pulmonary blood flow, gas exchange, and transport

Question 1

what are the two circulations that supply blood to the lungs?

Answer 1

bronchial circulation and pulmonary circulation

Question 2

what is the bronchial circulation supplied by?

Answer 2

bronchial arteries

Question 3

what circulation does bronchial arteries arise from?

Answer 3

systemic

Question 4

which circulation supplies oxygenated blood to the airway smooth muscle, nerves and lung tissue?

Answer 4

bronchial circulation

Question 5

what does the pulmonary circulation supply the blood to?

Answer 5

Supplies the dense capillary network surrounding the alveoli and returns oxygenated blood to the left atrium via the pulmonary vein

Question 6

what does the pulmonary circulation consist of?

Answer 6

consists of L & R pulmonary arteries originating from the right ventricle.

Question 7

is the rate of diffusion most rapid over shorter distances or longer?

Answer 7

short distances

Question 8

is rate of diffusion proportional to the partial pressure gradient?

Answer 8

yes

Question 9

is rate of diffusion proportional to gas solubility?

Answer 9

yes

Question 10

is rate of diffusion proportional to the available surface area?

Answer 10

yes

Question 11

is rate of diffusion proportional to the thickness of the membrane?

Answer 11

no

Question 12

what does partial pressure in alveoli correspond to?

Answer 12

partial pressure in systemic arterial blood

Question 13

what does partial pressure in pulmonary arterial blood correspond to?

Answer 13

partial pressure at tissue

Question 14

where is PO2 highest?

Answer 14

alveoli

Question 15

where is PCO2 highest?

Answer 15

pulmonary arterial blood

Question 16

what is the characteristics of the membrane in fibrotic lung disease? And what happens to the compliance

Answer 16

thick, slows gas exchange
loss of lung compliance may decrease alveolar ventilation
PO2 normal or low

Question 17

what is the characteristics of the membrane in emphysema?

Answer 17

destruction of alveoli reduces surface area for gas exchange

Question 18

what are the characteristics of pulmonary edema?

Answer 18

fluid in interstitial space increases diffusion distance. Arterial Pco2 may be normal due to higher CO2 solubility in water

Question 19

what are the characteristics of asthma?

Answer 19

increased airway resistance decreases airway ventilation
PO2 low
Bronchioles constricted

Question 20

what is perfusion?

Answer 20

local blood flow

Question 21

what is ventilation?

Answer 21

air getting to alveoli

Question 22

is ventialtion and perfusion matched?

Answer 22

yes

Question 23

does blood flow and ventilation increase or decrease with height across the lung?

Answer 23

decrease

Question 24

what happens to blood flow and ventilation at the base of the lungs?

Answer 24

blood flow is higher than ventilation because arterial pressure exceeds alveolar pressure. This compresses the alveoli

Question 25

what happens to blood flow and ventilation at the apex of the lungs?

Answer 25

blood flow is low because arterial pressure is less than alveolar pressure. This compresses the arterioles.

Question 26

where does the majority of the mismatch in the lungs take place?

Answer 26

apex

Question 27

what happens when ventilation decreases in a group of alveoli?

Answer 27

Pco2 increases and po2 decreases, blood passing those alveoli does not get oxygenated.

Question 28

how is bronchodilation caused?

Answer 28

increased PCO2

Question 29

what is a shunt?

Answer 29

term used to describe the passage of blood through areas of lung that are poorly ventilated

Question 30

what is the opposite of dead space

Answer 30

shunt

Question 31

true or false: | alveolar dead space refers to alveoli that are ventilated but not perfused

Answer 31

true

Question 32

what does the anatomical dead space refer to?

Answer 32

refers to air that cant take part in gas exchange as walls are too thick

Question 33

whats the physiological dead space?

Answer 33

alveolar dead space and anatomical dead space

Question 34

is pulmonary arterial pressure low?

Answer 34

yes

Question 35

what are the advantages of having pulmonary low pressure?

Answer 35

more suspectible to effects of gravity and this gives rise to a great degree of variability in blood flow within the lung

Question 36

what transports oxygen from lungs to tissue?

Answer 36

blood

Question 37

is Arterial partial pressure of O2 (PaO2 ) the same as arterial O2 concentration/content?

Answer 37

no

Question 38

what is arterial pressure of o2 determined by?

Answer 38

by O2 solubility and the partial pressure of O2 in the gaseous phase that is driving O2 into solution.

Question 39

how much oxygen does each litre of systemic arterial blood contain?

Answer 39

200ml

Question 40

if the oxygen is not bound to haemoglobin what happens to it?

Answer 40

dissolved in the plasma

Question 41

how much oxygen is bound to each gram of haemoglobin?

Answer 41

1.34ml

Question 42

what determines the degree to which haemoglobin is saturated with oxygen?

Answer 42

partial pressure of oxygen in arterial blood

Question 43

what two molecules have a higher affinity for oxygen than haemoglobin?

Answer 43

myoglobin and foetal haemoglobin

Question 44

what use is myglobin and HbF?

Answer 44

necessary for extracting o2 from maternal/arterial blood

Question 45

what is anaemia?

Answer 45

any condition where the oxygen carrying capacity of the blood is compromised

Question 46

what factors effect the haem-ox disssociation curve?

