[USMLE] Heart Summary Flashcards
The base of the heart is formed by the
atria that lie behind the ventricles
The apex of the heart lies in the
left fifth intercostal space slightly medial to the midclavicular (or nipple) line
location is for auscultating the mitral valve
left fifth intercostal space
crista terminalis
is a vertical muscular ridge running anteriorly along the right atrial wall from the opening of the SVC to the opening of the IVC, providing the origin of the pectinate muscles.
crista terminalis presents the junction between the
primitive sinus venarum and the right atrium proper
crista terminalis is indicated externally by the
sulcus terminalis
left vs right atrium
The left atrium is smaller and has thicker walls than the right atrium
left atrium
the most posterior of the four chambers
The left ventricle forms the
heart’s apex
left vs right ventricle
performs harder work, has a thicker wall, and is more conical-shaped than the right ventricle.
The papillary muscles contract to tighten the
chordae tendineae
an isolated band of trabeculae carneae that forms a bridge between the interventricular septum and the base of the anterior papillary muscle of the right ventricle
septomarginal trabecula (moderator band)
septomarginal trabecula (moderator band) carries the
right limb (Purkinje fibers) of the AV bundle
the first heart sound is caused by the
closure of the tricuspid and mitral valves at the
onset of ventricular systole
the second heart sound is caused by the
closure of the aortic and pulmonary valves and vibration of walls of the heart and major vessels at the onset of
ventricular diastole
most audible over the right lower part of the body of the sternum
tricuspid (right AV) valve
most audible over the apical region of the heart
in the left fifth intercostal space at the midclavicular line
bicuspid or mitral (left AV) valve
most audible over the left second intercostal space just lateral to the sternum
pulmonary valve
most audible over the right second intercostal space just lateral to the sternum
aortic valve
the pacemaker
SA node
The SA node (pacemaker) lies in the
myocardium at the upper end of the crista terminalis and initiates the heartbeat
Impulse travels from the
SA node through the atrial myocardium to the AV node that lies in the interatrial septum and then to the AV bundle (of His) that runs along the membranous part of the IV septum, right and left bundle branches that descend into the muscular part of the IV septum, terminal conducting fibers (Purkinje fibers), and the ventricular musculature.
These arteries arise from the ascending aorta
coronary arteries
coronary arteries have maximal blood flow during diastole and
diastole
coronary arteries have minimal blood flow during
systole (because of compression of the arterial branches in the myocardium during systole)
The right coronary artery gives off the
sinuatrial nodal, marginal, posterior IV, and AV nodal
arteries
The left coronary artery is shorter than the right one and divides into the
anterior IV and circumflex arteries
All cardiac veins , including the great, middle, small, and oblique cardiac veins, drain into the
coronary sinus except the anterior cardiac vein
the anterior cardiac vein drains into the
right atrium
formed by the union of the right ascending lumbar and right subcostal veins. Its lower end is connected to the IVC.
azygos vein
the azygos vein arches over the
root of the right lung
the azygos vein empties into the
SVC
thoracic duct begins in the
abdomen at the cisterna chyli , which is the dilated junction of the intestinal, lumbar, and descending intercostal trunks
thoracic duct drains all parts of the body except the
right head, neck, upper limb, and thorax
the right head, neck, upper limb, and thorax are drained by the
right lymphatic duct
the thoracic duct passes through the
aortic opening of the diaphragm, ascends between the aorta and the azygos vein
the thoracic duct empties into the
junction of the left internal jugular and subclavian veins
greater splanchnic nerve arises from the
fifth through ninth thoracic sympathetic ganglia and
greater splanchnic nerve ends in the
celiac ganglion
lesser splanchnic nerve arises from the
tenth and eleventh thoracic sympathetic ganglia
lesser splanchnic nerve ends in the
aorticorenal ganglion
least splanchnic nerve arises from the
twelfth thoracic sympathetic ganglia
least splanchnic nerve in the
renal plexus
All of these splanchnic nerves contain
preganglionic sympathetic GVE fibers and GVA fibers
cell bodies of the preganglionic sympathetic GVE fibers are located in the
lateral horn (intermediolateral cell column) of the spinal cord
cell bodies of GVA fibers are located in the
dorsal root ganglia
contain preganglionic sympathetic GVE fibers with cell bodies located in the lateral horn of the spinal cord and GVA fibers with cell bodies located in the dorsal
root ganglia.
White rami communicantes
White rami communicantes are connected to the spinal nerves and limited to the spinal cord segments between
T1 and L2
contain postganglionic sympathetic GVE fibers with cell bodies located in the sympathetic chain ganglia
Gray rami communicantes
Gray rami communicantes are connected to every spinal nerve and supply the
blood vessels, sweat glands, and arrector pili muscles of hair follicles
