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Jetzt kostenlos anmeldenBloodand bloodcellsare important components of thecirculatory system。血液的运输系统将所有of the vital nutrients around our body. Think about your heart as being a large pump that pushes blood out towards the rest of your body, whilst yourblood vesselsare the pipes that then transport this blood to all of the different areas of the body for respiringcells。Blood helps to supply yourcellswith the important nutrients and oxygen that it requires, and drains the waste products like CO2away from those cells too!
Blood is the liquid transport medium that flows through the circulatory system of vertebrateanimalsand allows the transport of glucose, nutrients, oxygen and waste products (like CO2and urea) around the body.
Blood is often thought of as being completely red, however, the main liquid component of blood is plasma, which is a yellow liquid! The presence of oxygenated red blood cells is what gives blood its characteristicred colour。
The circulatory systeminvolvesthe heart, theblood vesselsand the blood. Without blood, the system doesn't work! Have a look below at the role, function and components of blood.
Learn more about the extensive network and their role by checking out the article on theCirculatory System。
Blood is composed of 4 main parts, and we will discuss each component in detail below!
Plasmais the liquid suspension that holds the rest of the components of blood.
Plasma has a yellow colour, do not make the mistake of thinking that it is red!
Plateletsare small cell fragments which are involved in the formation of clots and scabs. This preventsblood loss。As you can imagine, this is an extremely important aspect of the healing process of wounds!
The final two important components of blood arewhite blood cellsandred blood cells。Red blood cells are involved in carryingoxygen, whereas white blood cells are involved in defending the body against disease. These cells, as well as the platelets, will be found in the blood plasma.
To learn more about the important function of white bloodcellsin ourimmune systemcheck out the articleHuman Defense System。It's important you're able to identify and distinguish each blood component in an image!
You may have heard ofblood groupsbefore. We will have a look at what these are and which groups can donate blood to each other or not.
The 4 main types of blood are –A, B, AB and O。Your blood group is determined by thegenesyou inherit from your parents. This system is called theABOblood system. The letters in these blood groups signify whatantigensare found in your blood. For example, blood group A contains A-antigens. Whether we can donate blood to other blood groups depends on these antigens and theantibodiesthat counteract them.
Antigens are molecules that ourimmune systemrecognises and acts against. They can beproteins,lipidsor other compositions. These antigens allow our body to detect self and non-self entities, giving them a vital role in enabling our immune system to defend us against diseases!
Our blood group is determined by thegenesthat we inherit from our parents. Each parent donates one of their blood group genes to their child. Using this information, we can create a genetic cross or Punnett square. Within the ABO system, the A and B genes are dominant and the O gene is recessive. If one parent donates an O gene, and the other parent donates an A gene, the blood type of the child will be A, as A is dominant. If one parent donates A, and the other donates B, the blood type would be AB, and if both parents donate O, the blood group would be O!
Do you know what a Punnett square is? Read our article onGenetic Crossesto make sure!
The donation of blood from one person to another is completely dependent on theantigenspresent in the donated blood, and theantibodiespresent in the recipient's blood. Let's list the antigens andantibodiespresent in each blood group.
The antibodies in the blood are found in the blood plasma, whilst the antigens are found on the surface of red bloodcells!
|
Blood Group |
Antigen Present |
Antibody Present |
|
A
|
A |
Anti-B |
|
B
|
B |
Anti-A |
|
AB
|
A and B |
None |
|
O
|
None |
Both Anti-A and Anti-B |
Table 1 Antigens andantibodiespresent in different blood groups.
You can see that blood group A has anti-Bantibodies。This means that if we were donate blood group B blood to a person with blood group A, the anti-bantibodiesfrom therecipient'sblood and the B antigens from thedonatedblood would react with each other. This reaction is calledagglutination。The antigens would clump together with the antibodies, forming clots and restricting blood flow, potentially leadingto serious and fatal consequences。However, if we donate from blood group A to blood group A, the A antigens from the donor will not react with the anti-B antibodies, so no agglutination occurs and we have a successfulblood transfusion。
Blood group O is theuniversal donor。This means that people with blood group O can donate blood to anyone. This is because there are no A or B antigens in their blood, so they will not react with any other blood types negatively. Blood type AB is theuniversal recipient。This means that people with blood group AB can receive blood from anyone. This is because this blood type contains noantibodiesfor A and B antigens!
You can remember that blood type O is the universal donor as the word dOnOr has two letter O’s!
The Rhesus system (Rh system)also further separates blood groups. Individuals can either be Rhesus Positive (Rh+) or Rhesus Negative (Rh-). A Rh+ person hasRh(D)antigens, whilst an Rh- individual doesn't have these antigens and can create anti-Dantibodiesif it receives Rh+ blood.
