1. The Respiratory System
Mrs. Legro’s 
Science

2. What You Need to Know…
Describe the functions of the respiratory system
Explain how oxygen and carbon dioxide are exchanged in the lungs and in tissues
Identify the pathway of air in and out of the lungs
Explain the effects of smoking on the respiratory system

3. What’s in the Air We Breathe?
Nitrogen 78
Oxygen 21
Argon
Carbon Dioxide
We breathe atmospheric gases that are closest to Earth.
The gas in the air that is necessary for life was not identified as oxygen until the late 1700s, by a French scientist. He discovered that an animal breathed in oxygen and breathed out carbon dioxide.
The human body uses more oxygen during exercise than when at rest.

4. Functions of the Respiratory System
Breathing and Respiration
Breathing is the movement of the chest that brings air into the lungs and removes waste gases. Breathing uses muscles.
Breathing
All animals need oxygen to live. Land animals get oxygen from the air. Their lungs pump in air. Their lungs also separate out the vital oxygen so it can be put to use inside the cells. Lungs are both pumpers and separators.

5. Functions of the Respiratory System
Respiration is movement of air in and out of the lungs. It is the chemical reaction that happens during this process:
Air entering the lungs contains oxygen.
It passes from the lungs into the circulatory system (because there is less oxygen in the blood than in cells of the lungs).
Blood carries oxygen to individual cells.
At the same time, the digestive system supplies glucose from digested food to the same cells.
The oxygen delivered to the cells is used to release energy from glucose.
Respiration
C6 H12 O6 + 6O CO2 + 6H2O + Energy
Glucose + Oxygen Carbon Water Energy
dioxide

6. Functions of the Respiratory System
Cellular respiration

7. Structures & Organs of the Respiratory System
Mouth and Nostrils: how air enters your body
Fine hairs inside nostrils trap dust from the air.
Air passes through your nasal cavity, where it gets moistened and warmed by the body’s heat
Glands that produce sticky mucus line the nasal cavity
This mucus traps dust, pollen, and other materials not trapped by nasal hairs
This process helps filter and clean the air you breathe.
Cilia, tiny hair-like structures, sweep mucus and trapped material to the back of the throat where it can be swallowed.
Nasal cavity
cilia
(dictionary definition) Respiration is the physical and chemical processes (i.e. breathing and diffusion) by which an organism supplies tissues with oxygen needed for metabolism and relieves them of the carbon dioxide formed in energy-producing reactions.

8. Structures & Organs of the Respiratory System
Pharynx: the warmed, moist air enters this tube like passageway used by food, liquid, and air.
At the lower end of the pharynx, is a flap of tissue called the epiglottis. When you swallow, the epiglottis folds down to prevent food or liquid from entering your airway.
Pharynx
epiglottis
The food enters your esophagus instead. If you begin to choke, what do you think will happen?

9. Structures & Organs of the Respiratory System
Larynx: Next, the air moves into your larynx, which is the airway to which two pairs of horizontal folds of tissue, called vocal cords, are attached.
Forcing air between the cords causes them to vibrate and produce sounds.
larynx

10. Structures & Organs of the Respiratory System
Trachea: From the larynx, air moves into here, which is a tube about 12cm long. Strong, C-shaped rings of cartilage prevent the trachea from collapsing. The trachea is lined with mucous membranes and cilia.
trachea

11. Structures & Organs of the Respiratory System
Bronchi: located at the lower end of the trachea, these are two short tubes that carry air into your lungs.
Within the lungs, bronchi branch into smaller and smaller tubes. The smallest are bronchioles. At the end of each of these are clusters of tiny, thin-walled sacs, called alveoli.
The exchange of oxygen and carbon dioxide takes place between the alveoli and capillaries.
Bronchi
Bronchioles
alveoli
Air passes into the bronchi, then into the bronchioles, and finally into the alveoli. Lungs are masses of alveoli arranged in grapelike clusters. The capillaries surround the alveoli like a net.
About 300 million alveoli are in each lung.

