Respiratory physiology 4

Question 1

What is the comparison of ventilation and perfusion at the base of the lungs and why?

Answer 1

Perfusion exceeds ventilation because arterial pressure exceeds alveolar pressure.

Question 2

What is the comparison of ventilation and perfusion at the apex of the lungs and why?

Answer 2

Ventilation exceeds perfusion because alveolar pressure exceeds arterial pressure

Question 3

What causes there to be greater blood flow at the base of the lung than the apex?

Answer 3

Gravity

Question 4

What is shunt?

Answer 4

Movement of blood from the right side of the heart to the left side without being ventilated.

Question 5

How is shunt limited?

Answer 5

Pulmonary vessels constrict in response to hypoxia, which redirects blood to areas of higher ventilation.

Question 6

When does alveolar dead space occur?

Answer 6

When ventilation exceeds perfusion

Question 7

What is the opposite of shunt?

Answer 7

Alveolar dead space

Question 8

What can increased PAO2 cause?

Answer 8

Pulmonary vasodilation

Question 9

What ensures the ventilation: perfusion ratio is close to 1?

Answer 9

Respiratory sinus arrhythmia (RSA)

Question 10

How is the majority of O2 transported in blood?

Answer 10

Haemoglobin

Question 11

How is the majority of CO2 transported in blood?

Answer 11

Travels in solution in plasma (77%)

Question 12

What is the resting demand of O2 in tissues?

Answer 12

250ml/min

Question 13

How many molecules of O2 can bind to one haemoglobin molecule?

Answer 13

4

Question 14

What is normal oxygen saturation in arterial blood?

Answer 14

95-100%

Question 15

What is normal oxygen saturation in venous blood?

Answer 15

75%

Question 16

How does O2 move from alveoli to haemoglobin?

Answer 16

It diffuses from alveoli to plasma, and is then taken up by haemoglobin

Question 17

Why does iron deficiency cause anaemia?

Answer 17

As the oxygen binds to Fe2+ within haemoglobin

Question 18

What 4 factors can effect oxygen saturation curve?

Answer 18

Ph (decrease moves curve to right)

Temperature (increase moves curve to right)

PCO2 (increase moves curve to right)

DPG (Increase moves curve to right)

Question 19

What percent of CO2 forms bicarbonate?

Answer 19

70%

Question 20

What is the term used to describe CO2 bound to deoxyhaemoglobin?

Answer 20

Carbamino compound

Question 21

If O2 travels in the gaseous state in plasma, what can this cause?

Answer 21

Air embolism

Question 22

By what process does oxygen bind to haemoglobin?

Answer 22

Oxygenation

Question 23

What type of haemoglobin accounts for 92% of the total haemoglobin?

Answer 23

Adult haemoglobin (HbA)