UNIT 3: Muscles of Respiration Flashcards
what is pressure?
force exerted on walls of a chamber by gas molecules
at rest what is the pressure inside the thoracic cavity the same as?
atmospheric pressure
pressure = ____/_____, therefore…
force over area, as area inc pressure dec, as area dec pressure inc
positive pressure in the thoracic chamber means it is ___ than atmospheric pressure
greater
negative pressure in the thoracic chamber means it is ___ than atmospheric pressure
less
according to boyle’s law, increasing the volume of the thorax/lungs and will ___and will lead to …
dec intrathoracic pressure, air being drawn into the lungs (to equalize pressure w atmosphere)
according to boyle’s law, decreasing the volume of the thorax/lungs and will ____ ___and will lead to …
inc intrathoracic pressure, air will move out of the lungs (to equalize w atmosphere)
what are the 3 planes of thoracic volume change?
vertical
transverse (bucket handle)
anterior-posterior (pump handle)
describe vertical thoracic volume change
- inc primarily due to contraction of the diaphragm
- elevation of manubrium and 1st rib may also inc vertical dimension
describe transverse thoracic volume change
- “bucket handle” - up and out
- inc w elevation of ribs afforded by accessory muscles
describe anterior-posterior thoracic volume change
- “pump handle”
- inc w elevation of ribs via accessory muscles
what are the 2 types of inspiration?
quiet (rest) and forced (inc oxygen needs)
quiet inspiration (active passive?, muscles?)
- requires muscle activation
- diaphragm is most important, does most of the work of quiet inspiration
forced inspiration (active passive?, muscles?)
- requires muscle activation
- accessory muscles
two types of expiration
quiet expiration, forced expiration
quiet expiration (active passive?, muscles?)
- involves passive forces only (no active forces)
- gravity pulls ribs back to rest
- elasticity: when lungs are stretched by inc thoracic volume they will return to original shape and size when released
forced expiration (active passive?, muscles?)
requires muscles activation + passive forces
how many attachment points do skeletal muscles often have?
2
muscle fibres pull ___ their origin, moving the ____ point closer to the _____
toward, insertion, origin
what are the 3 primary muscles of inspiration
- diaphragm
- external intercostals
- interchondral portion of internal intercostals
describe the diaphragm
- only unpaired muscle of respiration
- separates thoracic and abdominal cavities
- participates in quiet inspiration and forced inspiration
- contraction inc volume of thorax in vertical dimension
where does the diaphragm attach?
vertebrae via crura (right crus and left crus)
what is the central tendon of the diaphragm?
- leaf shaped aponeurosis
- striated muscle fibers that surround central tendon
- provides floor for mediastinal organ
- compresses abdominal structures cyclically during respiration
what are the 3 hiatuses of the diaphragm?
- aortic hiatus
- esophageal hiatus
- foramen vena cava
what is the aortic hiatus of the diaphragm for?
houses the descending abdominal aorta
what is the esophageal hiatus of the diaphragm for?
houses esophagus
what is the foramen vena cava of the diaphragm for?
inferior vena cava
diaphragm is shaped like
an inverted bowl
where does the diaphragm originate
- thoracic ribs inner surface
- xiphoid process
- upper lumbar vertebra via crura
where does the diaphragm have its insertion point
central tendon
The diaphragm increases the
vertical dimension of the thorax
The diaphragm is innervated by the
phrenic nerve
where does the phrenic nerve originate?
cervical plexus from C3, C4, C5 bilaterally
the phrenic nerve descends through the _____ into _______ space on left and right sides of the ______
neck
mediastinal space
heart
The phrenic nerve mediates ______ for the _____
both sensory and motor info for the diaphragm
the external intercostals are in the area of _______ and they keep the space between the ____ constant
costal cartilages
ribs
the external intercostals have ___ muscles running between ___ ribs
11, 12
where do the external intercostals originate?
inferior surface of each rib
where do the external intercostals have their insertion point?
superior surface of rib below
What is the action of the external intercostals?
raise ribs (up and out), elevate ribcage
what is the innervation of the external intercostals? (** not 100% i need to know this)
intercostal nerves
what are the 2 portions of the internal intercostals and where are they?
