Lecture 3 - Anatomy of the Respiratory System (Part 1) Flashcards
How does the respiratory system develop embryologically?
- The respiratory system develops as a ‘diverticulum’ from the pharynx
- Basically starts as evagination of pharynx, then starts to bifurcate and split further to form various lobes & alveoli of the lungs
What are the primary roles of the nasal cavity and what features allow them to do this?
1) Nasal cavity must warm and moisten inspired air:
- highly vascular mucosa lining the cavity
- nasal conchae increases SA considerably, and induces turbulent flow which increases time to make contact with mucosa and exchange water & heat
- nasal cavity also recovers water from expired air
2) Speech production (phonation)
3) Smell (olfaction)
What are/identify the 3 sections of the pharynx.
What do the larynx and pharynx work together to do?
1) Nasopharynx - connects to nasal cavity
2) Oropharynx = connects to oral cavity
3) Laryngopharynx = connects to airways via larynx
Larynx and pharynx work together to make sure substances take right path, i.e.: food into oesophagus and air into the trachea.
NB: Larynx (voice box) contains vocal chords (which promote safe swallowing) and runs continous with trachea
What are the main paranasal sinuses? (3)
1) Frontal sinus
2) Sphenoidal sinus
3) Maxillary sinus
What are the main paranasal sinuses? (3)
1) Frontal sinus
henoidal sinus
Locate the oesophagus and trachea on a cross-section of the upper airways.
What surround the trachea but is deficient posteriorly?
- Tracheal rings/Tracheal cartilages, deficient posteriorly so posterior aspect is more soft
Each 12 thoracic vertebrae within the thoracic cavity articulate/are associated with a rib, how do the ribs articulate anteriorly and posteriorly?
- Anterior portion of rib articulates with costal cartilages
- Posterior portion (head) articulates with demifacets of thoracic vertebrae (costovertebral joint), neck articulates with transverse process (constotransverse joint)
- Ribs 1-7 connect directly to sternum, ribs 8-10 connect indirectly with sternum with costal cartilages, ribs 11 & 12 are floating ribs which have no connection to sternum
Why can neck injuries (e.g.: stab wound) damage the lungs/thoracic cavity?
Apex of lungs spread up into the neck, so neck injuries will affect thoracic cavity
What are the possible movements of the rib cage?
- Rib articulates with vertebrae above and below via synovial joint, allowing for some movement.
- Superior and inferior movement, with limited amount of rotation around costovertebral joints
How do the ribs, chest wall & diaphragm move to facilitate inspiration & expiration?
- Ribs swing upwards & outwards (like a bucket handle) during inspiration
- Sternum moves anterior and superiorly during inspiration, allowing ribs to move in same direction (like a pump handle). important for increasing diameter of thoracic cage.
- diaphragm flattens to increase volume of the chest
How does movement of the ribs and chest wall cause movement of air into and out of the lungs?
- Movement of ribs & diaphragm increase the volume of thoracic cavity, decreasing the pressure. Air moves from atmosphere into lungs via pressure gradient.
- As ribs return to normal and diaphragm moves up, volume decreases and pressure increases in thoracic cavity. Air moves from lungs to atmosphere down pressure gradient.
What muscles (aside from diaphragm) are involved in inspiration & expiration?
1) External intercostals - fibres run inferomedially, hence they raise the ribcage increasing thoracic cavity volume (muscle of inspiration)
2) Internal + Innermost Intercostals - can be considered together, have fibres running at right angles to external intercostals that pull ribs inferiorly and posteriorly (muscles of expiration). Majority of expiration however is passive due to gravity and recoil, these are recruited more in exercise.
How does the diaphragm attach to the thoracic cavity?
What is the diaphragm innervated by?
What 3 structures penetrate the diaphragm to move from the thoracic to abdominal cavity?
- Diaphragm attaches to inferior thoracic aperture and has strong tendinous attachments to the spine.
- Innervated by L+R phrenic nerve (C3/4/5 keeps the diaphragm alive)
1) Vena Cava (T8 level)
2) Oesophagus (T10 level)
3) Aortic Hiatus (T12 level)
Count the letters, number of letters in each structure relate to their thoracic level.
How does the diaphragm attach to the thoracic cavity?
What is the diaphragm innervated by?
What 3 structures penetrate the diaphragm to move from the thoracic to abdominal cavity?
- Diaphragm attaches to inferior thoracic aperture and has strong tendinous attachments to the spine.
- Innervated by L+R phrenic nerve (C3/4/5 keeps the diaphragm alive)
1) Vena Cava (T8 level)
2) Oesophagus (T10 level)
3) Aortic Hiatus (T12 level)
Count the letters, number of letters in each structure relate to their thoracic level.
What other muscles are recruited in respiration during exercise or in pathological conditions?
- Pectoralis muscles are recruited during exercise to assist in ventilation
- SCM is recruited in COPD, notice bulging of neck muscles in patients
