Respiratory System Notes

February 4, 2013

Respiratory System

Functions:

1. Brings oxygen (O2) into the body from the environment

2. Removes waste gases (CO2 and H2O) from the body

Breathing!!!

Respiration = Breathing

• Breathing: bringing oxygen into the body and removing CO2 and H2O

• Respiration: The breaking down of glucose molecules inside of cells using oxygen to produce energy (also called cellular respiration)

Upper Respiratory Tract

• Nose

• Nasal Cavity

• Mouth

• Pharynx (Throat)

• Larynx (Voice Box)

Lower Respiratory Tract• Trachea (windpipe)• Bronchi • Lungs• -Bronchioles• -Alveoli

Lungs

• Major organs of the respiratory system

Inside the lungs:

• Alveoli: small sacs surrounded by capillaries (small blood vessels)

• Site of gas exchange

Gas Exchange

• In the alveoli the oxygen (O2) from the inhaled air passes into the blood, and carbon dioxide (CO2) and water (H2O) leave the blood and enter the alveoli

Gas Exchange

Pleura and Diaphragm

• Pleura: layer of epithelial tissue that covers the outside of the lungs

• Diaphragm: the muscle below the lungs that helps you breathe

Breathing: How its Done

• Inhalation (breathing in): diaphragm contracts, increasing the volume in the chest cavity, which lowers the air pressure; the higher air pressure outside the body forces air into the lungs

Breathing: How its Done

• Exhalation (breathing out): diaphragm relaxes, decreasing the volume in the chest cavity, which raises the air pressure; the higher air pressure inside the body forces air out of the lungs

Why do we breathe?• We breathe so that we can get oxygen into our

cells

Why do our cells need oxygen?Cells use oxygen in a process called cellular

respiration

Cellular Respiration:

Food + Oxygen = Energy (ATP) + CO2

CO2 is produced as a waste product in cellular respiration...it is removed from the body through the lungs!

Why is it dangerous to hold your breath too long?

• Holding your breath stops oxygen from getting to the cells in all of your organs (especially your brain cells).

• This stops the cells from producing enough energy to survive, which kills the cells!