Respiratory System pt. II Flashcards
Barometric pressure (Bp)
Pressure of air outside the body
Alveolar pressure (P sub A)
Air in alveoli that exerts pressure
Intrapleural Pressure (P sub IP)
Pressure in the pleural cavity between visceral and parietal pleura
Why does air move?
There is a pressure gradient. For air to go in, barometric pressure has to be greater than alveolar pressure. For air to go out, alveolar pressure is higher than barometric pressure.
What do you do to decrease alveolar pressure?
Lower diaphragm to increase thoracic cavity volume to make alveolar pressure drop. Alveoli is in thoracic cavity and their pressure will also drop.
How do you increase alveolar pressure?
Diaphragm needs to go up to decrease the size of the thoracic cavity and it will increase the alveolar pressure.
What is the start of breathing?
The diaphragm contracts (moves down)
What muscles help lift your rib cage when breathing?
Pectoralis minor muscles, scalene muscles sternocleidomastoid muscle, serratus anterior muscles
What is elastic recoil?
Allows the lungs to return to its resting size
What muscles are used for exhalation forcefully?
Internal innercoastal muscles pull ribs down and back.
Abdominal muscles
For a lung to work, what needs to happen?
Intrapleural pressure must be less than alveolar pressure
How does elastic recoil affect alveoli?
When alveoli pressure is more than barometric pressure, the elasticity in alveoli helps push the air out
What happens when someone has emphysema?
They lose elasticity in their alveoli, they work to breathe in
Anything that decreases the elastic recoil, will…
Make it harder work to breathe out even at rest
What are the pulmonary volumes
Tidal Volume (TV), Expiratory Reserve Volume(ERV), Inspiratory Reserve Volume(IRV), Residual Volume(RV)
What is Tidal Volume?
The normal volume of air expired after a normal inspiration.
Normal healthy adult volume: 500 ml
What is Expiratory Reserve Volume (ERV)?
The amount of air that you can expire after expiring a normal tidal volume
Normal adult ~ 1.0-1.2 L
What is Inspiratory Reserve Volume (IRV)?
The amount of air you can breathe in after inspiration of a volume equivalent to a tidal volume
Normal adult~3.3L
Why is IRV more than ERV?
It gives more ability to bring in more air
What is Residual Volume (RV)?
Amount of air trapped in alveoli
Normal adult ~1.2 L
Vital Capacity (VC)
Largest volume of air that can be moved in and out of the lungs.
VC = RV + ERV+ TV+ IRV
OR
VC = total lung capacity - RV
What is the difference between vital capacity and residual volume?
Vital capacity is air that you can move but residual volume is air that you can’t move.
What can affect your vital capacity?
The size of the thoracic cavity
Posture can change bc changing body position can change how much volume of thoracic cavity can change
Blood volume- more blood, less room for air
Excessive fluid in pleural or abdominal cavities (can compress the lungs)
Emphysema - loss of elastic recoil allows air to be trapped in the lungs ; increase in RV, decreases vital capacity
What is Inspiratory capacity? (IC)
The volume of air you can breathe in after a normal expiration.
Normal adult: 3.5-3.8L
IRV+TV
Functional Residual Capacity (FRC)
Volume of air that is in your lungs after a normal expiration
Normal is 2.2-2.4 L
Alveolar Ventilation
Is a volume of air that gets to gas exchange surfaces in the lungs
Anatomical dead space
The volume of air that is not involved in gas exchange and SHOULDN’T be.
Is normal
Physiological dead space
Abnormal; the volume of air that is not involved in gas exchange but SHOULD be
Types of breathing
Eupnea, Hyperpnea, Hyperventilation, Hypoventilation, Dyspnea, Orthopnea, Apnea, Apneusis, Respiratory Failure
Eupnea
Normal quiet breathing
12-20 resp/min
Hyperpnea
Increased in respiration because of increase in oxygen rate
Ex: exercise
Hyperventilation
Increase in breathing without an increase in oxygen demand; voluntary
Hypoventilation
Decrease pulmonary ventilation resulting in elevated blood CO2.
Dsypnea
Difficult breathing and person is aware of it
Orthopnea
Dyspnea when lying down, relieved sitting or standing ;fluid in lungs
Apnea
Temporary cessation of breathing after a normal expiration
Ex: swallowing, sleep apnea (abnormal)
Apneusis
Temporary cessation of breathing after a normal inspiration
Respiratory Failure
Stopping to breathe permanently.
