Notes: Regulation of Respiration (pg 10)

Respiratory Center

• Group of neurons in the pons and medulla oblongata that control the rate and depth of breathing

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

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

Output (pg 11)

• Paste in oval diagram• Color code: Red for inspiration, blue for

expiration

Chemoreceptors

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

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

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.

Stretch Receptors

• As alveoli in the lungs expand, stretch receptors are stimulated

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.

Stimulus from higher brain centers

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

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)

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

Temperature

• Increase in body temperature causes increase in breathing rate.

Temperature

• Increase in body temperature causes increase in breathing rate.

• Higher temperature leads to higher metabolism and more CO2 production

Respiratory Volumes• Tidal Volume (TV): ≈ 500 ml. Amount of air

inhaled and exhaled during normal quiet breathing

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

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

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

Respiratory Capacities

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

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

Output (pg 11)

• Label diagram