1. The Respiratory System
Chapter 11
The Respiratory System

2. Learning Goal
To learn more about the function of the respiratory system and gas exchange
To take a closer look at the human respiratory system

3. Introduction
Most of the cells in our bodies need a continual supply of Oxygen (O2) to carry out cellular respiration
This process releases energy from glucose inside cells and produces Carbon Dioxide (CO2) as a waste product
The left over chemical energy is used for the cell to carry out activities (cellular respiration – Gr. 12)

4. Introduction – Terms
Respiratory System – is the group of organs that provide living things with oxygen from outside the body and disposes of waste products like CO2
Respiration – all the processes involved in bringing O2 into the body, making it available to each cell, and eliminating CO2 as waste

5. Respiration & Gas Exchange
There are Four Stages in human respiration, where each stage has specialized structures to help it:
Breathing
External Respiration
Internal Respiration
Cellular Respiration

6. Respiration & Gas Exchange
Stage 1 – Breathing
Involves Inhalation (breathing in) and Expiration (breathing out)
Inhalation – moves air from outside the body into the lungs inside the body
Expiration – moves air from the lungs back to the outside of the body

7. Respiration & Gas Exchange
The inhaled air that enters the alveoli have a greater [ ] of O2 than CO2
The blood that circulates in the capillaries surrounding the alveoli has a greater [ ] of CO2 than O2
The differences in these concentration make a Concentration Gradient that helps gas exchange happen (step 2)

8. Respiration & Gas Exchange

9. Respiration & Gas Exchange
Step 2 – External Respiration
Here, CO2 and O2 is exchanged between the inside of the lungs and the blood
This stage is VERY IMPORTANT to our existence via the Gas Exchange Process
Is the Delivery of O2 from the lungs to the blood
Is the Elimination of CO2 from the blood to the lungs

10. Respiration & Gas Exchange
In the lungs, oxygen diffuses from air in the alveoli into blood in the capillaries
At the same time, carbon dioxide diffuses from the blood into the air in the alveoli
The carbon dioxide leaves the lungs and exits through your mouth as you breathe out

11. Respiration & Gas Exchange

12. Respiration & Gas Exchange
Step 3 – Internal Respiration
Is the exchange of O2 and CO2 between the blood and the body’s tissues

14. Respiration & Gas Exchange
Stage #4 – Cellular Respiration
Is a series of energy-releasing chemical reactions that takes place within cells
Go into more detail in Gr. 12 Biology!

15. Respiratory Surfaces There are 2 main requirements for respiration
The Respiratory Surface (place of the body where gas exchange happens) must be Large Enough for O2 and CO2 to exchange fast enough to meet the needs of the body
Respiration must take place in a MOIST Environment, so that the O2 & CO2 can dissolve in water

16. Respiratory Surfaces
Instead of Lungs, some animals exchange gases through their outer body surface, gills, or trachea
To improve the efficiency of respiration, all organisms use VENTILATION
Process of moving an O2 containing medium (water or air) over the respiratory surface (lungs, gills, or trachea)

18. Gas Exchange in Water
Aquatic environments contain Oxygen in a “dissolved gas” form
Many aquatic organisms, like Fish, take in O2 through gills
Gills help these organisms carry out gas exchange even in water

19. Gas Exchange in Water Fish exchange gas by
Taking water into its mouth and ventilating (pumping) it over the gills
As water flows across their gills, dissolved O2 in the water diffuses into the blood
At the same time, CO2 diffuses from the blood, across the gill tissue, into the water
CO2 is then carried out of the fish’s body when water passes out of the gill openings

20. Gas Exchange in Water

21. Gas Exchange with Water

22. Gas Exchange on Land
Air-breathing vertebrates like Mammals, birds, and reptiles rely on their lungs for gas exchange
Movements involved in breathing utilize the structure of the lungs and their cavity to aid gas exchange to its fullest potential

23. The Mechanics of Breathing
RECALL:
Inhalation causes air to move into the lungs
Exhalation causes air to move out from the lungs

24. The Mechanics of Breathing
When you Inhale
The muscular diaphragm and the intercostal muscles of the rib cage contract
The diaphragm has a dome shape ᴖ when its relaxed
INHALING causes the diaphragm to LOWER and FLATTEN
At the same time the rib intercostal muscles contract = RIB CAGE MIVES UP AND OUT
These contractions allow the lungs to expand, which increases their volume
When lung volume ↑ air pressure inside the alveoli ↓
This pressure difference between the lungs and alveoli allows air to flow into the nasal cavity, through the respiratory tract and into the alveoli for gas exchange
Respiratory Tract -

25. The Mechanics of Breathing
When you Exhale
The diaphragm and intercostal muscles of the rib cage RELAX
The diaphragm moves up and rests normally in the chest cavity
The rib cage moves downward and inward
These relaxations allow the volume of the lungs to ↓
Air pressure in the lungs is GREATER than air pressure outside the body
Hence, air flows naturally from the lungs to outside of the body

