Anatomy and Development of the Heart Flashcards
What makes up the right border of the heart?
Right atrium
What makes up the left border of the heart?
Mostly left ventricle and also the upper portion of the left atrium
What makes up the anterior surface of the heart?
Mostly the right ventricle with some right atrium on the right and some left ventricle on the left
What makes up the posterior surface of the heart?
Left atrium
What makes up the diaphragmatic surface of the heart?
Mostly the left ventricle with some right ventricle on the right side
Located behind the right third costal cartilage, 1/2 inch to the right of the sternum
Upper right corner of the heart
Located behind the right sixth costal cartilage, 1/2 inch from the sternum
Lower right corner of heart
Located behind the left second costal cartilage, 1/2 inch to the left of the sternum
Upper left corner of heart
Located behind the left fifth intercostal space, 3 1/2 inches to the left of the sternum
Lower left corner of heart
What are three surface landmarks of the heart?
- ) Coronary sulcus
- ) Anterior interventricular sulcus
- ) Posterior interventricular sulcus
Separates the atria from the ventricles
Coronary sulcus (atrioventricular sulcus)
The coronary sulcus contains what 4 blood vessels?
- ) Right coronary artery
- ) Circumflex branch of left coronary artery
- ) Coronary sinus
- ) Great cardiac vein
Separate the right and left ventricles on the anterior and posterioinferior surface of the heart
Anterior and posterior interventricular sulci
Which two blood vessels does the anterior interventricular sulcus contain?
- ) Anterior interventricular artery (left anterior descending artery) - branch of the left coronary artery
- ) Great cardiac vein
Which two blood vessels does the posteriointerventricular sulcus contain?
- ) posterior interventricular artery (right posterior descending) - branch of right coronary artery
- ) Middle cardiac vein
The heart cycle is divided into
Systole and Diastole
The period during which the heart chamber is contracting
Systole
The period in which the heart chamber is relaxing
Diastole
Atrial systole precedes ventricular systole by about
0.15 seconds
When we just use the terms systole and diastole, we are referring to the
Ventricular cardiac cycle
What are the two AV valves?
- ) Tricuspid
2. ) Mitral (Bicuspid)
AV valve between the right atrium and right ventricle
Tricuspid
AV valve between the left atrium and left ventricle
Mitral (Bicuspid)
What are the two outflow valves?
-semilunar valves
- ) Pulmonic
2. ) Aortic
Valve between the right ventricle and pulmonary trunk
Pulmonic valve
Valve between the left ventricle and ascending aorta
Aortic valve
The first heart sound (S1) is the sound of
Closure of the AV valves at the start of ventricular systole
The second sound (S2) is the sound of the
Closure of the outflow valves at the start of ventricular diastole
Normal valve sounds are heard best by placing the stethoscope on the anterior chest wall over the region
Distal (downstream) to the valve
Heard best over the right ventricle in the left fifth intercostal space at the left sternal margin
Tricuspid valve
Heard best over the left ventricle in the left fifth intercostal space about 3 inches to the left of the sternum (midclavicular line)
Mitral (bicuspid) valve
Heard best over the ascending aorta in the right second intercostal space at the right sternal margin
Aortic valve
Heard best over the pulmonary trunk in the left first or second intercostal space at the left sternal margin
Pulmonary valve
The sounds generated by turbulent blood flow within or near the heart
Heart murmurs
Caused by blood passing through a narrow opening
Turbulence
At the valves, a narrowed opening may be caused by one of which two things?
- ) Stenosis (valves dont fully open)
2. ) Incompetence (valves don’t fully close)
The normal direction of blood flow is called
Orthograde flow
Blood will pass through the valves in its orthograde flow, but there will be a turbulence in the flow, which produces a murmur
Stenosis
Blood flows through the defect in the valve in a retrograde flow (regurgitation) during the part of the heart cycle when the valve should be closed
Incompetence
Valvular stenosis will be herd as murmurs when the valve is
Open
Valvular incompetence will be heard as murmurs when the valve is
Closed
A systolic aortic murmur (aortic stenosis) will be best heard over the
Ascending aorta in the right second intercostal space as the sternal border
A diastolic aortic murmur (aortic insufficiency) will be heard best over the
Left ventricle at the left fifth intercostal space at the midclavicular line
Atrial landmark that is derived from embryonic veins near the heart
Smooth walled area or atria
What is the smooth walled area made up of in the
- ) Right atrium
- ) Left atrium
- ) Right horn of sinus venous
2. ) Pulmonary vein
An internal landmark of the atria that is derived from the primitive atrium
Rough walled area
Internal landmark of the atria that marks the region where embryonic septum secundum and septum primium did not overlap
Fossa ovalis
The floor of the fossa ovalis is derived from
Septum Primium
The upper margin of the fossa ovalis and the free edge of the septum secundum
Limbus of fossa ovalis
May remain anatomically patent (probe patency) in
up to 25% of population although it is functionally closed
Limbus of fossa ovalis
The site of embryonic foramen ovale
Limbus of fossa ovalis
Internal landmark of the atria that is a ridge that separates the rough walled from the smooth walled portion of the RIGHT atrium
