Chapter 22: Heart Anatomy and Physiology

A set of question-and-answer flashcards covering the anatomy, physiology, and clinical relevance of the heart as presented in Chapter 22.

What is the primary function of the pulmonary circulation?

To oxygenate blood and remove carbon dioxide in the lungs.

Trace the pathway of blood through the pulmonary circuit.

Right ventricle → pulmonary arteries → lung capillaries → pulmonary veins → left atrium.

Why are pulmonary arteries an exception to the usual artery rule?

They carry deoxygenated blood instead of oxygenated blood.

What is the main function of the systemic circulation?

To deliver oxygen and nutrients to body tissues and remove metabolic wastes.

Why does the left ventricle have a much thicker wall than the right ventricle?

It must generate higher pressure to pump blood throughout the entire body.

Define arteries in terms of blood flow direction.

Blood vessels that carry blood away from the heart.

Define veins in terms of blood flow direction.

Blood vessels that carry blood toward the heart.

What are capillaries and their primary role?

Microscopic vessels where gas, nutrient, and waste exchange occurs between blood and tissues.

Where is the heart located within the thoracic cavity?

In the mediastinum, left of the midline, posterior to the sternum.

What forms the base of the heart?

Mainly the left atrium at the superior aspect of the heart.

Which chamber largely forms the apex of the heart?

The left ventricle.

What are the two major layers of the pericardium?

Fibrous pericardium (outer) and serous pericardium (inner).

List two functions of the fibrous pericardium.

Anchors the heart and prevents overexpansion.

Name the two layers of the serous pericardium and the space between them.

Parietal layer and visceral layer (epicardium) with the pericardial cavity in between.

What clinical problem can result from excess fluid in the pericardial cavity?

Cardiac tamponade.

List the three layers of the heart wall from outermost to innermost.

Epicardium, myocardium, endocardium.

Which heart wall layer is responsible for contraction and why?

The myocardium; it is composed of thick cardiac muscle that generates pumping force.

Which chamber receives deoxygenated blood from the body?

The right atrium.

Name the three vessels that drain into the right atrium.

Superior vena cava, inferior vena cava, and coronary sinus.

Which chamber pumps blood into the pulmonary trunk?

The right ventricle.

Which chamber pumps blood into the aorta?

The left ventricle.

What structures prevent AV valve cusps from inverting into the atria?

Chordae tendineae anchored to papillary muscles.

How many cusps are found in the tricuspid and mitral valves?

Tricuspid has three cusps; mitral (bicuspid) has two cusps.

What heart event produces the "lubb" (S1) sound?

Closure of the atrioventricular (AV) valves at the start of ventricular contraction.

What heart event produces the "dupp" (S2) sound?

Closure of the semilunar valves at the start of ventricular relaxation.

Name the two main branches of the right coronary artery.

Right marginal artery and posterior interventricular (inferior interventricular) artery.

Name the two main branches of the left coronary artery and the regions they supply.

Anterior interventricular artery (anterior ventricles and septum) and circumflex artery (left atrium and ventricle).

Why are coronary arteries described as functional end arteries?

They have few interconnections, so blockage cannot be compensated by other vessels, risking myocardial infarction.

What are intercalated discs and what junction types do they contain?

Specialized connections between cardiac muscle cells containing gap junctions and desmosomes.

What is the heart’s natural pacemaker and its intrinsic rate?

The sinoatrial (SA) node at about 70–80 beats per minute.

Why is there a 100-ms delay at the AV node?

To allow the atria to finish contracting and fully empty into the ventricles before ventricular contraction begins.

Outline the conduction pathway from SA node to ventricular muscle.

SA node → internodal pathways → AV node → AV bundle (Bundle of His) → right & left bundle branches → Purkinje fibers.

Which autonomic division increases heart rate and contractility and what neurotransmitter does it use?

Sympathetic division using norepinephrine.

Which autonomic division decreases heart rate and through which nerve?

Parasympathetic division via the vagus nerve (cranial nerve X) using acetylcholine.

Define systole and diastole.

Systole is the contraction phase; diastole is the relaxation (filling) phase of the cardiac cycle.

During which cardiac cycle phase do the semilunar valves open?

Ventricular ejection.

What is the status of all heart valves during isovolumic contraction?

All valves are closed.

State the basic principle that determines the direction of blood flow in the heart.

Blood flows from regions of higher pressure to regions of lower pressure.

What is a myocardial infarction?

A heart attack caused by blockage of a coronary artery leading to tissue death.

Differentiate valvular stenosis from valvular insufficiency.

Stenosis is narrowing of a valve restricting flow; insufficiency is a leaky valve allowing backflow.

How do aging changes commonly affect heart valves and the conducting system?

Valves stiffen causing murmurs, and conducting system efficiency decreases, reducing cardiac reserve.