trachea, bronchial tree and lungs Flashcards
structure of trachea?
- fibrous and cartilaginous tube conducting air from larynx to bronchi
- 10-11 cm long
- around 2.5cm diameter
- from C6 to T4/T5
- c shaped rings to maintain latency
posteriorly of the trachea what is the muscle called?
What control is it under?
- trachealis which joins each end of the rings and controls the diameter
- under the control of the ANS and is responsible for altering tracheal diameter
Where does the trachea enter the thoracic cavity?
Where does the left recurrently laryngeal nerve lie in relation to the trachea?
Where does the trachea divide?
The trachea enters the thoracic cavity through thoracic inlet (rib 1, T1, superior manubrium)
The left recurrent laryngeal nerve lies in the groove between the trachea and the oesophagus
At the level of the Sternal angle (T4/5 intervertebral disc) the trachea divides into left and right principal (main) bronchi (at about 2cm below entry into thoracic cavity)
What is the trachea composed of?
Why is this?
What is the muscle in the trachea?
What is the role of this muscle?
What would happen if the trachea didn’t consist of cartilage?
The trachea is composed of C-shaped hyaline cartilages
This is to ensure the trachea stays open at all times
The trachealis muscle along with some fibrous tissue is found in the posterior trachea between the ends of the tracheal cartilages
The trachealis muscle is smooth muscle under the control of the ANS, and is responsible for altering the tracheal diameter
If the trachea didn’t consist of cartilage, it would collapse on inhalation due to the negative intra-thoracic pressure
what is the trachea continues with?
what does cricotrachael membrane connect with?
continuous airway from the larynx
the cricotrachael membrane will connect the first tracheal cartilage with cricoid cartilage
surrounding structures of the trachea:
posteriorly?
anteriorly?
posteriorly = oesophagus
anteriorly
= - thyroid gland
- brachiocephalic trunk, Left brrachiocephalic vein
- cardiac plexus nerves (sympathetic and parasympathetic)
- trachaebronchial nodes
- manubrium (manubriosternal joint)
what does the manubriosternal joint mark?
bifurcation of the trachea
lateral surrounding structures of trachea?
posterolateral surrounding structures of trachea?
lateral = - thyroid gland lobes
- parathyroid glands
- common carotid arteries
- aortic arch, common carotid and left subclavian artery
- azygos arch
- right vagus nerve.
posterolateral =
recurrent laryngeal nerves
arterial supply of the trachea?
inferior thyroid artery and bronchial arteries
venous drainage of trachea?
drains to the inferior thyroid and bronchial veins
lymph drainage of trachea?
lymph drains to pre and para tracheal nodes
neuro supply of the trachea?
- sympathetic and parasympathetic?
supplied by the pulmonary plexus
(Formed by pulmonary branches of the vagus nerve and the sympathetic trunk)
- sympathetic from sympathetic trunk (dilation)
- parasympathetic from vagus nerve (constriction)
If the trachea didn’t consist of cartilage what would happen to it?
It would collapse on inhalation due to the negative intra-thoracic pressure
Where does the trachea enter the thoracic cavity?
Where does the left recurrent laryngeal nerve lie in relation to the trachea?
Where does the trachea divide?
1- the trachea will enter through the thoracic inlet (rib 1, T1, superior manubrium)
2- the left recurrent laryngeal nerve will lie in the grove between trachea and the oesophagus
3- sternal angle
What 4 neurovascular structures will lie on the right of the trachea in the thoracic cavity?
What 2 neurovascular structures will lie on the left of the trachea in the thoracic cavity?
Right =
- right vagus nerve
- azygos vein
- SVC
- right brachiocephalic
Left =
- left vagus nerve
- left brachiocephalic vein
3 borders of the lungs?
1) Anterior border
* The anterior border of the lung corresponds to the pleural reflection, and it creates a cardiac notch in the left lung
2) Posterior border
* The posterior border is thick and extends from the C7 to the T10 vertebra, which is also from the apex of the lung to the inferior border.
3) Inferior border
* The inferior border is thin and separates the base of the lung from the costal surface
What prominent structures of the aortic arch can be seen at T3?
What prominent structures can be seen at T4?
T3=
- Brachiocephalic trunk
- left common carotid artery
- left subclavian artery
T4=
- cross section of aortic arch
- SVC (The right and left brachiocephalic veins have joined to form the SVC)
How does the right and left main bronchi is differ?
Right is short, wider and more vertical
What will the right and left main bronchi divide into?
How many lobar bronchi are in each lung?
Where does the bronchi receive blood from?
The main bronchi will divide into lobar (secondary) bronchi… which then subdivide into segmental (tertiary) bronchi
Left = 2 lobar bronchi
Right = 3 lobar bronchi
Bronchi receive blood from bronchial arteries (1right and 2 left )
How do segmental bronchi become respiratory bronchi?
Where is the greatest resistance to air flow?
What is the diameter of the bronchioles dependant on?
Segmental bronchi… terminal bronchi… respiratory bronchi
Bronchioles cause the greatest resistance to airflow in the conducting passages
The diameter of bronchioles is dependant on smooth muscle tone
What happens to the diameter of the bronchioles in asthma?
How can you treat it?
In asthma the smooth muscles contract strongly enough to almost completely shut
Salbutamol are B2 agonists and cause bronchodilation.