- interchondral - bw costal cartilages
- interosseuous - bw bony portion of ribs
are external intercostals involved in expiration or inspiration?
inspiration
are internal intercostals involved in expiration or inspiration?
muscles of expiration EXCEPT…. the interchondral portion are active during inspiration
where do the interchondral portion of the internal intercostals originate
inferior surface of rib above (from costochondral junction to sternum)
where do the interchondral portion of the internal intercostals have their insertion point
superior surface of rib below
what is the action of the interchondral portion of the internal intercostals
elevate ribs
what is the innervation of the interchondral portion of the internal intercostals (***not 100% i need to know this)
intercostal nerves
what do accessory muscles do in forced inspiration?
inc the volume of the thoracic cavity in anterior-posterior and transverse dimensions (uses the dorsal thorax, neck, arm/shoulder)
3 main muscles (or muscle groups) of forced inspiration
-levatores costarum (brevis and longis)
- serratus posterior superior
- erector spinae (sacrospinal muscles)
what are the 3 bundles of the erector spinae (sacrospinal muscles)?
- lateral bundle
- intermediate bundle
- medial bundle
levatores costarum brevis: origin, insertion, action , innervation (*)
- transverse processes of C7-T11
- tubercle on rib below (fibres run down and out)
- elevate rib cage
- intercostal nerves
levatores costarum longis: origin, insertion, action , innervation (*)
- transverse processes of vertebrae T7-T10
- Skips a rib, attaches to tubercle on next rib
- elevate rib cage
- intercostal nerves
serratus posterior superior: origin, insertion, action , innervation (*)
- spinous processes of C7-T3
- just beyond angle of ribs 2 thru 5
- elevates ribs
- intercostal nerves
What do the erector spinae muscles do? where do they arise from? lumbar and thoracic region are covered by?
- stabilize the vertebral column and rib cage
- arise from tendon of sacral crest, lumbar vertebrae, and lower ribs
- thoracolumbar fascia
The lateral (iliocosto) bundle of the erector spinae muscles has 3 parts, and what are their origins and insertions? What is their action? what is their innervation?
iliocostalis lumborum
- sacral crest
- angles of ribs 6-12
iliocostalis thoracis
- sacral crest
- angle of ribs 1-6
iliocostalis cervicis
- ribs 3-6
- vertebrae C4-C6
action: stabilize and move vertebral column (lateral)
inn: cervicall, thoracic, lumbar nerves
The intermediate (longissimus) bundle of the erector spinae muscles has 3 parts, and what are their origins and insertions? What is their action? what is their innervation?
longissimus thoracis
- sacral crest
- transverse processes of T1-T12
longissimus cervicis
- T1-T5 vertebrae
- C2-C6 vertebrae
longissimus capitis
- C1-C5 vertebrae
- mastoid process of temporal bone
action: stabilize and move vertebral column
inn: cervical, thoracic, and lumbar nerves
The medial (spinalis) bundle of the erector spinae muscles has 3 parts, and what are their origins and insertions? What is their action? what is their innervation?
spinalis thoracis
- T11, T12, L1-L3
- T1-T8
spinalis cervicis
- Nuchal ligament and C7
- C2 vertebra
spinalis capitis
- T1-T6, C4-C7
- nuchal line of skull
action: stabilize and move vertebral column
inn: cervical, thoracic, and lumbar nerves
what are the 2 muscles of inspiration in the neck?
- sternocleidomastoid
- scalenes (anterior, middle, posterior)
sternocleudomastoid: origin, insertion, action, and innervation
- mastoid process of temporal bone
- sternum and clavicle
- bilateral contraction elevates sternum, thus ribcage
- cervical spinal nerves and CN XI
scalenes: origin, insertion, action, innervation
- transverse process of C2-C7
- Upper surfaces of 1st and 2nd ribs
- elevates the ribs
- cervical plexus and branchial plexus
what are the 7 muscles of inspiration in the arm/shoulder?
pectoralis major
pectoralis minor
serratus anterior
subclavius
levator scapulae
rhomboids (major and minor)
trapezius
pectoralis major: origin, insertion, action, innervation
- humerus
- clavicle, sternum, cartilages of ribs (2-6), aponeurosis of external oblique muscles
- w arm fixed it pulls sternum and ribs upward during forced inspiration
- brachial plexus
pectoralis minor: origin, insertion, action, innervation
- outer surfaces of ribs 3-5
- coracoid process of scapula
- w scapula fixed it elevates ribs 3-5
- branchial plexus
serratus anterior: origin, insertion, action, innervation
- 8/9 upper ribs
- vertebral border and inferior angle of scapula
- w scapula fixed, elevates upper ribs
brachial plexus
subclavius: origin, insertion, action, innervation
- inferior surface of clavicle
- 1st rib at costochondral junction
- elevates first rib
- brachial plexus
levator scapulae: origin, insertion, action, innervation
- transverse proceses of C1-C4
- Superior vertebral border of scapula
- elevates and steadies scapula
- cervical spinal nerves
rhomboids: origin, insertion, action, innervation
- spinous processes of C7-T1 (minor) and T2-T5 (Major)
- vertebral border of scapula
- elevates, adducts, and steadies scapula
- cervical spinal nerves
trapezius: origin, insertion, action, innervation
- external occipital protuberance and superior nuchal line of occipital bone (skull)
- clavicle and scapula
- maintains trunk stability for respiration
- CN XI and cervical spinal nerves
when are the muscles of expiration active?
