Table of Content
Blood is necessary to supply nutrients to each cell in your body while you run, dance, mow the lawn, or shovel snow. Blood transports nutrition to cells and collects waste. Blood is more than only a suspension of cells. It is a well-organized system that has the capacity to transport objects, defend itself, and protect the body from infection. Red blood cells, platelets, plasma, and white blood cells make up the four primary components of blood.
Plasma and Blood Clotting
Plasma is a fluid liquid that contains blood cells. More than half of the blood in circulation is made up of plasma, the liquid component of blood. Plasma looks yellowish when separated from whole blood. About 90% of plasma is water, with the remaining 10% made up of dissolved materials. Many of these dissolved substances, including plasma proteins, nutrients, and hormones, are essential to the proper operation of your body.
Fats, amino acids, and glucose are among the nutrients found in plasma. Salts of sodium, potassium, and calcium are additional components of plasma. All bodily processes depend on the distribution and amount of these salts. These salts are required, for instance, in the transmission of nerve signals throughout the body.
In addition, the plasma includes a variety of proteins, including fibrinogen. Blood protein fibrinogen, pronounced [fy BRIN uh jun], is crucial for blood clotting. Blood platelets, which are tiny disk-shaped entities in the blood, adhere to the wall of a blood artery that has been ruptured as a result of an injury. On the platelets, fibrinogen collects and transforms into a tangled web of minute strands. More platelets and blood cells are attracted to the clot created by the platelets and fibrinogen. Blood flow is stopped by the clot, which seals the vessel walls. A dried clot on the skin is referred to as a scab.
Key Points:
- Plasma is the liquid part of the blood that constitutes more than half of the circulating blood.
- Plasma appears yellowish when separated from whole blood.
- Plasma contains various dissolved substances like hormones, nutrients, and plasma proteins, which are crucial for the body's healthy functioning.
- Plasma consists of fats, amino acids, and glucose, along with sodium, potassium, and calcium salts.
- The salts present in plasma are essential in transmitting nerve messages throughout the body.
- Fibrinogen is a blood protein found in plasma that plays a vital role in blood clotting.
- When a blood vessel is torn due to injury, blood platelets attach to the wall of the broken vessel, and fibrinogen gathers on these platelets.
- Fibrinogen changes into a tangled network of fine threads, and along with platelets, it forms a clot that catches more platelets and blood cells.
- The clot stops the bleeding by closing the vessel walls.
- On the skin, a dried clot is called a scab.
Red Blood Cells
Red blood cells are the components of blood that transport waste carbon dioxide from body tissues to the lungs and oxygen from the lungs to the body tissues. They make up the majority of blood cells. Red small saucer-shaped blood cells in good health. Haemoglobin is the chemical that gives them their colour. An iron-containing molecule called haemoglobin (HEE muh gloh bin) rapidly binds to oxygen in the blood.
Blood's vibrant red colour is caused by the interaction of oxygen and haemoglobin. The blood changes back to a dull red colour when red blood cells donate oxygen to bodily cells. Although it appears blue in the veins visible through your skin, blood with low oxygen levels is never blue. RBCs have a lifespan of roughly 120 days. Red blood cells must be replaced by your body on a regular basis. New red blood cells are created in the red bone marrow. Your red marrow creates new red blood cells every day to replace those that are lost.
Figure 12-9 The formed elements in blood include red blood cells, several types of white blood cells, and blood platelets.
Key Points:
- Red blood cells carry oxygen from the lungs to the body tissues and waste carbon dioxide from the body tissues to the lungs.
- They are the most numerous kind of blood cells and have a saucer-like shape.
- The coloring of red blood cells comes from a substance called hemoglobin, which readily attaches to oxygen in the blood.
- The combination of hemoglobin and oxygen gives blood a bright red color, but after giving up oxygen to cells of the body, the blood returns to a dull red coloring.
- Red blood cells have a lifespan of about 120 days and must constantly be replaced by the body.
- Red bone marrow is responsible for producing new red blood cells to replace the old ones that die.
White Blood Cells
White blood cells are the body's first line of defence against infection and illness. Compared to red blood cells, they are bigger. Normally, the body has more red blood cells than white blood cells. When the body is infected, white blood cells are produced in greater quantities. Less than 12 hours are usually spent by white blood cells in the circulation.
