CVS anatomy Flashcards
what is the mediastinum
the midline partition of the thorax separating the right and left pleural cavities
what does the mediastinum contain
heart and its great vessels thoracic trachea and bronchi thoracic oesophagus vagus nerves phrenic nerves thoracic duct
what is the sternal angle
surface landmark for the division of the mediastinum into the superior and inferior division
how is the mediastinum divided
into superior & inferior the inferior has 3 further subdivsions -anterior -middle -posterior
where is the superior mediastinum and what does it contain
above the sternal angle
contains the great vessels of the heart and upper portions of the thoracic trachea and oesophagus
where is the anterior mediastinum
between middle mediastinum and the body of the sternum.
anterior to pericardium
where is the middle mediastinum and what does it contain
sits behind the body of the sternum.
contains the heart and fibrous sac of pericardium
where is the posterior mediastinum
occupies area posterior to the middle mediastinum and the diaphragm
what does the posterior mediastinum contain
oesophagus
azygous veins
thoracic duct
intercostal neurovascular bundles
in which mediastinum is the heart located
middle
what is the function of pericardium
enclose the heart in situ in the thoracic cavity.
facilitates free movement of the heart when it contracts while isolating its movement from that of the structures surrounding the thorax
what are the 2 layers of pericardium
fibrous & serous
what is the function of fibrous pericardium
fibrous sac, anchors the heart in place
what are the further subdivisions of serous pericardium
visceral- stuck to the heart (myocardium- the heart muscle)
parietal -
how are visceral & parietal pericardium separated
by a narrow fluid filled space
- pericardial space
- pericardial fluid
where is pericardial fluid located
between the two layers of serous pericardium
what is cardiac tamponade
where increasing volume of pericardial fluid during bleeding following trauma will interfere with the ability of the heart to contract
which side of the heart is anterior
right
which side of the heart is posterior
left
what does the right atrium form
the entire right surface and border of the heart
1/4 of the anterior surface
what does the right ventricle occupy and form
occupies most of the anterior surface
forms 2/3 of the inferior border
what does the the left ventricle form
nearly all the left border and makes up large part of the posterior surface
small part on the left inferior border- apex
what does the left atrium make up
entirely on the posterior aspect of the heart
what is the sternocostal surface of the heart and what structures are visible
anterior aspect
right atrium
right ventricle
left ventricle
what is the diaphragmatic surface
inferior aspect of the heart
what structures are visible on the posterior surface of the heart
right and left atria and ventricles visible
where is the apex seen beating
in the left fifth intercostal space about 10cm from the midline
what does the atrioventricular groove indicate
the septum separating the two atria from the two ventricles
runs in vertical plane
what does the interventricular sulcus indicate
the septum separating the right and and left ventricles
divided into and anterior and interior aspect
what are the atrial and ventricular septa
connective tissue separates the right and left atria and right and left ventricles through muscular continuity maintained
what is the fibrous skeleton of the heart composed of
dense fibrous tissue between the atria and ventricles (corresponds to the atrioventricular grooves)
what is the function of the fibrous skeleton
provides opening for valves
supports and anchors valves
electrically isolates atria from ventricles except for atrioventricular bundles
what 3 layers does the heart wall consist of
epicardium
myocardium
endocardium
what is epicardium
an outer serous layer of the heart
what is myocardium
layer of cardiac involuntary muscles that originates and inserts into fibrous rings surrounding the valves orifices
what is endocardium
an inner lining of the endothelium
where does blood flow go after entering the sup and inf vena cava
Right atrium then right ventricle through r av opening and distributed to through the lungs by pulmonary trunk & arteries
how is blood distributed to the lungs
pulmonary trunks and arteries
how is blood returned to the heart from the lungs
pulmonary veins
after blood enters from the pulmonary veins where does it go
left atrium and into left ventricle through l av opening and to the body via aorta
what are the structures of the right atrium
orifice of sup vena cava orifice of inf vena cava crista terminalis fossa ovalis tricuspid valve pectinate muscles right auricle coronary sinus- post sinoatrial and av nodes
where is the fossa ovalis
right atrium above the vena cava
what is the function of the coronary sinus and where does it open
returns blood from the heart walls and opens into the right atrium
where are pectinate muscles
right atrium, they radiate out at right angles from the crista terminalis
what does the tricuspid (r av valve) consist of
three flaps, septa
what is attached the edges of the flaps of the bicuspid/tricuspid valves
chorda tendinae
what is crista terminalis
vertical ridge running between 2 vena cava. divides atrium into smooth and rough anterior wall
what drains into the right atrium as well as the sup and if vena cava
middle cardiac vein
coronary sinus
where does the right coronary artery lie
in the anterior atrioventricular groove
where does the right ventricle receive blood from
right atrium via the tricuspid valve (r av valve)
what does the right ventricle contain
trabecula carneae chorda tendiane papillary muscles pulmonary valve pulmonary trunk pulmonary artery moderator band
what is the difference between trabecula carneae and pectinate muscles
pectinate muscles are in the atria and TC are in the ventricle
where do chorda tendineae come out from
between the tricuspid valve flaps and papillary muscles
what do the papillary muscles do
anchor the chorda tendineae and cusps to the heart wall
what valves guard the opening of the pulmonary artery
semi lunar valves
what does the moderator band do
in the rv and is part of the econducting system of the heart
where does the left atrium receive blood from
pulmonary veins from the lungs carrying o2 blood
what valve is in the LA
bicuspid
L AV valve
what is the function of the left ventricle
pump blood to the whole body
