1. The document discusses the structure and function of the respiratory system, including the anatomy of the lungs and respiratory tract, the mechanics of breathing, gas exchange, and control of respiration. 2. Key topics covered include the roles of the diaphragm and intercostal muscles in breathing, the factors that influence oxygen binding to hemoglobin, chemical and neural control of the respiratory center, and how respiration is impacted by exercise and aging. 3. Diagrams are provided to illustrate concepts like lung volumes and capacities, gas exchange, and regulation of the respiratory center.

1. Sugeng Hadisaputra, M.Kep, Sp.Kep.An

2. The Student Objective
After attending the discussion of respiratory physiology,
students will be able to explain the normal function of
respiratory system, rightly

3. THE SUBTOPICS
1. Structure of the Respiratory System
2. The Pulmonary Ventilation
3. Lung Volume and Capacity
4. The O2 – CO2 Exchange
5. The Transport of O2 and CO2
6. The Control of Respiration
7. Exercise and The Respiratory System
8. Aging and Respiratory System

4. Structures of The
Respiratory System
Upper Respiratory System
•Nose
•Pharynx
•Associated structures
Lower Respiratory System
•Larynx
•Trachea
•Bronchi
•Lung

5. The respiratory Tract

6. Alveolus

7. The Muscles of
Breathing
Inspiratory muscles
• Diaphragm
• External
Intercostalis
• Sternocleido-
mastodeus
• Scalenus
Expiratory muscles
• Internal
Intercostalis
• Abdominal
Muscles

8. PULMONAL VENTILATION
(BREATHING)
1. Inspiration
2. Expiration
* The movement of air into and out of the lung depends on
pressure change (Boyle’s law)

9. INSPIRATION
Active
Boyle law
EXPIRATION
Passive
•Muscle relaxation
•Elastic recoil
Active
•Labor

10. BREATHING PATTERN
Eupnea = Normal quiet breathing
Apnea = A temporary cessation of breathing
Dyspnea = A painful or labored breathing + tachypnea
Costal breathing = Shallow (chest) breathing
Diaphragmatic breathing = Deep (abdominal) breathing

11. ALVEOLAR SURFACE TENSION
•Alveolar fluid surrounds air in alveoli  exerts tension (surface
tension)
•Lowered by Surfactant
•Great surface tension tend to collapse the lung

12. COMPLIANCE
•The ease of lung + thoracic wall to expand
•The higher the compliance the easer to expand
•The higher the surface tension the lower the compliance
•The lesser the elasticity the lower the compliance
•The Compliance decrease in:
Scar lung
Pulmonary edema
Surfactant deficiency
Muscle paralysis , emphysema

13. AIRWAY RESISTANCE
•The narrower the airway diameter the higher the resistance
•The broader the airway diameter the lower the resistance
MODIFIED RESPIRATORY MOVEMENT
•Laughing, Sighing, Sobbing
•Sneezing, Coughing
•Talking, Singing

14. LUNG VOLUME AND CAPACITY
6000 ml
5000 ml
4000 ml
3000 ml
2000 ml
1000 ml
LUNG VOLUMES LUNG CAPACITIES

15. O2 – CO2 EXCHANGE
Changes In Partial Pressure
During External and Internal
Respiration
(Dalton & Henry’s laws)

16. TRANSPORT OF O2 AND CO2
IN THE BLOOD
O2:
1. 1.5% Dissolved in
plasma
2. 98.5% as
Oxyhemoglobin
CO2:
1. 7% Dissolved in plasma
2. 23% as
Carbaminohemoglobin
3. 70% as Bicarbonate ions

17. O2 – Hb dissociation curve
at normal body temperature
As pO2 increase, more O2 combines
with hemoglobin
HEMOGLOBIN AND OXYGEN PARTIAL PRESSURE

18. HEMOGLOBIN AND OTHER FACTORS
The effect pH on affinity
of hemoglobin for oxygen
As pH decrease , the affinity of
hemoglobin for O2 is less, so less
O2 combines with hemoglobin and
more is available to tissue

19. The effect pCO2 on
affinity of hemoglobin
for oxygen
As pCO2 increase , the affinity of
hemoglobin for O2 decreases

20. The effect body temperature
on affinity of hemoglobin
for oxygen
As temperature increase , the affinity
of hemoglobin for O2 decreases

21. FETAL HEMOGLOBIN
Oxygen – hemoglobin
dissociation curve
comparing fetal and
maternal hemoglobin
Fetal Hb has a higher affinity for
O2 than does adult Hb

