Respiration: Exchange of O2 and CO2 between an organism and it’s external environment.

We breathe in order to make energy through cellular respiration, which can be summarized by: C6H12O6 + 6O2 6CO2 + 6H2O + Energy

Breathing involves two basic processes:a. Inspiration: breathing in (inhaling). The action of drawing oxygen-rich air

into the lungs b. Expiration: breathing out (exhaling). The action of releasing waste air from

the lungs

Functions of the Respiratory System:

1) To supply oxygen from the air we breathe to the cells of our body

2) To release carbon dioxide from our bodies into the atmosphere

3) To exchange oxygen and carbon dioxide between the air and the blood

The respiratory system consists of the nasal cavity, pharynx, larynx, trachea, bronchi, and lungs.

Upper respiratory tract refers to:• Nose, mouth, pharynx, larynx and tracheaLower respiratory tract refers to:• Lung, bronchi, bronchioles, alveoli and diaphragm

Important Design Features…

The surface area must be extensive. The greater the surface area, the greater the exchange

Thin membrane for diffusion

Moist membrane

Single-celled Organism (Protists)- don’t need a special respiratory system - rely on direct diffusion with environment

“Skin Breathers” (Earthworms and Frogs)- use their skin as a respiratory system- skin must be kept moist at all times to allow proper diffusion of gases

Gills (Fish and Amphibians)

- extensions of the outer surface of the body- extensive folding and branching of gills provide increased surface area for diffusion

of gases- uses countercurrent flow of water to exchange gases

Tracheal System (Insects)- respiratory membrane located inside the body- exoskeleton has openings called spiracles that directly connect the tracheal system to

the atmosphere- oxygen enters the body through the spiracles and is delivered directly to the cells by

trachea and blood

Lungs (mammals, reptiles, birds)

Homework:

1. Read over Table 1.1 on Pg. 444. 2. Answer questions 1-3, 5, 6 on Page 444, and questions 1-3, 5 on Page 449.