Heart and Great Vessels Flashcards
pericardium structure and function
structure:
- fibrous sac surrounding the heart and roots of the great vessels
- fused inferiorly with the central tendon of the diaphragm
function: Attachments keep the heart in position & limit cardiac distension
fibrous pericardium structure
- outer layer of dense connective tissue of pericardium
- fuses superiorly with tunica adventitia of SVC, ascending aorta, and pulmonary arteries
what is the pericardium reinforced by?
2 sternopericardial ligaments anteriorly and posteriorly by loose CT attaches the pericardium to the tracheal bifurcation and main bronchi.
what is the pericardium overlapped by?
two pleural sacs and lungs
where the pleural deviates, it contacts with what?
contacts with posterior sternum surface and 4ht & 5th left intercostal spaces
laterally, the mediastinal pleura drapes over what?
the surface of the pericardium with the phrenic nerve and pericardiacophrenic artery and vein sandwiched between pleura and pericardium
posteriorly, pericardium contacts what 3 structures?
- esophagus
- descending thoracic aorta
- main bronchi
serous pericardium includes what?
-parietal and visceral layer
pericardial cavity
an enclosed sac with a potential space between the parietal and visceral layers of serous pericardium
what does the pericardial cavity contain?
thin film of fluid that enables the heart to move and beat in a relatively frictionless environment.
fibrous pericardium function
to retain the heart in position and limit its distension—it prevents sudden overfilling
parietal layer of serous pericardium is closelt adherent to what?
fibrous pericardium
epicardium
visceral layer of the serous pericardium is more loosely bound to the heart
The heart is completely invested in epicardium except what?
the posterior, irregular area between the venae cavae and pulmonary vv. where myocardium contacts fibrous pericardium.
development of heart and pericardial sinuses
- Form during embryonic life due to folding of embryonic heart tube
- As heart tube folds, venous end moves posterior and up, so venous end then is up by arterial end, separated by transverse sinus
- As veins of heart grow and expand, oblique sinus is formed, a recess, a blind sac behind posterior side of the heart.
reflections of pericardium
where 2 layers of pericardium meet each other
transverse sinus location
at arterial end where pulmonary trunk and aorta leave heart
oblique sinus location
at venous end where SVC, INC pulmonary veins enter the heart
pericardial sinuses
- can reach by inserting finger under apex of heart and pushing up and right towards root of the right lung
- assists with frictionless movement of the heart in pericardial cavity
Blood supply to the pericardium is via
is via
- pericardiacophrenic arteries
- musculophrenic arteries
- branches of the thoracic aorta (bronchial, esophageal, and superior phrenic)
- coronary arteries (to visceral layer only).
venous drainage is via
percardiacophrenic vv, internal thoracic vv, and tributaries of azygos system
somatic sensory innervation to the fibrous and parietal layers in pericardium is via
via phrenic nerves
visceral sensory to epicardium in pericardium is via
the cardiac plexuses
what is insensitive to pain?
epicardium
sensory innervation of the pericardium: vagus unknown and sympathetic trunks
vagus unknown- unknown
sympathetic trunks- vasomotor
pericarditis
- inflammation
- causes chest pain.
- occurs when the irritated layers of the pericardium rub against each other.
pericardial effusion
- presence of an abnormal amount of fluid and/or an abnormal character to fluid in the pericardial space.
- caused by a variety of local and systemic disorders, or it may be idiopathic.
cardiac tamponade
build-up of blood or other fluid in the pericardial sac puts pressure on the heart, which may prevent it from pumping effectively
pericardiocentesis
- subxiphoid approach
- needle inserted between the xiphoid process and L costal margin 30-45 degree angle
- aim for L mid-clavicle
- directs needle toward anterior wall of R ventricle
sinus venarum
smooth thin-walled posterior part that receives that venae cavae and coronary sinus
(part of right atrium)
where is sinus venarum derived from
embryonic sinus venosus
pectinate muscles
divided from the sinus venarum by the crista terminalis
part of right atrium
what divides the right and left atrium?
interatrial septum
fossa ovalis
remnant of the fetal foramen ovale and valve
what happens wht the patent foramen ovale is too large?
t allows O2 blood to be shunted to the right atrium
- > resulting in an overloading of the pulmonary system.
- the right atrium, right ventricle and pulmonary trunk will become enlarged.
where does the right ventricle receive blood from?
the right atrium thru the right atrioventricular orifice
how is the right ventricle guarded?
tricuspid valve
trabeculae carneae
irregular muscular elevations on the internal surface of the right ventricle
the interventricular septum has what 2 parts?
- muscular part
2. membranous part that is superior and posterior
conus arteriosus
cone-shaped pouch that leads into the pulmonary trunk
pulmonary valve
semilunar valve guarding the pulonary trunk
blood flow thru the right ventricle
from the right AV valve to pulmonary valve follows a U-shaped path
tricuspid
right AV valve
what are the 3 cusps of the right atrioventricular valve?
=(tricuspid valve)
- anterior cusp
- posterior cusp
- septal cusp
what are the papillary muscles associated with the right AV valve?
- anterior
- posterior
- septal
the function of atrioventricular valves
- prevent backflow into the atria during ventricular contraction.
- Papillary muscles and chordae tendineae prevent the cusps from prolapsing into the atria.
function of left atrium
receives oxygenated blood from the lungs via 4 pulmonary veins
structure of left atrium
smooth interior except for pectinate muscles in the left auricle
function of left ventricle
receives blood from left atrium through the left atrioventricular orifice
how is the left ventricle guarded?
by mitral valve
trabeculae carneae
how the internal surface of left ventricle is characterized
size of the left ventricle compared to the right ventricle
left is 2x as thick as the right ventricle wall
aortic vestibule
part that leads into aorta is smooth-walled
aortic valve
semilunar valve guarding acending aorta
blood flow through left ventricle
takes two right turns resulting in a 180 change in direction
ventricular septal defects occurs?
- most occur in muscular portion
- opening between L & R ventricles, associated shunting of blood
what are the 2 cusps associated with mitral valve
=(bicuspid valve)
- anterior cusp
- posterior cusp
what is the most commonly disease of the heart valves?
mitral valve
what can form on the cusps to result in turbulent flow?
nodules
hemodynamics
associated with valvular prolapse can erode the endothelial surfaces of the valve and predispose a patient to endocardial infections
what can mitral valve prolapse result in?
enlargement of left atrium
semilunar valves consist of what 2 valves?
- pulmonary
2. aortic valves
semilunar valves
3 cusps to prevent backflow into the ventricular relaxation
what valve is not associated with chordae tendineae and papillary muscles?
semilunar valves
each cusp of semilunar has what?
- fibrous nodule
- lunule
lunule
a thin CT area on either side of the nodule
location of nodule
at the midpoint of its free edge
what happens to the nodules and lunule when the valves close?
they meet in the center
the coronary arteries arise from what?
aortic sinuses
coronary arteries fill as the what___ fill following ventricular contraction
aortic sinuses
early development of semilunar valves
- both ventricles has 4 cusps
- under division into 2 vessels
- partial rotation of heart results in the final arrangement of aorta and pulomonary trunk
