🩺 NEET🧬 Biology

Body Fluids and Circulation

6 solved NEET Biology previous year questions on Body Fluids and Circulation, each with the correct answer and a full explanation.

The pacemaker of the human heart is called:

aSino-atrial node (SAN)

bAtrio-ventriuclar node (AVN)

cPurkinje fibres

dPapillary muscle

✓ Correct answer: a) Sino-atrial node (SAN)

ExplanationSA node is called the pace maker of the heart as it regulate the rate of heart beat & AV node conducts these signals of contractility to heart muscles, lined by endothelium and called pace setter.

Globulins contained in human blood plasma are primarily involved in:

aClotting of blood

bOsmotic balance of body fluids

cDefense mechanism of body

dOxygen transport in blood

✓ Correct answer: c) Defense mechanism of body

ExplanationGlobulins primarily are involved in defense mechanism of the body.Albumins help in osmotic balance.Fibrinogens are needed for clotting or coagulation of blood.Haemoglobin of RBC is involved in transport of oxygen.

A person with unknown blood group under ABO system, has suffered much blood loss in an accident and needs immediate blood transfusion. His friend who has valid certificate of his own blood type, offers for blood donation without delay. What would have been the type of blood group of the donor friend?

aType B

bType AB

cType O

dType A

✓ Correct answer: c) Type O

ExplanationGroup ‘O’ blood can be donated to persons with any other blood group and hence ‘O’ group individuals are called ‘universal donors’.

Compared to those of humans, the erythrocytes in frog are:

anucleated and without haemoglobin.

bwithout nucleus but with haemoglobin.

cnucleated and with haemoglobin.

dvery much smaller and fewer.

✓ Correct answer: c) nucleated and with haemoglobin.

ExplanationThe blood of frog is composed of plasma and cells.The blood cells are RBC (red blood cells) or erythrocytes, WBC (white blood cells) or leucocytes and platelets.RBC's are nucleated and contain red coloured pigment namely haemoglobin.The lymph is different from blood.It lacks few proteins and RBCs.(NCERT 11th Edition (2020-21) Page No. 118)

The QRS complex in a standard ECG represents: [NEET 2020]

arepolarisation of auricles.

bdepolarisation of auricles.

cdepolarisation of ventricles.

drepolarisation of ventricles.

✓ Correct answer: c) depolarisation of ventricles.

ExplanationThe QRS complex represents the depolarisation of the ventricles, which initiates the ventricular contraction.The contraction starts shortly after Q and marks the beginning of the systole.

Given below are two statements: Statement I: Fatty acids and glycerols cannot be absorbed into the blood. Statement II: Specialized lymphatic capillaries called lacteals carry chylomicrons into lymphatic vessels and ultimately into the blood. In the light of the above statements, choose the most appropriate answer from the options given below:

aStatement I is incorrect but Statement II is correct.

bBoth Statement I and Statement II are correct.

cBoth Statement I and Statement II are incorrect.

dStatement I is correct but Statement II is incorrect.

✓ Correct answer: b) Both Statement I and Statement II are correct.

ExplanationFatty acids and glycerol, being hydrophobic, cannot be directly absorbed into the blood.Instead, they are converted into chylomicrons within the intestinal cells.These chylomicrons are then absorbed by specialized lymphatic capillaries called lacteals present in the intestinal villi.The lacteals transport them through the lymphatic system, which eventually drains into the bloodstream.Hence, both statements are correct.

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