Respiratory Lecture notes 1 Flashcards
What is the Primary Function of Respiratory system?
Provide O2 for tissue metabolism and remove CO2
What are Secondary Functions of respiratory system?
- Sense of Smell
- Speech Production
- Fluid Balance
- Acid Base Balance
- Thermoregulation
Upper Respiratory Tract includes:
- Nose
- Sinuses
- Oral Cavity
- Pharynx
- Larynx
Lower Respiratory Tract Includes:
- Trachea
- Main stem Bronchi
- Bronchioles
- Alveoli
- Lungs
- Blood Supply to Lungs
- Chest Wall Structures
- Accessory Muscles of Respiration
What is the Main stem Bronchi anatomy?
Two main stem bronchi:
• Right slightly shorter, wider, and more vertical than left – aspiration more likely to occur in right bronchi
• Subdivides into lobar, segmental, sub segmental bronchi down to form the bronchioles
How do the Bronchioles work?
- Branch into smaller tubes – terminal and respiratory bronchioles
- Depend on elastic recoil to remain open
What do alvelor cells do?
• Provide structure
• Secrete Surfactant – reduces surface tension and contributes to the elastic properties of lungs. Prevents the alveoli from collapsing during expiration.
Alveoli
What is the function of Pulmonary Circulation?
•Provides lungs with blood for gas exchange
What is the function of Bronchial circlulation?
• Provides O2 to the bronchi and other pulmonary tissue
What is the function of Pleura?
Pleura join and form closed, double walled sac
Filled with thin film of 20 – 25 mL fluid – provides lubrication
What is the function of Diaphragm?
- Separates thoracic cavity from the abdomen
* Contracts on inspiration to push the abdominal contents down
What is the function of External Intercostals?
• Contract on inspiration = ↑ size of thoracic cavity
Ventilation is controlled by:
Central Nervous System
- The RR is the ventilation rate
What happens with inspiration?
- Active process requiring energy
- Diaphragm contracts
- Intercostal muscles contract
- Scalene muscles contract
What is the function of the Scalene muscles?
- Muscle movements increase volume of the thoracic cavity
* Decreases intrathoracic pressure
What happens with expiration?
- Passive process
- Intrathoracic pressure increases causing air to move out of the lungs
- Elastic recoil of lungs and chest wall enable the chest to passively return to its normal position
- During labored respirations scalene muscles and sternocleidomastoid muscles assist with expiration
What is elastic recoil?
∗ Tendency for lungs to recoil after being stretched
• Elasticity due to elastin fibers in alveolar walls and muscles around the bronchioles and capillaries
What is compliance?
∗ Measure of the elasticity of the lungs (ease at which the lungs can expand) and thorax
What happens when compliance ↓ ?
(2° fluid, or condition that effects chest wall compliance) lungs are more difficult to inflate
What happens when compliance ↑ ?
(destruction of alveolar walls and loss of tissue elasticity) lungs are more easily inflated
What happens to compliance of lungs with age?
• With age compliance of lungs ↑ as a result of aging (2° loss elastin) and chest wall compliance ↓
What is diffusion?
Process by which O2 and CO2 move across alveolar-capillary membrane from an area of higher concentration to an area of lower concentration until equilibrium achieved
How is oxygen carried in the blood?
- O2 dissolved in arterial blood (PaO2) expressed mm Hg (normal value > 80 mm Hg)
- O2 bound to hemoglobin (SaO2/ SpO2) – measurement is compared with the amount of O2 the hemoglobin can carry. It is expressed as a percentage (normal value > 95%)
- Oxyhemoglobin Association and Dissociation
What is the Oxyhemoglobin Dissociation Curve?
∗ The curve illustrates the relationship between the partial pressure of O2 dissolved in the plasma (PaO2) and the O2 saturation (SaO2) of hemoglobin, Is useful in guiding the amount of supplemental O2 given to patients
