Biology ยท General Awareness

Human Circulatory System

818 Questions

The human circulatory system explores the network of blood vessels, heart valves, and structural pathways. Test items often target blood flow sequences and specific vascular functions. Mastering these details is vital for biology preparation.

Heart valves and chambersBlood vessels and venulesArteries of the bodyBlood supply to organsCentral nervous system supply

Human Circulatory System Questions

Multiple choice

Blood clot formed in vessels blocking flow of blood is called

  1. bolus

  2. pus

  3. ulcer

  4. thrombus
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A thrombus is a blood clot that forms in a blood vessel and remains attached to its place of origin. It can block blood flow by physically obstructing the vessel lumen. A bolus refers to a rounded mass of food or liquid, pus is an accumulation of dead cells and bacteria from infection, and an ulcer is an open sore on tissue surface.

Multiple choice

Heart attack involves the blockage of the

  1. carotid artery

  2. aorta

  3. pulmonary vein

  4. coronary arteries
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Heart attacks (myocardial infarction) occur when coronary arteries supplying the heart muscle are blocked, typically by atherosclerotic plaque or thrombus. The carotid artery supplies the brain, the aorta is the main artery from the heart, and pulmonary veins carry oxygenated blood from lungs to the left atrium.

Multiple choice

Blood pressure is defined as

  1. the force with which blood pushes against the wall of the blood vessels

  2. the force with which blood is pushed to the legs

  3. the force with which blood comes out of the atrium

  4. the force with which blood comes out of the ventricles
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Blood pressure is the force exerted by circulating blood against the walls of blood vessels, primarily arteries. It's measured in mmHg and expressed as systolic/diastolic pressures. Option B is wrong (not just legs), C is wrong (not from atrium), D is wrong (ventricles generate pressure, but blood pressure is defined against vessel walls throughout circulation).

Multiple choice

The blood vascular system of mammals is known as double vascular system, because

  1. a group of veins carry oxygenated blood and other group conduct deoxygenated blood

  2. oxygenated blood runs from heart to different organs by one set of vessels, while deoxygenated blood runs from heart to lung by another set

  3. the two different systems never meet

  4. all of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Mammals have a double circulatory system: pulmonary circulation (heart to lungs and back) carries deoxygenated blood, while systemic circulation (heart to body tissues and back) carries oxygenated blood. The two circuits are separate and don't mix. Option A is incomplete, C is wrong (circuits connect at the heart chambers).

Multiple choice

Mitral (bicuspid) valve in mammals guard the opening between

  1. left auricle and left-ventricle

  2. pulmonary vein and left auricle

  3. stomach and intestine

  4. liver and spleen
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The mitral (bicuspid) valve is located between the left atrium (auricle) and left ventricle of the heart. It prevents backflow of blood from the left ventricle to the left atrium when the ventricle contracts, ensuring one-way flow toward the aorta.

Multiple choice

Which of the following is true about arteries?

  1. They carry deoxygenated blood from different body parts to the heart.

  2. They carry oxygenated blood from heart to different body parts.

  3. In arteries, blood flows with low speed and under low pressure.

  4. They possess valves.

  5. Their lumens are thin and less elastic.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Arteries carry oxygenated blood from heart to various parts of the body.

Multiple choice

Why are semilunar valves present in the veins?

  1. To allow the movement of leucocytes through them

  2. To allow the diffusion of oxygen into the intercellular fluids

  3. To prevent the loss of nutrients form the blood

  4. To prevent the backward flow of blood

  5. To prevent the entry of pathogens into the veins
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Veins are provided with semilunar valves, which prevent the backward flow of blood.

Multiple choice

Consider the following statements: (a) Portal veins carry blood directly to the heart and forms a network of capillaries. (b) In human beings, two main portal systems; hepatic and the hypophyseal portal systems are present. (c) A pair of hepatic veins carries blood from liver to the inferior vena cava. (d) The blood from intestine, pancreas and spleen is drained into liver via. the hepatic portal vein.

Which of the above statements is/are incorrect about portal system of a man?

  1. Only (a)

  2. Both (a) and (b)

  3. Only (d)

  4. Only (c)

  5. Both (b) and (d)

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Portal vein does not carry blood directly to the heart but forms a network of capillaries on another organ before reaching the heart.

Multiple choice

Which among the following is supplied with enormous blood vessels?

  1. Germinal epithelium

  2. Tunica albuginea

  3. Cumulus oophorus

  4. Stroma
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The stroma of the ovary is a particular soft tissue, particularly supplied with enormous blood vessels consisting of spindle-shaped cells with a small amount of ordinary connective tissue.

Multiple choice

Neutrophils squeeze through the pores of blood vessels by the process of

  1. chemotaxis

  2. diapedesis

  3. opsonization

  4. phagocytosis

  5. margination
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

It is the passage of blood cells through the unruptured wall of a blood vessel into the surrounding tissues. The white cells may exhibit diapedesis to fight infection in the tissues surrounding blood vessels. The neutrophils are the first to arrive through diapedesis at the site of an infection.

Multiple choice

Which of the following does not characterise the blood supply of the central nervous system?

  1. The vertebrobasilar system which constitutes the anterior circulation.

  2. At the core of the brain, the arteries form the circle of Willis.

  3. Abnormalities of blood flow in the carotid arteries frequently leads to the problems in the cerebral hemisphere .

  4. Abnormalities of blood flow in the vertebral arteries frequently leads to the defects in brainstem, cerebellum and posterior parts of the brain.

  5. Thrombus and emboli are the chief causes of blood flow obstructions in the brain.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

It is the incorrect statement. The carotid arteries form the anterior circulation to the brain, whereas the vertebral arteries merge to become the basilar artery (so called vertebrobasilar system), which constitutes the posterior circulation.