Body Fluids and Circulation — Page 8 | NEET Biology

Q71

Systemic heart refers to:

A the two ventricles together in the human heart.

B the heart that contracts under stimulation from nervous system.

C left auricle and left ventricle in higher vertebrates.

D entire heart in lower vertebrates.

Correct Answer

Option C

Solution

(c) Systemic heart refers to the left ventricle in higher vertebrates which propels blood through the systemic circulation.

Q72

The cardiac pacemaker in a patient fails to function normally. It is likely that artificial pacemaker will be grafted at the site of

A Atrioventricular bundle

B Purkinje system

C Sinuatrial node

D Atrioventricular node

Correct Answer

Option C

Solution

(c) SA node is the natural pacemaker located in the right atrium, so artificial pacemaker will be grafted there.

Q73

Which of the following substances, if introduced into the blood stream, would cause coagulation of blood at the site of its introduction?

A Prothrombin

B Fibrinogen

C Thromboplastin

D Heparin

Correct Answer

Option C

Solution

(c) Thromboplastin released from injured platelets converts prothrombin into thrombin, which then converts fibrinogen to fibrin.

Q74

Which one of the following has an open circulatory system?

A Periplaneta

B Hirudinaria

C Octopus

D Pheretima

Correct Answer

Option A

Solution

(a) Periplaneta (cockroach) is an insect with open circulatory system. Blood vessels are absent.

Q75

Which one of the following mammalian cells is not capable of metabolising glucose to carbondioxide aerobically?

A Unstriated muscle cells

B Liver cells

C Red blood cells

D White blood cells

Correct Answer

Option C

Solution

(c) RBCs do not have mitochondria so they can respire only anaerobically.

Q76

In humans, blood passes from the post caval to the right atrium of the heart during diastole due to

A opening of the venous valves

B suction pull

C stimulation of the sinoatrial node

D pressure difference between the post caval and atrium

Correct Answer

Option B

Solution

(b) Blood passes from post caval to diastolic right atrium due to suction pull.

Q77

In a standard ECG which one of the following alphabets correctly represents the respective activity of the human heart?

A S - start of systole

B T - end of diastole

C P - depolarisation of the atria

D R - repolarisation of ventricles

Correct Answer

Option C

Solution

(c) P-wave is a small upward wave that indicates the depolarisation of the atria caused by activation of SA node.

Q78

If the chordae tendinae of the tricuspid valve is partially non-functional, what will be the immediate effect?

A The flow of blood into the aorta will be slowed down

B The pacemaker will stop working.

C The blood will tend to flow back into the left atrium.

D The flow of blood into the pulmonary artery will be reduced.

Correct Answer

Option D

Solution

(d) Tricuspid valve is between right atrium and right ventricle.

If non-functional, flow of blood into pulmonary artery will be reduced.

Q79

Which one of the following statements is correct regarding blood pressure?

A 130 / 90 mmHg is considered high and requires treatment.

B 100 / 55 mmHg is considered an ideal blood pressure.

C 105 / 50 mm Hg makes one very active.

D 190 / 110 mmHg may harm vital organs like brain and kidney.

Correct Answer

Option D

Solution

(d) 190/110 mmHg is hypertension which can harm vital organs like brain and kidney.

Q80

Arteries are best defined as the vessels which :

A supply oxygenated blood to the different organs.

B break up into capillaries which reunite to form one venous vessel.

C break up into capillaries which reunite to form a vein.

D carry blood from one visceral organ to another visceral organ.

Correct Answer

Option B

Solution

(b) Arteries are the vessels which break up into capillaries which reunite to form veins.