respiratory system structure and function

nasal cavity

Warms, filters, moistens air and allows air to be inhaled

Pharynx

Receives food from the mouth and moistens air

Larynx

Holds the vocal chords and manipulates pitch and volume

Trachea

Trovides air flow to the bronchi

Bronchi

Provides air flow to the lungs

Alveoli

The site of gaseous exchange

Bronchioles

Provides air flow to the alveoli

Diaphragm

Large muscle that sits at the bottom of the thoracic cavity

Double pump mechanism

The heart and the lungs work as a double pump mechanism with the pulmonary and systemic circuits

Gas exchange at the lungs

• diffusion of oxygen from the alveoli into the pulmonary capillaries

• Diffusion occurs down the concentration gradient as there is a higher partial pressure of O2 in the alveoli compared to the pulmonary capillary

• Oxygen binds to the heamoglobin in the red blood cells

Gas exchange at the muscles

• oxygen is transported via the cardiovascular system to the working muscles

• Diffusion occurs down the concentration gradient as there is a higher partial pressure of O2 in the capillaries compared to the working muscles

Mechanics of inhalation

Mechanics of exhalation