Module 10 - Respiration Flashcards
Lung Location
- In thoracic cavity
- Surrounded by rib cage & diaphragm
Airway Components
- Nasal cavity & mouth
- Pharynx
- Larynx (voice box)
- Trachea
Trachea Anatomy
- Divides into left & right bronchi
- Divide into smaller bronchioles
- Divide into alveoli
Alveoli Wall Composition
- Type I & type II cells
Type I Alveoli Cells
- Flat alveolar epithelial cells
Type II Alveoli Cells
- Secrete surfactant
- Line alveoli
Capillary Composition
- Vascularized tissues
- Thin endothelial wall
- Large cross-sectional area
- Low blood velocity
Capillary Function
- Diffuses O2 into blood & CO2 out
Respiratory Membrane
- Region between alveolar spaces & capillary lumen
- 0.3 microns thick
Respiratory Membrane Function
- Allows gas exchange between air & blood
- Immune cells for protection against airborne particles
Respiratory Immune Cell Types
- Macrophages
- Lymphocytes
Parietal Pleural Membrane
- Lines & sticks to ribs
Visceral Pleura Membrane
- Surrounds & sticks to lungs
Intrapleural Space Composition
- Formed by two membrane layers
- Small amount of pleural fluid
Pleural Fluid Function
- Reduce friction
- Between pleural membranes during breathing
Lung Movement during Respiration
- Recoil & collapse
- Due to elastin
Pressure Levels Between Breaths
- Alveolar & atmospheric high
- Intrapleural low
Cause of Lower Intrapleural Pressure
- Chest wall & lungs moving in opposite directions
Transpulmonary Pressure
- Difference between alveolar & intrapleural pressures
Transpulmonary Pressure Equation
TP = Alveolar pressure - Intrapleural pressure
Transpulmonary Pressure Importance
- Hold lungs open
Pneumothorax
- No pressure holding lungs open
- Causing collapse
- Puncture of intrapleural space
- Alveolar & intrapleural pressure become equal
Boyle’s Law Definition
- Volume decrease causes pressure increase
- Pressure inversely proportional to volume
Boyle’s Law Equation
Pressure ∝1/Volume
Pressures of Air Moving into Lungs
- High atmospheric pressure
- Low alveolar pressure
Pressures of Air Moving out of Lungs
- High alveolar pressure
- Low atmospheric pressure
Muscles of Inspiration
- Diaphragm moves downwards (contracts)
- External intercostal muscles of rib contract
Pressure Change of Inspiration
- Alveolar pressure drops
- Atmospheric pressure remains same
Inspiration Contraction Process
- Active process
- Relies on signals from respiratory center (brainstem)
- Inhibits expiratory muscles & centre
Muscles of Expiration
- Diaphragm moves upwards (relaxes)
- External intercostal muscles of rib relax
Pressure Change of Expiration
- Alveolar pressure increases
- Atmospheric pressure remains same
Expiration during Exercise
- Air forced out of lungs
- Contracts abdominal & internal rib intercostal muscles
- Creates larger pressure gradient
- Alveolar pressure increase
Compliance
- Stretchability of lungs
- More stretch = more compliance
Pulmonary Compliance
- Volume change from pressure change
- Determines ease of breathing
Compliance Equation
= Volume change/pressure change
Factors of Compliance
- Amount of elastic tissue in wall of alveoli, vessels, bronchi
- Surface tension of liquid film lining alveoli
Elastic Tissue
- Present in walls of alveoli, blood vessels, bronchioles
- Arranged to easily stretch elastin fibers, not collagen
- More elastin = less compliance
Surface Tension
- Force developed at liquid surface
- Caused by attractive forces between H2O molecules
- Water molecule tension is inward
Pulmonary Compliance Surface Tension
- Thin liquid film lining alveoli surface tension
- Collapse alveoli
- Decreasing compliance
- Difficult to inflate lungs
Pulmonary Surfactant
- Lipoprotein substances
- Produced by type II alveolar cells
Lipoprotein Composition
- Phospholipids
Lung Volume Types
- Tidal volume
- Residual volume
- Inspiratory reserve volume
- Expiratory reserve volume
Tidal Volume
- Air volume entering/leaving lungs
- During 1 breath at rest
Residual Volume
- Remaining air in lungs
- After max exhalation
Inspiratory Reserve Volume
- Maximum air to enter lungs
- In addition to tidal volume
Expiratory Reserve Volume
- Maximum air exhaled
- Beyond tidal volume
Lung Capacity Types
- Inspiratory capacity
- Functional residual capacity
- Vital capacity
- Total lung capacity
Lung Capacity Definition
- 2+ lung volumes
Inspiratory Capacity
- Max amount of air inhaled
- After exhaling tidal volume
- Tidal volume + inspiratory reserve volume
Vital Capacity
- Maximal amount of air exhaled
- After maximal inhalation
- Inspiratory reserve + tidal volume + expiratory reserve
Total Lung Capacity
- Maximum air lungs can hold
- Vital capacity + residual volume
Respiratory Zone Composition
- Alveoli
- No cartilage/cilia
Conducting Zones/Anatomical Dead Space Composition
- Cartilage in airways
- Cilia on bronchial epithelium
Conducting Zones/Anatomical Dead Space Function
- Conduct air
- Microbial defence
