W4 flashcards
thorax, ribcage, muscles,
thorax
= The area of the body between the neck and the abdomen
- consists of the 12 thoracic vertebrae
- Respiration requires muscular effort
respiration - mechanism
1) The thoracic rib cage acts as a mechanical pump for the lungs
2) The lungs must stick to the walls of the thoracic activity
3) Muscles acting on the ribs and bony thorax drive the pump
parietal pleura - breathing
- covers lungs + lines interior wall of the chest cavity
allows lungs to slide along easily - therefore, assists expansion & contraction of lungs to breathe
conchae - sinuses
covered by mucus membrane
increase SA:V so they can provide a humidifying air that passes through before it enters the lungs
thorax - breathing
inspiration = the diaphragm contracts & pulls downward
the muscles between the ribs also contract & pull upward
This increases the size of the thoracic cavity and decreases the pressure inside.
therefore = air moves in and fills the lungs
boyles law
outlines that if an amount of gas has a certain temperature, increasing its volume = a decrease in pressure
boyles law - breathing
inspiration = size of thoracic cavity increases when the lungs expand
this increases the volume
causing pressure in lungs to decrease - due to air coming in
pleural membranes & fluid support lung movement
PM & PF form seal in inner thoracic wall
seal allows thoracic cavity to change size, shape, volume
expiration process
volume of thoracic activity decreases
pressure within lungs increases
diagphram = returns to resting position
external intercostal muscles
= relax & reduce thoracic cavity
tidal volume
amount of air that moves in or out of the lungs within each respiratory cycle
inspiration process
volume of thoracic activity increases
pressure within lungs decreases
diagphram flattens = contracts
external intercostal muscles = elevate ribs & sternum (air in)
inspiratory reserve volume
amount of air forcibly inhaled after normal tidal volume (deep breathing)
expiratory reserve volume
extra air above the normal volume that can be forcefully exhaled out (exercise)
tidal capacity
total useable volume of the lungs that you can control
quiet breathing
breathing during rest, where the diaphragm & external intercostal muscles relax
decreases chest volume
increases pressure in lungs
forced breathing
internal intercostal muscles working to decrease size of thoracic cavity, to allow the ribcage to push all the air out
exercise & speaking
muscles - quiet breathing
- diaphragm
- external intercostals
muscles - forced breathing
diaphragm & intercostal muscles = contract
scalenes = contract & lift thoracic wall - increasing lung V
internal/external obliques = contract - forcing abs upwards against diaphragm (moves air out)
Breathing apparatus sub division
Pulmonary apparatus = lungs & airways
Chest wall = rib cage wall, abdominal wall, diaphragm & abdominal content
Pulmonary = chest wall unit
rib cage function
elevate and depress to support breathing
rib cage structure
ribs (1-10)
Directly (1-7)
Indirectly (8-10)
Coastal cartilage
helps to prolong the ribs forward & contribute to the elasticity of the walls of the thorax
sternum
a long flat bone located in the central part of the chest that protects the thoracic organs from trauma
clavicles
S-shaped bone that rests horizontally at the sternum across the upper part of the ribcage
Coastovertebral joints
allows for the Elevation and Depression of the ribs occurs at the costovertebral joints
True ribs
1-7 attach to the sternum and elevate the ribs by moving in a superior and anterior motion
ribs - labelled
articulator facets
head
neck
costal angle
shaft
costal groove
site of articulation (with costal cartilage)
false ribs
8-10 don’t attach directly to the sternum and move in a bucket handle motion to increase or decrease the thoracic cavity during respiration
floating ribs
(11-12) attach to the thoracic spine and protect our vital organs
muscles of the thorax
- Thoracic Diaphragm
- Intercostal muscles (External & Internal)
~ Accessory inspiratory muscles
~ Accessory expiratory muscles
Thoracic Diaphragm
the primary muscle of inspiration that is domed shape, allowing it to contract and flatten
EXTERNAL Intercostal muscles
allow for INSPIRATION to occur by contracting the ribs upwards, creating space in the thoracic cavity and expanding the lungs for air to enter
INTERNAL Intercostal muscles
allow for EXPIRATION to occur by contracting and compressing the thoracic cavity, decreasing its size and volume to expel air out
Accessory inspiratory muscles
provide assistance to the main breathing muscles when additional power is needed
Elevate top & anterior rib cage
lift the 3rd, 4th, 5th ribs to increase space for air in the lungs
Accessory expiratory muscles purpose
activated when we experience high respiratory load (coughing) or low inspiratory muscle capacity
Thoracic volume can be quickly decreased by large abdominal muscles
pulls down lower ribs = causing expiration
muscles of the thorax - forced inspiration
Thoracic Diaphragm
Phrenic nerve
External intercostals
Intercostal nerves
muscles of the thorax - forced expiration
Internal intercostals depress ribs & reduce size of thorax
Abdomen is compressed by abdominal muscles (push more air out)
