Identify and describe The Four Components of Blood, Red Blood Cells & Haemoglobin and Adaptations of Red Blood Cells in the context of blood.
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GCSE Biology Revision
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GCSE Biology revision
Blood
Animal tissues, organs and organ systems
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Explain the relationships between The Four Components of Blood, Red Blood Cells & Haemoglobin and Adaptations of Red Blood Cells and how they contribute to blood.
Apply and analyse knowledge of The Four Components of Blood, Red Blood Cells & Haemoglobin and Adaptations of Red Blood Cells to interpret unfamiliar information about blood.
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The Four Components of Blood
- Blood is made up of four main components: red blood cells, white blood cells, platelets, and plasma
- Red blood cells (RBCs) make up almost half of the blood's volume, while white blood cells account for less than 1%
- Plasma makes up just over half of the blood's volume and is a pale straw-coloured liquid that allows blood to flow
Red Blood Cells & Haemoglobin
- The role of red blood cells is to carry oxygen from the lungs to the body's tissues for use in cellular respiration
- Red blood cells contain a red pigment called haemoglobin, which combines with oxygen to form oxyhaemoglobin
- Once red blood cells reach the body's tissues, oxyhaemoglobin splits back into haemoglobin and oxygen, allowing oxygen to diffuse into the tissues
Adaptations of Red Blood Cells
- Red blood cells lack a nucleus, which creates more space for haemoglobin and oxygen
- Red blood cells are shaped like a biconcave disc, which gives them a large surface area for absorbing oxygen
White Blood Cells & the Immune System
- White blood cells are an essential part of the immune system, defending the body against infection
- Phagocytosis is the process by which a white blood cell engulfs and consumes a microorganism
- White blood cells can produce antibodies, which bind to pathogens and help destroy them
- White blood cells can also produce antitoxins, which neutralise toxins produced by pathogens
- Unlike red blood cells, white blood cells do contain a nucleus
Platelets & Blood Clotting
- Platelets are not full cells but small fragments of cells, and therefore do not have a nucleus
- When a cut occurs, platelets rush to the wound and clot the blood, sealing the hole to prevent blood loss
- Clotting also prevents microorganisms from entering the wound, reducing the risk of infection
The Role of Plasma
- Plasma is a pale straw-coloured liquid that carries red blood cells, white blood cells, and platelets throughout the body
- Plasma transports nutrients such as glucose and amino acids, as well as waste products like carbon dioxide and urea
- Plasma also carries hormones, proteins, and the antibodies and antitoxins produced by white blood cells
Artificial Blood
- Artificial blood is a blood substitute that consists mainly of salt water, used to add volume to the circulatory system
- The main benefit of artificial blood is that it keeps blood vessels full and allows the heart to continue pumping
- A key limitation is that artificial blood contains no red blood cells, so it cannot transport additional oxygen, meaning only about one-third of blood can be replaced with it
Blood Transfusions
- A blood transfusion involves giving a patient real donated blood, which contains its own red blood cells
- Blood transfusions are a more effective option than artificial blood because they restore the body's ability to transport oxygen
- Blood transfusions are used when a patient has lost too much blood, for example due to a knife wound or surgical complications, and their tissues are not receiving enough oxygen