Heart Physiology
What does heart contraction generate?
A. Blood pressure
B. Body temperature
C. Oxygen
D. Nutrients
A. Blood pressure
At birth, the heart is approximately what size?
Infant's fist
What is the outermost covering of the heart?
Pericardium
The pericardium protects the heart, reduces friction during heartbeats, holds the heart in place, and prevents excessive expansion.
Which chamber receives oxygen-poor blood from the body?
Right atrium
Which structure is known as the heart's natural pacemaker?
SA node
The heart separates which two circulations?
Pulmonary and systemic
The heart separates the pulmonary circulation, which carries blood between the heart and lungs, from the systemic circulation, which carries blood between the heart and the rest of the body.
How does heart weight change as a person grows?
A. It decreases continuously
B. It remains unchanged
C. It gradually increases
D. It suddenly disappears
C. It gradually increases
Rationale: As a person grows, the heart increases in size and weight as the body and cardiovascular system develop, allowing it to pump blood effectively to meet the body's increasing needs.
What is one important function of the pericardium?
A. Produces blood
B. Protects the heart and reduces friction
C. Pumps blood
D. Carries oxygen
B. Protects the heart and reduces friction
The right atrium sends blood to the:
Right ventricle
Which structure carries the impulse from the AV node toward the ventricles?
AV bundle (Bundle of His)
What is the approximate resting heart rate of a healthy adult? (beats/min)
60–100 beats/min
What is the approximate weight of an adult heart?
250–350 g
How many chambers does the heart have?
Four
Which chamber receives oxygen-rich blood from the lungs?
Left atrium
A. AV node → SA node → Purkinje fibers → AV bundle
B. SA node → AV node → AV bundle → bundle branches → Purkinje fibers
C. Purkinje fibers → SA node → AV node → bundle branches
D. SA node → Purkinje fibers → AV node → AV bundle
B. SA node → AV node → AV bundle → bundle branches → Purkinje fibers
What is the approximate stroke volume of a healthy adult at rest? (ml/beat)
70 mL/beat
What is the general shape of the heart?
Inverted cone
Which chamber receives oxygen-rich blood from the pulmonary veins?
Left atrium
Which sequence correctly shows the flow of blood through the heart?
A. Right atrium → right ventricle → lungs → left atrium → left ventricle → body
B. Left atrium → right atrium → lungs → left ventricle → body
C. Right ventricle → right atrium → lungs → left ventricle → body
D. Lungs → right atrium → right ventricle → body → left atrium
A. Right atrium → right ventricle → lungs → left atrium → left ventricle → body
A patient suddenly develops severe chest pain, sweating, shortness of breath, and nausea. The pain does not improve with rest. What condition should be suspected?
Myocardial infarction
Rationale: A myocardial infarction (heart attack) occurs when blood flow to part of the heart muscle is severely reduced or blocked, causing myocardial injury. Persistent chest pain with sweating, nausea, and shortness of breath is a classic warning pattern.
If the heart could no longer generate sufficient pressure, what would most directly happen?
A. Blood would not be effectively pushed through the vessels
B. Blood would become immediately oxygenated
C. Valves would produce more blood
D. Pulmonary circulation would stop permanently
A. Blood would not be effectively pushed through the vessels
Rationale: The heart's contractions generate pressure that pushes blood through the blood vessels. Insufficient pressure reduces blood flow and oxygen delivery to the tissues.
Why is knowing the size of the heart clinically important?
A. It helps identify abnormal enlargement or changes in heart size
B. It determines a person's height
C. It measures blood oxygen directly
D. It determines body temperature
A. It helps identify abnormal enlargement or changes in heart size
Rationale: Knowing the normal size of the heart is clinically important because an abnormally enlarged heart (cardiomegaly) may indicate underlying conditions such as hypertension, heart failure, or certain heart diseases.
What are the two atrioventricular (AV) valves?
Tricuspid and bicuspid
Why does blood travel from the right side of the heart to the lungs before reaching the left side?
A. To remove nutrients
B. To receive oxygen and release carbon dioxide
C. To decrease blood pressure
D. To prevent the heart from contracting
Explain your answer.
B. To receive oxygen and release carbon dioxide
The right side of the heart pumps oxygen-poor blood to the lungs, where it releases carbon dioxide and receives oxygen. The oxygen-rich blood then returns to the left side of the heart to be pumped to the body.
A patient has difficulty breathing when lying down and swelling of both ankles. Which condition best explains these findings?
Heart failure
Rationale: Heart failure occurs when the heart cannot pump enough blood to meet the body's needs. Fluid may accumulate in the lungs and peripheral tissues, causing shortness of breath and edema.