Blood and blood cells

Question 1

what are the 6 main functions of the blood?

Answer 1

• transport
• heat distribution
• immunity
• haemostasis
• support
• maintain homeostasis

Question 2

what are the 4 major components of blood?

Answer 2

• plasma
• red blood cells
• white blood cells
• platelets

Question 3

what is the importance of haemoglobin?

Answer 3

transport of oxygen to tissue cells and transport of carbon dioxide to lungs

Question 4

what is the basic structure of haemoglobin?

Answer 4

• 4 polypeptides each with a haem group
• 2 alpha chains, 2 beta chains
• each haem group contains Fe2+ which binds to an oxygen

Question 5

what does haemoglobin carry carbon dioxide in conjunction with?

Answer 5

carbonic anhydrase

Question 6

what adaptation does haemoglobin have in foetuses?

Answer 6

higher affinity for oxygen to take oxygen from the mother’s blood

Question 7

what are the essential features and functions of the erythrocyte?

Answer 7

• transport oxygen and carbon dioxide
• biconcave disk
• no organelles
• 120 day lifespan
• removed by macrophages
• dependent upon dietary iron
• produced in bone marrow
• production is stimulated by erythropoietin release from kidneys

Question 8

define anaemia

Answer 8

low blood haemoglobin concentration

Question 9

what are the major subclasses and causes of anaemia?

Answer 9

• microcytic (small MCV): ion deficiency - menstruation, GIT lesions, cancers
• normocytic (normal MCV): acute blood loss
• macrocytic (large MCV): vitamin B deficiency, folic acid deficiency during pregnancy

Question 10

what are the major functions of leukocytes?

Answer 10

fight infections:

• lymphocytes produce antibodies
• neutrophils and monocytes are phagocytic
• eosinophils are involved in allergic responses
• basophils produce heparin

Question 11

what are the major functions and main features of T-lymphocytes?

Answer 11

• cellular immunity
• produced in bone marrow and “educated” in thymus
• activated lymphocytes produce chemotaxins, lymphotoxin and interferon
• sub-groups include regulatory cells, helper cells and cytotoxic cells

Question 12

what are the major functions and main features of B-lymphocytes?

Answer 12

• humoral immunity (antibody production)
• primary response occurs after a dormant period where it peaks then falls
• secondary response is greater, quicker and longer due to memory cells
• passive immunity can be acquired from injected antibody

Question 13

what are the main features of monocytes?

Answer 13

• appear later
• become macrophages in tissue
• stimulate repair
• ingest, store and modify antigens and present them to lymphocytes

Question 14

what are the main features of platelets?

Answer 14

• many organelles but no nuclei
• granules
• surface receptors initiate activation
• adhere to exposed collagen
• release granules to recruit and activate platelets
• involved in clot formation
• involved in haemostasis (prevention of blood loss)

Question 15

what are the major functions of plasma?

Answer 15

• carrying cells
• carrying other key components: nutrients (glucose, lipids, amino acids), hormones (thyroxine, cortisol, erythropoietin), proteins (clotting factors, albumin, globulins), inorganic ions (Na+, K+, Ca2+), products of metabolism (urea, lactic acid)

Question 16

in what ways do antibodies reduce infection

Answer 16

• precipitation: assist phagocytosis
• agglutination: clump cells together
• opsonisation: coat pathogen in antibody and mark for destruction by phagocytes
• neutralisation: prevent attachment of microorganisms to tissue