Equation, Relationships and Numeracy

Question 1

What is Boyle’s Law?

Answer 1

P1V1 = P2V2

Question 2

How do you calculate Cardiac Output (CO) from Heart Rate (HR) and Stroke Volume (SV)?

Answer 2

HR x SV

Question 3

How do you calculate Cardiac Output (CO) from Mean Arterial Pressure (MAP) and Total Peripheral Resistance (TPR)?

Answer 3

MAP / TPR

Question 4

How do you calculate Mean Arterial Pressure (MAP) in mmHg?

Answer 4

Diastolic Pressure (mmHg) + 1/3 pulse pressure (mmHg)

Question 5

How do you calculate pulse pressure in mmHg?

Answer 5

Systolic Pressure (mmHg) - Diastolic Pressure (mmHg)

Question 6

VM is minute volume

How do you calculate VM in L/min?

Answer 6

VT x RR

Tidal Volume x Respiratory Rate

Question 7

How do you calculate Alveolar Ventilation (VA) in L/min?

Answer 7

(VT - Deadspace) x RR

(Tidal Volume - Deadspace) x Respiratory Rate

Question 8

How do you calculate Deadspace in ml?

Answer 8

2.2 x body weight in kg

Question 9

How do you calculate clearance of substance in ml/min?

Answer 9

(Concentration of substance x flow rate) /plasma concentration of substance

Question 10

How do you calculate sperm viability?

Answer 10

(number alive with normal morphology / total) x 100

Question 11

How do you calculate ml of viable sperm?

Answer 11

Density/ml x %viability / 100

Question 12

What is Fick’s Law?

Answer 12

Jx (flux) = Px x ([X]A – [X]B)

A & B are concentrations either side of the barrier; Px is permeability
coefficient made up of (S = surface area, Dx = permeability, a = surface thickness); thin and large area normally gives best flux.

Question 13

What is Van’t Hoff’s Law?

Answer 13

Change is osmotic pressure = iRT(Cx-Cy)

x and y represent the 2 solutions, C represents concentration.

i = number of ions formed from one solute molecule
T = temperature (in K),
C = concentration (mol/L)
R = the gas constant (8.34)

Question 14

What is the Nernst Equation for Equilibrium (reversal) Potential?

Answer 14

E_MV = 61.5 x log₁₀ ([ion]_out / [ion]_in)

Question 15

What is the GHK Equation for membrane potential?

(e = external or out, i = internal or in; P= permeability for the ion)

Answer 15

Vm = 67.5log₁₀ x (P_K[K⁺]_e + P_Na[Na⁺]_e / P_K + P_Na[Na⁺]_i)

Question 16

What is the Starling Equation?

Answer 16

J_vα[(P_c-P_if)-σ(π_c-π_if]

Jv = net volume flow, P = pressure, c= capillary, if= interstitial fluid, π = colloid, σ = reflection coefficient.

Question 17

How do you calculate Lung Compliance?

Answer 17

C_L = ΔV_L / ΔP_t

CL= lung compliance, Pt = transpulmonary pressure, VL= volume

Question 18

What is the Young-LaPlace Law?

Answer 18

PA = 2T/r

Question 19

What is Poiseuille’s Law?

Answer 19

Resistance of airway (RAW) R = 8ηL / πr4

η = Viscosity L = length r = radius

Question 20

How do you calculate Glomerular Filtration Rate?

Answer 20

GFR = KS (PGC – PT) – (∏GC – ∏T)

KS – filtration coefficient (permeability and surface area); PGC – hydrostatic pressure in glomerular
capillaries; PT – hydrostatic pressure in tubule; ∏GC – colloid osmotic pressure (oncotic pressure) in
glomerular capillaries; ∏T – colloid osmotic pressure (oncotic pressure) in tubule.