what are the structures in the left ventricle
trabeculae carneae- gives roughened aspect
left av valve (biscupid/mitral)
papillary muscles
aortic valves
where do the papillary muscles attach
to the cusps of the bicuspid/tricuspid valves via the chorda tendineae
how do the papillary muscles prevent the bicuspid/tricuspid valves from everting into the atria thus preventing a backflow during ventricular systole
they contract early in advance of the rest ventricular muscle causing a tensing of the chorda tendineae
what does the aortic valve do
prevents back flow of blood from aorta into left ventricle
what are the branches of the aorta
ascending aorta
arch of aorta
descending aorta
what are the branches of the ascending aorta
coronary arteries
what are the branches of the arch of aorta
brachiocephalic
left subclavian
left common carotid
what are the branches of the descending aorta
bronchial arteries
oesophageal
post intercostal arteries
paired pericardial
where does the left coronary artery arise from
left posterior aortic sinus
what are the two terminal branches of the left coronary artery
anterior interventricular branch
circumflex branch
where does the circumflex br of the left CA travel
to posterior aspect of heart into atrioventricular sulcus
where does the anterior interventricular br descend
in the sulcus towards the apex of the heart
what areas does the left CA supply blood to
both atria and some adjacent right ventricle
what happens if the left coronary artery is blocked
cardiac muscle distal blockage would no longer be supplied with blood and be irreversibly damaged (CA are end arteries)
what does the right coronary artery supply
right atrium & ventricle, sinoatrial node & AV node, portion of the left atrium & ventricle
what are the br of the right coronary artery
right marginal artery
posterior interventricular artery
where does most venous blood from cardiac veins drain
coronary sinus
what are the major tributaries the coronary sinus receives
great cardiac vein
middle cardiac vein
small cardiac vein of the RV
what happens to the great cardiac vein as it approaches the atrioventricular sulcus
turns sharply posteriorly and right as the coronary sinus
what tributaries does the great cardiac vein receive from the left ventricle
oblique vein
posterior vein of the left ventricle
when does the middle cardiac vein join the the coronary sinus
as it approaches the right atrium
what happens if small cardiac veins of the RV do not drain into the coronary sinus
they drain directly into the right atrium
which chamber of the heart does the coronary sinus drain into
right atrium
where do the left brachiocephalic veins drain
into the superior vena cava
what drains into the brachiocephalic veins
left subclavian and left int jugular veins
what is the function of the SA node
pacemaker- initiates heartbeat. impulse spreads over atrial walls causing them to contract and fill the ventricle
where is the SA node
sup aspect of crista terminalis and junction of sup vena cava and RA
what is the function of the AV node
pick up impulses from the atrial walls and replays the impulses down the interventricular septum via the bundle of His
where is the AV node
in the atrioventricular septum just above the coronary sinus
what is the function of the left and right atrioventricular bundles
synchronise contraction in different parts of the heart
what is the function of purkinje fibres
stimulate ventricular myocardium
what happens if there is damage to the SA node
other pacemakers act but may result in lowered heart rate or disturbed heart rhythm (arrhythmia)
what happens when there is damage to the AV bundles
bundle block- leads to heart failure & insufficient supply of blood to the body
what does it mean that the heart receives dual supply for extrinsic innervation
parasympathetic and sympathetic innervation
what supplies the ps innervation to the heart
vagus nerve (preganglionic axons)
what do the preganglionic ps fibres from left and right X reach the heart as
cardiac branches
where do the preganglionic fibres from X synapse
in ganglia located within the plexus or walls of the atria
what neurovascular bundle does X travel in
carotid sheath
where does the recurrent laryngeal br of X travel on the L and R
left- round aorta
right- round subclavian artery
where does X exit to
abdomen
what stimulation does X provide
lowers heart rate- (ActCh released)
reduces force of contraction
constricts the coronary arteries
where do to the sympathetic nerves originate from
sympathetic chain
thoracolumbar outflow
axons in these nerves postganglionic having synapsed in ganglia apart of the sympathetic chain
what is the stimulation of sympathetic nerves
raises heart rate
increases force of contraction (by releasing noradrenaline)
the superior mediastinum also subdivides further, what are these 3 divisiond
anterior
intermediate
posterior
what does the anterior part of the superior mediastinum contain (beneath sternum)
sternothyroid & sternohyoid
thymus gland
sup vena cava
brachiocephalic vein
what does the intermediate part of the superior mediastinum contain
aortic arches & branches
vagus & phrenic nerves
what does the posterior part of the superior mediastinum contain (in front of vertebra)
oesophagus
trachea
thoracic duct
left recurrent laryngeal nerve
what does the vagus nerve supply in the thorax
heart
bronchi
lungs
oesophagus
as X passes through the diaphragm what does it supply
stomach, part of intestines as far as transverse colon, liver, kidneys and spleen
where does the left recurrent laryngeal nerve originate
in the thorax but returns to the neck
what would happen if there was damage to the left recurrent laryngeal nerve
paralysis of the muscles of that move the vocal folds, except the cricothyroid muscle
what structures does the phrenic nerve supply in the thorax
motor to diaphragm & sensory supply also to diaphragm and pericardium
pleura covering the mediastinum and diaphragm
peritoneum on the abdominal side of the diaphragm
what does the phrenic nerve cross on the right to reach the structures it supplies
right brachiocephalic vein
sup vena cava
right side of pericardial sac to reach the caval opening of the diaphragm
what does the phrenic nerve cross on the left to reach the structures it supplies
left subclavian artery
left side of the pericardium to pierce the muscular part of the diaphragm
what joint forms at the sternal angle
symphysis
what would a left vocal fold paralysis indicate
damage to the left recurrent laryngeal nerve in the thorax because of advanced bronchocarcinoma
