Respiratory system 2

Question 1

Identify the key requirements for effective ventilation and diffusion.

Answer 1

ventilation:
- inhalation + exhalation of air
- O2 enters lungs + CO2 leaves lungs
diffusion:
- exchange of air between the atmosphere + the alveoli of the lungs

Question 2

Describe the physiological effects of altered ventilation and diffusion.

Answer 2

• faster / slower rate of diffusion
• lowered levels of oxygen in the blood

Question 3

Describe the common signs and symptoms of altered ventilation and diffusion.

Answer 3

• increased / decreased breathing rate
• noisy breathing

Question 4

3.4 Discuss the homeostatic processes that can alter ventilation and diffusion.

Answer 4

• central chemoreceptors in medulla + peripheral chemoreceptors in aortic + carotid bodies detects changes in CO2 conc.
• nerve impulses sent to dorsal respiratory group in medulla oblongata
• nerve impulses sent to muscles of inhalation + exhalation which contract more / less frequently
• CO2 conc. increases / decreases

Question 5

Apply the concepts of altered ventilation and diffusion to changes over the lifespan.

Answer 5

• airways + tissues of the respiratory tract, incl. alveoli, become less elastic + more rigid with age
• results in decreased lung capacity (lowered blood O2 level, decreased alveolar macrophage activity etc.)
• these age-related factors mean elderly people are more susceptible to pneumonia, bronchitis, emphysema etc.

Question 6

What two parts can the respiratory centre be split into?

Answer 6

Medulatory Respiratory Centre

Question 7

What are the roles of the medullary resp centre?

Answer 7

To control the rhythm and rate of breathing.

Question 8

What are the roles of the pontine resp centre?

Answer 8

To control the transition of inhalation and expiration.

Question 9

What factor can influence respiration?

Answer 9

Several factors include:

• Cortical influence
• Chemoreceptors
• Limbic system stimulation
• Proprioceptor stimulation
• Temperature
• Pain
• Irritation of airways
• The inflation reflex (stretch receptors)

Question 10

What is the role of the phrenic nerve?

Answer 10

The phrenic nerve connects the medulla oblongata to the diaphragm and the external intercostal muscles.

Question 11

Describe the process of the DSG (Dorsal respiratory group).

During normal quiet breathing.

Answer 11

When the DRG is active, it takes 2 seconds to contract the diaphragm and external intercostal muscles during their most active phase, causing normal quiet inhalation.

Whereas

When the DRG is inactive, it takes 3 seconds to relax the diaphragm and external intercostal muscles, becoming less active, followed by the recoil of the elasticity of the lungs, causing normal quiet exhalation.

Question 12

Describe the process of the VSG (Ventral respiratory group).

During Forceful breathing.

Question 13

Describe the negative feedback of breathing.

Answer 13

During intense exercise, your muscles require more oxygen than a normal breathing rate can supply them with. This creates a negative feedback loop that increases blood pressure and breathing rate to push oxygenated blood into working muscle tissue.