1. 9.1 Respiratory System

2. Atmosphere Composition
78% nitrogen
21% oxygen
1% everything else
Fig. 1 page 282

3. Breathing and Respiration
1. Breathing 2. External Respiration

4. Breathing and Respiration
3. Internal Respiration 2. Cellular Respiration

5. Human Respiratory System
pg. 283

6. Human Respiratory System
Air can enter in through 2 passages:
Functions:
Once air reaches the pharynx it proceeds to the
larynx through the
Epiglottis.
Larynx contains 2
thin sheets of elastic
ligaments
= vocal cords

7. Vocal Cords
How are different pitches made?

8. Trachea Top of the trachea is the larynx (enlarged
section to support epiglottis and
vocal cords)
Supported by cartilaginous
rings (keep open at all times)
Lined with mucous producing
cells and cilia. Why?

9. Human Respiratory System
Air moves from the trachea into two
Bronchi (singular: bronchus)
Bronchi carry
air to lungs and
split into even
smaller airways
called
bronchioles

10. Human Respiratory System
Air then moves from
bronchioles to alveoli
(singular: alveolus)
Each alveolus are
surrounded by capillaries,
this is the functional
structure of external
respiration.
150 x106 / lung = S.A. of a
TENNIS COURT = 40x body

11. Alveoli Gas diffuses between the air and the blood
due to concentration gradients.
Alveoli walls
are only one
cell thick.
Allow for fast
gas exchange

12. Alveoli During inhalation the alveoli are bulb shaped
When one exhales, the sacs collapse and the membranes touch
Alveoli have a lipoprotein layer to avoid staying stuck.
Newborns can experience Respiratory Distress
Syndrome – can`t inhale
due to alveoli staying
closed.

13. Pleural Space
Outer surface of the lung is surrounded by the pleural membrane which also lines the inner wall of the chest cavity, the two stick together.
Gap between in filled with fluid to reduce friction.
These two membranes
allow the lungs to
expand and draw in air
when the diaphragm
pulls down.

14. Breathing Movements
Pressure differences are responsible for the movement of air
Gases move from an
area of high pressure
to an area of low
pressure.

15. Fig 5 - pg. 286

16. Diaphragm
Diaphragm – Sheet of muscle that separates the thoracic cavity from the abdominal cavity
Inspiration – diaphragm contracts, pulling downward, pressure in lungs decreases, pulls in air.
Expiration – diaphragm relaxes, moves back up, pressure in lungs increases, pushes out air.
Intercostal muscles – help the ribs move to expand / contract chest cavity with nerve stimulus.

17. Practice Questions
pg. 287
2, 3, 5-7

18. 9.2 Gas Exchange & Transport
Partial Pressures
Oxygen Transport
Carbon Dioxide Transport

19. 1. Partial Pressure
Dalton’s Law of partial pressures states that each individual gas in a mixture exerts its own pressure.
This occurs with O2 and CO2 in the blood but depends on location in the body.

20. 1. Partial Pressure Gases diffuse from high pressure to low pressure.
O2 pressure is highest in the ______________
O2 pressure is lowest in the ______________
CO2 pressure is highest in the _____________
CO2 pressure is lowest in the ______________

21. 2. Oxygen Transport O2 is not very soluble in blood
Approx. 0.3 mL/100mL of blood
Hemoglobin greatly increases blood’s carrying capacity of O2
Approx. 20 mL/100mL
of blood

22. Hemoglobin Four polypeptides made of two components:
Heme = iron-containing pigment
O2 binding forms oxyhemoglobin
Globin = protein component

23. Hemoglobin

24. Hemoglobin
Drop in O2 partial pressure in tissue capillaries causes DISSOCIATION.
Dissociation of
oxygen from Hb
allows oxygen to
diffuse into the
tissues where it
is used for cell
respiration.

25. 3. CO2 Transport 20 times more soluble than O2
Carried in blood in three
forms:
Carbonic Acid
64%
Carbaminohemoglobin
27%
In Plasma 9%

26. Carbonic Acid CO2 + H2O  H2CO3
Enzyme - carbonic anhydrase – found in RBC’s
Causes CO2 and H2O to from carbonic acid.
Rapid conversion decreases [CO2] in blood, this decreases the partial pressure of CO2 and allows for continuous diffusion from the tissues to the blood.

27. Buffer Action Increased levels of Carbonic Acid = Possible Death.
H2CO3  H+ + HCO3-
Hemoglobin binds to H+ (making reduced hemoglobin) and removes them from solution = buffer
Hb also releases oxygen to diffuse into tissues.

28. Back at the Lungs H+ + HCO3-  H2O + CO2
O2 dislodges H+ from Hb, which then forms CO2 and H20.
Highly concentrated carbon dioxide diffuses from blood into alveoli and is eliminated in exhalation.

29. To Review… Hemoglobin’s (Hb) two roles:
Increase blood’s affinity for oxygen
Buffers carbonic acid in the blood
CO2 + H2O  H2CO3  H+ + HCO3-  H20 + CO2
STEP 1 - TISSUES STEP 2 - BLOOD STEP 3 - LUNGS

30. Practice Questions
pg. 288
# 1, 2
pg. 291
# 1, 3, 5