THE RESPIRATORY SYSTEM
¾All cells need O2 and release CO2
as a waste—WHY?
Cellular Respiration
C6H12O6 + O2Æ CO2 + H2O + E
¾Two systems that supply O2 and
eliminate CO2:
Cardiovascular & Respiratory
THE RESPIRATORY SYSTEM
FUNCTIONS: Review functions from text & lab
¾ Functions of the nose (on own)
¾Sound—phonation/vocalization (on own)
¾Conduction of air—inspiration and expiration
¾Gas exchange—external & internal respiration
¾Barrier functions
¾Regulation of blood pH (later)
¾Metabolic functions—remember ACE?
¾Non-specific immunity (mucous raft, macrophages)
3 PROCESSES OF RESPIRATON
¾Pulmonary Ventilation (breathing)
conducting air—to & from alveoli
(inspiration and expiration)
¾External Respiration
exchange of gases—alveoli and blood
¾Internal Respiration
exchange of gases—blood and tissues
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ANATOMY OF THE
RESPIRATORY SYSTEM
(review from lab studies)
¾ Respiratory Pathway (lab handout)
Note:
o Pathway for air (respiratory pathway)
o Tissue types lining pathway
o Cartilaginous transitions (significance?)
o Zones (conducting vs. respiratory)
¾ How are these related to each other?
¾ How are these related to the 3 processes of
respiration?
BRONCHIAL TREE
THE
RESPIRATORY
PATHWAY
Notes:
• Tissue types lining
pathway
• Cartilaginous
transitions
• Asthma Connection
(structure &
function are closely
related: compare
to emphysema)
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RESPIRATORY PATHWAY
PULMONARY
VENTILATION
Conducting Zone:
•Anatomical Dead
Space
EXTERNAL
RESPIRATION
•Cartilage
•High velocity
Respiratory Zone:
•No alveoli
•No gas exchange
• -Velocity
•Barrier Function
• + Surface Area
•Mucous Raft
ALVEOLI
• + Gas Exchange
(diffusion)
LOBULE OF THE LUNG
(see Fig.23.11a&b)
COMPONENTS of the
ALVEOLUS
Cells of the Alveoli:
¾ Type I (SSE)
¾ Type II (Septal)
¾ Type III (macrophages)
Respiratory Membrane:
¾
¾
¾
¾
Alveolar Wall
SSE basement membrane
Capillary basement membrane
Capillary endothelium (SSE)
See Fig. 23.12
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CONDUCTING AIRWAYS
Inspiration and Expiration
Mucous Raft & Goblet Cells
(Ventilation)
ALVEOLI
Diffusion of Gases Across Respiratory Membrane
Gas exchange between alveoli & pulmonary capillaries
=Blood-Gas Barrier
(External Respiration)
TISSUE CAPILLARIES
Diffusion of gases between blood and tissues
(Internal Respiration)
What is Perfusion?
What are metabolic fxns?
What are barrier fxns?
MECHANICS OF RESPIRATION
Ventilation depends on (overview):
¾ Producing physical changes
in the volume of the
thoracic cavity
¾ Creating pressure
gradients between thoracic
cavity, intrapleural
membranes & intraalveolar
spaces
¾ Atelectasis/elastic recoil
of lung and/or lung tissue
¾ Surface tension of alveoli
vs. surfactant
¾ Compliance
MUSCLES OF RESPIRATION
¾ Pulmonary ventilation
depends on muscles of
respiration (Fig. 23. 14):
o Muscles of inspiration:
9 Diaphragm (innervated
by the _____ nerve.)
9 External intercostals
9 Sternocleidomastoids
o Muscles of expiration
9 Normally passive
process
9 Internal intercostals
9 Abdominals (review
these)
¾ Muscles of respiration
change the internal volume
of the chest cavity
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PRESSURE GRADIENTS
Boyle’s Law: there is an
inverse relationship
between volume and
pressure.
Consider these pressures:
1. Intrathoracic pressure
2. Intrapleural pressure
3. Intraalveolar pressure
Think: increase volume
= ________ pressure.
Refer to Fig. 23.15 & 23.16 & Inspiration & Expiration study guide.
ATELECTASIS
¾ Definition: Elastic recoil of
lung and/or lung tissue
¾ Alveoli:
o Recoil of elastic fibers
o Surface tension
o Does elastic recoil and/or
surface tension enhance or
hinder expiration?
¾ Total “collapse” of the
lungs?
o Low intrathoracic pressure
o Surfactant (Type II cells)?
o What does Surfactant do?
o Does surfactant enhance or
hinder expiration?
Infant Respiratory Distress
Syndrome IRDS (was HMD)
¾What is it?
¾Diagnosis?
¾How do you prevent it?
¾How do you treat it—mother?
¾What do you do for the baby?
¾Respiratory therapy?
o CPAP= continuous positive airway p.
o PEEP= positive end expiratory p.
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COMPLIANCE
¾Definition
¾Does normal compliance help or
hinder inspiration?
¾Abnormal compliance
¾Related disorders
PNEUMOTHORAX
¾ Definition/describe
¾ Implications
¾ Causes
¾ Correction by chest
tube
GAS LAWS (YIKES!)
¾ Boyle’s Law = pressure/volume
o (inspiration and expiration)
¾ Dalton’s Law = mixture of gases-each acts individually
o
o
o
o
(air we breathe= pO2 + CO2 + N2 + H2O)
pO2 21% + CO2 0.04% + N2 78% + H2O 5% =100% (sea level)
Gas diffuses across RM from area of ____ to area of ___
Think about how O2 and CO2 move in external & internal
respiration.
