Questions: Body Fluids and Circulation

Q1. Why is blood called a connective tissue?

Answer (English): Blood is called a connective tissue because it has cells suspended in a liquid matrix, the plasma, and it connects the different parts of the body by carrying materials between them. The plasma is the matrix, the red cells, white cells and platelets are the cells, and the whole tissue is continuous through the blood vessels.

Hinglish: Blood connective tissue hai kyunki isme cells plasma naam ke liquid matrix mein suspended hain aur yeh body ke different parts ko materials pahunchakar jodta hai.

Q2. Name the formed elements and give one function of each.

Answer (English): The formed elements are red blood cells, white blood cells and platelets. Red blood cells carry oxygen attached to haemoglobin. White blood cells defend the body against infection, with neutrophils and monocytes phagocytic and lymphocytes involved in immunity. Platelets take part in the clotting of blood.

Hinglish: Formed elements RBC, WBC aur platelets hain. RBC oxygen le jate hain, WBC infection se bachate hain aur platelets clotting karte hain.

Q3. What is serum and how does it differ from plasma?

Answer (English): Plasma is the liquid part of blood, containing water, proteins, minerals and the clotting factors. Serum is the fluid left when the clotting factors, mainly fibrinogen, have been removed, so serum does not clot. Both contain the other plasma proteins and the dissolved substances, but serum lacks the clotting machinery.

Hinglish: Plasma mein clotting factors hote hain; jab fibrinogen jaise clotting factors nikal diye jate hain to bacha hua fluid serum kehlata hai jo clot nahi hota.

Q4. How are the human blood groups classified?

Answer (English): Blood groups are classified by the A and B antigens on the surface of red blood cells, giving groups A, B, AB and O. The plasma contains antibodies against the antigens that are absent, so group A has anti-B and group B has anti-A. Group AB carries both antigens and no antibodies and is the universal recipient, while group O carries neither antigen and is the universal donor. The Rh factor adds another antigen, positive or negative, which matters in pregnancy and transfusion.

Hinglish: Blood groups A, B, AB aur O A aur B antigens se bante hain. AB ke paas dono antigens hain isliye universal recipient, aur O ke paas koi antigen nahi isliye universal donor. Rh factor alag antigen hai.

Q5. What is lymph and what are its functions?

Answer (English): Lymph is the tissue fluid that has entered the lymph vessels. It is colourless, has fewer proteins than plasma and carries lymphocytes. Its functions are to drain the excess tissue fluid back into the blood, to carry absorbed fats from the intestine, and to support the immune response in lymph nodes and the spleen.

Hinglish: Lymph tissue fluid hai jo lymph vessels mein aata hai; yeh tissue fluid ko wapas blood mein laata hai, intestine se fats le jata hai aur immunity mein madad karta hai.

Q6. Why is the wall of the left ventricle thickest?

Answer (English): The left ventricle pumps oxygenated blood into the aorta and then to the whole body, so it must generate a much higher pressure than the right ventricle, which pumps blood only to the nearby lungs. A thicker muscular wall can produce that greater pressure. The atria have thin walls because they only move blood into the ventricles, and the right ventricle is thinner than the left for the same reason: it pumps to the lungs, which lie close by and offer little resistance.

Hinglish: Left ventricle blood ko aorta aur poori body mein pump karta hai, isliye usse zyada pressure chahiye; isi wajah se uski wall sabse moti hoti hai.

Q7. What is the cardiac cycle and how long does it last?

Answer (English): A cardiac cycle is one complete heartbeat, from the beginning of one contraction to the beginning of the next. At about 72 beats per minute it lasts about 0.8 seconds: atrial systole takes 0.1 second, ventricular systole 0.3 second and the joint diastole 0.4 second. During the cycle each chamber contracts and relaxes once in the correct order.

Hinglish: Cardiac cycle ek poora heartbeat hai jo lagbhag 0.8 second leta hai: atrial systole 0.1 s, ventricular systole 0.3 s aur joint diastole 0.4 s.

Q8. Define stroke volume and cardiac output.

Answer (English): Stroke volume is the amount of blood pumped out by each ventricle in one beat, about 70 mL at rest. Cardiac output is the amount pumped by each ventricle in one minute, which is stroke volume multiplied by heart rate. With a heart rate of 72 beats per minute and a stroke volume of 70 mL, the cardiac output is about 5 litres per minute. During heavy exercise the rate may rise to 150 beats per minute and the stroke volume may rise as well, so the output can reach several times the resting value.

Hinglish: Stroke volume ek beat mein nikla blood hai lagbhag 70 mL, aur cardiac output usse heart rate se multiply karke milta hai, lagbhag 5 litre per minute.

Q9. What does each wave of the ECG represent?

Answer (English): The P wave is the small first wave and it records electrical excitation spreading through the atria before they contract. The QRS complex is the large spike and it records excitation of the ventricles before their contraction. The T wave follows and records the ventricles returning to the resting electrical state after systole. The gap between two R peaks gives the time of one beat, and counting R peaks in a fixed interval gives the heart rate.

Hinglish: P wave atria ki depolarisation, QRS complex ventricles ki depolarisation aur T wave ventricles ki repolarisation batata hai. R peaks ke beech ka gap ek beat ka time deta hai.

Q10. How is the heart rate regulated by the nervous system?

Answer (English): The basic rhythm comes from the myogenic sino-atrial node, but the rate is adjusted by the special neural centre in the medulla oblongata. Sympathetic nerves increase the heart rate and the force of contraction, while parasympathetic nerves, mainly the vagus, slow the heart. Hormones such as adrenaline also raise the rate, so the heart speeds up during exercise or excitement and slows at rest.

Hinglish: SA node rhythm deta hai, lekin medulla ka cardiovascular centre autonomic nerves se rate control karta hai: sympathetic rate badhate hain aur parasympathetic kam karte hain; adrenaline bhi rate badhata hai.

Quiz pointer. A five question chapter quiz follows this page. Attempt it without looking back and read the explanation for every question you miss, because the quiz retests the formed elements, the cardiac cycle and the ECG waves.