- Answer: (A) 4
- Explanation: The four borders of the heart are:
- Superior border: Formed by the atria and the roots of the great vessels (aorta, pulmonary trunk)
- Right border: Formed by the right atrium
- Left border: Formed by the left ventricle and a small area of the left atrium
- Inferior border: Formed by both right and left ventricles
- Answer: (B) 0.8 sec
- Explanation: The cardiac cycle is the complete sequence of events in a single heartbeat. In a typical, resting adult heart rate, a single cycle takes about 0.8 seconds.
(A) 5.5 L/Min
(B) 5 L/Min
(C) 5.25 L/Min
(D) 5.35 L/Min
- Answer: (C) 5.25 L/min
- Explanation
- Cardiac output (CO) is the amount of blood pumped by the heart in one minute.
- Formula: CO = Stroke volume (SV) x Heart rate (HR)
- Calculation:
- SV = 70 ml/beat
- HR = 75 beats/min
- CO = 70 ml/beat x 75 beats/min = 5250 ml/min
- Convert to liters: 5250 ml/min / 1000ml/L ≈ 5.25 L/min