L4 Ventilation Perfusion Matching and Dead Space in Medical Physiology

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What is the definition of anatomical dead space?

Volume of air in the conducting zone where gas exchange does not occur (correct)

Volume of air involved in alveolar ventilation

Volume of air in the lungs where gas exchange occurs

Volume of air in the alveoli with poor blood supply

Which type of dead space is a combination of anatomical and alveolar dead space?

Physiological dead space (correct)

Ventilatory dead space

Alveolar dead space

Anatomical dead space

What effect does sympathetic stimulation have on dead space?

Transforms anatomical dead space to alveolar dead space

Decreases dead space volume

No effect on dead space

Increases dead space volume (correct)

What is the relationship between anatomical and physiological dead space under normal conditions?

Anatomical dead space is equivalent to physiological dead space Signup and view all the answers

Which factor leads to a decrease in the volume of dead space?

Parasympathetic stimulation Signup and view all the answers

What does physiological dead space encompass?

Anatomical dead space and alveolar dead space combined Signup and view all the answers

What is the main function of the upper respiratory tract?

To filter and warm the inspired air Signup and view all the answers

What is the difference between pulmonary ventilation and alveolar ventilation?

Pulmonary ventilation is the volume of air breathed in and out per minute, while alveolar ventilation is the volume of air reaching the alveoli per minute Signup and view all the answers

Which factor affects alveolar ventilation the most?

Dead space volume Signup and view all the answers

In the case of shallow rapid breathing, what happens to pulmonary ventilation and alveolar ventilation?

Pulmonary ventilation remains normal while alveolar ventilation decreases Signup and view all the answers

What is the primary purpose of alveolar ventilation?

To facilitate gas exchange in the lungs Signup and view all the answers

What is the formula for calculating alveolar ventilation?

Tidal volume - Dead space x Respiratory rate Signup and view all the answers

What is the relationship between perfusion and V̇/Q̇ ratio at the base of the lungs?

Perfusion is higher, and V̇/Q̇ ratio is lower Signup and view all the answers

Which type of dead space is defined by the sum of anatomical and alveolar dead spaces?

Total dead space Signup and view all the answers

How do ventilation and V̇/Q̇ ratio change from apex to base of the lungs?

Ventilation is higher at the base, V̇/Q̇ ratio is lower at the apex Signup and view all the answers

What is the consequence of impaired perfusion on the V/Q matching in the lungs?

Increased V/Q mismatching Signup and view all the answers

Differentiate between physiological and anatomical dead space.

Physiological dead space includes conducting airways Signup and view all the answers

In case of impaired ventilation, what happens to the V/Q matching in the lungs?

Increased V/Q mismatching Signup and view all the answers

In the standing position, which zone of the lung experiences no blood flow?

Zone 1 Signup and view all the answers

In which zone does blood flow occur only during systolic blood pressure?

Zone 2 Signup and view all the answers

Which zone experiences continuous blood flow throughout the cardiac cycle?

Zone 3 Signup and view all the answers

Which condition can lead to the appearance of Zone 1 in the lungs?

All of the above Signup and view all the answers

If the alveolar ventilation (VA) is 4 L/min and the cardiac output (Q) is 5 L/min, what is the ventilation-perfusion ratio (VA/Q)?

0.8 Signup and view all the answers

In the standing position, where is the ventilation-perfusion ratio (VA/Q) higher?

At the apex of the lung Signup and view all the answers

In which scenario would the ventilation/perfusion (VA/Q) ratio be the highest?

Partial mucus plugging of a bronchiole Signup and view all the answers

What condition is most likely to cause a low ventilation/perfusion (V̇/Q̇) ratio?

Severe right heart failure Signup and view all the answers

Which of the following lung conditions is likely to result in decreased gas exchange due to high ventilation and a V̇/Q̇ ratio greater than average?

Destruction of pulmonary capillaries by emphysema Signup and view all the answers

A scenario with severe left heart failure is most likely to result in which of the following pulmonary abnormalities?

High V̇/Q̇ ratio Signup and view all the answers

Which condition would cause a V/Q ratio closest to 1, representing almost perfect matching of ventilation and perfusion?

Pulmonary embolus Signup and view all the answers

What impact does emphysema have on the ventilation/perfusion (V̇/Q̇) ratio?

Increases both ventilation and perfusion Signup and view all the answers