Multiple Choice Questions (MCQs)
- Where is the heart located?
a) In the abdominal cavity
b) In the middle mediastinal space within the thoracic cavity
c) Behind the lungs
d) Near the brain
Answer: b) In the middle mediastinal space within the thoracic cavity - Which animal’s heart axis is oriented vertically?
a) Dog
b) Pig
c) Horse
d) Cat
Answer: c) Horse - What is the percentage range of body weight the heart constitutes in mammals?
a) 1–2%
b) 0.3–1.0%
c) 2–3%
d) 5%
Answer: b) 0.3–1.0% - Which valve is located on the right side of the heart?
a) Mitral valve
b) Tricuspid valve
c) Semilunar valve
d) Pulmonary valve
Answer: b) Tricuspid valve - What prevents the atrioventricular valves from everting during systole?
a) Papillary muscles and chordae tendineae
b) Semilunar valves
c) Aortic arches
d) Septum
Answer: a) Papillary muscles and chordae tendineae - Which chamber of the heart has the thickest wall?
a) Right atrium
b) Left atrium
c) Right ventricle
d) Left ventricle
Answer: d) Left ventricle - What is the primary function of the right ventricle?
a) Pump blood to systemic organs
b) Pump deoxygenated blood to the lungs
c) Receive oxygenated blood from the lungs
d) Store blood during diastole
Answer: b) Pump deoxygenated blood to the lungs - Which valve is located at the opening of the pulmonary artery?
a) Tricuspid valve
b) Mitral valve
c) Pulmonary semilunar valve
d) Aortic semilunar valve
Answer: c) Pulmonary semilunar valve - Which side of the heart is associated with pulmonary circulation?
a) Left side
b) Right side
c) Both sides
d) Neither side
Answer: b) Right side - What connects systemic circulation to pulmonary circulation?
a) Pulmonary veins
b) Pulmonary arteries
c) Aorta and vena cava
d) Mitral valve
Answer: c) Aorta and vena cava
Fill in the Blanks
- The heart is located in the _________ space within the thoracic cavity.
Answer: middle mediastinal - The _________ valve is located on the left side of the heart.
Answer: bicuspid/mitral - The _________ ventricle has the thickest wall to pump blood throughout the body.
Answer: left - The pulmonary _________ prevent backflow of blood into the right ventricle during diastole.
Answer: semilunar valves - Blood flows from the left atrium to the left ventricle through the _________ valve.
Answer: mitral/bicuspid
True or False
- The heart constitutes 1–2% of the body weight in mammals.
Answer: False - Chordae tendineae and papillary muscles prevent atrioventricular valves from everting during systole.
Answer: True - The left ventricle pumps deoxygenated blood to the lungs.
Answer: False - Semilunar valves prevent backflow of blood into the ventricles during diastole.
Answer: True - The heart’s orientation in ruminants is almost vertical.
Answer: True
Subjective Questions
- Describe the functional differences between the venous/pulmonary side and the systemic/arterial side of the heart.
Answer: The venous/pulmonary side, comprising the right atrium and right ventricle, handles deoxygenated blood. The right atrium receives blood from the venous system, and the right ventricle pumps it to the lungs for oxygenation. The systemic/arterial side, comprising the left atrium and left ventricle, manages oxygenated blood. The left atrium receives blood from the lungs, and the left ventricle pumps it to systemic organs via the aorta. - Explain the role of atrioventricular and semilunar valves in maintaining unidirectional blood flow.
Answer: Atrioventricular (AV) valves, including the mitral and tricuspid valves, prevent backflow of blood into the atria during ventricular systole. Chordae tendineae and papillary muscles support these valves. Semilunar valves, present at the openings of the aorta and pulmonary artery, prevent backflow of blood into the ventricles during diastole, ensuring unidirectional flow from the heart to the lungs and systemic organs.