Cardiovascular and Nervous System

The left and the right ventricles are separated from each other by a partition called the interventricular septum. Bundle of His is situated in the interventricular septum. It branches and forms a network of fibres throughout the walls of ventricles. These fibres are called the Purkinjee fibres.

The fibres of SA (Sinu-atrial) node express the ability of self excitation and control the rate of the entire heart beat. Hence, they are also called pacemakers. So, artificial pace makers are used when the SA node gets defected.

This is correct as the phase of heart when it contracts and pumps blood into veins is called systole.

The number of times a heartbeats in a minute is known as pulse rate. The average pulse rate of a resting person is usually 72 - 80 beats per minute.

Stimulation of the vagus nerve will make the heartbeat slower.

Lithium iodide is a compound of lithium and iodine. When exposed to air, it becomes yellow in colour due to the oxidation of iodide to iodine. It is used as an electrolyte for high temperature batteries. It is also used for long life batteries as required by artificial pacemakers.

This is the correct answer.

This is the correct answer.

Myocardium is thick and highly muscular layer of heart.

ECG stands for Electro Cardio Gram, which records the electrical activity of the heart over time. It's a diagnostic tool that helps detect heart rhythm problems and other cardiac conditions.

The normal resting heart rate for adults is 60-100 beats per minute, with 72 bpm being a commonly cited average. The range 71-80 bpm is within the normal healthy range and represents the most accurate choice among the options given.

The sixth week is correct. The human heart begins beating around day 22-23 of embryonic development (approximately 3 weeks), but it becomes detectable and more rhythmic by the sixth week. The heart is one of the first organs to function in the embryo. The first heartbeat occurs in the third week, but by the sixth week it's clearly established and can sometimes be detected via early ultrasound.

Tachycardia is the medical term for a heart rate that exceeds the normal resting rate (over 100 beats per minute). Bradycardia is the opposite - an unusually slow heart rate. A heart murmur is an abnormal sound, not a rate issue.

Pulse pressure is the difference between systolic and diastolic blood pressure. It reflects the force that the heart generates each time it contracts. Normal pulse pressure is around 30-50 mmHg.

Purkinje fibers are specialized cardiac muscle fibers located in the ventricles. They form the conduction pathway that rapidly transmits electrical impulses from the AV bundle to the ventricular myocardium, ensuring coordinated ventricular contraction. They are not in auricles or striated muscle generally.