22. HYPOXIA
1. Hypoxic hypoxia
 Low pO2 in arterial blood: high altitude, airways obstruction,
fluid in lung
2. Anemic hypoxia
 Low Hb: hemorrhage, anemia, CO poisoning
3. Stagnant (ischemic) hypoxia
 Low tissue blood flow
4. Histotoxic hypoxia
 Tissue unable uses O2 properly

23. CARBON DIOXIDE TRANSPORT
1. Dissolved CO2: 7 % dissolved in plasma
2. Carbaminohemoglobin
Hb + CO2 Hb.CO2
3. Bicarbonate ions
CO2 + H2O H2CO3 H+
+ HCO3
-

24. Summary of Gas Exchange and Transport in Lung and Tissue

25. CONTROL OF RESPIRATION
Respiratory center
1. Medullary
Rhythmicity
Area
2. Pneumotaxic
Area
3. Apneustic Area

26. REGULATION OF THE RESPIRAORY CENTER
1. Cortical influences
 Voluntary, protective
2. Chemical regulation
 Central Chemoreceptors: located in Medulla Oblongata
 Peripheral Chemoreceptors: Aortic & carotid bodies
3. Neural changes due to movement
4. Inflation reflex
 Baroreceptors = Stretch receptors
5. Other influences
 Blood pressure, Limbic system, Temperature, Pain, Stretching the anal
sphincter muscle, Irritation of airways

27. Proposed role of the medullary rhythmicity area in controlling the basic
rhythm of respiration

28. Return to
homeostasis
Stimulus (stress)
Increase arterial blood pCO2
Central & peripheral chemo-receptor
Inspiratory area control center (in MO)
Respiratory muscle:  hyperventilation
Decrease arterial blood pCO2; increase pO2
NEGATIVE
FEEDBACK

29. Positive feedback further
lowers pO2 so hypoxia
worsens
Stimulus (stress)
Decrease arterial blood pO2 (severe hypoxia)
Central chemo-receptor suffer hypoxia
Inspiratory area suffer hypoxia (in MO)
Respiratory muscle:  hypoventilation
Decrease arterial blood pO2
POSITIVE
FEEDBACK

30. 1
2
3
4
5
6
7
8 9
10
11
12
13
14
15
1. Voluntary
hyperventilation
controlled by cerebral
cortex
2. Anticipation of
activity via stimulation
of the limbic system
VENTILATION
RATE AND DEPTH
INCREASE WITH:

31. 5. Decrease in blood
pressure detected by
baroreceptors
7. Prolonged pain
4. Increase in sensory
impulses from
proprioceptors in
muscles and joints and
increase in motor
impulses from the
motor cortex
6. Increase in body
temperature
8. Stretching anal
sphincter
3. Increase in arterial
blood H+
level or pCO2
above 40 mm Hg and
decrease in arterial
blood pO2 from 100 to
50 mm Hg, detected by
central and peripheral
chemoreceptor

32. 13
1
2
3
4
5
6
7
8 9
10
11
12
14
15
VENTILATION RATE
AND DEPTH
DECREASE WITH:
9. Irritation of pharynx
or larynx by touch or
chemicals causes apnea
followed by coughing
or sneezing
10. Severe pain causes
apnea
11. Decrease in body
temperature (sudden
cold stimulus) causes
apnea

33. 14. Decrease in arterial
blood H+
level or pCO2
below 40 mm Hg and
decrease in arterial
blood pO2 below 50 mm
Hg, detected by central
and peripheral
chereceptors
15. Voluntary
hypoventilation
controlled by cerebral
cortex (limited by
buildup of CO2 and H+
)
12. Increase in blood
pressure detected by
baroreceptors
13. Decrease in
sensory impulses from
proprioceptors in
muscles and joints and
decrease in motor
impulses from the
motor cortex

34. EXERCISE AND THE RESPIRATORY SYSTEM
Exercise
Raises pulmonary perfusion
Raises the O2 diffusion
capacity
Pulmonary ventilation
1. Anticipation of the
activity, which stimulates
the limbic system

35. 2. Sensory impulses from proprioceptors in muscles and
joints
3. Motor impulses from the primary motor cortex
(precentral gyrus)
a. Decreased pO2, due to
increased O2 consumption
b. Increased pCO2, due to
increased CO2 production by
contracting muscle fibers
c. Increased temperature
due to liberation of more
heat as more O2 utilized

36. AGING AND THE RESPIRATORY SYSTEM
Aging
The airways and tissue
become more rigid
Decreases
1. Vital capacity, as much as 35%
2. Blood level of O2
3. Alveolar macrophage activity
4. Ciliary action
More susceptible to: pneumonia, bronchitis, emphysema, and other
pulmonary disorders