1. J. Hinson Human Anatomy and Physiology January 2007
Respiratory System
J. Hinson
Human Anatomy and Physiology
January 2007

2. I. Introduction Passages; air Respiration a. Breathing
b. Exchange of gases
c. Transport of gases
d. Exchange of gases
Cellular Respiration

3. II. Anatomy
Two Tracts
Upper respiratory system: nose, nasal cavity, sinuses, pharynx, and larynx
Lower respiratory system: trachea, bronchial tree, and lungs

4. II. Anatomy B. Nose 1. Bones: nasal and vomer; cartilage
II. Anatomy
B. Nose
1. Bones: nasal and vomer; cartilage
2. external nares or nostrils
a. hairs

5. II. Anatomy C. Nasal Cavity
1. nasal septum divides
2. nasal conchae support mucous membrane
a. epithelium contains goblet cells
(i) moisturize and trap dust
3. blood vessels
II. Anatomy C. Nasal Cavity

6. II. Anatomy D. Paranasal sinuses
1. maxillary, frontal, ethmoid, and sphenoid; reduce weight; voice
2. lining continuous with nasal cavity

7. II. Anatomy E. Pharynx 1. throat 2. Function: food, air, sound

8. II. Anatomy F. Larynx 1. airway enlargement 2. Functions: a. air
II. Anatomy
F. Larynx
1. airway enlargement
2. Functions:
a. air
b. filter
c. voice box
3. thyroid, cricoid, and epiglottic cartilages

9. II. Anatomy G. Trachea (windpipe)
1. cylindrical tube splits into bronchi
2. C-shaped cartilages

10. II. Anatomy H. Bronchial Tree 1. branched airways 2. Primary bronchi
3. Secondary bronchi: branches
4. Tertiary bronchi: to bronchioles
5. Alveolar ducts to alveoli for gas exchange

11. II. Anatomy I. Lungs 1. cone-shaped a. R: 3 lobes b. L: 2 lobes
2. mediastinum separates
3. visceral pleura and parietal pleura
a. pleural space between

13. III. Pulmonary Ventilation (BREATHING!)
Movement of external air into and out of the bronchial tree and alveoli
Inspiration (inhalation)
Atmospheric Pressure is the force that causes movement
Normal air pressure = 760 mmHg
Occurs when pressure inside alveoli reduced
As diaphragm moves down, thorax expands (volume ٨), thus pressure decreases.
Lungs expand
Surface tension of the pleural membrane also aids.
Surfactant decreases the tendency for alveoli collapse.

14. III. Pulmonary Ventilation (BREATHING!)
Expiration (exhalation)
Forces of expiration come from the elastic recoil of tissue and from surface tension within the alveoli.
Aided by the contraction of the internal intercostals and abdominal wall muscles, but is typically a passive process.

15. IV. Respiratory Air Volumes/Capacities
Spirometry: measure of air volumes
Respiratory Volumes:
Tidal: normal breathing; ~ 500 cc
Inspiratory Reserve: additional inhaled; ~ 3000 cc
Expiratory Reserve: additional exhale; ~ 1100 cc
Residual: remainder after forceful exhale: ~ 1200 cc
Remains in lungs and mixed with new air

16. IV. Respiratory Air Volumes/Capacities
Respiratory Capacities:
Vital: max air exhaled after deepest breath; ~ 4600 cc
Inspiratory: vol. of air inhaled after tidal vol. exhaled; ~ 3500 cc
Functional Residual: vol. remaining after tidal vol. exhaled; ~ 2300 cc
Total Lung Capacity: total air possible to hold; 5800 cc

17. V. Clinical Terms Apnea Asphyxia Dyspnea Hemothorax Hypoxia
Apnea
Asphyxia
Dyspnea
Hemothorax
Hypoxia
Pneumothorax

18. VI. Breathing Control Normal breathing is rhythmic & involuntary.
Controlled via brain stem’s respiratory center

19. VI. Breathing Control Rate and depth influenced by: Chemicals
Chemosensitive areas (brain): respond to change in CO2 and H+…rate increases when stimulated
Chemoreceptors (bvs): respond to change in O2…rate increases when O2 low
Stretching Tissues
Inflation reflex regulates depth
Stretch receptors in pleura, bronchioles, and alveoli prevent overinflation
Emotional State: fear and pain increase rate
Hyperventilation: lowers CO2 (increases pH)

20. VII. Alveolar Gas Exchange
Occurs at alveoli (tiny, distal air sacs)
Membrane consists of alveolar and capillary walls to allow gas exchange between alveolar air and blood via…
Diffusion
high to low partial pressure (determined by concentration of gas)
O2 to blood…CO2 to alveoli
Air: 78% N; 21% O2; .04% CO2
PO2 = 160 mmHg; PCO2 = 0.3 mmHg

21. VII. Gas Transport Blood transports between lungs and body.
Blood transports between lungs and body.
Oxygen Transport
98% by hemoglobin
Oxyhemoglobin: iron binds to O2 in hemoglobin
More O2 released as CO2 increases, the blood becomes more acidic (H+ high) or blood temperature increases.
Carbon Dioxide Transport
Carried in solution, on hemoglobin, or as bicarbonate (in plasma)
Carbonic anhydrase speeds reaction bw CO2 and H2O to form carbonic acid…dissociates to H+ and bicarb.