13 - Heart Flashcards
Layers of the Heart Wall
Epicardium
Myocardium
Endocardium
Epicardium =
visceral layer of serous pericardium
Endocardium =
lining the chambers (endothelium)
Atrioventricular (AV) valves
Separate atria & ventricles
Semilunar valves
Between ventricles & ejecting vessels
Interatrial (IA) septum
Separates R & L atria
Interventricular (IV) septum
Separates R & L ventricles
Smooth wall portion
: Derived from
sinus venosus
Auricle (roof)
rough with
Rough with pectinate mm.
Crista terminalis
Vertical ridge separating smooth part from rough
Fossa ovalis
Remnant of
foramen ovale in IA wall
The right atrium will receive deoxygenated blood from
SVC, IVC, & coronary sinus. This deoxygenated blood will flow towards the AV orifice to get to the right ventricle.\
Right AV Valve
Tricuspid valve
Anterior cusp
Septal cusp
Posterior cusp
Right AV Valve: Anchored via
chordae tendineae to papillary mm.
Interior wall – rough with Left Ventricle
trabeculae carneae
Septomarginal trabecula (moderator band) – located Left Ventricle
medially; this structure makes up part of conduction system of heart
Conus arteriosus (infundibulum) – funnel to
pulmonary trunk
Pulmonary Valve
In pulmonary trunk
At apex of infundibulum
Pulmonary valve consists of
Consists of 3 cusps
Left
Right
Anterior
Auricle (roof) – rough with
pectinate mm.
4 pulmonary vv. enter
atrium posteriorly
Valve of foramen ovale – define
fossa ovalis in IA wall
Left AV Valve
Bicuspid (mitral) valve
Anterior cusp
Posterior cusp
Left AV Valve: Anchored via
chordae tendineae to papillary mm.
Anterior & posterior papillary mm control both cusps
Left Ventricle: Interior wall – rough with
trabeculae carneae
Left Ventricle: Aortic orifice – leads into
ascending aorta
Left Ventricle:
no
moderator band muscle wall (myocardium) is typically 3x thicker (normally ~ 1 to 1.5 cm thick)
Aortic Valve
Consists of 3 cusps
Left
Right
Posterior
The four valves of the heart (along with the myocardium) are attached to this
fibrous skeleton which is composed of dense collagen rings (4) & trigones
The fibrous skeleton provides
attachment, support, & insulation
Coronary arteries arise from
either side of the aortic sinuses
will give off multiple branches
Most cardiac veins will drain into the
coronary sinus (located on the posterior of the heart) drains into right atrium
Right Coronary Artery
Supplies Right atrium Right ventricle Sinu-atrial node Atrioventricular nodes Interatrial septum Portion left atrium Posteroinferior 1/3 IV septum Portion posterior part left ventricle
Right coronary artery: Travels in
coronary sulcus around right side of heart
Right coronary artery: Turns inferior to become
posterior interventricular a.
Right coronary artery: Lies in the
posterior interventricular sulcus
Right Coronary Artery Branches:
Ant. right atrial a.
-Sinu-atrial nodal a.
Right marginal
Posterior interventricular a.
Right Coronary Artery: Right coronary a. travels in
coronary sulcus around right side of heart
Turns inferior to become posterior interventricular a.
Lies in the posterior interventricular sulcus
Right Coronary Artery supplies
The right coronary artery supplies the right atrium and right ventricle, the sinu-atrial and atrioventricular nodes, the interatrial septum, a portion of the left atrium, the posteroinferior one third of the interventricular septum, and a portion of the posterior part of the left ventricle.
Left Coronary Artery: supplies most of
Left atrium
Left ventricle
Interventricular septum,
Atrioventricular bundle and its branches
Left coronary a (proper) actually
very short
Divides into anterior interventricular a. & circumflex aa.
Left Coronary Artery Branches
Ant. interventricular a. (also called left ant. descending a. – LAD)
Circumflex a.
Left marginal a.
