Gas transport in blood

Question 1

role of haemoglobin

Answer 1

helps to deliver more oxygen to tissues than normal diffusion can (1000ml/min)

Question 2

shape of oxyhaemoglobin dissociation curve

Answer 2

sigmoidal curve- slow up curve up until plateau. very little change in the saturation of oxygen before the partial pressure falls to about 60%

Question 3

factors that affect oxyhaemoglobin dissociation curve (decrease haemoglobin affinity for oxygen)

Answer 3

decrease in pH, increase in pCO2, increase in temperature and increased 2,3-DPG

Question 4

anaemia

Answer 4

any condition where the oxygen carrying capacity of the blood is compromised eg iron deficiency, haemorrhage, vit B12 deficiency

Question 5

what happens to partial pressure of oxygen in anaemia

Answer 5

nothing happens. partial pressure of oxygen is normal despite total blood oxygen content is low

Question 6

carbonic anhydrase

Answer 6

catalyses carbon dioxide to carbonic acid

Question 7

carbon dioxide transport

Answer 7

CO2 diffuses from tissues into blood, 7% stays in plasma, 23% combines in erythrocytes with deoxyhemoglobin to form carbamino compounds, 70% combines in erythrocytes with water to form carbonic acid which dissolves into bicarbonate and hydrogen. bicarbonate then moves out into plasma in exchange for chloride ions and excess H ions bind to deoxyhaemoglobin. reverse happens in pulmonary capillaries and co2 moves down conc grad from blood to alveoli

Question 8

how much oxygen can bind to haemoglobin is directly determined by

Answer 8

PaO2, number of RBCs, amount of haemoglobin

Question 9

five types of hypoxia

Answer 9

hypoxaemic hypoxia, anaemic hypoxia, stagnant hypoxia, metabolic hypoxia, histotoxic hypoxia

Question 10

foetal haemoglobin

Answer 10

higher affinity for oxygen than HbA which is necessary for extracting oxygen from maternal/arterial blood

Question 11

what does glycosolated Hb show

Answer 11

patient has not controlled blood glucose well

Question 12

myoglobin

Answer 12

oxygen carrier molecule in cardiac and skeletal muscle which tends to store oxygen

Question 13

hypoxaemic hypoxia

Answer 13

most common. reduction in oxygen diffusion in lungs either due to decreased PO2atmos or tissue pathology

Question 14

anaemic hypoxia

Answer 14

reduction in oxygen carrying capacity of blood due to anaemia

Question 15

stagnant hypoxia

Answer 15

heart disease results in inefficient pumping of blood to lungs/ around body

Question 16

histotoxic hypoxia

Answer 16

poisoning prevents cells utilising oxygen delivered to them

Question 17

metabolic hypoxia

Answer 17

oxygen delivery to the tissues does not meet increased oxygen demand by cells