be challenged?

A

Gain/loss of water

Gain/loss of salt

Gain/loss of isotonic solution

16
Q

Why is it important to regulate electrolyte balance?

A
  1. Total electrolyte concentrations can directly affect water balance
  2. The concentrations of individual electrolytes can affect cell function
17
Q

Why is it importnant to regulate potassium balance?

A

May cause:

Muscle weakness

Cardiac irregularities

(it affects membrane potential)

18
Q

What is the biggest output of salt from the body?

A

Urine

19
Q

In terms of the ECF, what are the kidneys responsible for?

A

Composition and volume