Respiratory Physiology Lecture Powerpoint Flashcards
Respiratory system functions (5)
- Gas exchange
- Regulation of pH
- voice production
- olfaction (smell and taste)
- protective against infection
Conducting zone vs respiratory zone of the respiratory system
Conducting is down to terminal bronchioles, respiratory zone begins at respiratory bronchioles, and extends to alveolar ducts and alveoli
2 major functions of the conducting zone of the respiratory system
- warms and moistens air
- removal of microbes and toxins thru macrophages and mucociliary escalator
Respiratory membrane and its 4 layers
- The thickness that the gas has to move thru to be exchanged between the vasculature and the alveoli
- cell membrane of RBC, interstitial space, alveolar membrane, and fluid/content within the alveoli
Pleural membranes and their 2 functions
- Visceral and parietal adherant double layered serosa filled in potential space cavity with lubricating fluid
- functions to reduce friction when breathing, creates a slightly negative pressure gradient to promote inflation of the lungs
Stages of respiration (5)
1) ventilation - movement of air into and out of lungs
2) external respiration - gas exchange between air in lungs and blood
3) respiratory gas transport - movement of o2 and co2 throughout circulation
4) internal respiration - gas exchange between blood and tissues in the body
5) cellular respiration - usage of o2 and production of co2 from cells
Boyle’s law
States pressure of any given quantity of gas is inversely proportional to its volume assuming constant temperature
Dalton’s law
Total pressure of gas mixture is equal to the sum of its partial pressures of individual gases
Henry’s law
At the air water interface, the amount of gas dissolves in water is determined by its solubility in water (coefficient, property of the chemical) and its partial pressure in the air assuming constant temp
Atmospheric pressure value at sea level
1atm or 760mmHg
Air enters lungs when…
Air exits lungs when….
…alveolar pressure is less than atmospheric
….alveolar pressure is greater than atmospheric
Poiseuille’s law and importance
- States R=8n(viscosity)*l/pi r^4
- Small changes in the diameter of the bronchioles greatly impacts resistance of airflow
Pulmonary compliance, what dz states decrease and increase it?
- Refers to distensibility of lungs, change in lung volume relative to given change in transpulmonary pressure
- decreased with disease states such as pulmonary fibrosis and increased in diseases such as emphysema or copd (harder to get air out of lungs)
Triggers of bronchoconstriction (4)
- airborne irritants
- cold air
- paraysmpathetic stimulation
- histamine
Triggers of bronchodilation (2)
Sympathetic nerves, epi (or a b-2 agonist such as albuterol)
Most common causes of increased airway resistance (3)
- swelling (laryngedema)
- obstruction (mucus plugging)
- spasm of smooth muscle (asthma attack)
Muscles involved in inspiration and how do they move? (3)
- diaphragm (flattens and increases superior inferior aspect of chest cavity)
- external intercostals (elevate ribs moving the thoracic cavity up and out)
- pec minors, sternocleidomastoid, erector spinae muscles (accessory use for deep inspiration only)
Intrapleural pressure at rest vs during inspiration
Intrapleural pressure becomes even more neg (decreases***) going from -756mmHg at rest (creating the adherence of the pleura to each other) to -754mmHg on inspiration
Intrapulmonary (intraalveolar) pressure at rest vs. during inspiration
Pressure drops from resting value of 760mmHg to 757mmHg (subatmospheric)
Transpulmonary pressure at rest vs during inspiration
Rises from resting value of 0mmHg to 3-4mmHg due to gradient difference between atmosphere and intrapulmonary pressure, causes airflow inward
Passive expiration and what does it do to intrapulmonary pressure, intrapleural pressure, and transpulmonary pressure?
Refers to how during quiet breathing expiration is achieved by the elasticity of the lungs and thoracic cage creating a intrapulmonary pressure of approx 763mmHg, intrapleural pressure increase back to 756mmHg, and transpulmonary pressure to reverse to begin flow outward
Forced expiration
Use of internal intercostal muscles that lie underneath external intercostal muscles and function to contract rib cage down and inward decreasing size of thoracic cavity, alongside abdominal muscles contracting increasing intra-abdominal pressure forcing diaphragm upward and increasing pressure on thoracic cavity to improve force of expiration
Pneumothorax
Loss of negative intrapleural pressure due to air in pleural cavity causing lungs to recoil and collapse (atelectasis)
Elasticity of lungs
Ability of lungs to return to normal shape after being distended, function of elastin protein content within lungs