Middle Mediastinum / Heart Flashcards
what are the divisions of the mediastinum? where are they?
superior mediastinum - sternal angle at TV2 to the sternal angle of Louis at TV4-5
inferior mediastinum - sternal angle of Louis to diaphragm
what are the divisions of the inferior mediastinum?
anterior
middle
posterior
where does the anterior mediastinum lie?
between sternum and pericardium
what is in the anterior mediastinum?
fat and lymph nodes
where is the middle mediastinum
between mediastinal pleura and pericardium
what is in the inferior middle mediastinum
pericardium
heart
great vessels
where are the phrenic nerves located?
between mediastinal pleura and pericardium
what is the pericardium?what is in it?
sac that surrounds the heart and proximal aspect of great vessels
where is the pericardial cavity
located between parietal and visceral pericardial layers
where do the great vessels enter/exit the heart?
parietal and visceral layers of serous pericardium
what structures are in the posterior mediastinum?
structures that extend the full length of the thoracic cavity
what structures extend the full length of the thoracic cavity
thoracic aorta
esophagus
vagus nerves
azygos system of veins
thoracic duct
what does the aorta do?
carry oxygenated blood from left ventricle to body
what is the ligamentum arteriosum?
remanants of fetal ductus arteriosus that connects inferior arch of the aorta to the left pulmonary artery
what is the function of the superior vena cava vs inferior vena cava?
blood return from upper body to right atrium vs blood return from lower body to right atrium
what does the pulmonary trunk do?
carry unoxygenated, arterial blood from right ventricle to lungs via pulmonary arteries
what are the pulmonary arteries?
parallel bronchi that distribute to the bronchipulmonary segments
what do pulmonary veins do? how many of them are there?
two in each lung that return oxygenated blood to the left atrium
what is the atrioventricular sulcus
a coronary groove that separates atria from ventricles
what can be found in the AV sulcus?
right coronary artery
circumflex artery
coronary sinus
where is the right coronary artery?
at the av sulcus, on the right anterior aspect and loops around posteriorly
what is the circumflex artery?
a branch of the left coronary artery on left lateral side
what is the function of the coronary sinus? what is received there?
main venous channel of the heart
great, middle and small cardiac veins
what is the interventricular sulcus?
a division between right and left ventricle in anterior and posterior fashion
what is the LAD
left anterior descending artery
branch of the left coronary artery
what is the PDA
posterior descending artery
what is a right dominant heart vs a left dominant heart
if the PDA is a termination of the right coronary artery it is right dominant
if the PDA is a branch off the circumflex artery it is (left dominant)
what is the right border of the heart formed by? where is it located?
right atrium / right parasternal line
what is the left border of the heart formed by?
left ventricle and part of left auricle
what is the apex of the heart formed by?
left ventricle and lies in 5th ICS 3.5 inches to the left
what is the inferior border formed by?
right ventricle sitting on diaphragm
what is the superior border formed by?
great vessels
aorta
superior vena cava
pulmonary trunk
what makes up the internal surface?
right and left atrium
left and right ventricle
what are the pectinate muscles
original atrial portion of the heart and are in the right auricle
what is the coronary sinus?
cardiac vein that brings blood to the right atrium
what are the anterior cardiac veins and how many of them are there?
veins that are on the anterior wall of the right ventricle
3
what are the venae cordis minimae
capillary beds of the myocardium of the right atrium
what is the fossa ovalis
a depression in the interatrial septum
what is the foramen ovale
during embryo and fetus stages, it is a gap in the heart that allows for blood to pass from right to left side w/o going to lungs
is the right or left ventricle thicker?
left
what are the trabeculae carnae
rough interior surface of right ventricle that is formed by ridges of muscle
how many papillary muscles are there? what are their names
3
anterior, posterior and septal
what do the papillary muscles connect to?
chordae tendinae
septomarginal trabecula (moderator band)
what is the chordae tendinae? what is their function
cord-like structures that extend between valves to the papillary muscles
hold valves to prevent prolapse during systole
what is the septomarginal trabecula?
fibers of the conduction system that extend from the intraventricular septum to the base of anterior papillary muscle
what is the left atrium composed of?
smooth muscle wall that receives blood from 4 or 5 pulmonary veins
what is the left ventricle made of
extensive trabeculae carnae
2 papillary muscles (ant/post)
chordae tendinae
what are the four valves in the heart
pulmonary semilunar
aortic semilunar
tricuspid
bicuspid (mitral)
what does the pulmonary semilunar valve do? where is it?
3 semilunar cusps that control outflow of blood from right ventricle to pulmonary trunk
anterior to aortic valve
what is the aortic semilunar valve? what comes from it?
three semilunar cusps that control blood from left ventricle to the ascending aorta
right and left coronary arteries branching from aortic sinus
what is the tricuspid valve?
3 leaflets - right atrium to right ventricle
what is the bicuspid valve
2 leaflets - control blood from left atrium to left ventricle
what is the right coronary artery
artery that originates from ascending aorta in the AV sulcus
what are the branches of the right coronary artery
right atrial / SA nodal branch
right marginal branch
posterior interventricular descending branch
where is the right atrial branch of the right coronary artery
heads toward superior vena cava over the anterior surface of right atrium to the SA node
where is the right marginal branch
what does it do
apex along the acute margin to supply inferior aspect of right ventricle
what is the job of the posterior interventricular branch
small branch to the AV node and descends to posterior sulcus to supply both ventricles
what is the AV nodal artery
brach of the posterior IV branch
what are the branches of the left coronary artery?
LAD artery
circumflex artery
where is the left coronary artery
ascending aorta behind the left cusp of the aortic valve and foes between pulmonary trunk and left auricle
what are the veins
great cardiac
middle cardiac
small cardiac
coronary sinus
anterior cardiac
what does the great cardiac vein do
accompanies LAD / beginning of coronary sinus in AV groove
what does the middle cardiac vein do?
accompanies the PDA / empties into coronary sinus
what does the small cardiac vein do?
goes along the inferior, acute margin of the heart with right coronary artery / drains into coronary sinus at right atrium
what is the function of the coronary sinus
lies in AV groove posteriorly and empties into right atrium
what does the anterior cardiac vein do
bridges across AV sulcus and right coronary artery to empty into right atrium
what are the innervation points of the heart
SA node
AV node
AV bundle
Extrensic Nerves
what is the SA node / where is it
collection of specialized cardiac muscle cells in wall of right atrium at junction of superior vena cava and sulcus terminales
what does the SA node do? what special about it?
“pacemaker”
origin of intrinsic electrical impulse
has its own rhythm of 72 bpm
what is the AV node? what does it do?
specialized myocardial cells in the interatrial septum
relays nerve impulses to the AV bundle
what is the AV bundle
specialized myocardium that passes from the AV node and transmits impulses through the IV septum to right and left side
what fibers are found in the ventricular walls? what signals them?
Purkinje fibers signaled by AV bundle
what are the extrensic nerves that control the heart?
Vagus Nerve
Cardiac Sympathetic
what does the vagus nerve do to the heart? what can it be categorized as?
preganglionic parasympathetic fiber within the atria of the heart near SA/AV nodes
decreases heart rate
what does the cardiac sympathetic nerves do to the heart?
cardiac splanchnic nerves from cervical and upper thoracic symp chain that increase heart rate
