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1. THE FUNCTION OF THE RESPIRATORY SYSTEM IS TO CONDUCT AIR
IN AND OUT OF THE LUNGS FOR
GAS EXCHANGE.
2. EACH LUNG LIES WITHIN A PLEURAL
SAC.
3. AIR ENTERS THROUGH THE NASAL
CAVITIES. CILIA AND HAIR FILTER
DUST AND PARTICLES. BLOOD
VESSELS WARM THE AIR AND
MUCUS MOISTENS THE AIR.
4. AIR MOVES THROUGH THE PHARYNX,
LARYNX, VOCAL CORDS, TRACHEA,
BRONCHIAL TUBES, BRONCHI,
BRONCHIOLES AND INTO THE ALVEOLI.
5. EACH BRONCHIOLE BREAKS INTO
ALVEOLAR SACS. THE ALVEOLI PROVIDE A TREMENDOUS SURFACE AREA
FOR GAS EXCHANGE WITH THE BLOOD
LOCATED IN THE DENSE CAPILLARY
NETWORK THAT SURROUNDS EACH
ALVEOLAR SAC.
LE 42-23
Branch
from
pulmonary
vein
(oxygen-rich
blood)
Branch
from
pulmonary
artery
(oxygen-poor
blood)
Terminal
bronchiole
Nasal
cavity
Pharynx
Alveoli
Larynx
Left
lung
Esophagus
Trachea
Right
lung
Bronchus
Bronchiole
Diaphragm
Heart
SEM
Colorized SEM
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
http://health.howstuffworks.com/adam-200020.htm
Rib cage
expands as
rib muscles
contract
Air
inhaled
Rib cage gets
smaller as
rib muscles
relax
Air
exhaled
Lung
Diaphragm
INHALATION
Diaphragm contracts
(moves down)
EXHALATION
Diaphragm relaxes
(moves up)
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.
-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.
Exhaled air
Inhaled air
160 0.2
O2 CO2
Alveolar spaces
120 27
O2 CO2
104 40
Alveolar
epithelial
cells
Blood
entering
alveolar
capillaries
40
45
O2 CO2
O2 CO2
CO2
O2
Alveolar
capillaries
of lung
Pulmonary
arteries
Systemic
veins
Blood
leaving
alveolar
capillaries
104 40
O2 CO2
Pulmonary
veins
Heart
Systemic
arteries
Tissue
capillaries
Blood
entering
tissue
capillaries
Blood
leaving
tissue
capillaries
40
45
O2 CO2
CO2
O2
Tissue
cells
< 40 > 45
O2 CO2
100 40
O2 CO2
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:
A. CONSCIOUS BREATHING IS
BELIEVED TO BE CONTROLLED IN
THE CORTEX OF THE BRAIN.
B. UNCONCIOUS BREATHING IS
CONTROLLED BY THE PONS AND
MEDULLA OF THE BRAIN.
C. CHEMORECEPTORS MONITOR
THE BLOODS OXYGEN, CARBON
DIOXIDE AND PH LEVELS.
Cerebrospinal
fluid
Pons
Breathing
control
centers
Medulla
oblongata
Carotid
arteries
Aorta
Diaphragm
Rib muscles