Define words for 33.3

Warm-Up

Ch. 33.3 – The Respiratory System

All cells require a constant supply of oxygen for cellular respiration.

Recall C6H12O6 + 6O2 --> 6H2O + 6CO2 + ATP

Respiration means the process of gas exchange between a body and the environment.

Human respiratory system picks up oxygen from the air we inhale and releases carbon dioxide into the air we exhale.

With each breath air fills our lungs and gas exchange occurs there.

The circulatory system links the gas exchange to the rest of our body.

Background Information

Structures of the Respiratory System

Consists of The noseThe pharynxThe tracheaThe bronchiThe lungs

Air must be filtered, moistened and warmed before entering the lungs

Hairs lining the entrance to the nasal cavity trap large particles

Incoming air is warmed in the inner nasal cavity and sinuses.

Mucus is produced that moistens the air and further filters.

The Nose

A cavity at the back of the mouth

Also called the throat

Serves as a passageway for both air and food

The Pharynx

After the pharynx air moves through the larynx to the trachea.

Contains two highly elastic folds of tissue known as the vocal cords.

These tissues give you the ability to produce sounds

When muscles pull the vocal cords together, the air moving between them causes the cords to vibrate and produce sounds.

The Larynx

Also known as the windpipe

When you shallow food or liquids, the epiglottis (a flap of tissue) covers the entrance to make the food or liquids go down the esophagus.

Lined with mucus that trap any inhaled particles.

Cilia lining the trachea sweep both the mucus and trapped particles upwards towards the pharynx. From there, the mucus and particles can be swallowed or spit

out This helps keep the lungs clean and open form the important

work of gas exchange.

The Trachea

Air then moves into the bronchi (singular: bronchus) – which are two large tubes in the chest cavity leading to each of the lungs.

The bronchus divides into smaller bronchi which then divides into the bronchioles (even smaller)

Bronchi and bronchioles are surrounded by smooth muscle tissue controlled by the autonomic nervous system As the muscles contract and relax, the size of the passageways

change.

Further divide until they reach the alveoli (singular: alveolus) Alveoli are grouped into clusters Surrounded by a delicate network of capillaries where the gas

exchange occurs.

The Lungs