ET exam 1 - cardiovascular physiology

What are the main functions of the cardiovascular system?

Deliver O₂ and nutrients, remove CO₂ and wastes, transport hormones, regulate body temp, maintain acid-base and fluid balance.

What are unique characteristics of cardiac muscle tissue?

Involuntary, striated, branched fibers, intercalated discs with gap junctions, highly fatigue resistant, lots of mitochondria.

What is systole?

Ventricular contraction and ejection of blood.

What is diastole?

Ventricular relaxation and filling.

Walk through blood flow in the heart.

Body → RA → tricuspid valve → RV → pulmonary valve → pulmonary artery → lungs → pulmonary veins → LA → mitral valve → LV → aortic valve → aorta → body.

What is stroke volume?

The volume of blood ejected by the left ventricle per beat.

What is cardiac output and how is it calculated?

The amount of blood pumped per minute; Q = HR × SV.

What are arteries?

Thick-walled, high-pressure vessels that carry blood away from the heart.

What are capillaries?

Thin-walled vessels for exchange of gases/nutrients/wastes.

What are veins?

Low-pressure vessels carrying blood back to the heart; have valves.

What is vasodilation?

Widening of blood vessels → decreases resistance, increases blood flow.

What is vasoconstriction?

Narrowing of blood vessels → increases resistance, reduces blood flow.

Why is hemoglobin important in blood?

It binds and transports O₂ (and some CO₂); determines O₂-carrying capacity.

Why does the body redistribute blood during exercise?

To supply active muscles with more O₂ and nutrients while reducing flow to nonessential areas (like gut).

What does the sympathetic nervous system do to the heart?

Increases HR, contractility, and vasoconstriction (fight or flight).

What does the parasympathetic nervous system do?

Decreases HR, promotes rest and recovery (rest and digest).

How does sympathetic activity increase stroke volume?

↑ Preload (venous return), ↑ Contractility (stronger force), ↓ Afterload (less resistance).

What is the muscle pump?

Contraction of skeletal muscles compresses veins, pushing blood toward the heart (aided by valves).

What is the respiratory pump?

Pressure changes in thorax during breathing help venous return.

What structure is crucial for both?

Venous valves (prevent backflow).

Why can HR track exercise intensity?

HR rises proportionally with workload and oxygen demand → reflects exercise intensity.

What is normal resting blood pressure?

~120/80 mmHg.

How does endurance training affect BP?

Lowers resting BP slightly, especially diastolic.

How does resistance training affect BP?

Can increase BP during exercise but usually lowers resting BP over time.

What causes Q to increase at exercise onset?

Rapid rise in HR and SV from sympathetic activation and venous return.

What is A-V O₂ difference?

The difference in O₂ content between arterial and venous blood.

How does it change with exercise?

It widens as muscles extract more O₂.

Why does training increase stroke volume at rest?

Increased blood volume, stronger ventricular contraction, greater ventricular chamber size (eccentric hypertrophy).

How can HR be lower at rest with training but still deliver enough nutrients?

A higher stroke volume compensates → same or greater cardiac output at lower HR.

What is eccentric hypertrophy?

Enlargement of ventricular chamber size, associated with endurance training.

What is concentric hypertrophy?

Thickening of ventricular walls, associated with resistance/strength training.

How does aerobic training affect blood volume?

Increases plasma volume and RBC mass.

How does it affect blood pressure?

Slightly lowers resting BP.

How does it affect blood flow?

Improves distribution and capacity for flow to active muscles.