Major Cells in the Circulatory System
Plasma
Plasma is a yellowish liquid that suspends and transports food and wastes to and from all of the body's cells. The plasma carries food particles to the cells of the body where they are converted into energy or stored away for a later need. Plasma is also the medium in which all red blood cells, platelets, and white blood cells are transported around the body. It makes up 55% of the blood's volume and is made of 90% water and 10% dissolved food and wastes.
Plasma Contents:
= nutrients - glucose, amino acids, fatty acids
= wastes - carbon dioxide, urea
= hormones - growth hormone, adrenaline
= proteins - antibodies, fibrinogen (clotting proteins)
Plasma Contents:
= nutrients - glucose, amino acids, fatty acids
= wastes - carbon dioxide, urea
= hormones - growth hormone, adrenaline
= proteins - antibodies, fibrinogen (clotting proteins)
Red Blood Cells
Red blood cells carry oxygen to all of the body's cells to supply them with the needed energy for completing their assigned task. Afterwards, they then take the waste, carbon dioxide, to be removed before it poisons the body. Red blood cells are excellent at their job, transporting oxygen, because they're small, dimpled, disk-shaped cells with no nucleus so they can have the maximum space to store and transport oxygen.
There are so many red blood cells in the the body that they outnumber white blood cells 700 to one! They make up 44% of the blood's volume, but each cell is only 0.0008mm (or 0.0003in) and very flexible! Since some of the capillaries in the body are as small as a red blood cell itself, the cells are very flexible which enables them to squeeze through and gives them enough time to exchange gases with other cells.
Red blood cells only last for about 120 days before they are worn out and then recycled for their iron by white blood cells
by phagocytosis (a process called "cell eating"). About 250 million molecules of hemoglobin are packed into every blood cell. Hemoglobin is an iron-containing protein that picks up oxygen and releases it where it's needed. Hemoglobin is a red-coloured protein that gives red blood cells their red colour. Each
hemoglobin molecule can carry 4 oxygen molecules, and that means that each red blood cell can carry one bilion oxygen molecules. If a red blood cell is bright red, it means that it's oxygen-rich, but if it's dark red, it means that it's an oxygen-poor cell.
There are so many red blood cells in the the body that they outnumber white blood cells 700 to one! They make up 44% of the blood's volume, but each cell is only 0.0008mm (or 0.0003in) and very flexible! Since some of the capillaries in the body are as small as a red blood cell itself, the cells are very flexible which enables them to squeeze through and gives them enough time to exchange gases with other cells.
Red blood cells only last for about 120 days before they are worn out and then recycled for their iron by white blood cells
by phagocytosis (a process called "cell eating"). About 250 million molecules of hemoglobin are packed into every blood cell. Hemoglobin is an iron-containing protein that picks up oxygen and releases it where it's needed. Hemoglobin is a red-coloured protein that gives red blood cells their red colour. Each
hemoglobin molecule can carry 4 oxygen molecules, and that means that each red blood cell can carry one bilion oxygen molecules. If a red blood cell is bright red, it means that it's oxygen-rich, but if it's dark red, it means that it's an oxygen-poor cell.
White Blood Cells
Even though white blood cells are outnumbered by red blood cells 700 to one and make up less than 1% of the blood's volume, they still play a vital role for the body, they are a mobile defence force that also removes all of the blockages in th ecirculatory system. They patrol the bloodstream and tissues to protect the body by destroying any dangerous invaders. There are differnet types of white blood cells: neutrophils, monocytes, macrophages, and lymphocytes. Unlike red blood cells, they slip through blood vessels into the tissues to track and eliminate harmful pathogens. They're just like what my brother and I used to call them when we were little, the ninjas of the body!
Platelets
Although platelets are only one third the size of red blood cells, they play a key role in the body's self-repair mechanism because they repair damaged blood vessels at the site. Platelets congregate and become "sticky" to form a temporary plug that stops blood loss from a damaged blood vessel and strts the clotting process. They trigger clotting by releaseing chemicals that converts the blood protein fibrinogen into fibrin fibers that will act as a jelly-like netting that wil "catch" blood cells. The fibrin fibers will gradually shrink as the wound is repaired. Platelets make up less than 1% of the blood's volume because they're cell fragments rather than whole cells.
