Pressure changes during inspirations and expirations Flashcards
Pleurae
The pleural cavity is extremely ………, slit-like space between the pleurae, separating them by thin layer of pl….. f……..
Pleurae
The pleural cavity is extremely thin, slit-like space between the pleurae, separating them by ;la thin layer of pleural fluid.
Pleural cavity contains fl……. that allows lung to glide easily over tho……… wall. Slide but not ……… away from p……….
Pleural cavity contains fluid that allows lung to glide easily over thoracic wall. Slide but not pull away from pleura
Intrapulmonary Pressures
Also called intra-alveolar pressure and is the pressure in the lungs itself.
Inspiration:
Lung volume incr…….. and so pressure drops to about 1mm below atmospheric.
Air enters and pressure decreases to atmospheric.
Expiration:
Lung volume decr…….. and pressure rises to …mm above atm…………… pressure.
Air leaves until pressure in lungs e…………. atmospheric.
Also called intra-alveolar pressure and is the pressure in the lungs itself.
Inspiration:
Lung volume increases and so pressure drops to about 1mm below atmospheric.
Air enters and pressure decreases to atmospheric.
Expiration:
Lung volume decreases and pressure rises to 1mm above atmospheric pressure.
Air leaves until pressure in lungs equals atmospheric.
Intrapleural Pressure
This is the pressure inside the pleural cavity and is always ……-atmospheric, i.e. n……… compared to atmo…. pressure
This n………. pressure acts like a su…….. to keep the lungs in…………
The negative intra-pleural pressure is due to 3 factors within the lungs and chest wall :
Surface t………. of a……….. fluid
El…………. of the lu…….., and
El……….. of the tho……….. wall
Intrapleural Pressure
This is the pressure inside the pleural cavity and is always sub-atmospheric, i.e. negative compared to atmospheric pressure
This negative pressure acts like a suction to keep the lungs inflated
The negative intra-pleural pressure is due to 3 factors within the lungs and chest wall :
Surface tension of alveolar fluid
Elasticity of the lungs, and
Elasticity of the thoracic wall
Intrapleural Pressures during respiration
Always sub-atmospheric (…… m….. H…….)
As diaphragm con………. intr….-pl………. pressure decreases even more (………. mm Hg)
Helps keep pari…… & visc…….. pleura stick together
Always sub-atmospheric (756 mm Hg)
As diaphragm contracts intra-pleural pressure decreases even more (754 mm Hg)
Helps keep parietal & visceral pleura stick together
Intrapleural Pressures - Surface Tension
Intrapleural Pressure
Intrapleural pressure is the pressure within the pleural ……., Intrapleural pressure is always ……….., which acts like a …………. to keep the lungs …………….
The surface tension of the alveolar fluid tends to pull each of the alveoli inward and therefore ………. the entire lung inward. Surfactant ……….. this force.
Intrapleural Pressures - Surface Tension
Intrapleural Pressure
Intrapleural pressure is the pressure within the pleural cavity, Intrapleural pressure is always negative, which acts like a suction to keep the lungs inflated
The surface tension of the alveolar fluid tends to pull each of the alveoli inward and therefore pulls the entire lung inward. Surfactant reduces this force.
Intrapleural Pressures - elastic tissue of lungs
Intrapleural pressure
Intrapleural pressure is the pressure within the pleural cavity. Intrapleural pressure is always negative, which acts like a suction to keep the lungs inflated
The abundant elastic tissue in the lungs tends to r……… and p…….the lun.. in………… As the lung moves always from the th…….. wall, the cavity becomes slightly lar….., decreasing pre……….
the negative pres……… acts like suction to keep the lungs inflated
Intrapleural Pressures - elastic tissue of lungs
Intrapleural pressure
Intrapleural pressure is the pressure within the pleural cavity. Intrapleural pressure is always negative, which acts like a suction to keep the lungs inflated
The abundant elastic tissue in the lungs tends to recoil and pull the lung inward. As the lung moves always from the thoracic wall, the cavity becomes slightly larger, decreasing pressure.
the negative pressure acts like suction to keep the lungs inflated
Intrapleural Pressures – thoracic wall
The e………. tho……….. wall tends to pull away from the lung, further enlarging the pl……. cavity and creating this ne………… pressure. The surface tension of pleural fluid res……… the actual se……….. of the l………… and thor……… wall.
Intrapleural Pressures – thoracic wall
The elastic thoracic wall tends to pull away from the lung, further enlarging the pleural cavity and creating this negative pressure. The surface tension of pleural fluid resists the actual separation of the lung and thoracic wall.
Transpulmonary Pressure
This is the pressure difference between the intra-pul……… pressure and the intra p……… pressure
This pressure has a ………. effect on the way in which inspira……… and expir……….. occurs
Transpulmonary Pressure
This is the pressure difference between the intra-pulmonary pressure and the intra pleural pressure
This pressure has a direct effect on the way in which inspiration and expiration occurs
Inspiration & Transpulmonary pressure
During inspiration
1) Diaphragm and ext………. intercostal muscles contract
2) Volume of thor………. cavity increases
3) Intra……… pressure becomes more ne………….
