Mediastinum & Heart Flashcards
(31 cards)
pericardium
double walled fibrous membrane that encloses the heart (pericardial sac/fibrous pericardium AND visceral layer of serous pericardium)
pericardial sac/fibrous pericardium
- external fibrous layer of dense connective tissue
- fused with tunica advent of greater vessels & entering and leaving the heart
- prevents heart from overfilling
- comparable to spinal dura in toughness
visceral layer of serous pericardium
aka epicardium
- lines surface of the heart
- contains serous fluid
- can’t dissect it off
parietal layer of serous pericardium
- lines inner surface of fibrous pericardium
- continuous with visceral serous pericardium around great vessels & along lines of attachment between them
- fluid between the parietal and visceral layers allow for rubbing on a low friction surface
(liquid created by both layers)
recesses in pericardium
places where parietal & visceral layers come together & allow for structures to enter
- oblique sinus
- transverse sinus
oblique sinus
between posterior surface of the heart and pericardial sac –> where SVC, IVC and pulmonary veins enter the heart
transverse sinus
between aorta & pulmonary trunk - in front of SVC and left atrium
–> where aorta & pulmonary trunk leave the heart
Atrial supply to the pericardium
PRIMARY- from the pericardiacophrenic artery from the internal thoracic artery
SECONDARY- from the musculophrenic artery from the internal thoracic artery
- bronchial, esophageal & superior phrenic arteries from the thoracic aorta
venous drainage of pericardium
pericardiophrenic veins & azygos venous system
Nerve to pericardium
Phrenic nerve – C3, C4, C5 – vital for survival, innervates diaphragm…
- goes through the root of lung & descends past the parietal sac into the pleura
- sensory fibers: cause “referred pain”
Referred pain
visceral pain but the original presentation of this pain is to the cuteaneous areas of skin
ex: pain in left arm with a heart attack
- this is because dermatomes are located there - C3, C4, C5 (phrenic nerve) - provides pain from pericardium and refers it out to upper extremity
- referred pain eventually will become visceral pain
diastole
period of ventricular elongating & filling
systole
period of ventricular shortening and emptying
lub
blood is sucked from atria to ventricle
dub
ventricular contraction and expulsion of blood from the heart
epicardium
thin external layer of heart formed from the visceral layer of the serous pericardium
myocardium
thick, middle layer of heart composed of cardiac muscles
endocardium
thin internal layer of the heart – covers heart valves
- holds the orifices in place
- forms our fibrous skeleton wall
MV prolapse
btwn left AV orifice is mitral valve
- condition occurs if we didn’t get full closure of the valve and the blood pushes back into the atrium
fibrous skeleton of heart
- anchors muscle fibers
- forms 4 fibrous rings to surround orifices of valves & surround R & L trigones
FUNCTION-
- keeps orifices of the AV & semilunar valves patent & from being overly distended
- provides attachment for leaflets & cusps of valves
- provides attachment for myocardium
- forms an electrical insulator
- provides passage for initial part of AV bundle
Apex of heart
inferior point
- directly anterior & to left - is formed by the inferolateral part of the left ventricle
- located posterior to the left of the 5th intercostal space 9 cm from midline
- where sound of mitral valve closing is maximal
- underlies the site where the heartbeat may be osculated on the thoracic wall
Base of Heart
- heart’s posterior aspect
- formed mainly by the left atrium, some of right atrium
- faces posteriorly - towards bodies of T6-T9
- extends superiorly to the bifurcation of the pulmonary trunk & inferiorly to the coronary groove
- receives pulmonary veins on the right and left sides of its left atrial portion & the SVC & IVC at the right atrial portion
right border
- formed by the right atrium between SVC & IVC
inferior border
- formed mainly by right ventricle and slightly by left ventricle