Mitochondria
Mitochondria have a double membrane and are the cell's "power stations" because they're the site of energy release in all body cells. They rapidly consume oxygen to breakdown fuels, particularly glucose, so they can release energy, which is then stored in the cell's cytoplasm. This is called aerobic respiration.
Liver Cells
Liver cells are located, as you can guess, in the liver and they process the blood as it flows by. Liver cells deal with nutrients such as glucose, fats, and amino acids that were absorbed by the small intestine into the bloodstream so they can regulate their levels in the blood. They also store certain minerals and vitamins, remove poisonous substances from the blood, and break down hormones to stop them from working. Liver cells also create bile, a yellow-green liquid that lines the small intestine and is stored in the gallbladder. In the small intestine, it aids in digesting fats and wastes including pigment bilirubin, and is composed of mostly water, but also bile salts that aid in digestion. Pigment bilirubin is a substance produced from the breakdown of hemoglobin from worn-out red blood cells, and it also colours feces (poo) brown.
Major Defender (White Blood) Cells of the Circulatory System
Neutrophil
Neutrophils are a type of white blood cell that has a broad-based activity and doesn't target any specific pathogens. They are a type of granulocyte that has a short lifespan and is filled with microscopic granules, little sacs containing enzymes that digest micro organisms. Neutrophils are also known as polymorphonuclear leukocytes, or informally know as a "poly".
Monocyte
Monocytes are phagocytic, mononuclear leukocytes, a type of white blood cell, that are created by promonocytes in bone marrow. They make up 3% to 8% of the body's white blood cells and have broad-based activity. When they are formed, they first circulate in the blood for 24 hours before moving into tissues and organs where they transform into macrophages by dividing.
Macrophage
Macrophages are phagocytic white blood cells that are produced by the division of monocytes and are able to survive for up to several months. Unlike lymphocytes, macrophages do not only eat specific invaders, they have a broad-based activity. They keep the blood running smoothly by using phagocytosis to remove debris inside blood vessels to prevent blockages.
Kupffer Cell (Hepatic Macrophage)
Kuppfer cells, or hepatic macrophages, are irregularly-shaped, yellow white blood cells that live permanently in the liver. In the liver, they trap, eat, and then recycle worn-out red blood cells. Kupffer cells also remove bacteria and debris using phagocytosis from the blood in the liver.
Lymphocytes
Lymphocytes are the stalwarts of the immune system. They release antibodies for defence and are found in vast numbers in lymph nodes and other lymphoid organs. Antibodies are chemicals released by certain white blood cells that disable and mark pathogens for destruction.
T Lymphocytes
Also known as T cells, T lymphocytes patrol the body searching for harmful invaders. There are three types of T cells: helper, killer, and memory. Helper T cells "help" by stimulating activated killer T cells or/and B cells to destroy specific invaders by releasing chemicals called cytokines once they have recognized the antigens of a specific germ. Cytokines are chemicals released by Memory T cells are white blood cells that will "remember" pathogens for future references to make it easier the next time it invades. Memory T cells are produced by other lymphocytes as a memory system. Killer T cells are next...
Killer T Cells (Cytotoxic T Cells)
Also known as cytotoxic T cells, killer T cells are the only T lymphocytes that directly destroy other cells. Killer T cells destroy cells by launching chemical attacks on the invader causing it to disintegrate! They identify their targets by markers on the pathogen's outer membrane. Once activated by helper T cells, they produce masses of clones that travel through blood and lymph attacking and destroying body cells infected by viruses and cancer cells.
B Lymphocytes
B lymphocytes (AKA B cells) target mainly bacteria and only respond to specific pathogens by recognizing the antigens on the invader that make it different than those of the body cells. B cells work by releasing disabling chemicals called antibodies that disable and mark the invaders for destruction. After they have located their target, they attack by rapidly dividing to produce big plasma cells that pour out the invaders. B cells also produce long-lived memory T cells that "remember" the germ in case it reappears so it can have a much quicker reaction.
Antibodies
Antibodies are "Y"-shaped, disabling proteins/chemicals that are released into blood and lymph by B cells when viruses invade. Since each type of antibody reacts to a specific pathogen, the arms of the "Y" differ from one antibody type to the next because that's the part that binds it to the particular part of the pathogen. Pathogens are identified by their surface antigens, and once an invader is identified, the antibodies bind to the pathogen marking it for destruction by phagocytosis or by other blood proteins.