Heart Anatomy and Physiology Qui

What are the two main circuits of the cardiovascular system?

Pulmonary and systemic circuits.

Name the four chambers of the heart and their functions.

Right atrium (receives deoxygenated blood), left atrium (receives oxygenated blood), right ventricle (pumps blood to lungs), left ventricle (pumps blood to the body).

Where is the heart located in the body?

In the mediastinum of the thoracic cavity.

What is the function of the pericardium?

Protects, anchors, and prevents overfilling of the heart.

List the three layers of the heart wall and describe their roles.

Epicardium (outer layer), myocardium (muscle layer), endocardium (inner lining).

Which vessels bring blood into the right atrium?

Superior vena cava (SVC), inferior vena cava (IVC), and coronary sinus.

What are the valves located between the atria and ventricles called?

Atrioventricular (AV) valves: tricuspid and bicuspid/mitral valves.

Name the two semilunar valves and their specific locations.

Pulmonary valve (right ventricle) and aortic valve (left ventricle).

What structural differences exist between the right and left ventricles, and why?

Left ventricle has thicker walls and a circular cavity; right ventricle has thinner walls and a crescent-shaped cavity.

What is the role of the coronary arteries?

Supplies oxygen and nutrients to the myocardium.

Trace the pathway of blood through the heart, starting from the superior vena cava.

SVC/IVC → right atrium → tricuspid valve → right ventricle → pulmonary valve → pulmonary arteries → lungs → pulmonary veins → left atrium → mitral valve → left ventricle → aortic valve → aorta.

Define "coronary circulation" and explain its importance.

The ventricles contract, closing AV valves and opening semilunar valves to pump blood.

What are two potential consequences of a coronary artery blockage?

Angina pectoris (temporary blood deficiency) and myocardial infarction (heart attack).

What are pacemaker cells, and what makes them unique?

Specialized cells that regulate the heartbeat by initiating and distributing electrical impulses.

Define "arrhythmia" and name two types with their causes.

Abnormal heart rhythms; examples: fibrillation (irregular beats) and extrasystole (premature beats).

What is the role of the medulla oblongata in regulating heart activity?

It controls heart rate and force of contraction via sympathetic and parasympathetic systems.

What do the terms "lub" and "dup" refer to in heart sounds?

"Lub": closure of AV valves; "Dup": closure of SL valves.

Describe the sequence of events during the cardiac cycle.

Ventricular filling, isovolumetric contraction, ventricular ejection.

What factors affect cardiac output, and how is it calculated?

CO = HR × SV; heart rate × stroke volume.

Explain the Frank-Starling law of the heart.

Greater preload leads to stronger contractions due to optimal fiber length.

How does sympathetic stimulation affect heart rate and contractility?

Sympathetic stimulation increases heart rate and contractility.

What is the difference between preload and afterload?

Preload: stretch of cardiac muscles before contraction; afterload: resistance ventricles must overcome.

List two hormones that influence heart rate and their effects.

Epinephrine (increases HR and contractility), thyroxine (enhances metabolic rate and HR).

What are the effects of hyperkalemia and hypocalcemia on the heart?

Imbalances disrupt electrical conduction, leading to arrhythmias or weakened contractions.

Define tachycardia and bradycardia and provide potential causes for each.

Tachycardia: HR >100 bpm (e.g., stress); bradycardia: HR <60 bpm (e.g., hypothermia).

How does aging affect heart function?

Valve thickening, reduced cardiac reserve, and fibrosed nodes.

What is congestive heart failure, and what are two common causes?

Left-sided (pulmonary congestion) and right-sided (peripheral congestion) failure.

How does left-sided heart failure differ from right-sided heart failure in its effects?

Fluid builds up in the lungs, causing pulmonary edema.

Describe the condition of dilated cardiomyopathy and its consequences.

Heart ventricles become enlarged and weakened, reducing pumping efficiency.

How does regular exercise benefit heart health and reduce disease risks?

Enhances cardiac efficiency, reduces atherosclerosis, and lowers heart disease risks.