L24 Mediastinum 1 Flashcards
what is the mediastinum
space in the thorax that contains all the non-lung thoracic viscera
Space between the pleural cavities
the mediastinum is not only a location for_____, but also the important ____ through the thorax to other regions of the body
thoracic organs
conduit
Mediastinal structures are ___ and surrounded by
_____
highly mobile
loose connective tissues
label the borders of the mediastinum: superior, inferior, anterior, posterior, lateral
superior mediastinum wall
superior thoracic aperture
inferior
finish slide 4
what regions are in the mediastinum
superior
inferior
superior mediastinum
transverse thoracic plane T4/T5
structures communicating with neck, thymus
inferior mediastinum (3 plus roles)
anterior: very few structures of note
middle: heart and pericardial cavity
posterior: structures communicating with the abdomen
thymus
superior mediastinum
lymph organ positioned anteriorly in the superior mediastinum
the thymus is well developed and extensive in ___. location in youth?
youth
extends from superior mediastinum into anterior mediastinum
thymus in adults
degenerates into fatty mass and recedes
finish slide 6
___ system transports fluids around the body and is composed of the ____ and ___ systems, which do:
heart
muscular pump driving the flow of blood
blood vessels have three types
artery
vein
capillary
arteries
carry blood away from heart
veins
carry blood to the heart and often run adjacent to arteries of the same area
capillaries
sites of nutrient/waste exchange
arteries have to move blood under ___ pressure, and therefore have
high
thicker, muscular walls
arterial vessels ___ in size further from the heart
decrease
elastic artery
largest arteries expand when
blood is pushed and recoil to aid in blood pumping
closest to heart
muscular artery
primary transport arteries to
organs or locations
arms
intercostal
arteriole
change diameter to control flow
inner region transport from artery to capillary
veins transport blood under ___ pressure and have __
lower
thinner walls, valves to combat gravity (prevent backflow) and musculovenous pump
vein vessels ___ in size closer to heart
increase
venule
vein
collection of blood from capillary bed, extravasation of leukocytes
medium veins
organ and regional veins maintain flow towards proximally
large vein
major vessels collecting all the smaller tributaries and return blood to the heart
____ pressure ___ blood requires extra assistance in
returning against the flow of gravity.
low
venous
many distal veins in the extremities are located adjacent to_____. _____ of the muscles (in conjunction with
the valves) helps drive blood ____
large
muscle bellies
Contraction
back up toward the heart.
Distal veins tend to have ___ that allow only ___ flow
valves
unidirectional
Failure of valves results in
varicose veins – veins distended
with pooled blood
great vessels
the largest veins, elastic arteries associated with the heart itself
occur at T4/T5
superior vena cava
head and neck down to heart
right side of heart (drains in right atrium)
brachiocephalic veins (L and R)
inferior vena cava
abdomen to the heart
not in superior mediastinum
ascending aorta
aorta that goes up
pulmonary trunk
branches into L and R pulmonary arteries
carries oxygen-poor blood to lungs, but is an artery
includes ligamentum arteriuosum
ligamentum arteriosum
rememnant of fetal circulation shunt
and plays important role for nerves
pulmonary veins
oxygen rich blood from pulmonary system to left side of heart
arch of the aorta
posterolateral curvature from ascending to descending aorta
vessels that come off of arch of aorta
brachiocephalic trunk (goes to UE and head, fused of the next two on the right side which makes it equal on both sides))
left common carotid artery
left subclavian artery
thoracic/descending aorta
T4/T5 to T12
runs down left side of vertebral bodies
thoracic/descending aorta at T12
finsih
azygos system veins
variable and asymmetric system of valveless veins that drain the back, thoracoabdominal walls, mediastinum
azygos veins are on the ___ side of vertebral bodies and drains to
right SVC via arch of azygos
hemiazygos vein is on the ____ side of vertebral bodies and drains
inferior left
into azygos vein at T9
accessory hemiazygos
finish slide 15
every blood vessel is lined by a
simple squamous epithelium
if a space in the body has blood in it, it needs to be surrounded by ___
endothelium
finish slide 17
blood vessel has 3 layers
tunica intima
tunica media
tunica adventitia
tunica intima
innermost
endothelium
subendothelial layer of loose CT
internal elastic lamina
tunica media
middle layer of blood vessel
smooth muscle
external elastic lamina
tunica adventitia (externa)
outer layer of blood vessel
dense irregular CT
autonomic nerves
vasa vasorum (vessel in vessel)
label/draw artery and vein layers
histo of tunica intima
endothelium lines vessel lumen, subendothelial connective tissue supports endothelium and internal elastic lamina results in wavy appearance
histo of tunica media
in arteries the smooth muscle layer tends to dominate, external elastic lamina also presents wavy appearance
histo of tunica adventitia
connective tissue layer is dense, think and irregular
draw histo slide of three vessel layers
elastic arteries histo
largest arteries closest to the heart
tunica media is much thicker than the tunica adventitia
FIISH SLIDE 20
elastic arteries
__ and ___ overlap with initial symptoms
aortic dissection and myocardial infarction
aortic dissection facts
5-10 cases per 100,000 people annually and increasing
common in men than women and more common in older individuals
what happens in aortic dissection
Tears in the tunica intima permit high pressure aortic
blood to push into the potential space between intima and media layers
Can occur anywhere along the entire length from
ascending aorta to abdominal aorta
what happens in aortic aneurysm
Different from aortic aneurysm where the entire wall fails
and stretches (or ruptures)
muscular arteries histo
FINISH SLIDE 22
arterioles
FINISH SLIDE 22
arterioles
arterioles
arterioles
three types of capillaries
continuous (type 1) capillaries
fenestrated (type 2) capillaries
discontinuous (sinusoidal) capillaries
continuous/type 1 capillaries
Lumen is 5 – 10 μm wide
Very common (e.g., lung, heart, skin,
muscle)
Uninterrupted endothelium & basal lamina
Exchange is highly regulated
fenestrated/type 2 capillaries
Lumen is 15 – 20 μm wide
Restricted to endocrine glands and
absorptive organs (e.g., GI tract,
gallbladder, and kidney)
Fenestrations (50 nm pores) in endothelial
cells allow passage of small molecules &
proteins
finish slide 24
slide 25
esophagus
Gastrointestinal conduit between the pharynx (neck) and stomach (abdomen)
Flattened muscular tube
Between trachea and vertebral bodies (superior to T4/T5)
Between pericardial cavity and vertebrae (inferior to T4/T5)
there are places where the esophagus is ____ by adjacent structures representing potential points where __
compressed
swallowed material can get trapped
esophageal constrictions
Neck – cricoid cartilage
Thorax – structures of the
transverse thoracic plane
Abdominal diaphragm –
esophagus passes through
esophageal hiatus of
diaphragm at T10
nerves of the mediastinum
phrenic
vagus
sympathetic chain
phrenic nerve
superior and middle mediastinum
anterior to the root of the lung
vagus nerve
superior and posterior mediastinum
posterior to the root of the lung
sympathetic chain
superior and posterior mediastinum
along lateral side of the vertebral bodies
abdominoplevic splanchnic nerves
sympathetic innervation to abdominopelvic viscera arising from thoracic paravertebral ganglia
greater T5-9
lesser T10-11
least T12
SLIDES 30-32