26. The Mechanics of Breathing
VIDEOES

27. The Spirograph
A Spirograph – represents the amount (volume) and speed (rate of flow) of air that moves into and out of the lungs with each breath
Video:

28. The Spirograph - Key Terms
Definition
Tidal Volume
The volume of air that is inhaled and exhaled in a normal breathing movement when the body is at REST
Inspiratory Reserve Volume
The ADDITIONAL volume of air that can be taken into the lungs beyond regular / tidal inhalation
Expiratory Reserve Volume
The ADDITIONAL volume of air tat can be forced out of the lungs beyond regular / tidal inhalation
Vital Capacity
(Total Lung Volume Capacity)
The Total Volume of gas that can be moved into / out of the lungs:
Calculated by:
= Tidal Vol + Inspir. Res. Vol + Expir. Res. Vol
Residual Volume
The Volume of air that remains in the lungs AFTER a complete exhalation of the system

29. Section 11.2
Taking a Closer Look at the Respiratory System

30. Introduction
The structure of the respiratory system can be divided into2 main groups:
The Upper Respiratory Tract
The Lower Respiratory Tract

31. The Upper Respiratory Tract
Air enters through the nose and mouth into the nasal cavity
The NASAL CAVITY is lines with nose hairs and mucus to catch dust, bacteria, and other particles that were inhales with the air but are bad for the body

32. The Upper Respiratory Tract
Air then travels into the PHARYNX (throat)
Both inhaled air and food pass through the pharynx from the nasal and oral cavity
From here air passes into the LARYNX (vocal cords)

33. The Upper Respiratory Tract
A muscular tissue called the epiglottis works like a swing door opening on purpose for air to enter into the larynx and keeping food out, and vice versa, from food entering the esophagus and not into the larynx

34. The Upper Respiratory Tract
From the larynx air flows into a tube called the TRACHEA (windpipe)
The trachea is lined with cilia hairs and mucus to trap pollutants and other particles that made it past the nasal cavity when breathed in

35. The Lower Respiratory Tract
Includes the lungs, bronchi, bronchioles, and alveoli
Air continues to flow from the trachea down towards the lungs
Inside the lungs are two branching tubes called BRONCHI

36. The Lower Respiratory Tract
These bronchi then also are broken down into a smaller branching network of smaller tubes called BRONCHIOLES
Each lobe has its own portion of the network of bronchioles
This is beneficial in case one lobe gets injured – the other can still function and supply air to the tissues of the lungs

37. The Lower Respiratory Tract
The smallest bronchioles end at a cluster of tiny air pockets called ALVEOIL
Here O2 from inhaled air enters the alveoli and diffuses into the capillaries around them at the same time CO2 in the blood diffuses into the air in the alveoli

38. The Lower Respiratory Tract

39. Understanding Gas Exchange
During External Respiration (Stage #2), the thin walls of the alveoli and the capillaries allow gases to diffuse through their cell membrane easily

40. Understanding Gas Exchange

41. Understanding Gas Exchange
As you can see, the air that enters the alveoli AFTER inhalation has a higher [ ] of O2 than the blood in the capillaries next to the lungs

42. Understanding Gas Exchange
Thus, oxygen diffuses out of the alveoli into the blood in the capillaries
The blood in the capillaries has a HIGHER [ ] of CO2 than the air in the alveoli
This is because CO2 is a waste produce of cellular respiration (step #4) and is brought up to the lungs from other cells in the body to be exhaled out

43. Understanding Gas Exchange
Therefore, the body gets rid of CO2 (waste product) by having it diffuse out from the capillaries and into the alveoli
The CO2 is then exhaled out into the air and out of the body as NEW and FRESH O2 is breathed in and the cycle continues

44. Understanding Gas Exchange
The reason why CO2 is able to move out of the capillaries and into the alveoli to be exhaled out
And the reason why O2 is able to move from the alveoli and into the capillaries with fresh O2 for cells
Is because of DIFFUSION – The movement of a substance from a High [ ] to a Low [ ]

45. Understanding Gas Exchange
Where:
There is a high [ ] of CO2 in capillaries and moves to the low [ ] area of the alveoli
There is a high [ ] of O2 in the Alveoli from being breathed in and moves to the low [ ] of the capillaries in the blood

46. Understanding Gas Exchange

47. How do these gases move around in the body?
During respiration, both oxygen (O2) and carbon dioxide (CO2) are transported via the bloodstream
99% of O2 that reaches cells is carried by Hemoglobin (Hb)
Is a protein in RBC that is attracted to O2

48. How do these gases move around in the body?
When CO2 leaves tissue cells and diffuses into the capillaries, it enters the RBC
23% of CO2 is carried in the blood by Hemoglobin
The other 77% is in the blood as a dissolved gas
When CO2 reaches the lungs, it diffuses into the air in the alveoli and is exhaled

49. How do these gases move around in the body?