(a) What is blood ? Why is it red ?
(b) State the functions of blood in our body.
(c) Name a circulatory fluid in the human body other than blood.
(a) What is blood ? Why is it red ?
(b) State the functions of blood in our body.
(c) Name a circulatory fluid in the human body other than blood.
(a)
Blood is a connective tissue , a fluid that transports oxygen and nutrients to the cells and carries away carbon dioxide and other waste products. Technically, blood is a transport liquid pumped by the heart to all parts of the body, after which it is returned to the heart to repeat the process.
Blood is both a tissue and a fluid. It is a tissue because it is a collection of similar specialized cells that serve particular functions. These cells are suspended in a liquid matrix (plasma), which makes the blood a fluid. If blood flow ceases, death will occur within minutes because of the effects of an unfavourable environment on highly susceptible cells.
Blood is red because of the haemoglobin inside our red blood cells. Haemoglobin is a protein that forms a complex with iron molecules and together they transport oxygen molecules throughout the body. Iron has the property of reflecting red light and because there is so much iron in our blood, blood looks red. When haemoglobin is carrying a lot of oxygen (like when just leaving the lungs), blood is bright red. When most of the oxygen has been released to the body, blood is dark red. Therefore, contrary to popular belief, blood is never blue. Veins under light colored skin only look blue because the skin changes the optical properties of the light that passes through the skin. In other words, skin changes the way light is reflected from the blood and we perceive that as being of a different color.
(b)
Functions of Blood:
- It supplies oxygen and carbon dioxide between the lungs and rest of the body.
- It supplies essential nutrients to cells such as Amino acid, Fatty acid, Glucose etc.
- It transports waste products to be removed by kidney.
- It transports hormones.
- It has role in inflammation. Eg. leucocytes destroys microorganisms, Platelets initiates blood clotting etc.
- It regulates our body temperature.
- It regulates pH by interacting acid and bases.
(c)
Lymph is the circulatory fluid in the human body other than blood.
(a)
Blood is a connective tissue , a fluid that transports oxygen and nutrients to the cells and carries away carbon dioxide and other waste products. Technically, blood is a transport liquid pumped by the heart to all parts of the body, after which it is returned to the heart to repeat the process.
Blood is both a tissue and a fluid. It is a tissue because it is a collection of similar specialized cells that serve particular functions. These cells are suspended in a liquid matrix (plasma), which makes the blood a fluid. If blood flow ceases, death will occur within minutes because of the effects of an unfavourable environment on highly susceptible cells.
Blood is red because of the haemoglobin inside our red blood cells. Haemoglobin is a protein that forms a complex with iron molecules and together they transport oxygen molecules throughout the body. Iron has the property of reflecting red light and because there is so much iron in our blood, blood looks red. When haemoglobin is carrying a lot of oxygen (like when just leaving the lungs), blood is bright red. When most of the oxygen has been released to the body, blood is dark red. Therefore, contrary to popular belief, blood is never blue. Veins under light colored skin only look blue because the skin changes the optical properties of the light that passes through the skin. In other words, skin changes the way light is reflected from the blood and we perceive that as being of a different color.
(b)
Functions of Blood:
- It supplies oxygen and carbon dioxide between the lungs and rest of the body.
- It supplies essential nutrients to cells such as Amino acid, Fatty acid, Glucose etc.
- It transports waste products to be removed by kidney.
- It transports hormones.
- It has role in inflammation. Eg. leucocytes destroys microorganisms, Platelets initiates blood clotting etc.
- It regulates our body temperature.
- It regulates pH by interacting acid and bases.
(c)
Lymph is the circulatory fluid in the human body other than blood.
