The Respiratory System Key Concepts What are the functions of the respiratory system? What structures does air pass through as it travels to the lungs? What happens during gas exchange and breathing?

Key Terms Respiration Cilia Pharynx Trachea Bronchi Lungs Alveoli Diaphragm Larynx Vocal cords

The Respiratory System Main Functions: Moves oxygen from the outside environment into the body. It also removes carbon dioxide and water from the body Taking in Oxygen– oxygen is needed for respiration (the energy releasing process in cells) Removing Carbon Dioxide and Water - CO2 and water are produced during respiration. They are eliminated through your lungs.

Systems Working Together Works with digestive and circulatory system Respiratory System brings oxygen into lungs Digestive system absorbs glucose from food Circulatory system carries oxygen and glucose to cells for respiration

The Nose Air must travel through nose, pharynx, trachea and bronchi to get to lungs Usually enters through nose and moves into the nasal cavities Cells in nasal cavities make mucus which moistens the air and keeps the lining from drying out. Mucus also traps particles such as dust Cells that line the nasal cavities have cilia; tiny hair-like extensions . The cilia sweep the mucus into the throat, where you swallow it. Stomach acids destroy the mucus and any germs in it If particles irritate the nose or throat, you sneeze

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The Pharynx Next air enters the pharynx or throat Shared with the digestive system. Nose and mouth connect to the pharynx

The Trachea Trachea is also known as the windpipe Bumps are cartilage, held together by smooth muscle Trachea is lined with cilia and mucus which continues to filter the air. Cilia move the trapped particles up to mouth or nose to exit If particles irritate the trachea it triggers a cough Epiglottis keeps food from entering the trachea. If is does, a person can choke

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The Bronchi and Lungs Trachea branches into 2 tubes – left and right bronchi. Left enters left lung and right enters right lung Inside lungs the bronchi divide again and again like branches of a tree until they are tiny tubes At the end of tubes are hundreds of sacs called alveoli Each alveolus is surrounded by capillaries Blood picks up O2 from air here

Bronchial Tree

Gas Exchange Air enters an alveolus oxygen passes through the wall of the alveolus and then through the capillary wall into the blood. Carbon dioxide and water pass from the blood into the alveoli.

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Surface Area for Gas Exchange Adult lungs contain about 300 million alveoli. If opened flat they would have a surface area of 70 m2 Huge surface area enables the lungs to absorb a large amount of O2

How you Breathe In an average day a person breathes in and out 20,000 times. Rate depends on how much oxygen your body needs Breathing is controlled by muscles Ribs have muscles attached to them Base of lungs is the diaphragm, a large dome shaped muscle

The Process of Breathing Breathe in (inhale)– rib muscles contract, lift chest wall up and out Same time diaphragm contracts and moves downward. Makes chest cavity larger The same amount of air occupies a larger space causing the air pressure inside you to decrease Air pressure pushing on body is greater. Because of this difference in air pressure, air rushes into the lungs When you exhale or breathe out, the rib muscles and diaphragm relax. The chest cavity size is smaller. Decrease in size squeezes air out

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Relating Breathing and Speaking Larynx or voice box is located in the top part of trachea underneath the epiglottis Vocal cords are 2 small folds of tissue that are stretched across the larynx. There is a slit-like opening between them. Air from your lungs makes them vibrate as it moves out. The pitch of your voice changes as muscles tighten or relax around your vocal cords

Smoking and Your Health Chemicals in tobacco smoke – over 4000 Tar – dark, sticky substance that clumps cilia so that they can’t function. Contains chemicals shown to cause cancer Carbon monoxide – colorless, odorless gas. Binds to hemoglobin, so red blood cells carry less O2 Nicotine – stimulant, makes heart beat faster and increases blood pressure, produces an addiction

Health Problems and Smoking Chronic Bronchitis- irritation of breathing passages, where small passages become narrower and may be clogged with mucus, difficulty breathing, can cause permanent damage and increase in infections Emphysema – destroys lung tissue and causes breathing difficulties, cannot get enough O2 or rid of CO2

Health Problems and Smoking Lung Cancer – 140,000 Americans die each year from lung cancer caused by smoking, tumors take away space in lungs for gas exchange Atherosclerosis – Chemicals get into blood vessels and irritate them, contributes to build up of fatty material Passive Smoking – people involuntarily inhale the smoke from others’ cigarettes, contains same harmful chemicals, associated with the development of bronchitis, and other respiratory ailments such as asthma in about 300,000 children in US