4. Functional Anatomy - Pulmonary Flashcards
What are the thoracic components?
- Chest wall
- Conducting airways
- Lungs
- Respiratory muscles
- Pleura
What structures are within thoracic cage?
- Sternum (manubrium, body, xiphoid process)
- Ribs (1-7=true; 8-10=false; 11-12=floating)
- Thoracic vertebrae (T1-T12)
- Cartilage
- Muscles
- Pleura
What is the purpose of thoracic vertebrae in the thoracic cage?
- Structural support
- Protection
- Expansion of thoracic cage
What is the purpose of cartilage in the thoracic cage?
Attachment bones from sternum to vertebrae
What is the thoracic cage covered by?
Respiratory muscles
What is contained w/in thoracic cage?
Lungs + mediastinum (heart, esophagus, trachea, among others)
What structures define the thoracic cage?
Pleura + muscular coverings, superiorly
Diaphragm, inferiorly
Describe the structure of diaphragm.
Parachute like muscular structure that sep. abd. contents from thoracic –> contraction causes expansion of thoracic cage.
Has openings that allow passage of allow major vessels, esophagus and other structures to pass through thoracic cavity.
How does diaphragm contribute to respiration?
Contraction of diaphragm flattens muscle –> increases size of thoracic cage. B/c thoracic cavity is sealed, creates vacuum-pull on alveoli as cavity size increases –> draw air into lungs.
What are the three components of resp. mechanics?
- Intercostal muscles = fibers pointed in diff directions –> helps pull ribs up + down
- Accessory muscles = becomes primary muscles of resp. if diaphragm nonfxnl (e.g. interscalene, sternocladomastoid)
- Diaphragm = largest + most efficient
What muscles play the biggest part in forced breathing + how does it work?
Abd. muscles become big part of forced breathing: contraction of abd. muscles pushes abd. contents up –> collapse thoracic cage
What is the mechanism for exhalation?
- Diaphragm relaxes
- Compresses thoracic cavity + pushes down on lungs –> decreases lung vol
- Air rushes out
What is the mechanism for inhalation?
- Diaphragm contracts
- Increases space w/in thoracic cavity –> gen. negative P w/in pleural space
- Negative P transm. to lungs –> expand
- Draw in air from atm. to alveoli
How does movement of ribs affect respiration?
During expiration: ribs displaced caudad –> decrease anterior-posterior size of thoracic space + diaphragm becomes more dome-shaped
During inspiration: ribs displaced cephalad –> increases A-P size of thoracic space + diaphragm flattens
Describe what composes the conducting airways.
Trachea –> R+L main bronchi (3 R lobes; 2 L b/c heart takes up space) –> lobar bronchus –> segmental bronchus –> bronchi –> terminal bronchiole –> alveolus
As go down conducting airway… number increases but size decreases!
Describe the structure of alveoli.
Wrapped by capillaries (single-cell blood vessels) for gas exchange.
What two types of cells make up an alveoli?
Type I cells=flat squamous epithelial cells, in contact with capillaries for gas exchange
Type II cells=surfactant-secreting cells, decrease surface tension of alveoli –> easier to expand esp. at smaller volume
What other type of cell is also found within alveoli?
Macrophages
What are examples of significant pulmonary pathology?
- Rib fx
- Penetrating injuries (gsw, knife wounds, surgeon inflicted, fx)
- Pectus excavatum (sternum points inwards)
- Pectus carinatum (sternum points outwards)
- Scoleosis (bending of spine)
- Kyphosis (A-P bending of spine, often seen in aging pt w osteoporosis of vertebrae/thoracic spine fx –> limits FROM)
- Burns (constricts chest expansion)
How does rib fx affect respiration?
Can’t fix rib fx with cast as w other fx –> efficient breathing requires chest movement. Also sharp pieces can become another source of injury
