Body Fluids and Circulation for NEET UG
Blood carries oxygen, food, hormones and waste around the body, pumped by a heart that beats about 72 times a minute for a lifetime. Learn blood, the cardiac cycle and the ECG.
BiologyClass 1173 MCQs2 lessons14 flashcards3 memory tricks
Practise Body Fluids and Circulation free
What you'll learn
- Blood and blood groups
Describe the parts of blood and work out safe blood transfusions. - The heart, cardiac cycle and ECG
Trace blood through the heart, describe the cardiac cycle and read an ECG.
Key formulas
| Cardiac output | Stroke volume × heart rate ≈ 70 mL × 72 ≈ 5 L/min |
|---|---|
| Duration of one cardiac cycle | ≈ 0.8 s at 72 beats per minute |
Memory tricks
Left Atrium–Bicuspid (mitral) valve; Right Atrium–Tricuspid valve.
P wave: atrial depolarisation. QRS complex: ventricular depolarisation. T wave: ventricular repolarisation.
'Lub' is the closing of the AV (tricuspid and bicuspid) valves at the start of ventricular systole. 'Dub' is the closing of the semilunar valves.
Try 3 NEET-style questions
Q1. Which plasma protein mainly helps maintain osmotic balance?
- fibrinogen
- globulin
- albumin
- haemoglobin
Show answer
Answer: (3) albumin
Albumins help in osmotic balance. Fibrinogen is needed for clotting and globulins mainly for defence.
Q2. The vessel that carries deoxygenated blood from the right ventricle to the lungs is the
- pulmonary vein
- aorta
- pulmonary artery
- vena cava
Show answer
Answer: (3) pulmonary artery
The pulmonary artery carries deoxygenated blood from the right ventricle to the lungs; pulmonary veins return oxygenated blood to the left atrium.
Q3. The second heart sound, 'dub', is associated with the
- closure of the semilunar valves
- closure of the tricuspid and bicuspid valves
- opening of the AV valves
- contraction of the atria
Show answer
Answer: (1) closure of the semilunar valves
'Dub' is produced by the closure of the semilunar valves; 'lub' is closure of the tricuspid and bicuspid valves.
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