Blood Supply, Gas Exchange, Ventilation & Perfusion Flashcards Preview

Respiratory System > Blood Supply, Gas Exchange, Ventilation & Perfusion > Flashcards

Flashcards in Blood Supply, Gas Exchange, Ventilation & Perfusion Deck (17)
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1
Q

Describe Bronchial Circulation

A

1) 1% cardiac output from the aorta travels in the bronchial arteries and supplies oxygenated blood to the lung tissue, smooth muscle and nerves
2) Bronchial veins carry deoxygenated blood to SVC/IVC

2
Q

Describe Pulmonary Circulation

A

1) Left and Right Pulmonary arteries carry deoxygenated blood away from right ventricle to the lungs and return oxygenated blood to the left atrium and ventricle of the heart via the pulmonary vein
2) Supplies the dense capillary network surrounding the alveoli

3
Q

Rules of Diffusion (6)

A

Directly proportional to the partial pressure gradient
Directly proportional to gas solubility
Directly proportional to the available surface area
Inversely proportional to the thickness of the membrane
Most rapid over short distances
CO2 is much more soluble in water than O2 therefore it diffuses faster than expected despite the small partial pressure gradient

4
Q

Effect of emphysema on diffusion

A

Loss of surface area for gas exchange

5
Q

Effect of fibrosis on diffusion

A

Thickened alveolar membrane slows down rate of gas exchange and reduced lung compliance and ventilation

6
Q

Effect of pulmonary oedema on diffusion

A

Fluid in interstitial space increases diffusion distance

7
Q

What is the relationship between ventilation and perfusion

A

Ventilation (air getting to the alveoli L/min) compliments Perfusion (local blood flow L/min) through pulmonary capillaries

8
Q

Describe the relationship between the ventilation and perfusion in the base of the lungs

A

Blood flow is higher than ventilation because the the arterial pressure is greater than the alveolar pressure and the alveoli are compressed

9
Q

Describe the relationship between the ventilation and perfusion in the apex of the lungs

A

Blood flow is low because arterial pressure is less than alveolar pressure and the arterioles are compressed

10
Q

Ratio at Apex

A

Ventilation>Perfusion > 1.0

11
Q

Ration at Base

A

Perfusion>Ventilation < 1.0

12
Q

Where does the majority of mismatch occur

A

Apex

13
Q

What is a Shunt

A

Passage of blood through poorly ventilated areas

14
Q

What is Alveolar Dead Space

A

Alveoli that are ventilated but not perfused

15
Q

Anatomical Dead Space

A

Parts of the respiratory tract that are ventilated but not perfused and do not take part in gas exchange. This includes the trachea, bronchi and bronchioles

16
Q

How much is the anatomical dead space each time we take a breath

A

1/3 (150)

17
Q

Causes of Shunts

A
Collapse of alveoli
Pneumonia and Pulmonary Oedema
Tissue trauma (alveolar swelling)
Mucous plugging
Pulmonary Arteriovenous Fistula (abnormal connection between vein and artery in lung)