WEEK 2 Flashcards
What is interstitial fluid?
It is fluid trapped amongst filaments
About 1% is water & 95-99% is gel
What are (i) crystalloids (ii) colloids?
(i) low molecular weight solutes e.g. Na+, Cl-, K+
ii) plasma proteins - exists within interstitial & capillaries but more prominent in plasma (capillaries
What are the boundaries of the anterior mediastinum?
Between the sternum & pericardium
What are the boundaries of the superior mediastinum?
Between the thoracic inlet & sternal angle at T4-5; posterior to the manubrium; anterior to T1 - T4; oblique from the manubrium upwards to T1
What is the location of the thymus?
From the jugular notch to the 4th CC (& possibly beyond). It is a bi-lobed structure in the anterior mediastinum between the manubrium, sternum & pericardium
What is the function of the thymus?
It is active throughout life, particularly in childhood & puberty, with age fibro-fatty infiltration increases. Its function is to programme T-lymphocytes; recognise “self”
What is the blood supply of the thymus?
Int thoracic & inf thyroid arteries. Venous drainage to L.brachiocephalic vein
Structures on the left of the mediastinum are related to what?
Arteries & then the LV. (Left common carotid artery, left subclavian artery, arch of aorta & thoracic aorta)
What do the vagus & phrenic nerves lie between?
The venous & arterial planes
What can the superior mediastinum be considered as?
As a series of planes moving from anterior to posterior (once the thymus has been removed)
What are the 5 bony landmarks of the venous plane?
- Internal jugular and subclavian veins join to form right and left BCVs - Posterior to the sternoclavicular joint
- Left BCV passes anterior to the arch of the aorta; posterior to the manubrium
- RBCV & LBCV join to form the SVC - posterior to the 1st R CC
- Arch of the azygous vein joins SVC - posterior to the 2nd R CC
- SVC enters the RA - posterior to the 3rd R CC
What can happen with the LBCV in children?
It receives the thyroid vein & may protrude above the manubrium where it may be at risk in tracheostomy
What does the (i) azygous (ii) subclavian (iii) internal jugular veins(s) drain?
(i) posterior chest wall (ii) upper limb (iii) head & neck
In what mediastinum does the thoracic (descending) aorta lie?
Posterior
What 2 things is the trachea “clasped” by?
the left common carotid artery & brachiocephalic trunk
At what vertebral level is the jugular notch located?
T2/3
Where is the pulmonary trunk located?
Within the pericardium to the left of the ascending aorta
At T5, what does the pulmonary trunk do?
Divides into:
the R.pulmonary artery (posterior to the asc Ao & SVC) & enters the R lung.
the L.pulmonary artery (inferior to the arch of Ao & anterior to the thoracic aorta) & enters the left lung
What is the difference between the location of the pulmonary artery & bronchus on the left & right lung roots?
On the right the artery is inferior to the bronchus whilst on the left the artery is superior to the bronchus
In what mediastinum is the ligament arteriosum located?
superior mediastinum
Where is the trachea palpable? Where does it start & end?
anteriorly in the midline of the neck. Starts at C6 & ends at T4/5 (sternal angle) at carina
What is the location & function of trachealis?
Found posteriorly, between the ends of the C-cartilages. It alters tracheal diameter
In the superior mediastinum, what is the position of the trachea, the oesophagus & the left recurrent laryngeal nerve?
the trachea is anterior to the oesophagus - with the left recurrent laryngeal nerve between
What difference(s) is there between the right & left main brochi?
the right is shorter, wider & more vertical than the left