1. The Respiratory System

2. THE FUNCTION OF THE RESPIRA-
TORY SYSTEM IS TO CONDUCT AIR
IN AND OUT OF THE LUNGS FOR
GAS EXCHANGE.
2. EACH LUNG LIES WITHIN A PLEURAL
SAC.

3. 3. AIR ENTERS THROUGH THE NASAL
CAVITIES. CILIA AND HAIR FILTER
DUST AND PARTICLES. BLOOD
VESSELS WARM THE AIR AND
MUCUS MOISTENS THE AIR.

5. 4. AIR MOVES THROUGH THE PHARYNX,
LARYNX, VOCAL CORDS, TRACHEA,
BRONCHIAL TUBES, BRONCHI,
BRONCHIOLES AND INTO THE ALVEOLI.

6. 5. EACH BRONCHIOLE BREAKS INTO
ALVEOLAR SACS. THE ALVEOLI PRO-
VIDE A TREMENDOUS SURFACE AREA
FOR GAS EXCHANGE WITH THE BLOOD
LOCATED IN THE DENSE CAPILLARY
NETWORK THAT SURROUNDS EACH
ALVEOLAR SAC.

7. LE 42-23 Branch from Branch pulmonary from artery pulmonary
(oxygen-poor
blood)
Branch
from
pulmonary
vein
(oxygen-rich
blood)
Terminal
bronchiole
Nasal
cavity
Pharynx
Alveoli
Larynx
Left
lung
Esophagus
50 µm
Trachea
Right
lung
50 µm
Bronchus
Bronchiole
Diaphragm
Heart
SEM
Colorized SEM

8. 6. TO INHALE, THE DIAPHRAGM CONTRACTS AND FLATTENS. THE RIB
CAGE MOVES UP AND OUT,
THE CHEST CAVITY VOLUME
INCREASES, INTERNAL PRESSURE
DECREASES AND AIR RUSHES IN.
7. EXHALE – REVERSE OF INHALE.
*How Stuff Works – Animation

9. Rib cage gets
smaller as
rib muscles
relax
Rib cage
expands as
rib muscles
contract
Air
inhaled
Air
exhaled
Lung
Diaphragm
INHALATION
Diaphragm contracts
(moves down)
EXHALATION
Diaphragm relaxes
(moves up)

10. 8. GAS EXCHANGE – IN THE ALVEOLI,
OXYGEN DIFFUSES DOWN A
PRESSURE GRADIENT INTO THE
BLOOD PLASMA AND BINDS TO THE
HEMOGLOBIN OF THE RED BLOOD
CELLS. THIS OCCURS ONLY IF THE
MEMBRANE IS PERMEABLE AND
MOIST.

11. -THE BLOOD CARRIES THE OXYGEN
TO THE TISSUES AND GIVES IT
UP WHERE OXYGEN PRESSURE IS
LOW AND PH IS LOW.
-CO2 IS HIGHER IN THE BODY
TISSUES SO IT DIFFUSES INTO THE
BLOOD.
-CO2 IS RETURNED TO THE LUNGS
AND RELEASED DURING AN
EXHALE.

12. Inhaled air Exhaled air Alveolar spaces O2 CO2 O2 CO2 Alveolar
160
0.2
120 27
Alveolar spaces O2
CO2 O2
CO2
104 40
Alveolar
epithelial
cells O2
CO2
CO2 O2
Blood
entering
alveolar
capillaries
Blood
leaving
alveolar
capillaries
CO2 O2
Alveolar
capillaries
of lung 40 45
104 40 O2
CO2 O2
CO2
Pulmonary
arteries
Pulmonary
veins
Systemic
veins
Systemic
arteries
Heart
Tissue
capillaries
CO2 O2
Blood
leaving
tissue
capillaries
Blood
entering
tissue
capillaries 40 45
CO2 O2
100 40 O2
CO2 O2
CO2
Tissue
cells
< 40
> 45 O2
CO2

14. 9. BESIDES SIMPLE DIFFUSION,
GAS EXCHANGE RATES ARE
AFFECTED BY METABOLIC ACTIVITY
AND THE PH OF THE BLOOD. MORE
METABOLISM = MORE ACIDITY = HEMOGLOBIN
WITH LESS AFFINITY FOR O2
10. BREATHING IS CONTROLLED BY
SEVERAL DIFFERENT PARTS OF THE
BODY:
CONSCIOUS BREATHING IS
BELIEVED TO BE CONTROLLED IN
THE CORTEX OF THE BRAIN.

15. B. UNCONCIOUS BREATHING IS
CONTROLLED BY THE PONS AND
MEDULLA OF THE BRAIN.
C. CHEMORECEPTORS MONITOR
THE BLOODS OXYGEN, CARBON
DIOXIDE AND PH LEVELS.

16. Cerebrospinal
fluid
Pons
Breathing
control
centers
Medulla
oblongata
Carotid
arteries
Aorta
Diaphragm
Rib muscles