1. RESPIRATORY SYSTEM EXCHANGE OF GASES
PowerPoint® Lecture Slide Presentation by Robert J. Sullivan, Marist College
RESPIRATORY SYSTEM
EXCHANGE OF GASES
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings.

2. What is Human Respiration?
The human respiratory system allows a person to obtain oxygen and eliminate carbon dioxide.
Breathing consists of two phases, inspiration and expiration
Inspiration- the process of taking in air
Expiration- the process of blowing out air
In one day, you will
breath more than
times!

3. Human Respiratory System

4. The Respiratory Tract is often divided into two main areas:
From Atmosphere to Alveoli
Each time you inhale, air begins a journey that starts at your nose (or mouth) and ends inside one of millions of tiny air pockets within your lungs, called alveoli.
The Respiratory Tract is often divided into two main areas:
1) The Upper Respiratory Tract
2) The Lower Respiratory Tract
Let’s get a little more specific!

5. The Upper Respiratory Tract Includes:
1) Nose & Mouth
2) Nasal Cavity
3) Pharynx
4) Larynx
5) Epiglottis
6) Trachea

6. Nose, Mouth & Nasal Cavity
Components of the Upper Respiratory Tract
Nose, Mouth & Nasal Cavity
Nose & Mouth:
Point of entrance
Nasal cavity
Lined with cells that produce sticky mucus
Nostrils contain stiff hairs
Mucus and hairs trap dust, bacteria, and other particles.
Air is also moistened and warmed – keeping lungs from drying out.

7. Pharynx, Larynx, & Trachea
Components of the Upper Respiratory Tract
Pharynx, Larynx, & Trachea
Pharynx (throat)
Passageway for air and food
Larynx
Structure between the pharynx and trachea that contains the
vocal cords:
Muscles attached to the vocal cords can tighten them.
Cords move closer together.
When air from lungs forced through, they vibrate and produce sound.
5) Epiglottis
covers the entrance to the larynx & trachea. (Why?)

8. Components of the Upper Respiratory Tract
Trachea
6) Trachea
Made up of about 20 rings of tough cartilage
Some cells in the lining contain hair-like cilia which are able to move.
Some cells secrete mucus
Cilia & Mucus trap more pollutants and other particles.
Cilia sweeps them up to the mouth  swallowed or coughed up

9. The Lower Respiratory Tract Includes:
1) Lungs
2) Bronchi
3) Bronchioles
4) Alveoli

10. Components of the Lower Respiratory Tract Lungs
Contain the bronchi, bronchioles, and alveoli.
Soft
Take up most of the chest cavity
Grooves separate the lungs into portions called lobes.
Left Lung: 2 lobes
Right Lung: 3 lobes
Questions:
What structure protects our soft lungs?
Why does the left lung have less lobes than the right lung?

11. Components of the Lower Respiratory Tract
Bronchi & Bronchioles
2) Bronchi
The trachea branches off into two bronchi (plural)
Each bronchus (singular) braches off into smaller and smaller, narrower and narrower tubes.
3) Bronchioles
The smallest and narrowest of these tubes.

12. Components of the Lower Respiratory Tract
Alveoli
4) Alveoli
Tiny balloon-like air sacks at the end of each bronchiole.
There are over 3 million of these that make up most of the lungs.
The wall of each alveoli is 1 cell thick and is surrounded by a mesh of tiny blood capillaries.

13. How the Respiratory & Circulatory Systems Work Together
Each alveolus is surrounded by a mesh of capillaries from the circulatory system.
Air in the alveoli has a greater concentration of O2 than the blood.
Where will the O2 go?
Oxygen diffuses from the alveoli into the capillaries.
The blood is now oxygenated.
Recall: diffusion and concentration gradients!
Carbon Dioxide diffuses from the blood to the alveoli, to be expired!

14. The movement of these muscles “sucks” air in and “pushes” air out.
Breathing & Muscles
You could not take a breath without muscles!
Diaphragm Muscle
Underneath the lungs
Has a dome shape when relaxed (breathing out)
Flattened when contracted (breathing in)
Intercostal Muscles
“Rib Muscles”
When breathing in, they cause the rib cage to move upward and outward.
The movement of these muscles “sucks” air in and “pushes” air out.