Cardio and respiratory

Question 1

Which circulation pumps deoxygenated blood to the lungs?

Answer 1

Pulmonary circulation.

Question 2

Which circulation distributes oxygenated blood to the body?

Answer 2

Systemic circulation.

Question 3

What is the full pathway of blood flow through the heart?

Answer 3

Venae cavae → Right Atrium → Tricuspid Valve → Right Ventricle → Pulmonary Valve → Pulmonary Arteries → Lungs → Pulmonary Veins → Left Atrium → Mitral Valve → Left Ventricle → Aortic Valve → Aorta → Systemic circulation.

Question 4

What is the primary pacemaker of the heart?

Answer 4

The sinoatrial (SA) node.

Question 5

Name the components of the cardiac conduction system.

Answer 5

SA node, AV node, AV bundle (bundle of His), and Purkinje fibers.

Question 6

What role does the AV node play in cardiac conduction?

Answer 6

It delays the electrical signal so the atria can contract before the ventricles.

Question 7

Which nerve mediates parasympathetic control of the heart?

Answer 7

The vagus nerve (cranial nerve X).

Question 8

What neurotransmitter does the parasympathetic system release to slow heart rate?

Answer 8

Acetylcholine.

Question 9

How does the sympathetic nervous system affect heart rate and contraction?

Answer 9

It increases heart rate and force of contraction via norepinephrine.

Question 10

What is the maximum possible heart rate under sympathetic stimulation?

Answer 10

Approximately 250 beats per minute.

Question 11

— The Vascular System —

Question 12

What is systolic blood pressure?

Answer 12

The highest arterial pressure during heart contraction (~110-120 mmHg).

Question 13

What is diastolic blood pressure?

Answer 13

The lowest arterial pressure during heart relaxation (~70-80 mmHg).

Question 14

How is mean arterial pressure (MAP) calculated?

Answer 14

MAP = (2/3 DBP) + (1/3 SBP).

Question 15

Which mechanisms provide intrinsic control of blood flow?

Answer 15

Metabolic, endothelial, and myogenic mechanisms.

Question 16

How do metabolic byproducts affect local blood flow?

Answer 16

They cause vasodilation to increase blood flow.

Question 17

What endothelial factor promotes vasodilation?

Answer 17

Nitric oxide (NO).

Question 18

What happens in myogenic control when local pressure increases?

Answer 18

Vessels constrict.

Question 19

How does the sympathetic nervous system regulate blood flow extrinsically?

Answer 19

By increasing vasoconstriction at the organ level.

Question 20

What is functional sympatholysis in muscle blood flow?

Answer 20

Local factors reduce sympathetic vasoconstriction during exercise, increasing blood flow to muscles.

Question 21

What mechanisms assist in returning blood to the heart?

Answer 21

Venoconstriction, the skeletal muscle pump, and the respiratory pump.

Question 22

What is the role of venous valves in blood return?

Answer 22

They prevent backflow of blood.

Question 23

Is inspiration an active or passive process?

Answer 23

Active.

Question 24

Which muscles are primarily responsible for inspiration?

Answer 24

The diaphragm and external intercostals.

Question 25

What happens to lung volume and intrapulmonary pressure during inspiration?

Answer 25

Lung volume increases and intrapulmonary pressure decreases.

Question 26

What does Boyle’s law state about pressure and volume during breathing?

Answer 26

Pressure and volume are inversely proportional.

Question 27

Is expiration usually active or passive?

Answer 27

Usually passive.

Question 28

What occurs during passive expiration?

Answer 28

Inspiratory muscles relax, lung volume decreases, and intrapulmonary pressure increases, forcing air out.

Question 29

Which muscles are recruited during active (forced) expiration?

Answer 29

Internal intercostals, latissimus dorsi, quadratus lumborum, and abdominal muscles.

Question 30

What is the standard atmospheric pressure?

Answer 30

760 mmHg.

