Respiratory System

Respiratory System• Breathing is the movement of air into and out of the lungs.

• Breathing is how your respiratory system takes in oxygen and gets rid of carbon dioxide.

Launch Lab

1. Place your hands on your ribs as you breathe in and out normally. Record your observations below in the Data and Observations section.

2. Breathe in normally. Breathe out normally into a balloon. Twist and hold the end of the balloon.

3. Have your partner use a metric tap measure to measure around the balloon at its widest point. Record the measurement. Let the air out of the balloon.

4. Breathe in normally again. Breathe out as much air as you can into the balloon. Twist and hold the end. Repeat step 3.

5. Switch roles with your partner, and repeat the steps using a different balloon.

Taking in oxygen

Functions of Respiration

Eliminating carbon dioxide

Organs of Respiration

• Air enters body through mouth or nostrils.

• Fine hair inside the nostrils trap dust from the air.

• Air then passes through the nasal cavity, where it gets moistened and warmed by the body’s heat.

Organs of Respiration

• Mucus traps dust, pollen, and other materials that were not trapped by nasal hairs.

• Tiny, hairlike structures, called cilia, sweep mucus and trapped material to the back of the throat where it can be swallowed.

Organs of Respiration• Warmed, moist air then enters a tubelike passageway used for food, liquid, and air called the pharynx.

• At the lower end of the pharynx is a flap of tissue called the epiglottis.

Organs of Respiration

• The larynx 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.

Organs of Respiration

• The larynx 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.

Organs of Respiration

• Air moves from your larynx into your trachea.

• Your trachea is a tube that is held open by C-shaped rings of cartilage.

• The trachea is lined with mucous membranes and cilia that traps dust, bacteria, and pollen.

Organs of Respiration

• Your trachea branches into two narrower tubes called bronchi (singular - bronchus) that lead into your lungs.

Organs of Respiration

• Lungs are the main organs of the respiratory system.

• Inside your lungs, your bronchi branch into smaller and narrower tubes called bronchioles.

Organs of Respiration

Organs of Respiration• Your bronchioles end in microscopic sacs, or pouches, called alveoli (singular, alveolus), where gas exchange occurs.

Organs of Respiration• During gas exchange, oxygen from the air you breathe moves into your blood. Carbon dioxide from your blood moves into your alveoli.

Organs of Respiration• The thin walls of alveoli and the large surface areas make it possible for a high rate of gas exchange.

• If you could spread out all the alveoli in your lungs onto a flat surface, they would cover..............

half a tennis court

Organs of Respiration

• Together, the lungs contain approximately 2,400 km of airways and 300 to 500 million alveoli.

• The thin walls of alveoli and the large surface areas make it possible for a high rate of gas exchange.

• Every time you breathe, alveoli help your body take in billions of oxygen molecules. They also help your body get rid of billions of carbon dioxide molecules.

Breathing & Air Pressure

• When high levels of carbon dioxide build up in your blood, your nervous system tells your body to breathe out, or exhale. After you exhale, you breathe in, or inhale.

Breathing & Air Pressure

• Below your lungs is a large muscle called a diaphragm that contracts and relaxes and moves air in and out of your lungs.

Breathing & Air Pressure

• When your diaphragm moves, it changes the air pressure inside your chest. Breathing occurs because of these changes in air pressure.

• When you inhale, your diaphragm contracts and moves down. The space around your lungs gets expands. The increased space reduces the air pressure in your chest.

• Air rushes into your lungs until the pressure inside your chest equals the air pressure outside it.

• When you exhale, your diaphragm relaxes and moves up. The space around your lungs reduces.

• Air pressure in your chest increases. Waste gases rush out of your lungs.

Paralyzed DiaphragmIn the early and mid-1900s, many people were infected with the poliovirus. The poliovirus attacked the central nervous system and could cause paralysis. In some cases, people’s diaphragms were paralyzed, so they couldn’t breathe. The iron lung was a machine that helped people with paralyzed diaphragms to breathe.

The Iron Lung

Modern Day Ventilators

Respiratory Illnesses

Lung Transplant

Homeostasis

• The muscular system works with your respiratory system so you can breathe.

• The circulatory system and the respiratory system work together to bring oxygen to body cells and to remove carbon dioxide from cells.