Lesson 3 Flashcards
Describe the Chordae tendineae.
- fibrous cord-like structures that connect to the leaflets of the
atrioventricular valves - these cords prevent the leaflets from collapsing back into the atria during ventricular systole
Describe Papillary muscles.
- finger-like structures that project from the ventricular wall and attach to valve leaflets via chordae tendineae
- In the right ventricle, there are three papillary muscles; in the left there are two
Describe the tricuspid valve.
- prevents the backflow of blood from the right ventricle to the right atrium during ventricular systole
- tricuspid valve has three leaflets or cusps: the
anterior (superior), posterior (inferior), and septal - leaflets are twice the size of the orifice, so when the valves close during ventricular contraction, the leaflets bulge into the atrium like a parachute and overlap each other
- the junction between two leaflets is called a commissure
Describe the mitral valve.
- prevents the backflow of blood from the left ventricle to the left atrium during ventricular systole
- valve consists of two leaflets (anterior & posterior), an
annulus, two papillary muscles, and chordae tendineae - just like the tricuspid valve, the mitral valve’s leaflets are bigger than the orifice, which allow them to overlap when closed
Describe the function of the pulmonic valve.
- located at the opening of the pulmonary artery and prevents backflow from the artery into the right ventricle during diastole
- has three symmetrical leaflets or cusps
- attached or suspended to the root of the pulmonary artery
What is the sinus of Valsalva?
Each cusp of the pulmonic valve looks like a cup or upside down umbrella when closed. The
recessed part of the cusp is known as the sinus of Valsalva
The pulmonary valve does not have chordae tendineae. Instead, the free edge of each cusp has nodules known as, what?
Nodules of Arantius or nodules of Morgagni
What is the linea alba?
When the cusps of the pulmonic valve are closed, the junction between two leaflets is called the linea alba.
Describe the function of the aortic valve.
- located at the opening of the aorta and prevents backflow from the aorta into the left ventricle during diastole.
- composed of 3 symmetrical cusps.
- the aortic valve also has the sinus of Valsalva, nodules
of Arantius or Morgagni, and linea alba
What are the special features of the cusps of the aortic valve?
- The left and right aortic
leaflets have an opening or os that lead to the left coronary artery (LCA) and right coronary
artery (RCA) respectively. - The posterior cusp is also referred to as the non-coronary leaflet because it has no os.
- The os of the coronary arteries are located in the upper third of their respective sinus of Valsalva. After systole, the tail end of blood that was propelled into the aorta has a tendency to fall back into the left ventricle as it begins to relax. This blood fills
the sinus of Valsalva, forcing the valves closed, and then enters both the os of the left and
right coronary arteries, delivering blood to the myocardium
What are coronary arteries?
The coronary arteries are blood vessels dedicated to supplying the heart’s tissues with
nourishment.
Where do the RCA (right coronary artery), and LCA (left coronary artery) originate from?
Each of these arteries originates from the os of their respective aortic sinuses – the RCA originates from the os of the right aortic sinus; the LCA
originates from the os of the left aortic sinus.
What are the branches of the RCA?
- Conus Artery
- Atrial Artery (subbranches to the SA nodal artery)
- Acute Marginal Artery
- Right Posterior Descending
Artery (subbranches to the Posteroseptal Artery) - AV-Nodal Artery
- Posterior Left Lateral Branch
What does the Conus Artery of the RCA supply?
Conus arteriosus (infundibulum)
What does the Atrial Artery of the RCA supply?
- Bachmann’s bundle
- Crista terminalis
- Left and right atrial
free wall
SA-Nodal Artery
- SA-node in approx. 60% of population
What does the Acute Marginal Artery of the RCA supply?
- Acute margin
- Right ventricular septum
- Anterior and posterior wall of right ventricle
What does the Right Posterior Descending Artery of the RCA supply?
- Posterior wall of right ventricle
Posteroseptal Artery
- Posterior 1/3 of ventricular septum
What does the AV-Nodal Artery of the RCA supply?
- AV-node in approx. 90% of population
What does the Posterior Left Lateral Branch of the RCA supply?
- Diaphragmatic surface of left
ventricle - Posterior papillary muscle of bicuspid valve
What are the branches of the LCA?
- Left Anterior Descending
Artery (branches into First Septal Perforator, Second & Third Septal Perforators, First diagonal, Second Diagonal) - Ramus Intermedius Artery
- Circumflex Artery (branches into Left Atrial Artery, Obtuse Marginal Artery)
What does the Left Anterior Descending Artery of the LCA supply?
- Anterior 2/3 of ventricular septum
- Whole apex
First Septal Perforator
- High wall of left ventricle
- Bundle of His
- Proximal left bundle branch
Second & Third Septal Perforators
- Anterior 1/3 of ventricular septum
- Moderator band
First diagonal
- High lateral wall of left ventricle
Second Diagonal
- Lower lateral wall of left ventricle
What does the Ramus Intermedius Artery of the LCA supply?
- Anterolateral wall of left ventricle
What does the Circumflex Artery of the LCA supply?
Left Atrial Artery
- SA-Node in approx. 40% of population
Obtuse Marginal Artery
- Lateral free wall of left ventricle
- Anterior papillary muscle of bicuspid valve
What are collateral arteries?
Tiny, supplementary blood vessels that connect larger coronary vessels. In some cases, these vessels may act as the heart’s backup blood supply, enlarging their diameters to bypass occlusions.
Anatomically, collateral arteries vary greatly from person to person.
What is the circle of Vieussens?
Connection between a branch of the LAD and conus artery of the
RCA, supplying the infundibular muscles.
What is Kugel’s artery?
An additional and direct atrial anastomosis between the proximal RCA and
circumflex. Kugel’s artery provides a branch that runs through the base of the atrial septum toward the crux of the heart, where it gives additional circulation to the AV-node. Kugel’s artery is quite rare, appearing in only 6%