only during forced expiration … quiet expiration (or breathing at rest) is a passive phenomenon
during forced expiration: contraction of deep ____ muscles dec anterior-posterior and transverse dimensions
thoracic
during forced expiration: contraction of ____ muscles dec superior-inferior (vertical) dimension of the thorax
abdominal/back
what are the 4 muscles of expiration in the deep thorax?
internal intercostals
innermost intercostals
subcostals
transversus thoracis
internal intercostals: what are they deep to, origin, insertion, action, innervation
- deep to external-intercostal muscle layer of the thorax
- superior surface of rib
- inferior surface of rib above
- depress ribs
-intercostal nerves
describe the innermost intercostals
- deepest muscle layer of thorax; run parallel w internal intercostals (same origin/insertion/action/innervation)
- poorly developed
- depress ribs
subcostals: depth, origin, insertion, action, innervation
- deep muscle of thorax, same depth as innermost intercostals
- inner surface of rib below (near vertebral column)
- inner surface of rib just above
- pull ribs downward
- thoracic nerves
transversus thoracis: origin, insertion, action, innervation
- inner surface of sternum and costal cartilages 5-7
- inner surface of costal cartilages and adjacent ribs 2-6
- compresses ribcage by pulling ribs toward sternum
- thoracic nerves
what are the 4 muscles of expiration in the abdomen? (deep to superficial)
transversus abdomnis
internal oblique abdominis
rectus abdominis
external oblique abdominis
what do the abdominal muscles do in expiration?
- contraction dec vertical dimension
- compresses ribcage and abdominal cavity
- push up on diaphragm (compresses viscera in thorax)
what is the linea alba?
- midline of the abdominal aponeurosis, from xiphoid process to pubic symphysis
- separates R and L rectus abdominis muscles
transversus abdominis: origin, insertion, action, innervation
- iliac crest, inguinal ligaments, thoracolumbar fascia
- xiphoid process, linea alba
- compresses abdomen and ribcage
- thoracic and lumbar spinal nerves
interanl oblique abdominis: origin, insertion, action, innervation
- iliac crest, inguinal ligament, thoracolumbar fascia
- costal cartilages of last 3-4 ribs, linea alba
- compresses abdomen and rib cage (hands to mouth direction)
- thoracic nerves and 1st lumbar spinal nerve
rectus abdominis: origin, insertion, action, innervation
(intermediate layer)
- pubic symphysis and pubic crest
- costal cartilages of ribs 5-7 (true ribs) and xiphoid process
- compresses abdomen and rib cage
- thoracic nerves
external oblique abdominis: origin, insertion, action, innervation
(superficial layer)
- external surfaces of ribs 5-12
- iliac crest, inguinal ligament, linea alba
- compresses abdomen and ribcage (hands in pockets direction)
- thoracic nerves
what are the 3 muscles of expiration in the dorsal trunk (lower back)?
serratus posterior inferior
quadratus lumborum
latissimus dorsi
serratus posterior inferior: origin, insertion, action, innervation
- spinous processes for T11-L2/L3
- inferior surface of ribs 8-12
- lower ribs
- thoracic nerves
quadratus lumborum: origin, insertion, action, innervation
- iliac crest and iliolumbar ligament
- inferior border of rib 12 and L1-L4
- Pulls last rib inferiorly during expiration; anchors last rib against lifting force of diaphragm
- thoracic and lumbar nerves
latissimus dorsi: origin, insertion, action, innervation
- lumbar, sacral, and lower thoracic vertebrae
- humerus
- stabilizes posterior abdominal wall
- branchial plexus
describe muscular dystrophy
- degeneration of skeletal muscle resulting in progressive muscle weakness
- as affects respiratory sys, patient may become ventilatory dependent
