9.3 Regulation of Breathing Movements

& Respiratory

Disorders

• Breathing is controlled by nerves from the medulla oblongata

Chemoreceptors

Receptors in the body

sensitive to changes in

specific chemicals such as

O2 and CO2.

Alert Medulla to balance

levels using negative

feedback

• CO2 receptors are the main receptors because they are the most sensitive

• If carbonic acid accumulates in the blood it triggers the chemoreceptors.

• The medulla oblongata will send messages to the diaphragm and intercostal muscles

Chemoreceptors

• Oxygen chemoreceptors are found in the carotid and aortic arteries

• Detect low levels of oxygen and send a signal to the medulla oblongata

• Sends messages to the diaphragm and intercostal muscles

Chemoreceptors

Response to Exercise

• Ventilation of alveoli can increase up to 20 times

• 3 factors are important in increased ventilation:– decreased O2

– increased CO2

– increased H+

Accumulation of air inside the chest in

the pleural membrane space due to

puncture of the thoracic cavity.

Causes the lung to

collapse, breathing

becomes difficult to

impossible

Pneumothorax

Smoker’s Cough

• Smoking causes the paralysis and death of cilia = can’t clear debris.

• Also causes the mucus protecting the respiratory system to be less effective.

Pleurisy• Inflammation of the

pleura

• Causes chest pain inhalation issues

• Could cause lungs to collapse and/or suffocation

Bronchitis• Infection caused by bacteria,

viruses or a reaction to one’s environment

• Narrowing of the air passages and inflammation of the mucus lining the bronchial tubes

• VERY serious if it gets into the bronchioles = possible suffocation

Emphysema• Walls of alveoli become inflamed

• Destroys air sacs = less S.A.

• Difficult to exhale, air is trapped in lungs

• Decreased oxygen levels

Pneumonia

• Inflammation of the lungs

• Caused by viruses, molds, bacteria

• Chest pains and fevers

• Can be deadly

Bronchial Asthma• Caused by an allergic reaction

• Walls of the bronchioles become restricted

• Cells secrete abnormally large amounts of mucus

Lung Cancer• Uncontrolled growth of abnormal

cells cause tumors.

• Tumors kill normal cells

The Bends• Under water, with increased pressure, a

diver’s blood and tissues can absorb extra amounts of gases

• If one surfaces too quickly these gases can come out of solution in the blood, cause bubbles

• Diver experiences dizziness, nausea, muscle and joint pain, can be deadly

Pulmonary Tuberculosis • Caused by bacteria

• Very deadly

• Symptoms: – Fatigue– abnormal sounds in the lungs– Fever– Coughing up blood & pus

• Practice Questions

Pg. 297

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