Blood

1
Alveolar Membrane Gradients
Air
Blood
Oxygen
Carbon Dioxide
2
Clustered Alveoli
3
1
2
Airway Generations
3
4
5
6
4
17
Respiratory Bronchioles
18
The Primary Lobule
19
Alveolar Ducts
20
21
23
22
Alveolar Sac
5
Airway Cross-sectional Area
variation with distance from mouth
trachea
alveolar membrane
mouth
at RV (min lung volume)
at TLC (max lung volume)
6
Contrasting Emboli Effects
embolus
embolus
Pulmonary capillaries others cover for blocked
one emboli filtered safely
Systemic capillaries serve a particular area so
area killed
7
Face View of 1/6th of Alveolar Septum
The Alveolar Wall
60 um
Capillary endothelium
Transverse Section
Red cell
Basement membrane
Alveolar epithelium
10 um
Enlargement
Alveolar fluid lining
1 um
8
Lung Volumes
6.0
VC
Litres
IRV
IC
TLC
3.5
VT
3.0
ERV
FRC
1.5
RV
0
9
Volumes and Flows
VT 500 ml/breath
Ventilation 7.5 L/min VT X f (breaths/min)
VD 150 ml/breath the dead space volume
Alveolar Ventilation 5.25 L/min
FRC 3000 ml Gas exchange volume
Cardiac output 5 L/min
Capillary volume 70 ml
10
The Diaphragm Muscle
11
Rib
Muscle
The Intercostal Muscles
Rib
SPINE
Muscle
Rib
Muscle
Rib
12
Lung Inflation
PB 0
PB 0
P 0
P
P
13
The Intrapleural Space
Intrapleural Space
14
Pneumothorax
PB 0
PB 0
P0
P0
P-5
P0
NORMAL
PNEUMOTHORAX
15
Lung Compliance
Intrapleural Pressure
Lung Volume
Lung Volume
elastic limit
Slope CL
Intrapleural Pressure
negative
positive
16
Surface Tension
P
17
Types of Flow
Laminar
Intermediate
Turbulent
18
Types of Flow
Laminar Flow - R constant -silent -viscosity
dependent
Turbulent Flow - R varies with flow - noisy -
density dependent
Pressure Gradient
Airway Flow
19
Ventilation-Perfusion Matching
.
.
.
V 1
V 1
V 0
Obstruction
.
.
.
Embolus
Q 1
Q 1
Q 0
Venous Admixture
Normal
Wasted Ventilation
20
Pulmonary Gas Transfer
Pao2 97
alveolar gas PAo2 106
100
80
mixed venous blood pulmonary artery
Po2 mmHg
60
arterialized blood in pulmonary capillary
venous admixture in pulmonary veins
arterial blood
37
40
pulmonary capillary blood
50
46
Pco2 mmHg
Paco2 39
alveolar gas PAco2 39
40
21
Oxygen Dissociation Curve
100
20
arterial
70
14
venous
Pco2 40
Oxygen Concentration ml/100ml
Oxygen Saturation
Pco2 46
venous
40
30
100
arterial
Oxygen Partial Pressure mmHg
22
Carbon Dioxide Dissociation Curve
Carbamino CO2 at Po2 40 (venous blood)
at Po2 100 (arterial blood)
52
venous
arterial
46
Carbon Dioxide Concentration ml/100ml
CO2 as Bicarbonate
Dissolved CO2
venous
arterial
Carbon Dioxide Partial Pressure mmHg
23
Carbonic Acid Formation
H
HCO3-
CO2
H2O
H2CO3
H.Hb
Cl-
Carbonic anhydrase enzyme catalyzes (in red cell)
Hemoglobin buffers hydrogen ions (in red cell)
Bicarbonate leaves the red cell and chloride
enters in exchange chloride shift
24
Linear Henderson-Hasselbach
Normally
24 Pco2
H 40 nmol/L
H
HCO3
Pco2 40 mmHg
HCO3 24 mmol/L
25
Regulation of Breathing
Pulmonary Ventilation
Metabolic Carbon Dioxide Production
Pco2
Carbon Dioxide stores
Po2
Oxygen stores
Metabolic Oxygen Consumption
Pulmonary Ventilation
26
Respiratory Negative Feedback Regulator
Gas Exchange
Pco2
Po2
Other
Ventilation
Chemo-reflexes
Acid-Base
H
Alb
PO4-
SID
27
The Metabolic Hyperbola
Ventilation L/min
Arterial Pco2 mmHg
28
The Central Chemoreflex
Ventilation L/min
Arterial Pco2 mmHg
29
The Peripheral Chemoreflex
Arterial Po2 mmHg
40
Ventilation L/min
60
100
Arterial Pco2 mmHg
30
The Chemoreflex Control of Breathing
40
gt150
100
60
normal resting equilibrium point
Arterial Po2 mmHg
Ventilation L/min
wakefulness drive
anaesthetic depression
resting metabolic hyperbola
Arterial Pco2 mmHg
31
Neural Factors
Emotions (forebrain)
Voluntary Control (motor cortex)
Posture (cerebellum)
Cough Sneeze etc. (medulla)
Limbic System
Rhythm Generator (medulla)
Reticular Formation
Sensory Stimuli (pain, startle)
32
Neuron Firing Patterns
I INC
E INC
I DEC
E DEC
I CON
expiration
inspiration
expiration
inspiration
33
Medullary Respiratory Groups
DRG
VRG
Cross-sectional view at obex
obex anatomical landmark
Dorsal view
34
Feedback Hierarchy
EFFERENT
AFFERENT
Central Chemoreceptors (medulla)
Medullary Respiratory Neurons
X
IX
Peripheral Chemoreceptors (carotid bodies)
Spinal Respiratory Motoneurons
X
Muscle Receptors
Respiratory Muscles
Airway and Lung Receptors
Po2 and H
35
The Time Course of Changes During Moderate
Exercise
Changes (e.g. Ventilation)
0
5
time (min.)
rest
rest
exercise
36
Changes with increasing Work Rate
Aerobic
Anaerobic
Pco2
Respiratory Variables
Ventilation
Po2 , H lactate
Exercise Work Rate
37
Astrand Fitness Test Assumption 2
Heart Rate
Work Rate or Oxygen Cost
38
Astrand Fitness Test Assumption 3
max
Heart Rate
max
Work Rate or Oxygen Cost
39
Astrand Fitness Test Assumption 4
max
Heart Rate
max
Work Rate or Oxygen Cost
40
The Fitness Message
max
Heart Rate
Bs max
Cs max
As max
Work Rate or Oxygen Cost
41
Lance Armstrong
7-time Winner of the Tour de France
Resting Heart Rate
32 beats per minute