Lesson 2: Respiratory system (continued)

Question 1

What are the 3 factors involved in the regulation of pulmonary ventilation?

Answer 1

• Neural control
• Chemical control
• Hormonal control

Question 2

What does pulmonary ventilation mean?

Answer 2

Breathing

Question 3

What does neural regulation and chemical regulation consist of?

Answer 3

Brain and the nervous system
Blood acidity
They both work together to regulate breathing

Question 4

What happens when blood acidity is high?

Answer 4

The brain is informed and sends impulses to the nervous system to increase breathing..

Question 5

What does the sympathetic nervous system do to help regulate breathing?

Answer 5

Prepares your body for exercise so it will increase breathing rate.

Question 6

What does the parasympathetic nervous system do to help regulate breathing?

Answer 6

Will do the opposite and lower breathing rate.

Question 7

Where is the respiratory centre located and what does it do?

Answer 7

Its loacated in the medulla oblongata and it controls the rate and depth of breathing. It uses both nerual and chemcial control.

Question 8

What does an increased concentration of CO2 do to breathing?

Answer 8

It stimulates the respiratory centre to increase respiratory rate. The respiratory centre has two main areas; the inspiratory and the expiratory centre.

Question 9

What does the inspiratory centre do?

Answer 9

• Its responseible for inspiration and expiration.
• It sends out nerve impulses via the phrenic nerve to the inspiraotry muscles (diaphragm and external intercostals) to cuase them to contract.
• This stimulates for approx 2 secs then the impulses stop and passive expiration occurs due to elastic recoil of the lungs

Question 10

What does the expiratory centre do?

Answer 10

Stimulates expiratory muscles during exercise.

Question 11

What does the respiratory centre mainly respond to?

Answer 11

• Changes in blood chemistry
• During exercise,bloodaciditiy increases as a result of increased plasma concentration of CO2 and increased lactic acid production
• These changes are detected by chemoreceptors found in the carotid artery and the aortic arch. They send impulses to the inspiratiry sentre to increase ventilation until blood acidity has returned to normal.
• To achieve this, the respiratory centre sends impulses down the phrenic nerve. This stimulates more inspiratory muscles such as the sternocleidomastoid, scalene and pectoralis minor.
• As a result the rate, depth and rhythm of breathing will increase.

Question 12

What are some other factors that affect nerual control of breathing?

Answer 12

• Proprioceptors - sensory receptors located in the joints and muscles that provide feedback to the respiratory centre to increase breathing during exercise
• Baroreceptors - a decrease in BP detected by barorecpetors in the aorta and carotid arteries results in an increase in breathing rate.
• Stretch receptors - during excercise the lungs are also strectehd more.

Question 13

Order of neural/chemical control for inspiration.

Answer 13

1 - receptors
2 - medulla oblongata
3 - phrenic nerve
4 - diaphragm, external intercostals, sternocleidomastoid, scalenes and pectoralis minor

Question 14

Order of neural/chemical control for expiration.

Answer 14

1 - receptors
2 - medulla oblongata
3 - intercostal nerve
4 - abdominals, internals intercostals

Question 15

Hormonal regulation of pulmonary ventilation during exercise.

Answer 15

• Adrenaline is a natural stimulate made in the adrenal gland of the kidney.
• It’s transported in the blood and affects the nervous system
• It’s the body’s activator and is released in response to exercise.
• Before exercise, the brain sends impulses the adrenal glands and pump adrenaline into the blood.
• As a result, breathing rate increases.