Crista terminalis
Marks the embryonic junction of sinus venosus and primitive atrium
Crista terminalis
Fold of tissue in the right atrium to the left of the orifice of the inferior vena cava
Valve of inferior vena cava
In the embryo, directed blood from the inferior vena cava to the foramen ovale
Valve of the inferior vena cava
Internal landmark of the atria in the right atrium to the left of the inferior vena cava
Orifice of coronary sinus
Where we see venous return from most of the myocardium
Orifice of the coronary sinus
The orifice of the coronary sinus is derived from the
Central portion of sinus venosus
An internal landmark of ventricles that is derived from the embryonic artery near the heart (conus cordis)
Smooth walled area of ventricles
Derived from the primitive ventricle (left) and proximal part of the bulbus cordis (right)
Trabeculae carneae (rough walled area)
Internally projecting bundles of cardiac muscle
- bases are continuous with ventricular wall muscle
- internal landmark of ventricles
Papillary muscles
Fibrous strands that connect the papillary muscles to the free borders of the atrioventricular valves
Chordae Tendineae
Together with the papillary muscles, prevent prolapse of the A-V valves
Chordae Tendineae
The trabecula carneae in the right ventricle connecting the ventricular septum to the base of the anterior papillary muscle
Septomarginal Trabecula (moderator band)
The septomarginal trabecula (moderator band) contains
Conducting (Purkinje) fibers from the right bundle branch
The septomarginal trabecula provides a pathway for conducting fibers to reach the
Anterior papillary muscle
The muscular ventricular septum is derived from the
Embryonic ventricular septum
Derived from the aorticopulmonary septum and endocardial cushions
Membranous ventricular septum
The heart is supplied by two coronary arteries which are the only branches of the ascending aorta. The
arteries arise from the walls of the
Aortic sinuses
-behind right and left cusps of the aortic valve
Lies in the coronary sulcus and anastomoses with the circumflex branch of the left coronary artery
Right coronary artery
The right coronary artery supplies the
Right atrium, right ventricle, interatrial septums, and both the SA and AV nodes
Anastomoses with anterior interventricular artery. Supplies right and left ventricles
-branch of right coronary artery in 80% of people
Posterior interventricular artery (Posterior descending artery, RPD)
A branch of the right coronary artery that supplies the right ventricle
Right marginal artery
Arises from left side of aorta and passes behind pulmonary trunk and anterior to left auricle to reach the coronary sulcus
Left coronary artery
At the coronary sulcus, the left coronary artery divides into the
Anterior interventricular and circumflex arteries
Supplies right and left ventricles and interventricular septum
-anastomoses with posterior interventricular artery
Anterior interventricular artery (Left anterior descending artery, LAD)
Branch of left coronary artery that lies in the coronary sulcus and supplies the left atrium and left ventricle.
-Anastomoses with right coronary artery
Circumflex artery
Venous drainage of the heart is mostly by veins that drain into the
Coronary sinus
The coronary sinus then drains into the
Right atrium
What are two veins that do not drain into the coronary sinus but rather empty directly into the chambers of the heart?
- ) anterior cardiac veins (into right atrium)
2. ) Least cardiac (Thesbian) veins (into all chambers)
Composed of modified cardiac muscle cells (Purkinje fibers) NOT nerve cells
Cardiac conduction system
Located in the subepicardium of the right atrium near the entrance of the superior vena cava
Sinoatrial (SA) node
Contains cells that depolarize faster than typical cardiac muscle cells and therefore it acts as a pacemaker for the heart
SA node
Depolarization from the SA node spreads through the
Atrial walls
Retards (slows) the wave of depolarization from the SA node as it passes through the atrioventricular bundle
Atrioventricular (AV) node
Located in the subendocardium of the right side of the interatrial septum
AV node
Conducting fibers that leave the AV node and pass through the cardiac skeleton to reach the interventricular septum
Atrioventricular (AV) bundle
The only normal electrical connection between the atria and ventricles
AV bundle
Right and left branches of the AV bundle which travel in the right and left sides of the interventricular septum
Bundle branches
The heart can function without any
Innervation
The preganglionic sympathetic nerves that innervate the heart arise from the
Upper thoracic spinal cord
The preganglionic sypathetic nerves synapse and become the postganglionic sympathetic nerves that innervate the heart in the
Cervical and upper thoracic sympathetic ganglia
These postganglionic sympathetic axons travel from the sympathetic ganglia to the heart via the
Cardiac nerves
The preganglionic parasympathetic innervation of the heart is from the
Vagus nerve
The preganglionic parasympthetic nerves that innervate the heart synapse in the
Cardiac plexus
The nerves that can sense ischemia (i.e. reach conscious levels) course with the sympathetic fibers and enter the CNS at
Upper thoracic and cervical levels
-cell bodies are in dorsal root ganglia
Those sensory neurons that serve as the afferent limbs of cardiac reflexes (i.e. do not reach conscious levels) course with the vagus nerve and enter the CNS at the
Medulla
-cell bodies in the inferior ganglion of the vagus nerve