White blood cells fight infections in two ways. One method is through creating chemicals known as antibodies. Proteins called antibodies bind to and kill disease-causing bacteria. The organisms can then be attacked by white blood cells. The second way that white blood cells combat infections is through attacking. They encircle and consume the bacterium. Some white blood cells are destroyed along with the bacteria while combating illnesses. Additionally, some of the tissue cells in the vicinity die. Pus is made up of these dead cells, live white blood cells, and tissue fluids.
Key Points:
- White blood cells guard the body against disease and infection.
- They are larger than red blood cells and there are normally fewer white blood cells in the body.
- The production of white blood cells increases when the body has an infection.
- White blood cells generally stay in the bloodstream for less than 12 hours.
- White blood cells fight infections in two ways: by forming substances called antibodies that destroy disease-causing organisms by attaching to them, and by surrounding and digesting bacteria.
- Some white blood cells and surrounding tissue cells are killed while fighting infections, which can result in the formation of pus.
- Pus is formed by dead cells, tissue fluids, and living white blood cells.
The Lymphatic System
The many types of white blood cells. The majority develop in the red bone marrow. The lymphatic system produces others. Lymph [limf] is the term for the plasma that leaks from capillaries and fills the gaps between cells. Your lymphatic system, which is seen in Figure 12-10, collects it. The lymphatic system serves as one of the body's defences against infection by transferring bodily fluid from tissues back into the bloodstream. It comprises of lymph nodes and lymphatic veins.
The lymphatic vessels are thin tubes with capillary and vein-like features. They are found all over the body in large numbers. The body's muscles operate to force lymph through these channels. One-way valves on the main lymphatic veins stop lymph from building up within the body. Large veins in the neck are where lymph that has travelled through the lymphatic system ultimately empties. Lymph nodes are necessary for all lymph to flow through. White blood cells and other specialised cells found in lymph nodes are tissues that catch and filter out pathogens. The size of these nodes varies.
Some are as small as a pinhead. Others are as large as a thimble. These nodes may swell when the body is fighting an infection. Lymph nodes are located in the neck, armpits, and groin. In addition to fighting infection, lymph carries nutrients, especially fats. Lymph also can absorb waste substances and other materials that cannot be absorbed by the blood capillaries.
Key Points:
- There are several kinds of white blood cells formed in the red bone marrow and lymphatic system.
- Lymph is the plasma that seeps out of capillaries and fills the spaces between cells.
- Lymphatic system returns fluid from body tissues to the blood stream and acts as a defense against infection.
- The lymphatic system consists of lymphatic vessels and lymph nodes.
- Lymphatic vessels resemble small veins and capillaries and are widely distributed throughout the body.
- Lymph is pushed through these vessels by the action of the body's muscles, and one-way valves prevent lymph from backing up in the system.
- Lymph eventually drains into large veins in the neck region and passes through lymph nodes, which trap and filter out disease-causing agents.
- Lymph nodes vary in size and may swell when the body is fighting an infection.
- Lymph nodes are located in the neck, armpits, and groin.
- Lymph carries nutrients, especially fats, and can absorb waste substances and other materials that cannot be absorbed by the blood capillaries.
Blood Types and Blood Banks
A healthy individual has five quarts or so of blood. People who have lost blood, as in a serious accident, may require blood transfusions to prolong their lives or hasten their recovery. Others require more blood to compensate for a shortage of a necessary component in their blood. To do this, more blood must be obtained from other persons. A blood transfusion involves taking blood from one person and injecting it into the circulatory system of another.
A blood donor is someone who donates their blood so that it can be used by another person. Blood donation is not unpleasant or complicated. The donor is not harmed since their blood supply is replenished. Through the insertion of a sterile, or germ-free, needle into an arm vein, one person's donated blood is drawn. Blood pours into a bag for collecting. A preservative is combined with the blood within the bag. After that, the blood is chilled to keep it cold for longer. Red blood cells, white blood cells, platelets, and plasma or blood serum may later be extracted from the blood. Blood plasma without the clotting components is called blood serum.
All around the country, hospitals and health organisations collect and store donated blood. In the case of a significant community crisis, this blood is available for use by patients. The blood type of the patient must be ascertained by the physician before a transfusion may be carried out. Blood is not all created equal. The fresh blood may cause the red blood cells to clump together if it does not match the patient's own blood. These aggregates might kill the patient if they go via the heart or brain. Blood is categorised using a system of blood types based on the presence of molecules on the red blood cells that induce clumping.
The four major blood types are O, A, B, and AB. A donor's blood type must match that of the person receiving it.
