The respiratory center, located in the pons and medulla oblongata, controls breathing by sending signals to respiratory muscles. It is stimulated by chemoreceptors sensitive to CO2 and pH levels, as well as stretch receptors in the lungs. Higher brain centers can also influence breathing voluntarily or involuntarily. Various respiratory volumes and capacities describe lung functioning, including tidal volume, inspiratory reserve volume, and residual volume.

1. Notes: Regulation of Respiration
(pg 10)

2. Respiratory Center
• Group of neurons in the pons and medulla
oblongata that control the rate and depth of
breathing

3. Respiratory Center
• Group of neurons in the pons and medulla
oblongata that control the rate and depth of
breathing
• Inspiratory area sends impulses to the
diaphragm and, for deeper breathing, to the
external intercostal muscles. Muscles contract
and inspiration occurs

4. Respiratory Center
• Group of neurons in the pons and medulla
oblongata that control the rate and depth of
breathing
• Inspiratory area sends impulses to the diaphragm
and, for deeper breathing, to the external
intercostal muscles. Muscles contract and
inspiration occurs
• Nerves fatigue quickly and stop sending impulses.
Muscles then relax and expiration occurs. When
forceful expiration is necessary, expiratory area
sends impulses to the internal intercostal muscles

5. Output (pg 11)
• Paste in oval diagram
• Color code: Red for inspiration, blue for
expiration

6. Chemoreceptors
• Receptors in the medulla oblongata that are
sensitive to changes in CO2 and H+ (acidity)
levels

7. Chemoreceptors
• Receptors in the medulla oblongata that are
sensitive to changes in CO2 and H+ (acidity)
levels
• If CO2 and H+ levels increase, the
chemoreceptors stimulate the respiratory
center to increase the rate and depth of
breathing

8. Chemoreceptors
• Receptors in the medulla oblongata that are
sensitive to changes in CO2 and H+ (acidity) levels
• If CO2 and H+ levels increase, the chemoreceptors
stimulate the respiratory center to increase the
rate and depth of breathing
• Receptors sensitive to oxygen levels are located in
the aorta. However, low oxygen level is not as
strong a stimulus for breathing as high CO2 level.

9. Stretch Receptors
• As alveoli in the lungs expand, stretch
receptors are stimulated

10. Stretch Receptors
• As alveoli in the lungs expand, stretch
receptors are stimulated
• Stretch receptors initiate the Hering-Breuer
reflex, which prevents overinflation of the
lungs. Impulses travel to medulla oblongata
where they inhibit the inspiratory neurons.

11. Stimulus from higher brain centers
• Impulses from higher brain can temporarily
override the respiratory center.

12. Stimulus from higher brain centers
• Impulses from higher brain can temporarily
override the respiratory center.
• Impulses may be voluntary (singing, holding
your breath) or involuntary (emotions, sudden
pain or cold)

13. Stimulus from higher brain centers
• Impulses from higher brain can temporarily
override the respiratory center.
• Impulses may be voluntary (singing, holding
your breath) or involuntary (emotions, sudden
pain or cold)
• When CO2 levels reach a critical point,
impulses from the higher brain centers are
ignored and the respiratory center resumes
control

14. Temperature
• Increase in body temperature causes increase
in breathing rate.

15. Temperature
• Increase in body temperature causes increase
in breathing rate.
• Higher temperature leads to higher
metabolism and more CO2 production

16. Respiratory Volumes
• Tidal Volume (TV): ≈ 500 ml. Amount of air
inhaled and exhaled during normal quiet
breathing

17. Respiratory Volumes
• Tidal Volume (TV): ≈ 500 ml. Amount of air
inhaled and exhaled during normal quiet
breathing
• Inspiratory Reserve Volume (IRV): ≈ 3100 ml.
Maximum amount of air that can be forcefully
inhaled after a normal exhale

18. Respiratory Volumes
• Tidal Volume (TV): ≈ 500 ml. Amount of air
inhaled and exhaled during normal quiet
breathing
• Inspiratory Reserve Volume (IRV): ≈ 3100 ml.
Maximum amount of air that can be forcefully
inhaled after a normal exhale
• Expiratory Reserve Volume (ERV): ≈ 1200 ml.
Maximum amount of air that can be forcefully
exhaled after a normal inhale

19. Respiratory Volumes
• Tidal Volume (TV): ≈ 500 ml. Amount of air
inhaled and exhaled during normal quiet
breathing
• Inspiratory Reserve Volume (IRV): ≈ 3100 ml.
Maximum amount of air that can be forcefully
inhaled after a normal exhale
• Expiratory Reserve Volume (ERV): ≈ 1200 ml.
Maximum amount of air that can be forcefully
exhaled after a normal inhale
• Residual Volume (RV): ≈ 1200 ml. Amount of air
that remains in the lungs after maximum
expiration

20. Respiratory Capacities
• Vital capacity = TV + IRV + ERV. Maximum
amount of air that can be exhaled after a
maximum inspiration

21. Respiratory Capacities
• Vital capacity = TV + IRV + ERV. Maximum
amount of air that can be exhaled after a
maximum inspiration
• Total lung capacity = TV + IRV + ERV + RV.
Amount of air in the lungs after a maximum
inspiration

22. Output (pg 11)
• Label diagram