1. Respiration & Gas Exhange

2. Respiration Two processes:
1. Release of energy from breakdown of food molecules.
All living cells use oxygen to release energy.
This process produces waste carbon dioxide.
2.The exchange of gases between the atmosphere and body’s cells.
We will focus on the exchange of gases.

3. So what are the functions of the respiratory system?
Bring oxygen into the body
Remove carbon dioxide (CO2) from the body
Clean, moisten and warm air
Enable speech

4. Gas exchange supplies oxygen for cellular respiration and removes CO2
…………………………………………………………………………………………………………………
Gas exchange supplies oxygen for cellular respiration and removes CO2
Gas exchange – uptake of O2 from environment and discharge of CO2
Mitochondria need O2 to produce more ATP, CO2 is the by-product
C6H12O6 + 6O2  6CO2 + 6H2O + 36 ATP
DIFFUSION

5. How Does Oxygen Get Into Cells?
O2 and CO2 enter and leave the cells
(gas exchange) by diffusion
Different animals have different systems
Some examples:
Organism: Gas exchange between:
one-celled cell membrane and outside cell
earthworm skin and capillaries
insects trachea and body cells
fish gill filaments and capillaries
mammals air sacs (alveoli) and capillaries

6. Respiratory surfaces and gas exchange
Size of organism
Habitat
Metabolic demands
Unicellular organisms
Entire surface area for diffusion
Simple invertebrates
Sponges, cnidarians, flatworms
diffusion

7. Human Respiratory System
Our own pathway, in order:
Mouth/Nasal Cavity
Pharynx
Larynx
Trachea
Bronchi
Bronchioles
Alveoli (tiny air sacs)

8. Mammalian respiration

9. Organs of the respiratory system
Nose and sinuses
Q. List the advantages of breathing in from the nose? (page 170 )
1. Cleans dust and bacteria in the air by hair
and mucus,
2. warms and moistens the air
3. Detect harmful chemicals by sensory cells

10. Organs of the respiratory system
Hyoid Bone
Epiglottis
Thyrohyoid
Membrane
Cricothyroid
Ligament
Muscles
Cartilage
Trachea
Thyroid
Pharynx – short tube leading to larynx
Epiglottis – cartilaginous flap covering opening to larynx (glottis)
Larynx – voicebox containing vocal cords

11. Organs of the respiratory system
Trachea – tubes leading into lungs.
These branch into primary bronchi then into bronchioles
mouth
trachea
bronchi
alveoli

12. larynx
bronchiole
sinuses
pharynx
trachea
alveoli
bronchial
tube

13. Organs of the respiratory system
Bronchioles end in sac like structures called Alveoli
Gas exchange occurs between the alveoli and capillaries
Primary
bronchus
Alveoli
Terminal
bronchiole
Bronchiole
Tertiary
Secondary

14. Bronchial Tubes

15. Gas Exchange Capillaries surround the alveoli
Gases are exchanged between the thin walls of the alveoli and capillaries

16. How Does O2 Get Into the Blood?A i r To
heart
From
heart A i r
Alveolus
(air sac) O2
CO2
Pulmonary capillary

17. How Does O2 Get Into the Blood?
Blood needs a special chemical to “carry” the oxygen:
Hemoglobin
oxygen “sticks to” or binds with hemoglobin in red blood cells
hemoglobin contains iron which binds with oxygen
Can you follow the oxygen?
In the lungs:
Oxygen diffuses from the air in the alveoli into capillaries
Oxygen passes into red blood cells and binds with hemoglobin
In the blood, oxygen remains bound to hemoglobin until it reaches your cells
At your cells:
CO2 diffuses from cells into capillaries
Hemoglobin releases oxygen and binds with CO2
Oxygen diffuses from red blood cells into your body cells

18. How Air Moves in and Out Inhaling: getting air with oxygen in
Exhaling: getting air with carbon dioxide out
Air is forced into and out of your lungs.
But how?
When you squeeze a plastic bottle, what does the air do? Which direction does it move?
When you let the plastic bottle spring back into shape, what does the air do? Which direction does it move now?
This is because of an important law of how gases work:
Boyle’s Law

19. Boyle’s Law Robert Boyle discovered that if:
volume decreases, pressure increases
volume increases, pressure decreases
Pressure and volume are inversely related:
If one increases, the other decreases
This is called an inverse relationship
Gases always move from:
areas of higher pressure to areas of lower pressure
Boyle’s Law explains how air is forced into and out of your lungs !

20. 1. Diaphragm & rib muscles (external intercostal muscles) contract
2. Rib cage expands
3. Volume in lungs increases
4. Pressure in lungs decreases
5. Air pressure outside is greater
6. Air rushes into lungs 1. 2. 3. 4. 5. 6.
Can you fill in steps 1- 6 for exhaling?

21. Lung ventilation through breathing
Negative pressure breathing in reptiles and mammals
Rib muscles and diaphragm change lung volume and pressure

22. Lung volumes Factors Vital capacity Residual volume Tidal volume
Smoking, increase due to CO
Anxiety, increase due to the effect of adrenaline
Drugs, some may cause an increase
Environmental factors, increased by high CO2 concentration in the atmosphere
Altitude, increased by low O2 conc. In the atmosphere
Weight, can increase because fat makes lung ventilation harder (i.e tidal volume falls),
Tidal volume
Volume of air inhaled and exhaled with each breath
Vital capacity
Maximum volume inhaled and exhaled during forced breathing
Residual volume
Air left in alveoli after forced exhalation

23. Control centers in the brain regulate breathing

24. Gases diffuse down pressure gradients concentration and pressure drives the movement of gases into and out of blood

25. Respiratory System Problems
Dirt, pollen, dust, and smoke damage the system and interrupt the flow of oxygen to your cells
Respiratory System Defenses:
White blood cells
Surround, consume, and digest bacteria
Cannot consume asbestos
Cilia
Tiny hairs lining trachea
Hairs “wave” upward to expel foreign particles
Cigarette smoke paralyzes cilia
Defense against choking:
The epiglottis
Flap of tissue that closes trachea when you swallow
Makes certain food travels through esophagus instead

26. Respiratory Disorders
Asthma
Bronchial tubes become constricted
Symptoms: shortness of breath, wheezing, coughing
Causes: environmental factors: allergies, stress, certain foods
Emphysema
Alveoli lose ability to expand and contract when breathing
Alveoli stretch and rupture; scar tissue develops
Less oxygen to cells + buildup of CO2
Lung cancer
Caused by “tars” and other carcinogens in cigarette smoke
Cancerous tumors destroy lung tissue
Effects of smoking:
Short term: carbon monoxide (CO) replaces oxygen in blood
Long term: heart disease, emphysema, lung cancer
Without smoking, these disorders are a minor problem in society

27. Review Questions
Which term does not belong with the others and why not?
gills, alveoli, diaphragm, trachea
asthma, respiration, emphysema, lung cancer
gills, lungs, hemoglobin
lung cancer, asthma, emphysema
alveoli, diaphragm, trachea
Explain what happens to your diaphragm and ribcage when you inhale and exhale.
What are the reactants and products of cell respiration?
Use Boyle’s Law to explain inhaling, exhaling, and why the Heimlich Maneuver works.
Describe how gas exchange occurs in the lungs.
Why is your trachea lined with cartilage?
What is the function of your nasal cavity?
What is your epiglottis and what is it for?
Why do you have cilia inside your trachea?
Which respiratory condition can be the result of allergies?