Blood plasma is the fluid part of blood that contains nutrients, glucose, proteins, minerals, enzymes, waste products, antibodies, clotting proteins and hormones. Its role is transporting the substances around the body. Plasma contains 90% water and only 10 the solutes.
Erythrocytes (also called red blood cells) are biconcave disks, containing haemoglobin that transports oxygen. They transport the oxygen to cells all over the body. The surface area to volume ratio is very large on the erythrocytes so
oxygen can diffuse very quickly into the cell. They lack organelles meaning that there is more room for haemoglobin. They are small and have a flexible membrane which allows them to fit through tiny capillaries and transport oxygen extremely close to cells.
Leucocytes (also called white blood cells) have a nucleus, are much larger than red blood cells and are spherical or irregular in shape. There are two main types of leucocytes called granulocytes (they have granular cytoplasm and lobed nuclei) and agranulocytes (the cytoplasm appears smooth and the nucleus is rounded or horseshoe in shape).
Agranulocytes consist of monocytes (phagocytic against foreign cells) and lymphocytes which produce antibodies. Granulocytes consist of neutrophils (phagocytic and contain lysosomes), eosinophils (phagocytic against allergens) and basophils which makes heparin to prevent unnecessary blood clots and serotonin to allow phagocytes to leave the blood and enter the site of infection.
The Essay on Rafael, the Red Blood Cell
My name is Rafael, the Red Blood Cell, doctors call me erythrocyte and born in the bone marrow. My shape is bi-concave disk. Also do not possess a nucleus. I am one of trillions of red blood cells that live inside and travel through your body. I deliver oxygen to all the organs and tissues and transport wastes as carbon dioxide out of your body. Oxygen helps keep the body running and healthy. I ...
The different cells are shown below:
Oxygen combines with haemoglobin in red blood cells to form oxyhaemoglobin. Haemoglobin is a protein and is made up of 4 polypeptide chains, each with a haem group. Each haem group can pick up 1 molecule of O2. The protein, being fairly small, could pass out of the blood during ultrafiltration in the kidneys so, to ensure that it is not lost, it is found within red blood cells.
The relationship between partial pressure of oxygen and the quantity of oxygen is called the oxygen dissociation curve (shown below).
It is S-shaped because of the behaviour of the haemoglobin in different partial pressures.
The exact position of the curve depends on factors such as the partial pressure of carbon dioxide, temperature and pH. If the partial pressure of carbon dioxide increases, the curve will move to the right. This is known as the Bohr effect. It results in the dissociation of oxygen from haemoglobin and other respiratory compounds.
Skeletal muscle contains a pigment called myoglobin. It is very similar to haemoglobin but has a higher affinity for oxygen.
About 85% of the carbon dioxide produced by respiration diffuses into the red blood cells and forms hydrogencarbonate ions (HCO”¯).
The HCO3- diffuses out of the red blood cell into the plasma. This leaves a shortage of negatively charged ions inside the red blood cells so chloride ions move into the red blood cells.
Some CO2 diffuses into the red blood cells but instead of forming hydrogencarbonate, attaches directly onto the haemoglobin molecules to form carbaminohaemoglobin.
The movement of water and dissolved substances through capillary walls occurs by diffusion and filtration but is dependent on various forces or pressures. Some pressures force fluid out of capillaries into the surrounding tissue spaces and this results in filtration of the fluid. So that fluid does not remain in the tissue spaces and accumulate, opposing pressures force fluid from the tissues spaces back into the blood capillaries and this results in reabsorption of fluid. Any fluid not reabsorbed into the capillaries is returned to the blood as lymph, via the lymphatic vessels.
The Essay on The Adaptation Of Red Blood Cells
Aerobic respiration provides the energy required by all living organisms to function normally, as muscle movement and certain cell reactions are reliant on energy the transport of oxygen to the cells of tissues and organs by blood vessels is vital for respiration to occur. Oxygen is carried in red blood cells by the pigment haemoglobin, a globular protein consisting of four polypeptide chains. ...