The Rh factor's existence or absence must also be taken into account by doctors. Some people have a molecule called the Rh factor on their red blood cells. Between 85% and 95% of people have the Rh factor in their blood. Rh positive people are those who possess the Rh factor. Rh negative refers to the 5 to 15% of the population who are deficient in this substance. An Rh negative individual may develop antibodies against the Rh factor while receiving Rh positive blood. When a son receives Rh positive blood the following time, this may result in blood clumping, among other issues.
Donated blood is examined for its blood type and Rh factor as well as for the presence of any infections that could be transmitted to the recipient. Blood is examined for the presence of AIDS and hepatitis.
Key Points:
- A person may need blood transfusions due to severe accidents or blood deficiencies.
- Blood donors give blood through a sterile needle in their arm, and the blood is collected in a bag mixed with a preservative and cooled to stay fresh.
- Donated blood is stored by hospitals and health organizations for patients and disasters.
- A doctor must determine the patient's blood type before a transfusion can be performed.
- Blood is classified into four major types (O, A, B, and AB) based on the presence of substances on the red blood cells that cause clumping.
- A donor's blood type must match the recipient's blood type to avoid clumping.
- The presence or absence of the Rh factor on red blood cells is also considered.
- About 85-95% of people have the Rh factor (Rh positive), while 5-15% do not (Rh negative).
- An Rh negative person receiving Rh positive blood may produce antibodies against the Rh factor, causing problems in future transfusions.
- Donated blood is also tested for diseases such as hepatitis and AIDS before transfusion.
Blood Disorders
One of the most popular methods for obtaining specific details about your health is through blood testing. It's possible that you'll be requested to provide a blood sample during a medical examination. Compared to the quantity donated for a transfusion, this sample is substantially smaller. This one blood sample may be subjected to more than 30 tests. The blood tests might reveal a health issue that exists in other areas of the body. The blood itself may be the source of other issues.
Blood disorders can sometimes be fatal, but more frequently they make it harder to live an active life. For instance, some persons get anaemia. Anaemia, pronounced "nee-mee-uh," is a condition in which there are insufficient red blood cells or haemoglobin to deliver enough oxygen through the body. A vitamin or iron shortage, the oxidation of red blood cells, or a hereditary flaw can all contribute to anaemia. A person who is anaemic will as a result be frail, pale, and quickly exhausted.
Women are more prone to iron-deficiency anaemia because they normally lose blood during menstruation. When iron supplements are included in the diet, iron deficiency anaemia may frequently be successfully treated. Sickle-cell illness is a kind of anaemia where the red blood cells' defective haemoglobin prevents the transport of oxygen. Red blood cells have a sickle form rather than a spherical shape. These cells have a short lifespan and have trouble passing through capillaries. People with Black ancestry are more likely to contract the disease, which is inherited. It can be very painful and life-threatening. There is no cure, but blood tests can detect it.
|
Blood Group |
Donates to |
Receives from |
|
O |
O, A, B, AB |
A |
|
A |
A, AB |
O, A |
|
B |
B, AB |
O, B |
|
AB |
AB |
O, A, B, AB |
Table 12-11 Learn your blood type. To which types can you donate blood?
Key Points:
- Blood tests are common and can provide important information about a person's health.
- More than 30 tests can be conducted on a single blood sample.
- Blood tests can detect health problems in other parts of the body and can reveal issues with the blood itself.
- Anemia is a disorder in which the blood lacks enough red blood cells or hemoglobin to carry oxygen.
- Anemia can be caused by a variety of factors, including vitamin or iron deficiencies, destruction of red blood cells, or an inherited defect.
- Women are more susceptible to iron-deficiency anemia due to blood loss during menstruation.
- Iron supplements can be effective in treating iron-deficiency anemia.
- Sickle-cell disease is a type of anemia in which abnormal hemoglobin inhibits the carrying of oxygen and causes red blood cells to be sickle-shaped.
- Sickle-cell disease is inherited and occurs most often in people of Black ancestry.
- Sickle-cell disease can be painful and life-threatening, but can be detected through blood tests.
Lesson Review
Your body's transportation system is provided by your blood and lymph, which also work to protect you from infection. Your cells receive oxygen through red blood cells. Infectious pathogens are captured and combated by lymph nodes and white blood cells. Blood coagulation depends on fibrinogen and platelets, two components. Blood from a different individual who has given blood can be added if a significant volume of blood is lost, as can occur in an accident or during surgery.
- Explain how blood clots.
- What is the function of red blood cells?
- What are the two main functions of the lymphatic system? 4 Explain the importance of the blood being matched in any blood transfusion.
- List two disorders of the blood.
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