1. The Respiratory System
Part Two

2. Breathing

3. Respiration Center - Brain
Medulla oblongata
(can’t control with our will)
Stimulates of diaphragm and (rib) muscles for
Stretch receptors
Receptors that for the nervous which give on mechanical pressure or
stretch receptors in alveoli limit depth to over inflation by expiration

4. Pressure air moves in or out of lungs to pressure with atmosphere
air moves from area of pressure to area of pressure
an expanded volume will lower the pressure and allow air to into the lungs through the
passages
Upon inspiration, the pressure in the alveoli is on the order of 2-3 mmHg below the atmospheric pressure of 760 mmHg
The relaxing of the diaphragm reduces the volume and the pressure, allowing air to flow out of lungs
provides a pressure some 3 mmHg above atmospheric pressure to accomplish expiration.

5. Inspiration/Expiration

6. Inspiration/Expiration
Diaphragm and the dome shape changes to a flat shape
External muscles contract and ribs
Volume of cavity increases
Pressure inside thoracic cavity
Diaphragm and returned to its natural shape
External muscles relax
Volume of cavity decreases
Pressure inside thoracic cavity

7. Gas exchange between the air and lungs
External Respiration
Gas exchange between the air and lungs

8. Red Blood Cells
In each red blood cell, there are approximately hemoglobin
Each hemoglobin molecule binds to oxygen
Researchers believe that each molecule also binds 4 carbon dioxide molecules (not confirmed)

9. External
In lungs, O2 from air diffuses into and CO2 from blood diffuses into air within
i.e. O2 diffuses down into blood, while CO2 diffuses into air

10. Oxygen 1.5% of oxygen is as gas
98.5% binds to hemglobin (Hb) at the and is transported as HbO2 or
O2 + Hb → HbO2

11. Carbon Dioxide Leaves the red blood cell and out into the alveolar air
Leaves as:
Dissolved gas
Dissociated from
Broken down from
CO2(g) + H2O(l) H2CO3(aq) HCO3–(aq) + H+(aq)

12. Gas exchange between the blood and body cells
Internal Respiration
Gas exchange between the blood and body cells

13. Internal
In tissues, from blood diffuses into tissues and from tissues into

14. Oxygen
concentration
Oxygen from the hemoglobin molecule due to temperature and differences
Oxygen is now free to the concentration gradient and diffuse out of the and into the tissue
hemoglobin molecule will bind H+ to become

15. Carbon Dioxide 7% dissolves in and is as solution
23% diffuses into , binds to hemoglobin, and is as
(HbCO2)
CO2 + Hb → HbCO2

16. 70% diffuses in RBC and is to HCO3– and H+ by
CO2(g) + H2O(l) → H2CO3(aq) → HCO3–(aq) + H+(aq)
HCO3 (bicarbonate ions) move out from RBC and is transported via plasma
H+ combines with to form reduced (HHb)
H+ + Hb → HHb
Therefore, HCO3– and Hb act as to help maintain in blood

18. Regulating Breathing Rate
Breathing rate and depth to maintain O2 and CO2 levels in blood, which are by in the medulla oblongata and and bodies (found in the carotid and aortic arteries)
Medulla Oblongata
detects H+ concentration (decreasing pH) caused by increased CO2 in blood
causes to contract
Carotid and Aortic Bodies
detect O2 in blood causing to contract

19. By end of this section you should be able to:
identify and give functions for each of the following:
– nasal cavity
– pharynx
– larynx
– trachea
– bronchi
– bronchioles
– alveoli
– diaphragm and ribs
– pleural membranes
– thoracic cavity
explain the roles of cilia and mucus in the respiratory tract
explain the relationship between the structure and function of alveoli

20. compare the processes of inhalation and exhalation
describe the interactions of the following structures in the breathing process:
– respiratory centre in the medulla oblongata
– lungs
– pleural membranes
– diaphragm
– intercostal (rib) muscles
– stretch receptors
compare the processes of inhalation and exhalation
explain the roles of carbon dioxide and hydrogen ions in stimulating the respiratory centre in the medulla oblongata
explain the roles of oxygen, carbon dioxide, and hydrogen ions in stimulating carotid and aortic bodies

21. write the chemical equations for internal and external respiration
describe the exchange of carbon dioxide and oxygen during internal and external respiration, including
– location of exchange
– conditions that favour exchange (e.g., pH, temperature)
explain the roles of oxyhemoglobin, carbaminohemoglobin, reduced hemoglobin, bicarbonate ions, and carbonic anhydrase in the transport of carbon dioxide and oxygen in the blood
write the chemical equations for internal and external respiration

22. Mandatory Vocabulary
alveoli, aortic bodies, bicarbonate ions, bronchi, bronchioles, carbaminohemoglobin, carbon dioxide, carbonic anhydrase, carotid bodies, cilia, diaphragm, exhalation, external respiration, hydrogen ions, inhalation, intercostal (rib) muscles, internal respiration, larynx, lungs, mucus, nasal cavity, oxygen, oxyhemoglobin, pH, pharynx, pleural membrane, reduced hemoglobin, respiratory centre in the medulla oblongata, respiratory tract, ribs, stretch receptors, thoracic cavity, trachea