Answer 46

decreased by a decrease in pH, or and increase in PCO2, or temperature.

Question 47

does carbon monoxide have a higher affinity for haemoglobin than oxygen?

Answer 47

yes 250 times greater

Question 48

what are symptoms of carbon monoxide poisoning

Answer 48

hypoxia and anaemia, nausea and headaches

Question 49

what are the fates of carbon dioxide in transport?

Answer 49

7% remains dissolved in plasma and erythrocytes 23% combines in the erythrocytes with deoxyhemoglobin to form carbamino compounds 70% combines in the erythrocytes with water to form carbonic acid, which then dissociates to yield bicarbonate and H+ ions. Most of the bicarbonate then moves out of the erythrocytes into the plasma in exchange for Cl- ions (chloride shift) & the excess H+ ions bind to deoxyhemoglobin

Question 50

why is pH normally stable?

Answer 50

all CO2 that is produced is eliminated in expired air.

Question 51

when will pH not be stable?

Answer 51

hypo/hyperventilation will alter plasma PCO2 and plasma H will vary

Question 52

will hypoventilation lead to increased or decreased H+

Answer 52

increased

Question 53

which type of ventilation causes acidosis?

Answer 53

hypoventilation

Question 54

which type of ventilation causes respiratory alkalosis

Answer 54

hyperventilation

Question 55

will hyperventilation lead to increased or decreased H+

Answer 55

decreased

Question 56

whats the normal systolic pressure

Answer 56

25mmHg

Question 57

in pulmonary circulation is the pressure low or high and is the flow low or high

Answer 57

high flow, low pressure

Question 58

learn slide 7/27 chart shell test in lecture 1

Answer 58

snake

Question 59

how much oxygen dissolves per litre of plasma?

Answer 59

3ml

Question 60

which molecule carries oxygen round the blood?

Answer 60

haemoglobin

Question 61

whats the solubility of oxygen in water?

Answer 61

0.03

Question 62

do gases travel in the gaseous phase in plasma?

Answer 62

no they travel in solution, if it was gas it there would be bubbles and this is fatal i.e., divers.

Question 63

what is the oxygen demand of resting tissues?

Answer 63

250ml

Question 64

what percentage of arterial oxygen is extracted by peripheral tissues at rest?

Answer 64

25%

Question 65

how many polypeptide chains does haemoglobin consist of/?

Answer 65

4

Question 66

what are the two types of chains in the haemoglobin polypeptides

Answer 66

2 alpha and 2 beta

Question 67

how many oxygen does haemoglobin bind?

Answer 67

4

Question 68

what are the different types of combination a haemoglobin can have?

Answer 68

92% haemoglobin in RBC is in the form HbA (below). Remaining 8% is made up of HbA2 (δ chains replace β), HbF (γ chains replace β), and glycosylated Hb (HbA1a, HbA1b, HbA1c)

Question 69

why can you lose 40 units of partial pressure of oxygen and only lose a very little amount of saturation?

Answer 69

60 mm Hg is enough for haemoglobin to have a high affinity for oxygen

Question 70

whats the saturation like belwo 60 mm Hg PO2?

Answer 70

steep decline

Question 71

where is deoxyhaemoglobin found?

Answer 71

venous blood

Question 72

where is haemoglobin found?

Answer 72

arterial blood

Question 73

what would happen to PaO2 in anaemia?

Answer 73

remain the same as its the amount of oxygen in plasma, doesnt have anything to do with rbc

Question 74

what happens to the affinity for oxygen if there is a decrease in pH?

Answer 74

decrease

Question 75

what happens to the affinity for oxygen if there is there is a decrease in PCO2?

Answer 75

increase

Question 76

what happens to the affinity for oxygen if there is a decrease in temperature?

Answer 76

increase

Question 77

what happens to the affinity for oxygen if 2,3-DPG is added?

Answer 77

decreases

Question 78

what are the four factors that affect % saturation of Hb?

Answer 78

pH temp 2,3-DPG Pco2

Question 79

why is carbon monoxide so dangerous?

Answer 79

binds to haem making deoxyhaemoglobin and then you cant get anymore oxygen

Question 80

how much carbon monoxide is needed to cause progressive carboxyhaemoglobin formation?

Answer 80

0.4 mmHg

Question 81

when you have carbon monoxide poisining, why do you still have normal respiration rate?

Answer 81

becuase you still have a normal arterial PCO2

Question 82

what is hypoxaemic hypoxia?

Answer 82

Reduction in O2 diffusion at lungs either due to decreased PO2atmos or tissue pathology.

Question 83

what is Anaemic Hypoxia

Answer 83

Reduction in O2 carrying capacity of blood due to anaemia (red blood cell loss/iron deficiency).

Question 84

what is Stagnant Hypoxia

Answer 84

Heart disease results in inefficient pumping of blood to lungs/around the body

Question 85

what is Histotoxic Hypoxia

Answer 85

poisoning prevents cells utilising oxygen delivered to them e.g. carbon monoxide/cyanide

Question 86

what is Metabolic Hypoxia

Answer 86

oxygen delivery to the tissues does not meet increased oxygen demand by cells.