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The Human Respiratory System

    Breathing is an involuntary action, controlled by the medulla oblongata 

   High levels of carbon dioxide in the blood trigger the breathing response

 

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The Process of Breathing

Gas Exchange in the Lungs

• Gas exchange takes place in the alveoli

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Diffusion of Gases

• Oxygen diffuses into the blood, the oxygen molecule attaches to the hemoglobin forming a molecule called oxyhemoglobin

   Carbon dioxide diffuses from the blood into the lungs, the carbon dioxide is a waste product that is exhaled 4

The Mechanics for Breathing

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Exhalation (Breathing Out)

Inhalation (Breathing In)

Diaphragm relaxed Diaphragm contracted

Rib cage moves in and down

Rib cage moves up and out

Volume of chest smaller

Volume of chest larger

Lungs squeezed Lungs expand

Air pushed out Air pulled in

Increased pressure in the chest cavity

Decreased pressure in the chest cavity

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Diseases of the Respiratory System

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BronchitisInflammation of the bronchi

Usually caused by infection

Also caused by irritants such as exposure to smoke, chemicals, or air pollution

Symptoms include throat pain, fever, coughing, and coughing up mucus

Treatment includes cough medicine and antibiotics

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Emphysema• Destruction of alveoli so

gas exchange is reduced

• Almost always caused by smoking, but in rare cases may be due to a genetic disorder

• Symptoms include shortness of breath and chronic cough

• No cure, not reversible

• Patients must be on oxygen

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Pneumonia

• Inflammation or swelling in the lungs in which air sacs fill with pus and other fluids, making it difficult for oxygen to reach the blood. Caused by bacteria or viruses.

• Symptoms include pain in chest, fever, chills, spitting up bloody mucus, and coughing. Treatment: antibiotics and rest

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Lung Cancer• Cancer that originates in the

lung, often caused by smoking

• Occurs when cells in the lungs start to grow rapidly in an uncontrolled manner

• No symptoms in early stages; in later stages symptoms include coughing, wheezing, and loss of weight

Treatment includes removing part of lung with cancer and using chemotherapy and/or radiation if cancer has spread to other parts of the body

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Asthma• A disease of the bronchial tubes

in which airways constrict and mucus secretion increases, making breathing difficult

• May be caused by allergies, infection, exertion, emotions, and weather changes

• Common symptoms include shortness of breath, coughing, tightening in the chest, and wheezing

• Is a chronic disease; people with asthma live with it every day and very often for their whole livesTreatment: inhalers,

antihistamines, steroids

Extreme Respiration: Carbon Monoxide

Poisoning• CO, poisonous gas

released by cars and cigarettes

• Binds to hemoglobin preventing O2 from binding as well

• Symptoms: flushing, nausea, and pain

• Occurs under cold water• Breathing and pulse slows • Blood shunts away from skin, stomach, and

muscles and is sent to the brain, heart, and lungs

• Conserves O2 improving chances of survival• See UP 78-81

Extreme Respiration: Mammalian Diving Reflex

Extreme Respiration: Diving

• High pressure deeper in the ocean

• Tanks release pressurized air containing O2

Extreme Respiration: High Altitudes

• Low atmospheric pressure, less O2

• Hypoxia – body is deprived of O2

• Body compensates by hyperventilation

• Pulmonary Edema may result