An artificial pacemaker is implanted subcutaneously and connected to the heart in patients

• having 90% blockage of the three main coronary arteries

• having a very high blood pressure

• with irregularity in the heart rhythm

• suffering from arteriosclerosis

Assertion: Pulmonary circulation consists of flow of deoxygenated blood from right ventricle to the lungs and flow of oxygenated blood from lungs to the left atrium.

Reason: Systemic circulation consists of flow of oxygenated blood from the left ventricle to all parts of the body and deoxygenated blood from different parts to right atrium

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

Assertion: ADH and RAAS work in response to low blood volume and blood pressure.

Reason: ANF works in response to high blood volume and blood pressure.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

The given figure shows schematic plan of blood circulation in humans with labels A to D. Identify the labels along with their functions and select the correct option.

• C- Vena Cava - takes blood from body parts to right atrium, Pco₂ = 45 mm Hg

• D- Dorsal aorta - takes blood from heart to body parts, Po₂ = 95 mm Hg

• A- Pulmonary vein - takes impure blood from body parts to heart, Po₂ = 60 mm Hg

• B- Pulmonary artery - takes blood from heart to lungs, Po₂= 90 mm Hg.

Mature RBCs lose their ability for

• DNA replication

• Anaerobic respiration

• Aerobic respiration and DNA replication

• Aerobic respiration, DNA replication and RNA synthesising machinery

Intercalated discs are characteristic of muscles found in

• heart

• thigh

• urinary bladder

• stomach

In a standard ECG which one of the following alphabets is the correct representation of the respective activity of the human heart

• S- start ofsystole 

• T- end of diastole

• P- depolarisation of the atria

• R - repolarisation of ventricles

Assertion: The enlarged Q and R waves indicate myocardial infarction.

Reason: The QRS complex represents ventricular repolarisation.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

Assertion: Human heart is myogenic.

Reason: The contraction is initiated by a specialized patch of modified heart muscles without requiring stimulation from nerve cells.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

Assertion: Pulmonary circulation consists of flow of deoxygenated blood from right ventricle to the lungs and flow of oxygenated blood from lungs to the left atrium.

Reason: Systemic circulation consists of flow of oxygenated blood from the left ventricle to all parts of the body and deoxygenated blood from different parts to right atrium.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.