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Functions of blood: Transport Around the Body

Functions of blood: Transport Around the Body

Edited By Irshad Anwar | Updated on Jul 02, 2025 06:40 PM IST

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.

This Story also Contains
  1. What Is Blood?
  2. Composition Of Blood
  3. Red Blood Cells (RBCs)
  4. White Blood Cells (WBCs)
  5. Platelets
  6. The Transportation Function
  7. Regulatory Function
  8. Protective Functions
  9. Diagnostic Uses Of Blood
  10. Blood Diseases
  11. The Video Recommended For The Functions Of Blood
Functions of blood: Transport Around the Body
Functions of blood: Transport Around the Body

Understanding the functions of blood is very basic for class 9 students as well as for those preparing for the NEET exam. Hence, it becomes highly imperative to have in-depth knowledge of blood composition with its multiple functions to have a complete overview for academic purposes.

Composition Of Blood

Blood consists basically of plasma and formed elements; these two components perform certain functions to maintain health and homeostasis.

Plasma

  • Definition and Composition: 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)

  • Structure and Function: 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.

  • Haemoglobin and Oxygen Transport: 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)

  • Types: Neutrophils, Lymphocytes, Monocytes, Eosinophils, Basophils.

  • Functions: 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.

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Platelets

  • Structure and Function: Small cell fragments are known mainly to play their role in blood coagulation thus ensuring that there might not be excessive blood loss.

The Transportation Function

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

Transport Of Oxygen And Carbon Dioxide

  • Role of RBCs and Hemoglobin: RBCs and Hb carry oxygen from the lungs to tissues and carry peripheral back to the lungs.

  • Gas Exchange in Lungs and Tissues: At the alveoli in the lungs and the cellular level in tissues, oxygen for carbon dioxide.

Nutrient Transport

  • Transportation of Glucose, Amino Acids, and Lipids: Blood carries all nutrients required by body cells, such as glucose, amino acids, and lipids, for energy generation and growth of cells.

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

Waste Removal

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

  • Detoxification role: The liver purifies the venom pores carried by the blood.

Regulatory Function

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

Homeostasis

  • pH Regulation: Buffers present in blood maintain a pH within a very narrow range.
  • Temperature Regulation: Blood transports heat generated in the organic system. Heat is dissipated through the skin, helping to maintain temperature.

Transport Of Hormones

  • Endocrine Hormones to Target Organs: Blood carries hormones secreted by the endocrine glands that are required by target organs.

  • Homeostatic Regulation of Body Functions: Hormones carried by blood regulate many body functions such as growth, metabolism, and reproduction.

Protective Functions

  • 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.

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

Blood Clotting

  • Process of Coagulation: 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 and Clotting Factors: Platelets bind at the site of injury while clotting factors activate a cascade that results in clotting.

Diagnostic Uses 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.

Blood Diseases

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

  • Genetic causes: Genetic fault in clotting factors.

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

Conclusion

Knowledge of the functions of blood is critical to appreciating how the body maintains health and responds to disease. Blood is responsible for far more than mere transportation; it functions in regulation mechanisms, protection, and even as a diagnostic tool. Further research on the functions and disorders of blood might produce more enlightened information relating to human biology and the medical sciences.

The Video Recommended For The Functions Of Blood


Frequently Asked Questions (FAQs)

1. What are the chief functions of blood?

Blood carries oxygen and nutrients, regulates body temperature and pH, and offers protection against infections.

2. How does blood transport oxygen?

Oxygen is carried to tissues attached to haemoglobin in red blood cells.

3. What are the components of blood?

Blood consists of plasma, red blood cells, white blood cells, and platelets.

4. What is the role of white blood cells?

White blood cells play a crucial role in the defence from infections.

5. What are the common blood disorders?

The common blood disorders are as follows- anaemia, leukaemia, and haemophilia.

