W2e3

Question 1

Name and state the locations of the respiratory centres- whatre theyre functions?

Answer 1

medulla oblongata
1. The botzinger complex- involved in inspiration by contracting the inspiratory muscles

Pons
2. Pneumotaxic centre- involved in inhibition of inspiration

Question 2

How is rhythmic breathing established and modified?

Answer 2

1. Botzinger complex causes firing of the dorsal resp. neurones causing contraction of inspiratory muscles causing diaphragm and external intercostal muscles to contract (inspiration)
2. Expiration is a passive process
3. Pneumotaxic centre controls the rhythm of breathing where there will be inhibition of inspiration

Question 3

What are the location and stimuli of the peripheral and central chemoreceptors

Answer 3

Peripheral:
- Aortic and carotid bodies
- stimulated by (oxygen), co2, and (H+) conc in blood
- not hugely sensitive to o2 only below 8Kpa will take large drop before kicking in, will cause increased ventilation until neurones become hypoxic known as hypoxic drive (important in copd)
Central:
- surface of medulla
- stimulated by H+ concentration in cerebrospinal fluid which can be affected by CO2 and Hco3- concentration. Very sensitive to (co2 )concentrations

Question 4

What are some of the adaptions to chronic and acute hypoxia in the body?

Answer 4

Increased:

1. Rbc production
2. 2,3 BPG production in RBC (causing o2 easier offloading to tissues)
3. Number of capillaries
4. Number of mitochondria (so o2 can be used more effectively)
5. Kidneys conserve acid (to cause an arterial PH decrease)