- NO gas exchange
Respiratory Zone Function
- Gas exchange
- Microbial defence
Pulmonary Ventilation (VE)
- Air entering all conducting & respiratory zones
- In 1 MIN
- 7500mL/min at rest
Pulmonary Ventilation Equation
Tidal volume(mL) x respiratory rate (breaths/min)
*mL/min
Alveolar Ventilation (VA)
- Air entering respiratory zones
- Each minute
- Volume of fresh air available for gas exchange
- Take anatomical dead space into account
Alveolar Ventilation (VA) Calculation
Pulmonary ventilation (VE) - Dead space ventilation (VD)
Dead Space Ventilation (VD)
- Equal to persons body weight in pounds
High O2 Parietal Pressure
- Alveolar (Highest)
- Systemic Artery
- Pulmonary Vein
High CO2 Parietal Pressure
- Pulmonary Artery
- Systemic Vein
- Tissue
Partial Pressure Movement
- O2 & CO2 move from high-low partial pressure areas
- Down partial pressure gradients
Oxygen Movement
- From alveolar space (105mmHg)
- To bloodstream (40mmHg)
Carbon Dioxide Movement
- From blood (46mmHg)
- To alveolar space (40mmHg)
Hemoglobin O2 Transport
- Transports majority of O2
- Each hemoglobin molecule carries 4 O2 molecules
Plasma O2 Transport
- Transports very low amount
- Can’t supply enough O2 to meet body needs
Erythropoiesis
- RBC production
- Within bone marrow
Erythropoiesis Requirements
- Amino acids
- Iron
- Folic acid
- Vitamin B12
Amino Acids & Iron Function
- Components of hemoglobin
Folic Acid & Vitamin B12 Function
- Formation of DNA
- Cell division
RBC Life Span
- 120 days
- Destroyed by liver & spleen
Erythropoietin (EPO) Hormone
- Erythrocyte production
- Ensure RBC production equals RBC loss
Erythropoietin (EPO) Hormone Secretion
- 90% kidneys
- 10% liver
Testosterone Effects on RBC
- Increase EPO Secretion
- Larger amount of RBC in males than females
Immature RBC’s
- Contain nucleus
- Direct production of hemoglobin
Mature RBC’s
- No nucleus
- Circulating in blood
- No more hemoglobin produced
High PO2 Levels
- In lungs
- O2 binds to Hb
- Forming HbO2
Low PO2 Levels
- In tissue
- O2 unloads from Hb
HbO2 Dissociation Factors
- Temperature
- Acidity (pH)
PO2 at Rest
- 50% of Hb saturated
PO2 During Exercise
- Body warms up & pH decreases (acidity increase)
- 5% saturation of Hb
- Unloading of O2 from Hb
CO2 Transport Mechanisms
- Dissolved & carried in plasma (PCO2)
- Carried as bicarbonate ion (HCO3)
- Attached to proteins in blood forming carbamino compounds
CO2 Dissolved in Plasma
- 20x more soluble than O2
- Dissolves easy
- 7-10% of CO2 transport
CO2 as Bicarbonate Ion
- 70% of CO2 transport
- CO2 reacts with H20 to produce carbonic acid (H2CO3)
- H2CO3 dissociates in bicarbonate (HCO3) & H+
CO2 as Carbamino Compound
- 20-23% of CO2 transport
- Hb unloads O2 picks up CO2
- Forms HbCO2
- Returns to lungs
- Diffuses into alveolar space
CO2 Chloride Shift
- CO2 converted to HCO3-
- HCO3- diffuses out of RBC into plasma
- HCO3- leaving cell = more negative
- Cl- diffuses in to balance charge
High PCO2 Levels
- In tissue
- Loading hemoglobin with CO2
- Form bicarbonate ion (HCO3-)
Low PCO2 Levels
- At lungs
- CO2 unloads from Hb
- HCO3- coverts back to CO2
- CO2 diffuses out of RBC into alveoli
Spontaneous Respiration
- Originates in medullary respiratory center
- Produced by rhythmic activity from neurons
Voluntary Respiration
- Located in cerebral cortex
- Can override medullary respiratory center
Quiet Exhalation
- Passive process
- Relaxation of inspiratory muscles
- Elastic properties & muscle recoiling
Forceful Exhalation
- During exercise
- Contraction of abdominal muscles
- Contraction of internal intercostal muscles of ribs
Pneumotaxic Center
- Regulates rate of breathing
Apneustic Center
- Controls depth of breathing
Role of Pons in Respiration
- Modify spontaneous signals from medulla centre
- Ensures proper gas concentrations in blood
Voluntary Respiration Center
- Originates in cerebral cortex
- Modify ventilation
- Modify signals in apneustic or pneumotaxic center
Chemeoreceptors
- Special receptors to detect ion concentrations in blood
- O2, CO2, H+
Peripheral Chemoreceptors
- Located in aortic arch & carotid sinus
- Cardiovascular system
Central Chemoreceptors
- Located in medulla of brainstem
- Close to respiratory center
Peripheral Chemoreceptor Characteristics
- Primarily sensitive to O2
- Slightly sensitive to CO2
- Detect levels & send signals to respiratory center
- Increase ventilation
- Restoration of PO2 & PCO2
Central Chemoreceptor Characteristics
- Sensitive to H+ levels in interstitial space of brain
- Diffuse interstitial space crossing blood brain barrier
- Detect levels & signal to respiratory center
- Increase ventilation
- Restore normal blood gas concentrations
Respiration Negative Feedback System
- Set point (proper gas concentration)
- Control center (brain)
- Sensors (chemoreceptors detect gas levels)
- Effector (muscles of respiration)
- Controlled variable (ventilation of lungs)