¾ Henry’s Law = pressure/dissolved gases in a liquid
o CO2 and cokes
o Nitrogen (and nitrogen narcosis)
o Think about how O2 and CO2 move in external & internal
respiration and quantities dissolved in the blood.
o Hyperbaric oxygen
o Bends (decompression sickness, Caisson’s disease)
¾ Charles’s Law = temperature/volume
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Changes in Partial Pressures of
O2 and CO2 (know Fig.23.18)
PP of Atmospheric Oxygen:
¾ pO2 = %O2 X 760mmHg
¾ pO2 =21% X 760mmHg=
159.6 or 160mmHg
On an average cool, clear
day at sea level.
Partial Pressures of Gases
¾
¾
¾
¾
¾
¾
¾
¾
¾
¾
Boyle’s Law?
Atmospheric pO2 = 159
Alveolar pO2 =105
Dexoygenated b. pO2 =40
Oxygenated b. pO2 = 100
Tissue pO2 =40
Tissue pC02 = 45
Deoxygenated b. pC02 =45
Alveolar pCO2 =40
Oxygenated b. pCO2 =40
Atmospheric pCO2 = 0.3
Dalton’s Law?
Henry’s Law?
Factors that AID
alveolar gas exchange-explain each
¾ Relatively thin (.004mm) Respiratory Mbr.
¾ Partial pressure differential of respiratory
gases
¾ Maximum surface area for gas exchange
between alveoli & capillaries
¾ Capillary structure (SSE & close contact)
¾ Solubility of respiratory gases
¾ Good perfusion of lung tissue
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Factors that HINDER
alveolar gas exchange-explain each
¾ Increased altitude (hypoxia, altitude sickness, &
HAPE—why lasix?)
¾ Pulmonary disorders that decrease surface area
¾ Poor perfusion of lung tissue
¾ Insufficient surfactant
¾ Increased alveolar surface tension
¾ Atelectasis
¾ Poor ventilation
¾ Poor compliance
¾ Decreased minute volume of respiration
¾ Slow replacement of alveolar air-good or bad?
Transport of Respiratory Gases
¾ OXYGEN
¾ Dissolved in plasma (only 3%)
¾ Oxyhemoglobin (97%)
Hb + O2 Æ HBO2 vs. HbO2 Æ Hb +O2)
¾ CARBON DIOXIDE
¾ Dissolved in plasma (7%)
¾ Carbaminohemoglobin (23%)
Hb + CO2 Æ HbNHCOOH (HbCO2)
¾ Bicarbonate ions (70%)
CO2 + H2O (ca)Æ H2CO3 Æ H+ + HCO3-
Transport of Respiratory Gases
(know Fig. 23.19)
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Transport of Respiratory Gases Fig.23.19
OXYGEN
¾ Dissolved in plasma (3%)
¾ Oxyhemoglobin (97%
Hb + O2 Æ HBO2 vs.
HbO2 Æ Hb +O2
CARBON DIOXIDE
¾ Dissolved in plasma (7%)
¾ Carbaminohemoglobin (23%)
Hb + CO2 Æ HbCO2
¾ Bicarbonate ions (70%)
CO2 + H2O (ca)Æ H2CO3 Æ
H+ + HCO3-
Oxygen-hemoglobin Dissociation
Curve
¾ pO2 =most important
factor
¾ Hb saturation
¾ HbO2 saturation curve
o High pO2 (alveoli) =
O2 + Hb Æ HbO2
o Low pO2 (tissues) =
HbO2 Æ O2 + Hb
(O2 dissociates from Hb)
Hemoglobin and pH
¾ Acid environment-O2
splits off Hb
¾ Bohr Effect
¾ CO2 + H2O (ca)Æ
H2CO3 Æ H+ + HCO3¾ CO2 translates to H+
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Factors that move the curve to the right:
causes O2 to dissociate from Hb
(decreases Hb saturation by O2)
¾
¾
¾
¾
¾
¾
Decreased O2
Increased CO2
Increased H+
Decreased pH
Increased temperature
Increased BPG
CARBON MONOXIDE
POISONING
¾Hb has a great affinity for CO.
¾Hb does not split apart from CO
very easily.
¾pCO 0.5mHg (.1% concentration) will
combine with ½ of all Hb.
¾Hyperbaric Chamber?
¾Why Henry’s Law?
CARBON DIOXIDE TRANSPORT
1. Dissolved in plasma (7%)
2. Carbaminohemoglobin—HbCO2 (23%)
¾
¾
¾
pCO2 as influencing factor
Hb + CO2 Æ HbCO2 (at tissues)
HbCO2 Æ Hb + CO2 (alveoli)
3. Bicarbonate ions (70%)
¾
¾
¾
¾
¾
¾
¾
CO2 + H2O (ca)Æ H2CO3Æ H+ + HCO3H+ joins with Hb—buffers H+
HCO3- goes to plasma—buffers blood
Reaction moves in either direction
Kidney eliminates H+ or HCO3- where necessary
Lungs eliminate CO2
Chloride Shift
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CHLORIDE SHIFT
Tissues—Internal Respiration (Fig 23.24)
¾HCO3- leaves RBC & enters plasma
¾Cl- diffuse from plasma & enter RBC where they join with K+ to
form KCL
¾HCO3- in plasma join with Na+ to form NaHCO3
¾What happens to H+, Hb, and O2?
REVERSE CHLORIDE SHIFT
Lungs—External Respiration
¾O2 diffuses from alveoli into RBC & joins w/Hb, knocking off H+
¾H+ dissociates from Hb then H+ + HCO3- Æ H2CO3Æ (ca) ?
¾CO2 leaves the RBC & dissociates from Hb then diffuses to ?
¾Where does HCO3- come from? What happens to Cl-?
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