Respiratory Embryology Flashcards
What does the upper respiratory tract consist of?
Larynx + trachea
What does the lower respiratory tract consist of?
Bronchi + lungs
What develops first, the URT or the LRT?
Upper respiratory tract
What are the stages of lung development?
- Pseudoglandular
- Canalicular
- Saccular
- Alveolar
From what does the larynx, the trachea and the lung buds develop from?
An outpouching of the esophagus
At what stage in-utero does the primordial respiratory system arise?
3rd-4th week
And from WHERE does the primordial respiratory system arise?
The laryngotracheal grove on the ventral foregut
What partitions the outpouching of the esophagus, that becomes the laryngotracheal tube, from the esophagus?
The tracheoesophageal septum
What are the functions of the larynx?
- Airway protection
- Aid in respiration
- Vocalization
What marks the first division between the respiratory and the digestive systems?
Larynx
To what is the larynx attached superiorly?
Hyoid bone
To what bone is the larynx attached?
Hyoid bone
From what are the laryngeal cartilage and musculature derived?
4th + 6th pharyngeal arch mesenchyme
How many pharyngeal arches do humans have?
6
From what are the pharyngeal arches derived?
Neural crest tissues
What does the 1st pharyngeal arch form? (Mainly M’s)
Muscles - Mastication muscles; anterior belly of digastric; Mylohyoid; tensor tympani; tensor veli palatini
Skeletal - Maxilla; Mandible; Malleus; incus; Meckel cartilage
Nerves - V2 and V3
Arteries - Maxillary artery; external carotid artery
What does the 2nd pharyngeal arch form? (Sort-of Solely S’s)
Muscles - muscles of facial expression; Stapedius; Stylohyoid; buccinator; platysma; posterior belly of digastric
Skeletal - Stapes; Styloid process; Reichert cartilage; lesser horn + upper part of body of hyoid
Nerves - VII
Arteries - Stapedial artery
What does the 3rd pharyngeal arch form?
Muscles - stylopharyngeus
Skeletal - thymus; greater horn and lower part of body of hyoid
Nerves - IX
Arteries - common carotid; internal carotid artery
What does the 4th pharyngeal arch form?
Muscles - cricothyroid; intrinsic muscles of the soft palate
Skeletal - thyroid and epiglottic cartilage
Nerves - X, superior laryngeal nerve
Arteries - R subclavian + aortic arch
At what point are the false and true vocal cords formed?
Week 10, when the epithelial tissue occluding the primitive laryngeal orifice breaks down and the surrounding epithelial folds differentiate into them
What does the 6th pharyngeal arch form?
Muscles - intrinsic muscles of the larynx, except cricothyroid
Skeletal - cricoid; arytenoid; corniculate cartilages
Nerves - X, recurrent laryngeal nerve
Arteries - pulmonary arteries; ductus arteriosus
From what are the cartilage, smooth muscle and connective tissue of the trachea derived from?
Splanchnic mesoderm
Which bronchi is more lateral, L or R?
L bronchi
Which bronchi is more central, L or R?
R bronchi
How many divisions does the R bronchi give rise to?
3
How many divisions does the L bronchi give rise to?
2