1. The Human Respiratory System

2. Aim: What are the parts and functions of the human respiratory system?
I. Parts of Human Respiratory System
A. Nasal Cavity
1. Warms the air (capillary beds)
2. Filters the air (cilia and mucus)
3. Moistens the air (mucus membranes)

4. B. Pharynx (Throat)
1. Air just passes through
C. Larynx (Home of the vocal chords)
1. Air just passes through
D. Trachea (Windpipe)
1. Held open by rings of cartilage

5. 2. Cilia – tiny hairs that sweep mucus with dust particles upward towards the pharynx.
E. Bronchi (Bronchus-singular)
1. Two tubes that branch off from trachea and direct air to each lung.
2. Also held open with cartilage rings.

6. F. Bronchioles
1. Smallest subdivision of bronchial tubes.
2. Each bronchiole terminates with a cluster of alveoli.
3. No cartilage rings.

8. G. Alveoli (Alveolus-singular)
1. Alveoli are sites of gas exchange. Alveoli are surrounded by beds of capillaries.
Oxygen diffuses out of the alveoli into the capillaries.
Carbon dioxide diffuses out of capillaries into the alveoli to be exhaled out of body.
2. The alveoli are the respiratory surfaces in the human.