4) Lungs …………….
5) Intrapulmonary pressure becomes n…………..
6) Air flows into the lungs
Inspiration & Transpulmonary pressure
Inspiration & Transpulmonary pressure
During inspiration
1) Diaphragm and external intercostal muscles contract
2) Volume of thoracic. cavity increases
3) Intrapleural pressure becomes more negative
4) Lungs expand
5) Intrapulmonary pressure becomes negative
6) Air flows into the lung
Expiration & Transpulmonary pressure
During expiration
1) diaphragm and external intercostal muscles r……..
2) Volume of th…………… cavity d………………
3) Intrapleural pressure becomes less ne…………..
4) lungs recoil
5) Intra……………. pressures rises above atmospheric pressure
6) Air flows ……. of the lungs
1) diaphragm and external intercostal muscles relax
2) Volume of thoracic cavity decreases
3) Intrapleural pressure becomes less negative
4) lungs recoil
5) Intrapulmonary pressures rises above atmospheric pressure
6) Air flows out of the lungs
Respiratory Measurements
Forced Vital Capacity (FVC)
Amount of gas expelled when a subject takes a ………….. breath and then for…….. exhales maxi……… and as rap……… as possible
Forced Expiratory Volume (FEV)
The amount of air expelled during a specific ……… interval of the FVC Test. Typically this is taken over the first …………. and called the FEV1
The FEV1 / FVC ratio is typically 80% in normal individuals
These measurements can be made with a Vit……
Respiratory Measurements
Forced Vital Capacity (FVC)
Amount of gas expelled when a subject takes a maximal breath and then forcefully exhales maximally and as rapidly as possible
Forced Expiratory Volume (FEV)
The amount of air expelled during a specific time interval of the FVC Test. Typically this is taken over the first second and called the FEV1
The FEV1 / FVC ratio is typically 80% in normal individuals
These measurements can be made with a Vitalograph
Chronic Obstructive Pulmonary Disease
Characterised by an in…….. in Airway R………..
Asthma - there is an intermittent attack in which airway sm……… muscle co…….., increasing airway resistance enough to impair ventil……… May also involve an increased viscous muco….. production and formation of mucous ………… Basic defect is inflammation of the airways, causes varies from person to person and include among others, allergy and virus infection.
Emphysema - there is a des………… of the alv………. walls and an enlarg………. of alveolar air spaces and lo….. of pulmo……… capillaries. Small airways from the term……… bron……… downward - are reduced in num…. and have atr……… walls. Because there is a loss of el……… tissue there is a coll………..of the airways.
Chronic Obstructive Pulmonary Disease
Characterised by an increase in Airway Resistance
Asthma - there is an intermittent attack in which airway smooth muscle contracts, increasing airway resistance enough to impair ventilation. May also involve an increased viscous mucous production and formation of mucous plugs. Basic defect is inflammation of the airways, causes varies from person to person and include among others, allergy and virus infection.
Emphysema - there is a destruction of the alveolar walls and an enlargement of alveolar air spaces and loss of pulmonary capillaries. Small airways from the terminal bronchioles downward - are reduced in number and have atrophied walls. Because there is a loss of elastic tissue there is a collapse of the airways.
Chronic Obstructive Pulmonary Disease
Bronchitis - there is an ex…………. m……….. production in the br………. and chronic inflammatory changes in the ……….. airways. An obstruction due to accumulation of m……….. and a thickening of the inflamed airways increases airway resistance
Typically these persons have FEV1 which is less than 80% because it is difficult for them to ex………… air rapidly enough through the narrowed airways. FVC is usually ………….
Chronic Obstructive Pulmonary Disease
Bronchitis - there is an excessive mucous production in the bronchi and chronic inflammatory changes in the small airways. An obstruction due to accumulation of mucous and a thickening of the inflamed airways increases airway resistance
Typically these persons have FEV1 which is less than 80% because it is difficult for them to expire air rapidly enough through the narrowed airways. FVC is usually normal.
Restrictive Lung disease
Here the Airway Resistance is normal but there are im……….. respiratory movements because of abnormalities in the lung tissue, the pleu.., the chest w………, or the neuromuscular machinery e.g. tuberculosis and fibr………….
Characterised by a reduced Forced Vital capacity (FVC) but a normal FEV1/FVC ratio
Restrictive Lung disease
Here the Airway Resistance is normal but there are impaired respiratory movements because of abnormalities in the lung tissue, the pleura, the chest wall, or the neuromuscular machinery e.g. tuberculosis and fibrocytis
Characterised by a reduced Forced Vital capacity (FVC) but a normal FEV1/FVC ratio