6. What role does blood play in transporting coagulation inhibitors?
Blood carries natural anticoagulants, such as antithrombin and protein C, throughout the circulatory system. These proteins help prevent inappropriate blood clotting by regulating the activity of clotting factors. Their continuous circulation in the blood is crucial for maintaining a balance between clotting and anticoagulation.
7. How does blood transport assist in waste removal from the body?
Blood transports waste products, such as urea and excess ions, from tissues to excretory organs like the kidneys and liver. In the kidneys, blood is filtered to remove these waste products, which are then excreted in urine. The liver processes other waste products, which are then released into the intestines for elimination.
8. How does blood assist in the transport of cholesterol?
Blood transports cholesterol in the form of lipoproteins, such as low-density lipoprotein (LDL) and high-density lipoprotein (HDL). These lipoproteins allow the hydrophobic cholesterol molecules to move through the aqueous environment of the bloodstream, delivering cholesterol to tissues for cell membrane synthesis or returning excess cholesterol to the liver for excretion.
9. What is the importance of blood in transporting antioxidants?
Blood transports various antioxidants, such as vitamins C and E, throughout the body. These molecules help protect cells from oxidative stress and free radical damage. The circulatory system ensures that antioxidants can reach all tissues, supporting overall cellular health and function.
10. How does blood contribute to the transport of amino acids?
Blood transports amino acids from the digestive system, where proteins are broken down, to various tissues throughout the body. These amino acids can then be used for protein synthesis, energy production, or converted into other molecules as needed. This transport function is essential for maintaining protein balance and supporting cellular functions.
11. What role does plasma play in the transport function of blood?
Plasma, the liquid component of blood, serves as a medium for transporting various substances, including nutrients, hormones, waste products, and proteins. It also carries blood cells and platelets throughout the circulatory system, enabling them to perform their functions in different parts of the body.
12. What is the importance of blood in transporting glucose throughout the body?
Blood is essential for glucose transport, carrying this vital energy source from the digestive system to cells throughout the body. It also transports insulin and other hormones that regulate glucose uptake and metabolism, helping to maintain stable blood sugar levels.
13. How does blood transport affect the distribution of medications in the body?
Blood plays a vital role in drug distribution by carrying medications from the site of administration to their target tissues. The circulatory system allows for rapid and widespread distribution of drugs throughout the body, influencing their effectiveness and potential side effects.
14. How does blood contribute to the transport of fatty acids?
Blood transports fatty acids bound to albumin, a protein in plasma. This allows these hydrophobic molecules to move through the aqueous environment of the bloodstream. Fatty acids are carried from storage sites like adipose tissue to organs that need them for energy production or other metabolic processes.
15. How does blood assist in the transport of vitamins and minerals?
Blood transports both water-soluble and fat-soluble vitamins, as well as minerals, from the digestive system to tissues where they are needed. Some vitamins and minerals bind to specific carrier proteins in the blood, while others are dissolved in plasma, ensuring their efficient distribution throughout the body.
16. What is the importance of blood in transporting natriuretic peptides?
Blood transports natriuretic peptides, such as atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP), from the heart to target tissues. These hormones play crucial roles in regulating blood pressure and fluid balance by promoting sodium and water excretion in the kidneys and causing vasodilation.
17. How does blood contribute to the transport of thyroid hormones?
Blood carries thyroid hormones (T3 and T4) from the thyroid gland to target tissues throughout the body. These hormones are primarily bound to transport proteins in the blood, such as thyroxine-binding globulin, which helps regulate their availability and half-life in circulation.
18. What is the significance of blood in transporting complement proteins?
Blood transports complement proteins, a group of plasma proteins that play a crucial role in the immune system. These proteins circulate in an inactive form and can be rapidly activated in response to pathogens. Blood transport ensures that complement proteins are readily available throughout the body to assist in immune responses and inflammation.
19. How does blood transport assist in maintaining calcium homeostasis?
Blood transports calcium ions, as well as hormones that regulate calcium levels, such as parathyroid hormone and calcitonin. This transport function allows for the distribution of calcium to tissues that need it, such as bones and muscles, while also facilitating the removal of excess calcium through the kidneys.
20. How does blood contribute to the transport of vitamin B12?
Blood transports vitamin B12 bound to a protein called transcobalamin. This complex is carried from the site of absorption in the ileum to tissues that require vitamin B12, particularly the bone marrow for red blood cell production and nerve cells for maintaining myelin. This transport function is crucial for preventing vitamin B12 deficiency and its associated health problems.
21. What is the significance of blood in transporting growth factors?
Blood transports various growth factors, such as insulin-like growth factor (IGF) and platelet-derived growth factor (PDGF), throughout the body. These proteins play crucial roles in cell growth, differentiation, and tissue repair, and their efficient distribution via the bloodstream ensures they can reach their target tissues.
