Haemostasis

Question 1

what are the components of blood

Answer 1

red blood cells/erythroctytes
white blood cells/leukocytes
platelets/thrombocytes

Question 2

describe the function of erythrocytes and how their structure helps this

Answer 2

their primary function is to transport oxygen from the lungs to the venous tissues of the body, and to transport carbon dioxide from the tissues to the lungs. due to the biconcave shape of RBCs they have increased surface area, allowing rapid movement of gases into and out of the red blood cell

Question 3

what is the main function leukocytes and what are the 5 types

Answer 3

protect the body against invading microorganisms and remove dead cells and debris from the body

• neutrophils
• eosinophils
• basophils
• lymphocytes
• monocytes

Question 4

describe neutrophils

Answer 4

most common type of WBC

seek out foreign matter and secrete lysosomes (type of enzyme)

Question 5

describe eosinophils

Answer 5

enter tissues during inflammatory reaction
most common in tissues undergoing an allergic response
reduce inflammatory réponse by producing enzymes that destroy inflammatory chemicals

Question 6

describe basophils

Answer 6

least common type of WBC
contain large amounts of histamine which they release to increase inflammation
also release heparin to inhabit blood clotting

Question 7

describe lymphocytes

Answer 7

originate in red bone marrow the migrate through blood to lymphatic tissues
further drivelled into B-cells, which produce antibodies, and T-cells, which protect against viruses and microorganisms by attacking and destroying the cells in which they are found

Question 8

describe monocytes

Answer 8

turn to macrophages for phagocytosis

Question 9

describe thrombocytes (platelets)

Answer 9

they are cell fragments
play an important role in preventing blood loss by
1) forming platelet plugs which seal small holes in vessels
2) promoting the formation of clots which help seal off larger wounds

Question 10

how is clot formation normally prevented when appropriate

Answer 10

to prevent unwanted clotting, the blood contains several anticoagulants which prevent coagulation factors from initiating clot formation. only when coagulation factors concentration exceeds a given threshold in a local area will coagulation occur

Question 11

what are 2 conditions that can cause abnormal bleeding

Answer 11

thrombocytopenia

haemophilia

Question 12

what is thrombocytopenia

Answer 12

when blood platelet count is too low, either due to reduced platelet production to increased platelet destruction

Question 13

what is haemophilia

Answer 13

a congenital disorder where a faulty gene codes for abnormal clotting factors, causing people to experience repeated episodes of server and prolonged bleeding at any site, with little evidence of trauma

Question 14

what is needed for safe blood transfusion

Answer 14

donor and recipient must have same ABO and Rh blood group

Question 15

what is the cardiovascular response to exercise

Answer 15

increased heart rate
peripheral vasodilation
increased cardiac contractility and therefore increased cardiac output and venous return

Question 16

what is the pulmonary response to exercise

Answer 16

As soon as exercise starts but before demands are made on aerobic and anaerobic metabolism ventilation increases
After exercise has started, the increase in ventilation rate is maintained and is modified by a change in arterial pCO2 and lung stretch receptors

Other important factors that control the rate of respiration are:-
a) irritant receptors (cells between epithelial cells stimulated
by noxious gases)
b) nose-airway receptors cause bronchi to constrict
c) joint and muscle receptors
d) arterial baroreceptors
e) pain receptors

Exercise causes vasodilatation of bronchial smooth muscle (post-junctional β-receptors to allow the increase in ventilation rate to occur).