Cardiovascular System ch12 Review

These flashcards cover key concepts, definitions, and details related to the cardiovascular system from the lecture notes.

Where is the heart located relative to the sternum and midline?

The heart lies near the anterior chest wall, directly behind the sternum, slightly to the left of the midline, and is rotated to the left.

What indicates possible cardiac enlargement in a patient?

If a patient’s heart apex is displaced laterally beyond the 5th intercostal space.

Which chamber forms most of the right border of the heart?

The right atrium.

What are the layers of the heart wall from superficial to deep?

Epicardium (visceral pericardium), myocardium, endocardium.

What happens if the pericardium produces too little serous fluid?

Increased friction between heart layers, causing pericarditis.

Which layer is responsible for contraction of the heart?

The myocardium.

Why does the myocardium require an extensive capillary network?

To meet its high oxygen demand due to reliance on aerobic metabolism.

What is the primary function of intercalated discs?

They allow electrical impulses to pass quickly between cells, enabling coordinated contraction.

Can cardiac muscle contract without nervous input?

Yes, due to automaticity from pacemaker cells.

Why is it important cardiac tissue is richly supplied with mitochondria and capillaries?

Because cardiac cells depend on continuous oxygen supply for ATP production.

What is the purpose of the pericardial cavity?

To reduce friction between the heart and surrounding structures during contraction.

What condition occurs if fluid accumulates excessively in the pericardial cavity?

Cardiac tamponade, which restricts heart expansion.

Describe the serous membrane lining the pericardial cavity.

It consists of the visceral and parietal pericardium with a thin layer of lubricating fluid between them.

What structure separates the right and left atria?

The interatrial septum.

What happens if the foramen ovale fails to close at birth?

A patent foramen ovale results, allowing oxygenated and deoxygenated blood to mix.

Which valve prevents backflow into the right atrium during ventricular contraction?

The tricuspid valve.

What prevents the AV valves from swinging into the atria?

Chordae tendineae anchored by papillary muscles.

Which valve’s failure would cause blood to back up into the lungs?

The mitral (bicuspid) valve.

Why is the left ventricle more muscular than the right ventricle?

It must generate higher pressure to pump blood through the systemic circuit.

What is the function of coronary arteries?

To deliver oxygen-rich blood to the myocardium.

When does most coronary blood flow occur, systole or diastole?

Diastole, when the myocardium relaxes.

What happens if a coronary artery is blocked for more than a few minutes?

Myocardial infarction (heart attack) due to tissue death.

What causes coronary ischemia?

Partial or complete blockage of coronary circulation, reducing oxygen supply.

What is systole?

The contraction phase of the cardiac cycle.

What is diastole?

The relaxation phase when chambers fill with blood.

During which phase are all valves closed but pressure is increasing?

Isovolumetric contraction.

What is the pacemaker of the heart?

The sinoatrial (SA) node.

Is the heart always pumping blood when pressure in the left ventricle is rising?

No, during isovolumetric contraction the pressure rises but valves remain closed.

What happens to heart rate if the AV node is damaged?

It would slow to 40–60 bpm due to the AV node’s pacemaker cells.

What prevents simultaneous contraction of atria and ventricles?

The delay at the AV node.

What does the P wave represent?

Atrial depolarization.

What does the QRS complex represent?

Ventricular depolarization.

What does the T wave represent?

Ventricular repolarization.

What could a prolonged P–R interval indicate?

Damage to the AV node or conduction delay.

Why isn’t atrial repolarization visible on an ECG?

It’s hidden by the QRS complex.

Compare bradycardia with tachycardia.

Bradycardia = HR < 60 bpm; Tachycardia = HR > 100 bpm.

Define cardiac output.

The amount of blood pumped by each ventricle per minute (CO = HR × SV).

How does increased venous return affect stroke volume?

It increases SV via Starling’s law.

What happens to stroke volume if heart rate increases excessively?

It decreases due to reduced filling time.

What is a problem if the heart beats too rapidly?

Inadequate filling time reduces cardiac output.

What hormones can increase heart rate?

Epinephrine, norepinephrine, and thyroid hormones.

Where is blood pressure highest and lowest?

Highest in the aorta; lowest in the venae cavae.

What drives filtration at the capillaries?

Capillary hydrostatic pressure (CHP).

Why does more water leave capillaries than is reabsorbed?

Excess fluid enters lymphatic vessels.

Define blood flow and its relationship to blood pressure and resistance.

Flow is directly proportional to pressure and inversely proportional to resistance.

What triggers the baroreceptor reflex?

Changes in blood pressure.

Where are baroreceptors located?

In the carotid sinuses, aortic sinuses, and right atrium.

Which reflex increases heart rate when blood pressure falls?

Activation of cardioacceleratory and vasomotor centers.

Identify hormones responsible for short-term regulation of low blood pressure.

Epinephrine and norepinephrine.

List the hormones that increase blood pressure long-term.

ADH, angiotensin II, aldosterone, erythropoietin (EPO).

What hormone lowers blood pressure by promoting sodium and water loss?

Atrial natriuretic peptide (ANP).

How does light exercise affect cardiac output?

CO rises due to increased venous return and dilation of vessels.

During heavy exercise, which organs receive reduced blood flow?

Abdominal viscera and nonessential organs.

Does brain blood flow change during exercise?

No, it remains constant.

Why does blood flow to visceral organs decrease during exercise?

Blood is redirected to muscles and skin for thermoregulation.

If a patient’s ECG shows a missing P wave, which structure might be malfunctioning?

SA node.

The left ventricle is weakened. Which symptom would appear first?

Lung congestion (pulmonary edema).

If a blockage occurs in the left coronary artery, which area is at greatest risk?

Left ventricle and interventricular septum.

Heart rate is 75 bpm and stroke volume is 70 mL. Calculate cardiac output.

5.25 L/min.

During ventricular diastole, which valves are open?

AV valves (mitral and tricuspid).