Pulmonary blood flow, Gas exchange & Transport 1-3

Question 1

What is the name of the branch of the systemic circulation that provides nutritive support to the lungs ?

Answer 1

Bronchial Circulation

Question 2

What are the partial pressures of Oxygen and Carbon Dioxide in the arterial circulation ?

Answer 2

PaO2 = 100 mmHg/13.5 kPa
PaCO2 = 40 mmHg/5.3 kPa

Question 3

What are the partial pressures of Oxygen and Carbon Dioxide in the venous circulation ?

Answer 3

PaO2 = 40 mmHg/ 5.3 kPa
PaCO2 = 46 mmHg/6.2 kPa

Question 4

What are the partial pressures of Oxygen and Carbon Dioxide in the tissues ?

Answer 4

PaO2 = 40 mmHg/ 5.3 kPa
PaCO2 = 46 mmHg/6.2 kPa

Question 5

What are the partial pressures of Oxygen and Carbon Dioxide in the lungs ?

Answer 5

PaO2 = 100 mmHg/13.5 kPa
PaCO2 = 40 mmHg/5.3 kPa

Question 6

What is ‘Tidal Volume’ ?

Answer 6

The amount of air per breath that enters the lungs at rest (500ml per breath)

Question 7

What is ‘Total Lung Capacity’ ?

Answer 7

The maximum amount of air the lungs can hold upon deep inhale and forced exhale (6000ml/6L)
TLC = VC + RV

Question 8

What is ‘Vital Capacity’ ?

Answer 8

The amount of air that can be forced out of the lungs from rest (4800ml/4.8L)

Question 9

What is ‘Residual Volume’ ?

Answer 9

No matter how much you breathe out the residual volume will always remain within the Alveoli (stops Alveoli from collapsing)

Question 10

What is ‘Functional Residual Capacity’ ?

Answer 10

Residual volume + Expirartory Reserve Volume

Question 11

Name 4 pathologies that may affect gas exchange ?

Answer 11

Emphysema - Reduces surface area
Fibrotic lung disease - Thickened Alveolar membrane
Pulmonary Oedema - Interstitial space increases
Asthma - Constricted bronchiole

Question 12

What is the total O2 carrying capacity of plasma ?

Answer 12

3ml O2/L blood

Question 13

What is the total O2 carrying capacity of plasma that contains RBC ?

Answer 13

200ml O2/L blood

Question 14

How many molecules of Oxygen can 1 RBC carry ?

Answer 14

4 Molecules (1 for each haem group)

Question 15

How much Oxygenated blood is produced per minute ?

Answer 15

1000ml/min

Question 16

What is the tissues demand for oxygenated blood ?

Answer 16

250ml/min

Question 17

Name the chemical factors that will affect the oxyhaemaglobin dissociation curve ?

Answer 17

PCO2
pH
Temp.
2,3-DPG

Question 18

Exercise will shift the oxyhaemaglobin dissociation curve to the Left/Right ?

Answer 18

Right

Question 19

Where is Myoglobin found and what is its affinity for oxygen ?

Answer 19

Skeletal muscle, high affinity for oxygen (higher than Hemoglobin)

Question 20

How is CO2 transported in the blood stream ? (explain the process)

Answer 20

Gasses travel in the blood stream in soloution.

1: CO2 combines with water inside RBC forming carbonic acid (carbonic anhydrase)
2: This dissociates becoming bicarbonate and H ions
3: Bicarbonate moves out of RBC in exchange for chloride ions

Question 21

What is the chloride shift ?

Answer 21

When Bicarbonate moves out of the RBC in exchange for Cl ions

Question 22

Where in the lungs is blood flow greatest ?

Answer 22

The base

Question 23

What shape are the Alveoli at the apex and the base of the lungs ?

Answer 23

Apex: Long and not compressed
Base: Short compressed and easily inflated

Question 24

Around what rib number does this change in alveolar presentation occur ?

Answer 24

Rib 3

Question 25

Name two types of V/Q (ventilation/perfusion) mismatch

Answer 25

Shunt: Where this is normal perfusion but decreased ventilation. The CO2 in the alevolus increases and O2 decreases and the blood flowing past this alveolus is not getting oxygenated.
Alveolar ‘Dead Space’: Where there is normal ventilation but decreased perfusion due to a blockage or clot within a vessel

Question 26

What occurs during Hypoxaemia in the pulmonary circulation ?

Answer 26

Vasoconstriction

Question 27

What does Hypo-ventilation do to the respiratory system ?

Answer 27

Causes CO2 retention, increases H ions, causing respiratory acidosis.

Question 28

What does Hyperventilation do tho the respiratory system ?

Answer 28

Blows off more CO2, decreases H ions, causing respiratory alkalosis.