External&Internal Respiration

1. RESPIRATION
INTERNAL AND EXTERNAL
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2. INTERNAL RESPIRATION
zCELLULAR METABOLISM
zANAEROBIC GLYCOLYSIS
zAEROBIC OXIDATIVE METABOLISM IN
THE MITOCHONDRIA
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3. EXTERNAL RESPIRATION
zVentilation or breathing: air moved in and
out of lungs
zOxygen and Carbon Dioxide exchange in
the lungs
zOxygen and Carbon Dioxide transported
by blood to and from tissues
zExchange of Oxygen and Carbon Dioxide
between tissue and blood
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4. EXTERNAL AND INTERNAL
RESPIRATION
HEART
TISSUE
CELL
O
2
+ FOOD
CO
2
+ H
2
O
+ ATP

LUNGS
ATMOSPHERE
PULMONARY
CIRULATION
SYSTEMIC
CIRCULATION
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5. THE RESPIRATORY
SYSTEM
zNasal Passages
zMouth
zPharynx
zLarynx
zTrachea
zBronchi
zAlveoli
zLung
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6. Alveoli
zSmall, thin walled, inflatable sacs at end
of bronchioles
zSurrounded by jacket of pulmonary
capillaries
zProvide thin barrier and enormous surface
area for gas exchange by diffusion
zType II secrete surfactant
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7. Alveoli and Pulmonary
Capillaries
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8. RESPIRATION
The Mechanics of
Breathing
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9. PRESSURES AT REST
zAtmospheric pressure: 760 mm Hg
zIntra-alveolar pressure: 760 mm Hg
zIntrapleural pressure: 756 mm Hg
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10. BAROMETRIC PRESSURE
Mercury Hg
VACUUM
WEIGHT OF COLUMN
OF AIR = FORCE
FORCE/AREA = PRESSURE
Sea Level
760 mm
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11. REST PRESSURES
760 MM Hg
756 mmHg
Lungs
Intrapleural pressure
Airways
Atmosphere
Pleural Sac
Thoracic
Wall
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12. THE TRANSMURAL
PRESSURE GRADIENT
INFLATES THE LUNGS
zThoracic cavity larger than lungs
zTransmural (Across Lung Wall) pressure
gradient holds thoracic wall and lungs in
close apposition
zThis pressure gradient is balanced by the
elastic forces in the alveoli producing
equilibrium
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13. REST PRESSURES
760 MM Hg
756 mmHg
Lungs
Intrapleural pressure
Airways
Atmosphere
Pleural Sac
Thoracic
Wall
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14. AIR IS A COMPRESSABLE GAS
WHICH OBEYS BOYLE’S LAW
zP
1
V
1
= P
2
V
2
zIf Volume increases, Pressure must
decrease
zAs lungs expand, pressure inside falls
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15. INSPIRATION
zElevation of ribs expands lungs
zLowering of diaphragm by contraction also
expands lungs
zExpansion of lungs causes pressure inside
to drop below atmospheric pressure
zAir rushes in to fill the expanded lungs
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16. INSPIRATION
760 mm Hg
754 mmHg
Lungs
Intrapleural pressure
Airways
Atmosphere
Pleural Sac
Thoracic
Wall
759mm Hg
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17. EXPIRATION
zReturn of ribs to rest position causes
diminishing of lung volume
zReturn of diaphragm to rest position also
causes diminishing of lung volume
zDiminishing of lung volume causes
pressure in lung to raise to a higher value
than atmospheric pressure
zAir flows out of the lungs
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18. EXPIRATION
760 mm Hg
756 mmHg
Lungs
Intrapleural pressure
Airways
Atmosphere
Pleural Sac
Thoracic
Wall
761 mm Hg
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19. MUSCLES OF INSPIRATION
zSternocleidomastoid
zScalenus
zExternal Intercostals
zDiaphragm
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20. MUSCLES OF EXPIRATION
zInternal intercostals
zAbdominals
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21. AIRWAY RESISTANCE
zFlow of air depends on the pressure
gradient (atmospheric, P
a
, and intra-
alveolar, P
i
) and the airway resistance, R
zF = (P
a
- P
i
)/R
zResistance depends primarily on the
radius of the conducting airways
zParasympathetic stimulation constricts,
while sympathetic dilates
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22. Resistance and Disease
zColds
zAsthma: Constriction of small airways, excess mucus,
and histamine-induced edema
zBronchitis:Long term inflamitory response causing
thickened walls and overproduction of mucous
zEmphysema: Collapse of smaller airways and breakdown
of alveolar walls
zAlveolar surface tension
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23. LUNG VOLUMES
zTidal Volume (TV): 500 ml
zInspiratory reserve volume (IRV): 3 liters
zInspiratory capacity (IC): 3.5 liters
zExpiratory reserve volume (ERV): 1 liter
zResidual volume (RV): 1.2 liters
zFunctional Residual Capacity (FRC): 2.2 l
zVital Capacity (VC): 4.5 liters
zTotal Lung Capacity (TLC): 5.7 liters
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24. LUNG VOLUMES
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25. LUNG VOLUMES:
RELATIONSHIPS
zIC = IRV + TV
zFRC = ERV + RV
zVC = IRV + TV + ERV
zTLC = VC + RV
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