Functions of blood: Transport Around the Body

What Is Blood?

Blood is a fluid that travels in every part of the human system, performing highly variant functions that are vital for life. The blood, comprising different constituents, supplies not only oxygen and nutrition but also plays an important role in the scavenging process for waste products and defending against infection.

The major four parts include plasma, RBCs, WBCs, and platelets. All these components have certain specified purposes and features to make one complete circulatory system.

Composition Of Blood

The components of blood consist of plasma and formed elements. These two components perform certain functions to maintain health and homeostasis.

Plasma

• Plasma is a fluid constituent of blood, containing mostly 90% water, and the balance comprises proteins, nutrients, hormones, gas, waste products, and salts.

• Functions of Plasma: Maintenance of blood pressure and volume and a medium of transport of nutrients, hormones, and waste products.

Formed Elements

The elements are comprised of:

Red Blood Cells (RBCs)

• The RBCs are without a nucleus and have a biconcave shape.

• Their function is related to delivering oxygen from the lungs to the body tissues and returning the carbon dioxide so that it is exhaled outside.

• Hemoglobin is a protein of RBCs that determines the amount of oxygen attached to them and thus is transported throughout the body.

White Blood Cells (WBCs)

• The different types of WBCs are neutrophils, lymphocytes, monocytes, eosinophils and basophils.

• WBCs are an integral component of the immune response, and each one has specific functions in the battles of various kinds of infections and other foreign bodies which may intrude within the mammalian system.

Platelets

• Platelets are small cell fragments that are known mainly to play their role in blood coagulation thus ensuring that there might not be excessive blood loss.

Transportation Functions of Blood

The transport aspect of blood is significant in the carriage of different important substances to the whole body.

Gas Transport (Oxygen & CO₂)

• RBCs and Hb carry oxygen from the lungs to tissues and carry peripheral back to the lungs.

• At the alveoli in the lungs and the cellular level in tissues gaseous exchanges take place, oxygen for carbon dioxide.

Nutrient Transport

• Blood carries all nutrients required by body cells, such as glucose, amino acids, and lipids, for energy generation and growth of cells.

• Blood chaffer in nutrients used by body cells for various metabolic functions.

Waste Removal

• Waste metabolic products are extracted by the blood, carried to the kidneys and liver, and are finally excreted.

• The liver purifies the venom pores carried by the blood.

Hormone Transport

• Blood carries hormones secreted by the endocrine glands that are required by target organs.

• Hormones carried by blood regulate many body functions such as growth, metabolism, and reproduction.

Regulatory Functions of Blood

Blood helps to regulate various physiological functions to maintain a state of equilibrium or homeostasis.

pH Regulation

• Buffers present in blood maintain a pH within a very narrow range.

• It prevents harmful shifts in acidity.

Temperature Regulation

• Blood transports heat generated in the organic system.

• Blood absorbs and distributes heat.

• Heat is dissipated through the skin, helping to maintain temperature.

Protective Functions of Blood

Blood protects the body by preventing excessive bleeding and eliminating harmful substances that enter the body.

Immunity

• Blood is the predominant amount involved in the natural defence mechanism of the body.

• Blood proteins are closely associated, directly or indirectly, with several physiological mechanisms of the immune response.

• WBCs recognise and kill the pathogen. Other groups are WBCs and the cell groups related to the immune response.

• Blood helps in innate nonspecific and adaptive specific parts of the immune response.

Blood Clotting

• The process of blood clotting is one where through a series of steps, platelets and clotting factors act in cooperation to form a clot.

• Platelets bind at the site of injury while clotting factors activate a cascade that results in clotting.

Diagnostic Importance Of Blood

Blood is used for medical testing to detect and monitor health problems.

Blood Tests

• Some common blood tests can tell us about complete blood count.

• Blood glucose and cholesterol are some important indicators of our health.

Indicators Of Disease

Abnormalities in blood elements can reveal such diseases as anaemia, infections, and coagulation diseases.

Disorders Related to Blood Functions

Several diseases of the blood can disrupt normal blood activity.

Anaemia

• Types: Iron deficiency, sickle cell, and aplastic anaemia.

• Signs and therapy: weakness, pallor, and the treatments are iron pills and taking blood.

Leukaemia

• Types: Acute and chronic leukaemia.

• Signs and therapy: Signs are weakness and infection, and treatment is chemotherapy and bone marrow transplant.

Haemophilia

• Causes: Genetic fault in clotting factors.

• Management and treatment: Infusion of clotting factors at regular intervals and preventive care.

Functions of Blood NEET MCQs (With Answers & Explanations)

This is an important topic and carries significant weightage in NEET exam. Types of questions asked from this topic are:

• Functions of blood

• Disorders related to blood

Practice Questions for NEET

Q1. Which instrument is used to determine the red cell count?

1. Haemocytometer

2. Haemoglobinometer

3. Electrocardiogram

4. Sphygmomanometer

Correct answer: 1) Haemocytometer

Explanation:

Red cell count measures the number of red blood cells in a given volume of blood. It is typically carried out using a device called a hemocytometer. A hemocytometer is a specialized microscope slide with a grid pattern etched onto its surface. By diluting a small volume of blood and placing it on the hemocytometer, the red blood cells can be counted under a microscope, allowing for the determination of the red cell count.

Explanation for incorrect options :

Option (2)The Haemoglobinometer is incorrect because it is a device used to measure the concentration of haemoglobin in the blood, not the red cell count.

Option (3) Electrocardiogram (ECG) is a diagnostic tool used to record the electrical activity of the heart, and it is not directly involved in determining red cell count.

Option (4) Sphygmomanometer is a device used to measure blood pressure, and it is not used for red cell count assessment.

Hence, the correct answer is option 1) Haemocytometer.

Q2. There is no DNA in:

1. Mature RBCs

2. Mature spermatozoan

3. Hair Root

4. An enucleated ovum

Correct answer: 1) Mature RBCs

Explanation:

As we learnt in

RBCs -

RBCs are formed in the red bone marrow in adults. RBCs lack nuclei in most mammals and are biconcave in shape.

- wherein

They have a red-coloured, iron-containing complex protein called haemoglobin, hence the colour and name of these cells. A healthy individual has 12-16 gms of haemoglobin in every 100 ml of blood.

Mature RBCs are devoid of nucleus and DNA is absent.

Hence, the correct answer is option 1) mature RBCs.

Q3. Which of the following changes (a-d) usually tend to occur in the plain dwellers when they move to high altitudes (3,500 m or more)?

1. Increase in red blood cell size

2. Increase in red blood cell production

3. Increased breathing rate

4. Increase in thrombocyte count

Correct answer: 2) Increase in red blood cell production

Explanation:

When plain dwellers move to high altitudes (3,500 m or more), they typically experience an increase in red blood cell production to cope with lower oxygen levels. Additionally, their breathing rate increases to compensate for the reduced oxygen availability. However, there is no evidence to suggest that red blood cell size or thrombocyte count changes significantly in response to high altitudes.

Hence the correct answer is Option 2) Increase in red blood cell production

Also Read-

• MCQs on Composition of Blood

• Cardiac Cycle

• Facts about Blood

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