Chapter 33.3: The Respiratory System

Structures of the Respiratory System- Nose

- Warms incoming air- Hairs trap larger particles- Mucus moistens air

- Pharynx- Connects nose and mouth to the

trachea- Epiglottis

- Closes off trachea to prevent inhalation of solids or liquids

- Larynx- Contains vocal cords

Structures of the Respiratory System- Trachea

- Stiff tube that connects pharynx to bronchi

- Bronchi- Tubes that split from trachea to

each lung- Lungs

- Contain bronchioles and alveoli- Bronchioles

- Tubes that split from bronchi into smaller tubes in the lungs

- Alveoli- Are tiny sacs where gas exchange

occurs

Gas Exchange- Occurs in the alveoli

- Oxygen diffuses into the blood- Carbon dioxide diffuses into the lungs- This occurs because there is less oxygen in

the blood, and less carbon dioxide in the lungs

Gas Transport- Oxygen

- Is carried by hemoglobin from the lungs to the body

- A protein in red blood cells that can bind 4 oxygens

- Carbon Dioxide- Can be carried by hemoglobin- Can be carried in the blood plasma

- Is converted into carbonic acid first- Moves from the body to the lungs

Breathing- Uses the lungs, intercostal muscles,

and the diaphragm

- Inhalation- Diaphragm contracts and flattens- Intercostal muscles pull the ribs up

and out- Air pressure in the chest becomes less

than atmospheric pressure- Lungs expand, and air rushes in

Breathing- Exhalation

- Intercostal muscles and diaphragm relax

- Causes lungs to shrink- Air pressure in the lungs becomes

greater than atmospheric pressure- Air rushes out of the lungs

Breathing and Homeostasis- Breathing can be consciously

controlled

- Breathing is also unconsciously controlled

- By the breathing center in the brain- Monitors carbon dioxide levels- Forces breathing when carbon dioxide

levels get too high

Smoking and the Lungs- Puts nicotine, carbon monoxide, and

tar into lungs- Causes several diseases

- Chronic Bronchitis- Bronchi are enflamed and clogged with

mucus- Emphysema

- Breakdown of lung tissue means that gas exchange becomes impossible

- Lung Cancer- Can easily spread to other nearby organs

- Affects the circulatory system- Raises blood pressure which causes the

heart to work harder