Ant. interventricular a. runs in
anterior IV sulcus
Circumflex a. runs in
coronary sulcus
Gives off L marginal br. to supply lateral L ventricle
Circles around L side of heart
The distribution pattern of the .
left coronary artery enables it to supply most of the left atrium and left ventricle, and most of the interventricular septum, including the atrioventricular bundle and its branches
Frequently one coronary a. is more
dominant
This means that it gives off the posterior interventricular artery and supplies more of the heart.
R coronary a. = dominant in
~65% of cases
crosses over to supply L ventricle posteriorly
L coronary a. = dominant in
~15% of cases
crosses over to supply R ventricle posteriorly
Balanced arterial pattern
~ 20% of cases
Most vv of heart are tributaries to
coronary sinus
Lies in posterior portion of coronary sulcus
Opens into right atrium (between the IVC & AV orifice)
Venous Drainage of Heart – Great Cardiac Vein: Travels with
anterior IV a. in anterior IV sulcus
Turns left to run in coronary sulcus superiorly
Travels with circumflex a. around left side of heart
Empties into coronary sinus posteriorly
Venous Drainage of Heart – Middle Cardiac Vein: Travels with
posterior interventricular a. in posterior IV sulcus
Empties into coronary sinus superiorly
Venous Drainage of Heart – Small Cardiac Vein
Travels with right marginal a. along lateral right ventricle
Turns right to run in coronary sulcus superiorly
Travels with right coronary a. around right side of heart
Empties into coronary sinus posteriorly
Venous Drainage of Heart – Anterior Cardiac Veins: travels with
Travels with anterior right ventricular aa. along anterior right ventricle
Ascend toward right auricle empty directly into right atrium
Do NOT empty into coronary sinus
Cardiac Catherization
A procedure used to diagnose and treat cardiovascular conditions. During cardiac catheterization, a long thin tube called a catheter is inserted in an artery or vein in the groin, neck or arm and threaded through blood vessels to the heart.
Occlusion of major coronary artery, usually due to
atherosclerosis, leads to inadequate oxygenation of an area of myocardium and eventually cell death
Great Saphenous v. – commonly used for
bypass grafts
Harvested from the anterior/medial region of the thigh or leg
Can be sutured into aorta & distal branch of a coronary a.
Must consider the arrangement of valves within the saphenous vein
Int. Thoracic a. & Radial a. may also be used
Heart has its own
conduction system
Heart Does not REQUIRE
CNS innervation to initiate heartbeat
With sufficient O2 & nutrition, heart will beat without CNS initiation
Normal ~70 beats per min
Damage to Conduction System causes
cardiac arrhythmias
Damage to AV node will cause
heart block
uncoordinated contraction
Pacemaker may be inserted to control the
contractions Different types: single chamber dual chamber biventricular
Placement of a Pacemaker
battery pack inserted
subcutaneously below clavicle
Electrode threaded down thru SVC to R atrium
Passed thru AV valve into R ventricle
Electrode terminal firmly fixed to trabeculae carneae
Placed in contact with endocardium of ventricular wall
A chest x-ray can be very useful in detecting abnormalities in the
structure of the heart and great vessels.
This requires an understanding of the cardiac and vascular structure anatomy
ANS does affect rate of
heartbeat
Heart receives sympathetic innervation from
T1-T5
Heart receives parasympathetic innervation from the
Vagus n. (CN X)
Both sympathetic & parasympathetics contribute to both
superficial and deep cardiac plexuses of nerves
Impulses initiated by
SA node travel to AV node
Propagation allow for atrial contraction
Impulses then travel to
AV bundle & IV septum
Bundle divides into
R & L bundle branches
Purkinje fibers travel to
ventricles for contraction
also supply
papillary muscles
The heart’s conduction system is formed
by specialized cardiac muscle cells that form nodes and by unidirectional conduction pathways that initiate and coordinate excitation and contraction of the myocardium
Consists of SA node, AV node & AV bundle, bundle branches & purkinje fibers
The SA node is called the
“pacemaker” where the initiation of action potentials occurs
in crista terminalis between R atrium & SVC
AV Node & Bundle
in
IA septum near coronary sinus opening
Bundle branches course down the
IV septum (R&L)
