Biology

Cardiovascular and Nervous System

981 Questions

Review the human cardiovascular system through these competitive exam practice questions. Key areas include heart valves, cardiac impulse pathways, and blood pressure regulation. A solid grasp of these fundamentals is crucial for science sections.

Heart anatomy and valvesCardiac impulse conductionBlood pressure mechanicsHeartbeat regulation

Cardiovascular and Nervous System Questions

Multiple choice

Cardiac cycle in man takes about ______.

  1. 0.5 second

  2. 0.8 second

  3. 1.0 second

  4. 1.2 seconds
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The human cardiac cycle consists of one complete heartbeat (systole + diastole) and takes approximately 0.8 seconds at a normal resting heart rate of about 75 beats per minute (60/75 = 0.8 sec). 0.5s would mean 120 bpm (too fast), while 1.0-1.2s would mean only 50-60 bpm (unusually slow for a healthy adult at rest).

Multiple choice

When a person is resting and feels relaxed, which among the following systems is responsible for the constriction of the pupil and the slowing of the heart beats?

  1. Peripheral nervous system

  2. Central nervous system

  3. Sympathetic nervous system

  4. Parasympathetic nervous system

  5. Visceral sensation system
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

When the stress subsides, the parasympathetic nervous system of the body produces opposite effects of sympathetic nervous system. It conserves energy as it calms an individual by decreasing heart rate, lowering blood sugar, and so forth.

Multiple choice

The pacemaker of the heart is situated

  1. in the wall of the left atrium close to the opening to pulmonary veins

  2. in the wall of the right atrium close to the eustachian valve

  3. on interauricular septum

  4. on the interventricular septum
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The heart's natural pacemaker is the sinoatrial (SA) node, located in the wall of the right atrium near the opening of the superior vena cava and close to the eustachian valve (valve of the inferior vena cava). It initiates each heartbeat by sending electrical signals.

Multiple choice

The sino-auricular valve occurs

  1. in the sinus venosus

  2. between the sinus venosus and the atrium

  3. in the truncus arteriosus

  4. at the auriculo-ventricular aperture
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The sino-auricular (sinuatrial) valve is located between the sinus venosus and the right atrium in non-mammalian vertebrates. It prevents backflow of blood from the atrium into the sinus venosus. In mammals, the sinus venosus is incorporated into the right atrium.

Multiple choice

The atrioventricular node is situated

  1. near the bicuspid valve

  2. in between the atrium

  3. at the base of inter-auricular septum

  4. in the interventricular septum
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The atrioventricular (AV) node is located at the base of the interatrial (inter-auricular) septum, between the right atrium's lower part and the fibrous ring. It's not near the bicuspid valve (A), between atria generally (B), or in the interventricular septum (D).

Multiple choice

The heart rate is increased by

  1. an increase in the activity of the sympathetic nerves that supply the heart

  2. a decrease in the activity of the parasympathetic system

  3. an increase in the level of adrenalin in the circulation

  4. all of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Heart rate increases through multiple mechanisms: increased sympathetic nervous activity (A), decreased parasympathetic activity (B), and elevated circulating adrenaline (C). Since all three mechanisms increase heart rate, option D is correct.

Multiple choice

The heart sound murmurs during

  1. closing of bicuspid and tricuspid valves

  2. closing of aortic and pulmonary semilunar valves

  3. leaking of blood through one of valves

  4. none of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Heart murmurs are abnormal heart sounds produced when blood flows turbulently through the heart, often due to leaking or narrowing of heart valves. Normal valve closure produces the characteristic 'lub-dub' sounds (S1 and S2). Murmurs indicate turbulent flow caused by valve incompetence, stenosis, or other structural abnormalities.

Multiple choice

Cardiac output is defined as the amount of blood

  1. received by the heart in one minute

  2. pumped by each ventricle per minute

  3. pumped by both ventricles per second

  4. pumped by the left atrium per hour
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Cardiac output is the volume of blood pumped by one ventricle (usually the left ventricle) per minute, calculated as stroke volume × heart rate. It represents the heart's pumping effectiveness. Option A is wrong because blood passes through, it's not 'received' by the heart. Cardiac output is measured per minute, not per second or hour.

Multiple choice

The three-chambered heart of frog is not as efficient as the human heart with four chambers, because

  1. the muscles of the heart are not strong

  2. both oxygenated and deoxygenated blood mix in the ventricle

  3. the ventricle cannot pump blood properly

  4. it cannot hold enough quantity of blood
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The three-chambered frog heart has one ventricle where oxygenated blood from the lungs and deoxygenated blood from the body partially mix, reducing oxygen delivery efficiency. The mixing occurs because there's no complete septum separating the ventricle. This is the key disadvantage compared to the four-chambered human heart which keeps oxygenated and deoxygenated blood completely separate.

Multiple choice

Which of the following statements about heart is incorrect?

  1. Heart possesses upper small sized auricles or atrium and lower large sized ventricles.

  2. The auricles are demarcated externally from ventricles by the coronary sulcus.

  3. Auricles are the thin walled chambers and are called the receiving chambers.

  4. The wall of left ventricle is thicker than that of light ventricle.

  5. The walls of atria are thinner than that of ventricles.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The auricles are demarcated externally from the ventricles by an irregular groove called coronary sulcus.

Multiple choice

Blockage of ________________leads to a heart attack.

  1. carotid artery

  2. aorta

  3. pulmonary vein

  4. coronary arteries

  5. pulmonary artery
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Coronary arteries are the network of blood vessels that carry oxygen and nutrient-rich blood to the cardiac muscle tissue. Its blockage leads to heart attack.