A level Biology 4.3

• What is blood?

  A transport medium
• What are platelets

  Tiny fragments of large cells (Megakaryocytes) found in bone marrow
• In platelets, what are the large cells the tiny fragments come from called?

  Megakaryocytes (sp)
• What does Plasma transport?

  Digested food products from small intestine to where is needed for immediate use or storage

  Nutrient molecules from storage areas to cells that need them

  Excretory products from cells to organs

  Chemical messages (hormones) from where they are made to where they cause changes in the body
• What digested food products does plasma transport?

  Glucose and amino acids
• What excretory products does plasma transport?

  Urea and carbon dioxide
• What are the functions of plasma?

  Transport

  Helps maintain a steady body temp

  Acts as a buffer for pH change
• How does plasma help maintain a constant body temp?

  Transfers heat around the system from deep-seated organs or very active tissues
• Define circulation

  The passage of blood through the blood vessels
• What does the cardiovascular system do?

  Delivers materials needed by the cells and carries away waste products of their metabolism

  Carries hormones

  Part of the body’s defence system

  Distributes heat
• What are the role of Erythrocytes?

  Contain haemoglobin

  Transports oxygen from lungs to cells and carbon dioxide (produced in cells via respiration) back to lungs
• How does the role of Erythrocytes relate to their function?

  No nucleus so more room to transport more haemoglobin

  Biconcave disc shape makes a large surface area for rapid oxygen diffusion
• Which part of blood transports oxygen from lungs to cells?

  Erythrocytes
• What is the role of Leucocytes?

  Immune defence - prevents infection
• Describe structure of Leucocytes

  Can change their shape

  Larger than Erythrocytes

  Contain nucleus and clear cytoplasm
• What are the two types of Leucocyte?

  Granulocytes and Agranulocytes
• What are Granulocytes?

  Leucocytes that have granules in the cytoplasm and lobed nuclei
• Can Granulocytes take up stain?

  They take up stain due to the granules
• What are the types of Granulocytes?

  Neutrophils

  Esoinophils

  Basophils
• Do the 3 types of Granulocyte have a specific or non-specific immune system?

  Non-specific immune system
• What do Neutrophils do?

  Engulf and digest pathogens by phagocytosis

  Have a multi lobed nuclei
• What do Esoinophils do?

  Important in response against parasites, in allergic reactions and inflammation, and in immunity to disease
• What stain does Esoinophils take up?

  Eosin stain

  Turns red
• What do Basophils do?

  Produce histamines involved in inflammation and allergic reactions

  Two lobed nuclei
• What are Agranulocytes?

  Leucocytes that do NOT have granules

  They have unlobed nuclei
• Can Agranulocytes take up stain?

  No as they have no granules to hold the stain
• What are the types of Agranulocyte?

  Monocytes

  Lymphocytes
• Do the Agranulocytes have a specific or non-specific immune system?

  Specific
• What do monocytes do?

  The largest Leucocyte

  Move out of blood into tissues to form macrophages

  Engulf pathogens by phagocytosis
• What do lymphocytes do?

  Small with a large nucleus

  Vitally important in the specific immune response of the body