NS - Respiration IV

Question 1

What is the Haldane effect?

Answer 1

Refers to the ability of deoxygenated haemoglobin to carry and release carbon dioxide

Question 2

What occurs in the tissue capillaries (chloride shift)?

Answer 2

CO2 combines with H2O
1. Carbonic acid dissociates to H+ and HCO3-
2. HCO3- leave the RBC and Cl- enter to maintain charge
3. H+ reacts with Hb

Question 3

What does the respiratory centre consist of?

Answer 3

Several groups of neurons located bilaterally in the medulla oblongata and pons

Question 4

What are the 4 types of respiratory groups?

Answer 4

1. Dorsal respiratory group
2. Ventral respiratory group
3. Pneumotaxic centre
4. Apneustic centre

Question 5

What does the dorsal respiratory system cause?

Answer 5

Inspiration

Question 6

Where is the apneustic centre and what does it excite?

Answer 6

Lower pons

Excites the inspiratory centre

Question 7

Where is the Pneumotaxic centre and what does it do?

Answer 7

Upper pons

Acts as a rate controller:
1. Limits rate of inspiration
2. Increases rate of breathing

Question 8

What does the ventral respiratory group do?

Answer 8

Modifies both inspiration and expiration

Question 9

What 3 ways is respiratory centre activity regulated?

Answer 9

1. Central chemoreceptors
2. Peripheral sensory signals
3. Voluntary corticol factors

Question 10

What is the Herring-Breuer Reflex?

Answer 10

Stretch receptors in chest wall and in the bronchi and bronchioles send impulses to the brain to terminate inspiration

Question 11

When do peripheral chemoreceptors play a role?

Answer 11

When the blood oxygen falls too low

Question 12

How do oxygen sensors work? (6)

Answer 12

1. Carotid body chemoreceptor cells respond to low O2 by closing K+ channels
2. Depolarisation occurs
3. Ca2+ channels are activated and influx occurs
4. Exocytosis of dopamine-containing vesicles occurs
5. Dopamine acts to increase activity of chemosensory fibres
6. Signals to medulla respiratory centres to increase ventilation