Cardiovascular and Nervous System

Depolarization and repolarization phases of an action potential occur very rapidly, typically taking only 1-5 milliseconds total. This speed allows neurons to transmit signals quickly over long distances, enabling rapid communication within the nervous system.

This is the correct answer. The chambers of a heart are separated by a partition called septum.

This is the correct answer choice as this statement is incorrect. The pulse rate of an adult while resting is 70 to 72 per minute.

Arterial elasticity normally dampens pressure fluctuations during cardiac cycle. When arteries become rigid (arteriosclerosis), they cannot expand during systole, causing systolic pressure to rise significantly. This explains isolated systolic hypertension in elderly patients. Diastolic pressure may actually decrease due to reduced arterial recoil.

Chordae tendineae are fibrous cords that connect the AV valve cusps to the papillary muscles in the ventricles. During ventricular contraction (systole), they prevent the tricuspid and bicuspid (mitral) valves from prolapsing into the atria by resisting the high pressure generated.

Bradycardia is defined as a heart rate of fewer than 60 beats per minute in adults. This can be normal in well-trained athletes during rest, but may indicate issues with the heart's electrical conduction system in other individuals. Options A and C incorrectly describe tachycardia (elevated heart rate), not bradycardia.

A cardiologist specializes in diagnosing and treating diseases of the heart and cardiovascular system. The prefix 'cardio-' comes from the Greek word for heart. Pulmonologists treat lungs, hepatologists treat liver, and neurologists treat brain conditions.

The human heart has four chambers: two atria (receiving chambers) and two ventricles (pumping chambers). The right side pumps blood to the lungs, and the left side pumps blood to the body. This four-chamber design is efficient for separating oxygenated and deoxygenated blood.

The upper two chambers of the heart are called atria (singular: atrium). The right atrium receives deoxygenated blood from the body, and the left atrium receives oxygenated blood from the lungs. Ventricles are the LOWER chambers, and 'Coronus' is not an anatomical term related to the heart.

The lower two chambers of the heart are called ventricles. The right ventricle pumps blood to the lungs, and the left ventricle pumps oxygenated blood to the rest of the body. Atria are the UPPER chambers, and sinuses are not related to heart chambers but are air-filled spaces in the skull.

The septum is the thick muscular wall that separates the left and right sides of the heart. This separation ensures that oxygenated and deoxygenated blood do not mix. The pericardium is the protective sac around the heart, not an internal partition.

A heartbeat is one complete cycle of cardiac contraction (systole) and relaxation (diastole). Dialysis is blood filtration, blood pressure is the force of blood against vessel walls - neither describes the cardiac cycle.

A normal resting heart rate for a healthy young adult is 60-100 beats per minute, with 72 bpm being a commonly cited average. The range of 70-72 bpm falls within normal limits. Options A and B are also within normal range, but C is most precise.

Diastolic pressure is the minimum pressure in arteries when the heart is in relaxation phase (diastole). Systolic pressure is the maximum pressure during contraction. The relaxation phase allows chambers to fill with blood before the next contraction.

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