Cardiovascular System Flashcards
What is the anatomy of the respritatory system
- breath air through our nose and mouth/trachea/bronchi/broncioles=alveoli
Airway resistance
- as you go through system the diameter gets smaller and therefore the resistance of airflow increases as it’s harder for air to flow through the system the system overcomes this as the total cross sectional area of the branching increases the overall resistance is decreased.
Quiet inspiration
-increased thorax volume
-diaphragm flattens
-external intercostal muscles contracts
-increased elastic recoil
Quiet expiration
-passive process
-external intercostal muscles relax
-decrease pressure in thoracic cavity
Forced inspiration
- same as quiet but additional muscles used
Contraction of the accessory muscles of breathing
Scalenes – lift the upper ribs
Sternocleidomastoid – elevate the sternum Pectoralis major and minor
Serratus anterior
Latissimus dorsi
Which work to lift up ribs
Forced expiration
Forced Expiration
Contraction of thoracic and abdominal muscles and Internal intercostal muscles
Pulmonary compliance
a measure of the lungs ability to stretch and expand.
Compliance (mL/mmHg) = Volume (mL) /Pressure
(mmHg)
What is pulmonary compliance influenced by
The elasticity of the lungs:
-Due to the presence of elastin and collagen in the connective tissue in the lungs
-by age (gradual loss of elastic tissue with age increases compliance) Impacted by disease
-surface tension :Decreased by the production of surfactant
Mechanisms of breathing
-the lung walls are like a ballon in the when air is let out the rest goes with it so have a tendency to recoil inwards
-the chest walls a tennis ball when air is let out it reforms back to its shape so has a tendency to recoil Outwards
-when the chest moves the lungs go with it
Transpulmonary pressure
- the pressure inside relative to outside of a compartment (the lungs).
-required to inflate the lungs
-Contraction of inspiratory muscles expands the chest wall and increases transpulmonary pressure.
Intrapleural pressure (space between the chest wall and lungs) alveoli pressure before expiration
-intrapleural pressure is negative usually -5
-alveolar pressure is zero which equals atmospheric pressure of zero
Intrapleural pressure and a alveolar pressure during inspiration
-the chest wall expands, putting greater stretch on the lungs and Ppl becomes more negative usually from -5 to -8
- alveoli pressure becomes negative allowing us to pull in air from the atmosphere. Usually from 0 to -1
Surface tension and surfactant in the alveoli
-The walls of the alveoli are lined by a thin film of water.
-This creates a force called surface tension which tends to collapse the alveoli.
- surfactant is naturally produced and costs the alveoli reducing surface tension to prevent the lungs collapsing
Inspiratory reserve volume (IVR)
The additional volume of air that can be inspired at the end of a normal or tidal inspiration
Expiratory reserve volume (ERV)
-The additional volume of air that can be expired at the end of a normal or tidal inspiration
Tidal volume (TV)
-the amount of air breathed in and out during normal,restful breathing
Residual volume (RV)
-the volume remaining in the lung after a maximum expiration
Vital capacity (VC)
-The largest volume of air that can be expired from a maximal inspiration.
VC = ERV + TV + IRV