1. The Respiratory System
Sections 10.1 & 10.2

2. The Respiratory System
Learning Goal: To explore the respiratory system of humans.
Success Criteria:
I know I am succeeding when I can…
explain that all organisms require oxygen during cellular respiration in order to release the energy stored in food
explain how are cells get oxygen (ventilation and gas exchange)
label the respiratory system
describe the pathway of air
explain the mechanisms of breathing

3. The Need for Oxygen all animal and plant cells need oxygen to survive
cells use oxygen to obtain energy from food in a process called aerobic cellular respiration
C6H12O6 +
6O2 
6CO2
6H2O
energy
(glucose
oxygen
carbon dioxide
water
energy)

4. The Need for Oxygen Cont’d…
energy is stored in molecules called adenosine triphosphate (ATP)
ATP is formed when energy from the breakdown of glucose is used to attach a phosphate group (Pi) onto adenosine diphosphate (ADP)
energy for cellular processes is released when ATP reacts with other molecules

5. Gas Exchange
ventilation: brings a supply of air containing oxygen to the lungs and removes air with carbon dioxide

6. Gas Exchange Cont’d…
gas exchange: the process by which oxygen diffuses into the body cells and carbon dioxide diffuses out of the cell
occurs at 2 locations
lungs (oxygen diffuses into the blood from the lungs and carbon dioxide diffuses out of the blood into the lungs)
body cells (oxygen is transported through the bloodstream and diffuses into all the cells of the body, carbon dioxide diffuses out cells into the blood )

7. The Structure of the Respiratory System
Animation

8. The Pathway of Air
air from the outside enters the respiratory system through the nose and mouth
air is warmed and moistened in the nasal passages and mouth (protests the thin, delicate tissue of the respiratory membrane)
nasal passages are lined with tiny hairs and mucus that filter out and trap dust and other airborne particles, preventing them from entering the lungs

9. The Pathway of Air Cont’d…
air then travels from the mouth or nasal passages into the pharynx
glottis remains open so that air flows into the trachea, or windpipe

10. The Pathway of Air Cont’d…
trachea is a semi-rigid tube of soft tissue wrapped around c-shaped bands of cartilage (keeps the trachea open)

11. The Pathway of Air Cont’d…
walls of the trachea are lined with mucus-producing cells (mucus is sticky and traps dust and other particles )and cilia (tiny hair-like structures that sweep foreign substances upward through the trachea, where it is swallowed or coughed or sneezed out)

12. The Pathway of Air Cont’d…
trachea branches into two bronchi
each bronchus connects to a lung (enclosed within the thoracic, or chest, cavity an protected by the rib cage)
inside the lungs, the bronchi branch repeatedly into smaller and smaller tubes called bronchioles
at the end of the bronchioles are clusters of tiny sacs called alveoli
Each alveolus is tiny, measuring only 0.1 µm to 0.2 mm (micrometres) in diameter. It is the sheer number of alveoli, approximately 150 million in each lung, that provides the necessary surface area for gas exchange. If the entire surface area inside the lungs were flattened out, it would cover an area about the size of a tennis court!

13. The Pathway of Air Cont’d…
gas exchange occurs at the alveoli
respiratory membrane that forms the alveoli is moist (oxygen cannot diffuse across the respiratory membrane unless it is dissolved in a liquid)
alveoli are surrounded by a network of capillaries
alveoli walls are extremely thin (one cell layer thick), so oxygen and carbon dioxide can easily diffuse across the respiratory membrane into the bloodstream

14. The Mechanism of Ventilation (breathing)
lung ventilation (breathing) depends on negative pressure

15. The Mechanism of Ventilation (breathing) Cont’d…
inhalation
diaphragm and external intercostal muscles contract
ribs are pulled upward and outward
volume of the chest cavity increases
air pressure inside the lungs is reduced (atmospheric pressure is greater than the pressure in the thoracic cavity)
air flows into the lungs (to equalize the pressure)

16. The Mechanism of Ventilation (breathing) Cont’d…
exhalation
diaphragm and external intercostal muscles relax
ribs move down and in
volume of the chest cavity decreases
air pressure inside the lungs increases (atmospheric pressure is less than the pressure in the thoracic cavity)
air flows out of the lungs

17. The Mechanism of Ventilation (breathing) Cont’d…
during strenuous exercise or forced exhalation, a second set of intercostal muscles, called the internal intercostal muscles, start contracting and relaxing
when they contract, they pull the rib cage downward, increasing the pressure inside the lungs and forcing more air out of the lungs

18. The Mechanism of Ventilation (breathing) Cont’d…
pleural membranes cover the lungs and line the chest cavity
space between the pleural membranes is called the pleural cavity
pleural cavity is filled with fluid to prevent the membranes from separating and also to allow them to slide past each other easily

19. The Respiratory System
Learning Goal: To explore the respiratory system of humans.
Success Criteria:
I know I am succeeding when I can…
explain that all organisms require oxygen during cellular respiration in order to release the energy stored in food
explain how are cells get oxygen (ventilation and gas exchange)
label the respiratory system
describe the pathway of air
explain the mechanisms of breathing

20. Homework
10.1 questions #1-5
10.2 questions #1-5