P1 Body Fluids and Membranes

Question 1

The main component of our body accounts for what percentage of our body weight?

Answer 1

50-70%

Question 2

Total body water is divided into what two compartments?

Answer 2

Extracellular fluid and intracellular fluid

Question 3

Describe the characteristics of the extracellular fluid.

Answer 3

1/3 TBW 20% of bodyweight ECF is further divided into the plasma volume (20%) and the interstitial fluid (80%)

Question 4

Describe the characteristics of the intracellular fluid.

Answer 4

2/3 TBW 40% of BW

Question 5

What is blood volume?

Answer 5

Blood volume is plasma volume and volume occupied by the blood cells

Question 6

What is the most abundant solute species in body fluids?

Answer 6

electrolytes

Question 7

Why are the ionic composition of the plasma and interstitial fluid are similar because?

Answer 7

highly permeable capillaries separate them

Question 8

What is the main difference between the plasma and interstitial fluid?

Answer 8

The presence of proteins in the plasma.

Question 9

Describe the ionic composition of the ICF and ECF.

Answer 9

Inside - high potassium; low sodium Outside - High sodium and chloride

Question 10

The cell membrane is highly impermeable to what?

Answer 10

ions

Question 11

What is the main cation in the ECF?

Answer 11

sodium

Question 12

What is the main anion in the ECF?

Answer 12

Chloride Bicarbonate

Question 13

What is the main anion in the ICF?

Answer 13

phosphates proteins

Question 14

What is the main cation in the ICF?

Answer 14

potassium

Question 15

What is diffusion?

Answer 15

random thermal motion of particles causes them to spread out

Question 16

What is simple diffusion?

Answer 16

small, uncharged molecules can pass through the lipid bilayer because they are highly permeable

Question 17

Diffusion depends on what?

Answer 17

solubility of the membrane

Question 18

Positive charges move in what direction?

Answer 18

A positive charge will move from an area of high electrical potential to low electrical potential; downhill.

Question 19

Define bulk electric neutrality.

Answer 19

Total net charge is zero.

Question 20

Flux can be determined by?

Answer 20

concentration; there must be a difference in concentration for flux to occur

Question 21

What defines permeability?

Answer 21

1. Diffuse coefficient of the solute 2. Partition coefficient of the membrane 3. Width of the membrane

Question 22

What is Vm?

Answer 22

Electrical potential across the membrane; voltage across a membrane

Question 23

What happens when there is a movement of ions?

Answer 23

Generation of a membrane potential

Question 24

What happens to the chemical concentrations when there is a movement of ions?

Answer 24

There is no significant change in the chemical concentrations.

Question 25

What happens to the bulk electric neutrality?

Answer 25

No change to overall bulk electric neutrality.

Question 26

Define electrochemical potential.

Answer 26

Difference in electrochemical potential represents the combination of two moving forces. -chemical potential (concentration) -electrical potential

Question 27

What happens if the electrical and chemical potential are equal?

Answer 27

No net change in energy; no flux.

Question 28

What does the net flux depend on?

Answer 28

Difference between the chemical potential and electrical potential. Ion flow will continue until equilibrium is reached again.