🫀(Harder) ch 19 heart - mc questions

A blockage occurs in the pulmonary trunk. Which immediate change would occur?

Oxygen-poor blood cannot reach the lungs

A patient has damage to the left ventricle. Which function is MOST directly affected?

Pumping blood into systemic circulation

During ventricular contraction, which valves should be open?

Semilunar valves only

A student observes that both AV and semilunar valves are closed. What phase is occurring?

Isovolumetric contraction

If the AV node delay did NOT occur, what would happen?

Ventricles would not fill completely

Blood is flowing from the left atrium into the left ventricle. Which valves are open/closed?

AV open, SL closed

A patient has a myocardial infarction. What is the MOST immediate cellular consequence?

Death of cardiac muscle cells

Why does cardiac muscle NOT undergo tetanus?

It has a long refractory period

A graph shows a plateau phase in cardiac muscle. What is occurring?

Ca²⁺ influx sustaining contraction

If K⁺ channels fail to open, what happens?

Repolarization is impaired

Which event occurs FIRST in the conduction system?

SA node fires

A signal is delayed before reaching the ventricles. Where is it?

AV node

A patient has an ECG where the QRS complex is missing. What is MOST likely affected?

Ventricular depolarization

Ventricles begin contracting immediately after which ECG event?

QRS complex

Atrial repolarization is not visible on ECG because:

It is hidden by ventricular depolarization

A patient has a resting heart rate of 120 bpm. This is:

Tachycardia

A trained athlete has a resting heart rate of 55 bpm. This is:

Bradycardia

Increased sympathetic stimulation will:

Increase HR and contractility

Parasympathetic stimulation affects the heart by:

Slowing pacemaker firing

A patient has increased venous return. What happens to stroke volume?

Increases

According to the Frank-Starling law, increased EDV results in:

Increased contraction

A patient has hypertension. What happens to afterload?

Increases

Increased afterload will:

Decrease SV

During ventricular ejection, which must occur?

SL valves open

A patient has a defective SA node. What happens?

AV node takes over at slower rate

If the AV node is completely blocked:

Ventricles beat independently

An ectopic focus is:

Abnormal pacemaker

Fibrillation results in:

Ineffective pumping

During ventricular filling, what happens?

AV valves open

End-diastolic volume represents:

Blood before contraction

Stroke volume is calculated as:

End-diastolic volume - End-systolic volume (EDV − ESV)

Cardiac output increases during exercise because:

HR and SV increase

Why is the left ventricle thicker than the right?

Pumps against higher resistance

Which ion is highest inside the cell at rest?

K⁺

Which ion triggers contraction in cardiac muscle?

Ca²⁺

If Ca²⁺ influx increases, what happens?

Stronger contraction

What causes blood to flow through the heart?

Pressure gradients

Blood will only flow if:

Pressure gradient exists