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What is Human Respiration?• The human respiratory

system allows one to obtain oxygen & eliminate carbon dioxide.

• Breathing consists of two phases,  inhalation and exhalation.– Inhalation- the process of

taking in air– Exhalation- the process of

blowing out air

Humans have 2 lungs. Lungs are made up of a bronchus and it’s bronchioles, and alveoli.

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Organs in the Respiratory SystemSTRUCTURE FUNCTION

nose / nasal cavity  warms, moistens, & filters air as it is inhaled

pharynx (throat)  passageway for air, leads to trachea

larynx  the voice box, where vocal chords are located

trachea (windpipe) keeps the windpipe "open"

 trachea is lined with fine hairs called cilia which filter air before it reaches the lungs

bronchi two branches at the end of the trachea, each

lead to a lung

bronchioles a network of smaller branches leading from the

bronchi into the lung tissue & ultimately to air sacs

alveoli the functional respiratory units in the lung

where gases are exchanged

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Gas ExchangeThe air that enters the alveoli is rich in oxygen. The blood in the capillaries surrounding the alveoli is oxygen-poor and contains wastes of cellular respiration (carbon dioxide and water). The oxygen diffuses from the alveoli into the blood, where it enters the red blood cells. Next the oxygen diffuses out of the capillaries into the body cells.

Carbon dioxide and water diffuse out from the cells into the blood. When the blood returns to the lungs, these wastes diffuse into the alveoli and are expelled from the body in the exhaled air.

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•The breathing rate or respiratory rate is the number of breaths a living being, such as a human, takes per minute. •The medulla of the brain controls breathing.•When the carbon dioxide levels in the body are high, a signal is sent from the brain to the ribs and diaphragm to increase breathing rate.•As the carbon dioxide levels in the body decreases, the body will slow the breathing rate again.•This is an example of a feedback mechanism (helps keep the body at homeostasis).

Breathing Rate

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Disorders of the Respiratory System

•Bronchitis is an inflammation of the linings of the bronchial tubes. Because of swelling, air passages become narrowed and filled with mucus, causing breathing difficulties and coughing.•Asthma is an allergic reaction producing narrowing of the bronchial tubes, causing difficulty breathing. Asthma cannot be cured, but most people with asthma can control it so that they have few and infrequent symptoms and can live active lives. •Emphysema is a disease in which the walls of the alveoli break down, decreasing the surface area for gas exchange, causing shortness of breath and decreased breathing and lung capacity.

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Why Do I Yawn?     When you are sleepy or drowsy the lungs do not take enough oxygen from the air. This causes a shortage of oxygen in our bodies. The brain

senses this shortage of oxygen and sends a message that causes you to take a deep long breath---a YAWN.

Why Do I Sneeze?     Sneezing is like a cough in the upper breathing passages. It is the

body's way of removing an irritant from the sensitive mucous membranes of the nose. Many things can irritate the mucous membranes. Dust, pollen,

pepper or even a cold blast of air are just some of the many things that may cause you to sneeze.

What Causes Hiccups?    Hiccups are the sudden movements of the diaphragm. It is involuntary --- you have no control over hiccups, as you well know. There are many

causes of hiccups. The diaphragm may get irritated, you may have eaten to fast, or maybe some substance in the blood could even have brought on

the hiccups.