22. How does blood transport contribute to the body's response to hemorrhage?
In response to hemorrhage, blood transports clotting factors to the site of injury to form a clot and stop bleeding. It also carries hormones like vasopressin and angiotensin II, which cause vasoconstriction to help maintain blood pressure. Additionally, blood transports oxygen more efficiently to vital organs during blood loss by redistributing flow.
23. What role does blood play in the body's defense against pathogens?
Blood transports white blood cells and antibodies throughout the body, which are crucial components of the immune system. These cells and proteins can quickly reach sites of infection or injury, helping to fight off pathogens and promote healing.
24. What is the significance of blood in transporting antibodies?
Blood transports antibodies, also known as immunoglobulins, throughout the body. These proteins, produced by B lymphocytes, are crucial for the immune response. They circulate in the bloodstream, ready to recognize and bind to specific antigens, helping to neutralize pathogens and mark them for destruction by other immune cells.
25. What is the importance of blood in transporting immune cells?
Blood serves as a highway for immune cells, allowing them to patrol the body for signs of infection or injury. It transports various types of white blood cells, including neutrophils, lymphocytes, and monocytes, enabling them to quickly reach sites where they are needed to mount an immune response.
26. What is the role of blood in transporting clotting factors?
Blood carries various clotting factors, proteins that are essential for blood coagulation. When an injury occurs, these factors are transported to the site of damage, where they work together to form a clot, preventing excessive blood loss and promoting wound healing.
27. What role does blood play in transporting heat during fever?
During a fever, blood helps distribute heat throughout the body by increasing circulation to raise overall body temperature. This elevated temperature creates an environment less favorable for pathogen growth and enhances immune system function. Blood also carries pyrogens, substances that trigger the fever response, to the hypothalamus.
28. What is the role of blood in transporting erythropoietin?
Blood transports erythropoietin, a hormone produced mainly by the kidneys, to the bone marrow. There, it stimulates the production of red blood cells (erythropoiesis). This transport function is crucial for maintaining an adequate supply of oxygen-carrying red blood cells in response to changes in oxygen levels or blood loss.
29. What role does blood play in transporting bilirubin?
Blood transports bilirubin, a breakdown product of hemoglobin, from sites of red blood cell destruction to the liver. In the liver, bilirubin is processed and eventually excreted in bile. This transport function is crucial for preventing the toxic accumulation of bilirubin in the body.
30. How does blood transport assist in the body's response to hypoxia?
When tissues experience low oxygen levels (hypoxia), blood transports this information to the kidneys, stimulating the production of erythropoietin. Blood then carries erythropoietin to the bone marrow, where it promotes red blood cell production. This transport function helps the body adapt to low oxygen conditions by increasing oxygen-carrying capacity.
31. What is the role of blood in transporting lactic acid during exercise?
During intense exercise, muscles produce lactic acid as a byproduct of anaerobic metabolism. Blood transports this lactic acid away from the muscles to the liver, where it can be converted back to glucose or used for energy production. This transport function helps prevent the buildup of lactic acid in muscles, which can contribute to fatigue.
32. How does blood contribute to the transport of trace elements?
Blood transports essential trace elements, such as iron, zinc, and copper, from the digestive system to tissues where they are needed. Many of these elements are bound to specific carrier proteins in the blood, ensuring their efficient distribution and preventing potential toxicity from free ions.
33. How does blood help maintain body temperature?
Blood helps regulate body temperature by distributing heat throughout the body. As blood circulates, it absorbs heat from active tissues and organs, then redistributes it to cooler areas. Additionally, when blood vessels near the skin dilate, they allow more blood flow, helping to release excess heat from the body.
34. How does blood contribute to maintaining the body's pH balance?
Blood contains buffer systems, such as bicarbonate ions, that help maintain a stable pH. It also transports excess hydrogen ions to the lungs for expulsion as carbon dioxide and carries acidic or basic substances to the kidneys for excretion, thus helping to regulate the body's acid-base balance.
35. How does blood help in maintaining fluid balance in the body?
Blood helps maintain fluid balance by transporting water and electrolytes between different body compartments. It also carries hormones that regulate fluid retention and excretion, such as antidiuretic hormone (ADH) and aldosterone, to their target organs.
36. How does blood contribute to the body's thermoregulation during exercise?
During exercise, blood flow to active muscles increases, delivering oxygen and nutrients while removing waste products and heat. Simultaneously, blood flow to the skin increases, allowing for heat dissipation through sweating and radiation. This redistribution of blood helps maintain optimal body temperature during physical activity.
37. What is the significance of blood in hormone transport?
Blood serves as the primary medium for hormone transport, carrying these chemical messengers from endocrine glands to their target tissues throughout the body. This allows for rapid and widespread communication between different organs and systems, coordinating various physiological processes.
38. What are the main functions of blood in transporting substances around the body?
