cell physiology

Question 1

Body compartments percentages

Answer 1

TBW=60% –> 2/3 ICF (40%) + 1/3 ECF (20%) [ECF: 5% vascular system + 15% interstitial fluid]
Protein=18%
Fat=15%
Minerals=7%

Question 2

Mole definition

Answer 2

1 mole = 6.022 x 10^23 / Na (Avogadro number). So the mole is the amount of substance of a system that contains 6.022.10^23 specified elementary entities.

Question 3

Solute concentration in biological fluids

Answer 3

extracellular: Na+=142 K+=4 Mg2+=1 Cl-=102 PO24-=1 Bicarb=26
intracellular: Na+=10 K+=160 Mg2+=13 Cl-=2 PO24-=57 Bicarb=8

Question 4

pH and buffer equations

Answer 4

pH=-Log[H+]
Henderson Haselbach equation: pH=pKa + Log (Base/Acid]
(The buffering capacity of a weak acid is best when pka of that acid is equal to pH of the solution)

Question 5

Diffusion definition / Ficks law

Answer 5

Diffusion: migration of solutes from area of high concentration to a lower concentration area
Ficks law: J (net rate of diffusion) = -D(diffusion coeff) x A (area) x [delta c/delta x)] (concentration gradient)

Question 6

Osmosis definition

Answer 6

diffusion of solvents molecules into a region in which there’s a higher concentration of solutes to which the membrane is impermeable. in order to equalize the concentrations of the solutions
P (osmotic pressure) =n (nb of particles) x R (gas constant) x T (temperature) / V (volume)

Question 7

Na,K ATPase

Answer 7

-Hydrolysis ATP to ADP
-Extrudes 3Na+ and intrudes 2 K+ into the cell
-Activity inhibited by ouabain and digitalis
-alpha (through which the Na an k transport occurs) and beta subunits
a1= most cells, a2=muscle/heart/adipose/brain, a3=heart and brain
b1=widely distributed, absent in astrocytes and inner ear, b2= fast twitch muscles
-Molecular weight = 55000
-Both units extend through the cell membrane