This can become an issue during pregnancy: If an Rh- mother has a Rh+ baby, she will begin to createanti-D antibodies。This won't affect them during this pregnancy, however, if the mother were to have another Rh+ baby in a future pregnancy, agglutination betweenRh(D) antigens and already formed anti-D antibodies can occur。This is calledhaemolytic disease of the newborn, and if not treated could be life-threatening. However, this is easily treated with blood transfusions and scans early on in the pregnancy!
Blood pressurerefers to the pressure at which blood travels through thelumenof differentblood vessels。This is linked to our heart health, asthe heartpartially controls the pressure at which blood travels through these vessels. Large increases or decreases in normal blood pressure can negatively impact our health.
Thelumen实际就是血液的血管的一部分吗ly flows through. It's the cavity of the blood vessel!
High blood pressureis linked to obesity anddiabetesas well as other non-communicable diseases such ascardiovascular disease。Low blood pressurecan also be detrimental to our health.Low blood pressuremeans that your organs may not be getting adequately supplied with oxygen. This lack of oxygen can lead to dizziness or fainting in the short term if there is a sudden decrease in blood pressure, or even death and organ failure if the blood pressure is decreased by a large amount over a prolonged period of time.
It's important to be aware that our blood pressure can be linked to the non-communicable diseases mentioned above. Read theNon-Communicable Diseasesarticle to learn how.
Blood has many different functions. To start with, blood plays an important role in transporting glucose, oxygen and other important solutes around our body. Without blood,respiring cells and tissueswould not have a constant supply of oxygen and glucose to carry out these important processes. Blood also plays an important role in removing waste products from different tissues around the body.
Finally, blood plays an important role in fighting against disease. It does so through its white blood cells. These cells, such as lymphocytes and phagocytes, help to defend the body againstpathogens。
There are many different types of blood cells that have different roles in the body. A lot of students get blood cells and blood vessels confused.Blood vesselsare the tubes that carry blood around the body, includingarteries,veinsandcapillaries。Blood cellsare the components of the blood that is transported in these different vessels, includingred blood cellsandwhite blood cells。We do not include platelets as blood cells, as they are too small. Instead, they areconsideredcell
Blood cells are formed in the bone marrow. The bone marrow contains the stem cells that can go on to produce red blood cells, white blood cells and platelets!
Bone marrowis the soft, spongy tissue that is found in the centre of our bones.
Stem cells are cells that are undifferentiated. This means that they still have the ability to divide into different more specialised types of cells. Have a look at our article onStem Cellsfor more information!
Plateletsare also found in blood, however, we rarely describe them as blood cells. Instead, we describe them as small cell fragments. Platelets play an important role in blood clotting. Platelets prevent extensive bleeding and are involved in scab-formation.
As we mentioned above, red bloodcellstransport oxygen around the body. They do this by usinghaemoglobin。Red bloodcellscontain a lot of haemoglobin to which oxygen can bind and so be transported around the body.Haemoglobincontains ahaemgroup and this haem group containsiron。
Red bloodcellshave many different particular adaptations. One of these adaptations is that these cells have a biconcave shape. This increases thesurface areafor the transport of oxygen. Thesecellsalso donotcontain anucleus。Again, this helps to increase the space available for the transport of oxygen. As you can see, all of the above adaptations help the red blood cells to transport oxygen as efficiently as possible.
Here is a list of the most relevantadaptationsof red blood cells:
Biconcave Shape - Increases surface area for transporting oxygen
No Nucleus - Increases space available for transport of oxygen
Lots ofhaemoglobin- Transport as much oxygen as possible
Small size - Allows them to travel through allblood vesselsefficiently
There are many types of white bloodcells, but for the most part, their role is to defend the body against disease.Phagocytesare the first type of white blood cell that we will discuss. The role of phagocytes is toingestandengulfpathogens once they get past the body’s first line of defence.
How doesphagocytosishappen? In broad terms through the following steps:
The phagocyte is attracted to the pathogen by the chemicals that it secretes
The phagocyte surrounds the pathogen and engulfs it
The phagocyte ingests the pathogen
The next white blood cell that we will talk about are lymphocytes. Lymphocytes have two important functions:
They produceantibodies。They produce theseantibodiesin response to antigens that are found on the surface of pathogens. Theseantibodiesclump the pathogens together so that they can be destroyed by phagocytes and other white bloodcells!
They produceantitoxins。These antitoxins counteract the toxins that pathogens can produce.
Bloodhas an extremely important role in the functioning of our body overall. Understanding that blood is pumped around the body by theheart, and transported throughblood vesselsis very important! It's also vital for us to understand the role that blood plays in helpingfight against diseasethroughwhiteblood cells.
Blood is made up of red blood cells, white blood cells, platelets and plasma.
Blood transports useful substances to respiring cells, and carries waste products away from them
Blood is red because of the presence of red blood cells carrying haemoglobin bonded to oxygen.
White Blood Cells play a vital role in immunity and defending our body against disease.
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