Describe The Chemical And Neural Aspects Of Breathing

Question 1

Explain acid-base homeostasis in the respiratory system + kidney system

Answer 1

The respiratory system controls CO2 levels - thus affects pH homeostasis through changing levels of CO2.
Kidney system controls HCO3- levels.
Disorders of the respiratory system can disturb pH. Respiratory systems can compensate for kidney / metabolic disorders

Question 2

What is acidosis?

Answer 2

Too many hydrogen ions

Question 3

What is alkalosis?

Answer 3

Too few hydrogen ions

Question 4

What is pH?

Answer 4

Inverse measurement of hydrogen ions.
Low pH means high hyodrgen ions
High pH means low hydrogen ions

Question 5

What happens if the body is in acidosis?

Answer 5

Proteins don’t function properly and if pH further drops, proteins denature.

Question 6

What happens if the body is in alkalosis?

Answer 6

Causes drop in ionised calcium (promotes binding calcium to albumin) - this affects function of muscles and nerves.

Question 7

What happens in respiratory acidosis?

Answer 7

Ventilation inadequate (slow respiratory rate and depth)
Inadequate alveolar ventilation- impaired gas exchange
Carbon dioxide removal insufficient
CO2 retention
Increase in hydrogen ions

Question 8

What happens In respiratory alkalosis?

Answer 8

Ventilation too high ( high respiratory rate and depth)
Excess alveolar ventilation- increased gas exchange
Carbon dioxide removal increased
Alveolar CO2 levels fall, blood CO2 levels falls
Leads to decreased amount of hydrogen ions

Question 9

What are the control centre, effectors and sensors in ventilators control?

Answer 9

Sensors = peripheral chemoreceptors + central chemoreceptors + pulmonary mechanoreceptors
Respiratory Control centre = medulla + pons
Spinal cord sends messages to effectors = respiratory muscles + diaphragm

Question 10

Describe Neural control ventilation

Answer 10

Respiratory centres in brain stem receive inputs from many sources
It respond appropriately to the situation - sends modifying signals to effectors = muscles

Question 11

Explain what central chemoreceptors do

Answer 11

• Brainstem neurones respond to changes in pH of cerebrospinal fluid.
• pH of cerebrospinal fluid reflect the CO2 levels in the blood
• By regulating respiration to maintain stable pH, respiratory centres also ensure stable CO2 level in blood.

Question 12

Explain what peripheral chemoreceptors do

Answer 12

• located in the carotid and aortic bodies of the large arteries above the heart.
• it’s sensitive to pCO2 but also sensitive to low arterial pO2.