12. Putting it All Together…
Air enters your body through your mouth and nostrils.
Air passes through your nasal cavity, where it gets moistened and warmed by your body’s heat.
Mucus traps dust, pollen, and other materials not trapped by nasal hairs.
Cilia sweep mucus and trapped material to the back of the throat where it can be swallowed.
The warmed, moist air enters the pharynx. Next, the air moves into your larynx and to the trachea.
At the lower end of your trachea, air moves into your bronchi, which then eventually branch into the bronchioles. At the end of each of these are clusters of tiny, thin-walled sacs, called alveoli. The exchange of oxygen and carbon dioxide takes place between the alveoli and capillaries.
Oxygen moves through the cell membranes of the alveoli and then through the cell membranes of the capillaries into the blood. There, the oxygen is picked up by hemoglobin (a molecule in red blood cells). At the same time, carbon dioxide and other cellular wastes leave the body cells.
The wastes move through the cell membranes of the capillaries and then carried by the blood. In the lungs, waste gases move through the cell membranes of the capillaries and through the cell membranes of the alveoli. Then waste gases leave the body during exhalation.
Know the 8 steps, in order
This happens easily because the walls of the alveoli and the walls of the capillaries are each only one cell thick.

13. Inhaling and Exhaling
Signals from your brain tell the muscles in your chest and abdomen to contract and relax.
Your brain can change your breathing rate depending on the amount of carbon dioxide present in your blood.
As carbon dioxide increases, your breathing rate increases.
Your diaphragm is a muscle beneath your lungs that contracts and relaxes to help move gases into and out of your lungs.
First bullet
diaphragm
Breathing is partly the result of changes in air pressure…a gas moves from an area of high pressure to an area of low pressure. When you squeeze an empty, soft-plastic bottle, air is pushed out. This happens because air pressure outside the top of the bottle is less than the pressure you create inside the bottle when you squeeze it. As you release your grip on the bottle, the air pressure inside the bottle becomes less than it is outside the bottle. Air rushes back in, and the bottle returns to its original shape.

14. Diseases and Disorders of the Respiratory System
Many serious respiratory diseases are related to smoking.
Chemical substances in tobacco (nicotine and tars) are poisons and can destroy cells.
The high temperatures, smoke, and carbon monoxide produced when tobacco burns can also injure a smoker’s cells.
Second-hand smoke can be just as harmful.

15. Smoking and Related Risks
Disease
Smokers’ Risk Compared to Nonsmokers’ Risk
Lung Cancer
23 times higher for males
11 times higher for females
Chronic bronchitis and emphysema
5 times higher
Heart disease
2 times higher
23 times higher

16. What’s in a Cigarette?
There are approximately 600 ingredients in cigarettes. When burned, they create more than 7,000 chemicals.
At least 69 of these chemicals are known to cause cancer, and many are poisonous.
600
7000 69

17. What Will Your Lungs Look Like?

18. Respiratory Infections
Bacteria, viruses, and other micro-organisms can cause infections that affect organs of the respiratory system
The common cold: upper part of the respiratory system
Influenza (flu): many of the body's systems
Pneumonia: an infection in the alveoli

19. Chronic Bronchitis
Bronchitis: when bronchial tubes are irritated and swell and too much mucus is produced
Bronchitis usually clears up within a few weeks with treatment of antibiotics
Chronic: it happens often and a person must cough often to try to clear excess mucus from airway.
Bronchitis
However, the more a person coughs, the more the cilia and bronchial tubes can be harmed.  When cilia are damaged, they cannot move mucus, bacteria, and dirt particles out of the lungs effectively.

20. Emphysema A disease in which the alveoli in the lungs enlarge
Makes it difficult to breathe (shortness of breath) and some people require extra oxygen.
emphysema
When cells in the alveoli are reddened and swollen, an enzyme is released that causes the walls of the alveoli to break down.  As a result, alveoli can't push air out of the lungs, so less oxygen moves into the bloodstream from the alveoli.  When blood becomes low in oxygen and high in carbon dioxide, shortness of breath occurs.

21. Asthma
A lung disorder that can cause shortness of breath, wheezing or coughing.
Can be caused by allergic reactions, stress, exercise, etc.
Asthma attack = bronchial tubes contract quickly.
An inhaler will help relax the bronchial tubes
asthma

22. Lung Cancer 3rd leading cause of death in men and women in the U.S.
More than 85% of all lung cancer is related to smoking.  
Inhaling the tar in cigarette smoke is the greatest contributing factor to lung cancer
Smoking has also been linked to the development of cancers of the esophagus, mouth, larynx, pancreas, kidney, and bladder.
3rd leading cause
85%
Inhaling tar…
Smoking has also been linked…

23. Nicotine Addiction
Relapse rates remain high—75-80% of smokers who try to quit relapse within 6 months.
Each day, more than 3,200 people under 18 smoke their first cigarette, and approximately 2,100 youth and young adults become daily smokers.
 9 out of 10 smokers start before the age of 18, and 98% start smoking by age 26.
1 in 5 adults and teenagers smoke.
On average, smokers die 13 to 14 years earlier than nonsmokers.
13-14 years earlier
9 out of 10
08%
75-80% relapse