Lungs

Question 1

outline the dissociation curves of adult hemoglobin, fetal hemoglobin and myoglobin

Answer 1

• cooperative binding in adult hemoglobin (higher affinity in oxygen rich tissues (oxygen loaded) (lower affinity in oxygen deficient tissue (oxygen unloaded)
• fetal hemoglobin has higher affinity for oxygen, it allows for oxygen transfer from mother to fetus in the placenta
• myoglobin has only one polypeptide chain (no cooperative binding) so the graph looks like a normal enzyme to substrate graph

Question 2

How is CO2 transported?

Answer 2

• bound to hemoglobin
• dissolved in plasma
• hydrogen carbonate ions in plasma

Question 3

What is the pH range of the blood?

Answer 3

7.35-7.45
maintained by plasma proteins (i.e. produced by the liver) zwitterion acts as buffers
lungs can change the rate of ventilation
kidneys can excrete hydrogen carbonate ions with the urine

Question 4

What is the Bohr shift?

Answer 4

• decrease in pH changes shifts oxygen dissociation curve to the right
• it allows oxygen to be released in respiring tissues (a lot of carbon dioxide makes the environment low pH so hemoglobin is promoted to release oxygen)

Question 5

What controls the rate of ventilation?

Answer 5

respiratory control center in medulla oblongata
detects pH changes of blood
during exercise higher CO2 levels in the blood –> higher ventilation rate

Question 6

What is the benefit of high altitude training?

Answer 6

• more erythrocytes
• more hemoglobin in the erythrocytes
• higher affinity of hemoglobin for oxygen
• more myoglobin in the muscles
• increased vascularization in the muscles
• higher lung surface area
• higher vital capacity

Question 7

What are the causes and treatment of emphysema?

Answer 7

emphysema - loss of elasticity of alveoli resulting in their enlargement and dicreased surface area of lungs
- caused by smoking which irritates alveolar cells , phagocytes produce elastase which breaks down elastic fibers in the alveoli
TREATMENT
- elastase enzyme inhibitors
- dilation of bronchi
- oxygen supply
- corticosteroids reduce inflammatory response