Cardiopulmonary Circulation

Question 1

what is henry’s law?

Answer 1

At a constant temperature, the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid.

Question 2

what is boyle’s law?

Answer 2

Pressure (P) of a gas is inversely proportional to the volume (V). This law is valid under constant temperature and amount of gas

Question 3

what is charles’ law?

Answer 3

• the volume occupied by a fixed amount of gas is directly proportional to its absolute temperature, if the pressure remains constant.

Question 4

what is Fick’s law?

Answer 4

The rate of diffusion is proportional to both the surface area and concentration difference and is inversely proportional to the thickness of the membrane

Question 5

what is Dalton’s law?

Answer 5

total pressure of a mixture of gases is the sum of the partial pressures of each gas in the mixture

Question 6

what is Poiseille’s law?

Answer 6

The resistance to flow offerent by a tube is proportional to length of the tube and the viscosity of the fluid and inversely proportional to the calibre of the tube

Question 7

what is the consequence of increased O2 and N2 into tissues due to increased pressure?

Answer 7

decompression illness

Question 8

what is the consequence of too much O2?

Answer 8

= toxicity and seizures

Oxygen toxicity risk below 60m due to the pressure

Question 9

do free dives supper decompression illness?

Answer 9

• don’t suffer decompensation illness as lung act as a closed circuit- no more gas can be take up
  
  • But can exchange at alveolar surface continues so can become severely hypoxic as they ascent- lose consciousness in final 5m

Question 10

what are the functions of pulmonary circulation?

Answer 10

• filtration system to stop venous reach
• gas exchange
• metabolism of vasoactive substances
• autonomic regulation of blood flow

Question 11

what is the effect of holding breath during ascent from depth?

Answer 11

pulmonary barotrauma due to Boyle’s law- decrease pressure= increase vol

Question 12

how does rapid decompression cause symptoms?

Answer 12

Question 13

how does the pulmonary circulation act as a filtration system?

Answer 13

• The pulmonary circulation filters before systemic arteries

Question 14

what is an embolus?

Answer 14

mass within circulation capable of causing an obstruction

Question 15

what is an embolism

Answer 15

event characterised by obstruction of major artery

Question 16

what is the normal pulmonary transit time?

Answer 16

0.75s

Question 17

how does pulmonary circulation metabolise vasoactive substances?

Answer 17

Question 18

what is a pulmonary shunt?

Answer 18

circumstances associated with bypassing the respiratory exchange surface

Question 19

when might pulmonary shunts be used?

Answer 19

structural heart disease: problem with tissues or valves of the heart

Question 20

where might pulmonary shunts be present?

Answer 20

1. bronchial circulation
2. foetal circulation
3. congenital defect
   
   1. atrial septal defect (ASD) (or patent foramen ovale :PFO)
   2. ventricular septal defect (VSD)

Question 21

what is a PFO?

Answer 21

• Congenital malformation in 25% of population
• Patency varies between individuals
• Allows blood to bypass pulmonary filter
• blood flows from right atrium to left atrium
• gives risk to VGE becoming arterial gas embolism (AGE)
• fatal sequelae: myocardial infarction, stroke, pulmonary embolism

Question 22

what are the effects of valve disease?

Answer 22

hardening of valve reduces ventricular filling (AV) or ejection (Semilunar)

Question 23

what is the effect of IHD?

Answer 23

narrowing of coronary arteries cause ischaemia in heart muscle

Question 24

what are the effects of myocardial infarction?

Answer 24

significant occlusion leads to death of heart muscle

Question 25

what are the effects of hypertension on heart muscle?

Answer 25

hypertension increases afterload which means the ventricle must work harder

Question 26

what is the effect of dilated cardiomyopathy on heart muscle?

Answer 26

dilated LV reduces generatable pressures which reduces ejection

Question 27

what is the effect of hypertrophic cardiomyopathy on heart muscle?

Answer 27

increased LV thickness reduces internal ventricular volume & impedes filing