Question 31

What are the approximate percentages of N₂, O₂, and CO₂ in atmospheric air?

Answer 31

79.04% N₂, 20.93% O₂, and 0.03% CO₂.

Question 32

How is the partial pressure of a gas calculated?

Answer 32

By multiplying the total pressure by the gas’s percentage in air.

Question 33

What is the approximate partial pressure of O₂ in air?

Answer 33

About 159 mmHg.

Question 34

What is the typical alveolar PO₂?

Answer 34

Approximately 105 mmHg.

Question 35

What is the typical pulmonary artery PO₂?

Answer 35

About 40 mmHg.

Question 36

What is the PO₂ gradient across the alveolar-capillary membrane?

Answer 36

Approximately 65 mmHg.

Question 37

According to Fick’s law, what factors affect the rate of oxygen diffusion?

Answer 37

Surface area, partial pressure gradient, and tissue thickness.

Question 38

How does the CO₂ gradient compare to the O₂ gradient in the alveoli?

Answer 38

The CO₂ gradient is much smaller (around 6 mmHg), but CO₂ diffuses easily.

Question 39

What is the primary function of the respiratory (alveolar-capillary) membrane?

Answer 39

To facilitate gas exchange between alveoli and capillaries.

Question 40

In oxygen transport, what does hemoglobin saturation refer to?

Answer 40

The percentage of hemoglobin binding sites occupied by oxygen.

Question 41

What determines blood oxygen-carrying capacity?

Answer 41

The amount of hemoglobin available and its saturation level.

Question 42

In CO₂ transport, what is the main form in which CO₂ is carried in blood?

Answer 42

As bicarbonate ion.

Question 43

Name two other ways CO₂ is transported in the blood.

Answer 43

Dissolved in plasma and as carbaminohemoglobin.

Question 44

What factors regulate pulmonary ventilation?

Answer 44

Neural control, chemical signals (such as CO₂ levels), and mechanical factors.

Question 45

What is end systolic volume (ESV)?

Answer 45

The volume of blood remaining in a ventricle after contraction.

Question 46

What is the normal range for resting heart rate (RHR)?

Answer 46

Between 60 and 100 beats per minute.

Question 47

How does heart rate change during exercise?

Answer 47

It increases significantly to meet metabolic demands.

Question 48

How does stroke volume change during exercise?

Answer 48

It increases due to enhanced contractility and improved venous return.

Question 49

Why is stroke volume important for V̇O₂max?

Answer 49

A higher stroke volume increases cardiac output, which is crucial for maximal oxygen uptake.

Question 50

What mechanisms contribute to an increased stroke volume during exercise?

Answer 50

Enhanced contractility, increased venous return, and reduced end-systolic volume.

Question 51

How does blood pressure generally change during exercise?

Answer 51

Systolic pressure increases while diastolic pressure remains relatively stable or slightly decreases.

Question 52

What happens to ventilation during acute exercise?

Answer 52

Ventilation increases to supply more oxygen and remove CO₂.

Question 53

How does the respiratory system adjust to increased metabolic demands during exercise?

Answer 53

By increasing both the rate and depth of breathing.

Question 54

What is the ventilatory equivalent for oxygen?

Answer 54

The ratio of ventilation to oxygen uptake.

Question 55

What is the ventilatory threshold?

Answer 55

The point during exercise when ventilation increases disproportionately to oxygen uptake.

Question 56

What is the function of heart valves?

Answer 56

They ensure unidirectional blood flow and prevent backflow.

Question 57

How is stroke volume calculated?

Answer 57

Stroke volume = End-diastolic volume (EDV) minus End-systolic volume (ESV).

Question 58

What is the main form of CO₂ transport in blood?

Answer 58

Bicarbonate ion.

Question 59

How is CO₂ also transported in blood besides bicarbonate?

Answer 59

It is dissolved in plasma.

Question 60

What is carbaminohemoglobin?

Answer 60

CO₂ bound to hemoglobin.