8 Science RESPIRATORY SYSTEM Respiratory System The Function

8 Science RESPIRATORY SYSTEM

Respiratory System

The Function of the Nose For smelling and breathing. � Allows air into and out of the respiratory system. � Contains cilia to prevent dust particles from getting into the system � Warms the incoming air � Nose

The Function of the Mouth � Allows air in and out when breathing. � Doesn’t filter the air as well as the nose does. � Warms the air Mouth

The Function of the Larynx � Also called the voice box. � Passageway for air � Sounds are made when air vibrates through the larynx Larynx

The Function of the Throat � Contains two passageways. Throat � One is for passing food & is called the esophagus (food pipe) � One is for passing air & is called the trachea (wind pipe)

The Function of the Trachea “Windpipe” Long tube leading from the nose/mouth Trachea to the lungs � Carries warmed air to the lungs from the mouth/nose � Lined with rings of cartilage that you can feel when you touch your throat. � �

The Function of the Bronchus 1 bronchus on each side of the trachea � 2 bronchi in total (plural form is bronchi) � bronchi pass air from trachea to left lung or. Bronchus right lung � Note: right lung is on the same side as your right hand �

The Function of the Diaphragm � Muscle stretching across the abdomen under the lungs � Pulls air into the lungs (when it moves down toward your belly button) � Pushes air out of the lungs (when it relaxes or moves up) Diaphragm

The Function of the Lungs � Main organ of the respiratory system � Balloon shaped, full of sacs called alveoli � allows exchange of oxygen and carbon dioxide (oxygen into blood; carbon dioxide out of blood) Lung

The Function of the Bronchiole(s) � Carry (transport) air � They are smaller and smaller branches off the bronchi Bronchiole(s)

The Structure of the Alveolus Tiny sacs with a membrane located at the end of each bronchiole � 1 alveolus; 2 alveoli (plural) Alveolus � Very small blood vessels (called capillaries) surround the alveoli �

The Human Respiratory System � Alveoli are grouped in clusters. Pulmonary artery � A network of capillaries surrounds each alveolus Pulmonary vein � Capillaries are tiny blood vessels (pipes) Capillaries Copyright Pearson Prentice Hall

The Function of the Alveolus Gas exchange (oxygen into the body cells and carbon dioxide out of the body cells) happens through their membrane � Gases move in and out by diffusion. � Very small blood vessels (called capillaries) surround. Alveolus the alveoli � These capillaries carry the carbon dioxide rich blood to the alveoli and the oxygen rich blood back to the body. �

Gas Exchange � RESPIRATION ○ Gas exchange takes place in the alveoli. ○ Oxygen diffuses into the blood. ○ Carbon dioxide in the blood diffuses into the alveolus. ○ Let’s examine this up close O 2 Capillary Copyright Pearson Prentice Hall

For gas exchange to occur we need: � � � air sacs and blood vessels with thin membranes Moist (watery) surface Concentration difference Large surface area to volume ratio (alveoli) The gases must be exchanged close to the circulatory system Because… � � � So that oxygen and carbon dioxide can pass through the membranes So that oxygen and carbon dioxide can dissolve in the water Diffusion can only happen when one area has a high concentration and the other area has a low concentration More surface to trade (exchange) gases Circulatory system can now move the gases to all cells in the body

Breathing Movements: Inhalation Intercostal muscles between ribs allow chest cavity to expand. The ribs move upward and outward, the diaphragm moves downward. 2. Volume is increased inside chest cavity. 3. Pressure in lungs is decreased inside chest cavity. 4. Air enters lungs to equalize pressure. 1.

Breathing Movements: Exhalation Relaxation of intercostals allow chest and ribs to relax. Cavity shrinks in size. The ribs move inward and downward, the diaphragm moves upward. 2. Volume is decreased inside chest cavity. 3. Pressure in lungs is increased inside chest cavity. 4. Air is forced out. 1.