1. The Respiratory System
Copyright Pearson Prentice Hall

2. The Human Respiratory System
Epiglottis
Trachea
Nose
Pharynx
Larynx
Lungs
Bronchi
Mouth
Diaphragm
Bronchioles
The respiratory system is responsible for the exchange of oxygen and carbon dioxide. Air moves through the nose, pharynx, larynx, trachea, and lungs. After reaching the lungs, the trachea branches into smaller and smaller tubes called bronchioles, which end in alveoli, or air sacs.
Copyright Pearson Prentice Hall

3. Organs in the Respiratory System
STRUCTURE
FUNCTION
Nose / nasal cavity
 warms, moistens, & filters air as it is inhaled
Pharynx
Aka “throat”- the passageway for air, leads to trachea & esophagus
Larynx
 the voice box, where vocal chords are located
Epiglottis
Flap that covers esophagus or trachea
Trachea
 aka “windpipe”  Trachea is lined with fine hairs called cilia which filter air before it reaches the lungs

4. Organs in the Respiratory System
STRUCTURE
FUNCTION
Bronchi
 two branches at the end of the trachea, each lead to a lung
Bronchioles
 a network of smaller branches leading from the bronchi into the lung tissue & ultimately to air sacs
Alveoli
 the “air sacs” in the lung where gases are exchanged
Diaphragm
Muscle below ribcage that controls breathing

5. What Is Respiration? In biology, respiration means different things.
Cellular respiration is the release of energy from the breakdown of food in the presence of oxygen (occurs in your cells!)
At the organism level, respiration is the process of gas exchange - the release of carbon dioxide and the intake of oxygen that occurs between red blood cells (RBCs) and alveoli in lungs
Breathing is the actual mechanical intake of air

6. Breathing
BREATHING
Lungs are sealed in membranes inside the chest cavity.
At the bottom of the cavity is a large, flat muscle known as the diaphragm.
During inhalation the rib cage rises and the diaphragm contracts, increasing the size of the chest cavity.

7. Breathing
Inhaling:
Diaphragm contracts down and the rib cage rises up & out.
This creates a partial vacuum inside the cavity.
The change in pressure causes air to rush in.
During inhalation the rib cage rises and the diaphragm contracts, increasing the size of the chest cavity.

8. Breathing Exhaling: Diaphragm relaxes and moves up.
Air Exhaled
Exhaling:
Diaphragm relaxes and moves up.
Ribcage moves down and in.
Air is pushed out of the lungs.
Rib cage lowers
During inhalation the rib cage rises and the diaphragm contracts, increasing the size of the chest cavity.
Exhalation

9. How Breathing Is Controlled
Breathing is controlled by the brain.
Brain monitors carbon dioxide in the blood, and send signals to diaphragm to increase/decrease breathing rate as necessary

10. So what’s a hiccup? Muscle spasms in your diaphragm
Longest bout of hiccups – 68 years!!!

11. Pathway of Air
Mouth/Nose  Pharynx  Trachea  Bronchi  Bronchioles  Alveoli  into capillaries! (then reverse it!)

12. Focus on Alveoli
Alveoli are grouped in clusters at the end of each bronchiole
A network of capillaries surrounds each alveolus.

13. Gas Exchange Gas exchange takes place in the alveoli.
Oxygen diffuses from alveoli into the blood.
Carbon dioxide diffuses from blood into the alveoli.
CO2
Gas exchange occurs by diffusion across the membrane of an alveolus and a capillary.
Capillary

15. Gas Exchange

16. Relationship between Respiratory & Circulatory Systems
Could one function without the other?
Pickup O2 but no way to get to cells!
Blood is circulating but no way to get O2!
Lungs
(get O2, leave CO2)
Heart (right side)
Heart (left side)
Cells in Body
(leave O2, get CO2)