Blood has three primary transport functions: 1) Carrying oxygen from the lungs to tissues and carbon dioxide from tissues back to the lungs, 2) Transporting nutrients from the digestive system to cells and waste products to excretory organs, and 3) Distributing hormones and other signaling molecules throughout the body.
39. How does hemoglobin contribute to oxygen transport in blood?
Hemoglobin is a protein in red blood cells that binds to oxygen molecules. Each hemoglobin molecule can carry up to four oxygen molecules, significantly increasing the oxygen-carrying capacity of blood. This allows for efficient oxygen delivery to tissues throughout the body.
40. Why is blood referred to as a "transport medium"?
Blood is called a transport medium because it acts as a vehicle for carrying various substances throughout the body. It moves oxygen, nutrients, hormones, waste products, and other molecules between different organs and tissues, facilitating essential physiological processes.
41. What is the difference between systemic and pulmonary circulation in terms of blood transport?
Systemic circulation involves blood flow from the heart to all body tissues and back, delivering oxygen and nutrients while removing waste products. Pulmonary circulation involves blood flow between the heart and lungs, where blood picks up oxygen and releases carbon dioxide.
42. How does blood transport carbon dioxide in the body?
Blood transports carbon dioxide in three ways: 1) Dissolved in plasma (about 7%), 2) Bound to hemoglobin in red blood cells (about 23%), and 3) As bicarbonate ions in plasma (about 70%). This multi-modal transport system efficiently removes carbon dioxide from tissues and delivers it to the lungs for exhalation.
43. What is the role of blood in transporting lipids throughout the body?
Blood transports lipids, such as cholesterol and triglycerides, in the form of lipoproteins. These complexes of lipids and proteins allow for the efficient movement of fat-soluble molecules through the aqueous environment of the bloodstream, delivering them to tissues for energy or storage.
44. How does blood transport contribute to the regulation of blood pressure?
Blood transport plays a crucial role in regulating blood pressure by carrying hormones and other signaling molecules that affect blood vessel dilation and constriction. For example, it transports angiotensin II, which causes vasoconstriction, and nitric oxide, which promotes vasodilation, helping to maintain appropriate blood pressure levels.
45. How does blood transport contribute to the body's response to dehydration?
When the body is dehydrated, blood becomes more concentrated, triggering osmoreceptors in the hypothalamus. Blood then transports antidiuretic hormone (ADH) from the pituitary gland to the kidneys, promoting water reabsorption. It also carries the sensation of thirst to the brain, encouraging fluid intake.
46. How does blood transport contribute to the removal of excess water from tissues?
Blood helps remove excess water from tissues through its role in the lymphatic system. As blood flows through capillaries, it creates hydrostatic pressure that pushes some fluid into the interstitial space. This excess fluid is then collected by lymph vessels and eventually returned to the bloodstream, helping to maintain proper fluid balance in tissues.
47. How does blood assist in the transport of bile acids?
Blood transports bile acids from the liver, where they are produced, to the gallbladder for storage. After a meal, these bile acids are released into the small intestine to aid in fat digestion. Blood then reabsorbs most of the bile acids from the intestine and returns them to the liver, completing the enterohepatic circulation.
48. How does blood transport contribute to the regulation of blood calcium levels?
Blood transports calcium ions as well as hormones that regulate calcium levels, such as parathyroid hormone and calcitonin. When blood calcium levels drop, parathyroid hormone is released and transported to bones, where it stimulates calcium release. Conversely, when levels are high, calcitonin is transported to promote calcium deposition in bones.
49. What is the significance of blood in transporting prostaglandins?
Blood transports prostaglandins, locally acting hormone-like substances, from their site of production to nearby target tissues. Although prostaglandins typically act locally, blood transport allows them to reach slightly more distant targets, influencing processes such as inflammation, blood flow, and smooth muscle contraction.
50. What role does blood play in transporting albumin?
Blood transports albumin, the most abundant protein in plasma, throughout the body. Albumin plays crucial roles in maintaining osmotic pressure, transporting hormones and fatty acids, and serving as a buffer. Its continuous circulation in the blood is essential for these various physiological functions.
51. How does blood transport contribute to the regulation of blood pH during exercise?
During exercise, blood transports lactic acid and carbon dioxide, both of which can lower blood pH, away from active muscles. It also carries these substances to the lungs for expiration (CO2) and to the liver for processing (lactic acid). Additionally, blood's buffering systems, such as bicarbonate, help minimize pH changes during physical activity.
52. What role does blood play in transporting leptin?
Blood transports leptin, a hormone produced by adipose tissue, to the brain and other tissues. Leptin plays a crucial role in regulating energy balance and body weight by signaling satiety and influencing metabolism. The circulatory system ensures that leptin can reach its target tissues to exert its effects.
53. What role does blood play in transporting ghrelin?
Blood transports ghrelin, a hormone primarily produced in the stomach, to the brain and other tissues. Ghrelin stimulates appetite and plays a role in energy homeostasis. The circulatory system allows for the efficient distribution of ghrelin, enabling it to exert its effects on food intake and metabolism.

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