Anatomy of the Heart Flashcards
The pericardiacophrenic artery and vein are branches of which artery and vein?
Internal thoracic artery and vein
Where is pericardial pain often referred?
Supraclavicular skin on the same side
Ligamentum arteriosum is found in between which two structures?
Aorta and the left pulmonary artery
Cardiac tamponade
A clinical syndrome caused by the accumulation of fluid in the pericardial space, resulting in reduced ventricular filling and subsequent hemodynamic compromise.
What events can lead to the accumulation of fluid in the pericardial space?
Bleeding
Over production of pericardial fluid
Explain what happens in the case of slow accumulation of fluid vs. fast accumulation of fluid.
Slow accumulation of fluid can allow for stretching of the pericardium, with build-up of a liter of fluid before tamponade.
Fast accumulation allows no time for stretching of the pericardium and can lead to tamponade with as little as 100 ml of fluid
What are the components of the fibrous skeleton of the heart?
- Fibrous rings (partial)- surrounds valves and extensions into semilunar leaflets
- Fibrous trigones- between aortic valve and AV valves
- Membranous portion of interventricular septum
What roles does the fibrous skeleton play?
- Provides a strong framwork for attachment of cardiac muscle fibers
- Physically separates atrial and ventricular myocardia and blocks the spread of myocardial excitation across the AV border (coronary sulcus)
- Supports all 4 heart valves by providing achoring rings, and also forms fibrous ribs in the semilunar valves
The AV border is also known as the _____________.
Coronary sulcus
What are the three cusps of the tricupsid valve?
Anterior
Posterior
Septal
The tricuspid valve is anchored by a surrounding fibrous ring called _______.
Annulus
Septomarginal trebecula is also known as ___________.
Moderator band
Failure of teh valves to open widely during ventricular diastole is known as valve ____________.
Stenosis
During ventricular systole, attachment to the ___________ and ____________ prevents prolapse of the valve leaflets into the right atrium by arresting the leaflets exactly in contact with one another.
Tendinous cords
Papillary muscles
NOTE: If the cusps do not meet preceisely during closure they will leak and aloow regurgitation of blood back into the RA.
The conus arteriosus is also known as _________
Infundibulum
Where is the infundibulum found?
Just beneath the pulmonary valves
What are the two fetal cardiac shunts?
Foramen ovale
Ductus arteriosus
The ventricles wring themselves out during __________ (systole/diastole).
Systole
Whata re the three aortic semilunar leaflets?
Right coronary
Left coronary
Posterior (non-coronary)
Thin membranous edge of cusp is called a ___________.
Lunule
The ______ is a fibrous reinforcement in the center of the edge of each cusp.
Nodule
*The three nodules meet in the middle when the valve closes
How does hypertrophic cardiomyopathy differ from dilated cardiomyopathy?
Dilated cardiomyopathy
- Left ventricle enlarged with thin walls
Hypertrophic cardiomyopathy
- Thickening of the walls and reduction of volume
Conduction branches terminate as ____________
Purkinje fibers
What is the course of the right and left bundle branches respectively?
Right bundle branch
- Runs along moderator band and anterior papillary muscle
Left bundle branch
- Runs down septal wall and then fans out on papillary muscles and extends fibers throughout apical region
REMEMBER: Conduction branches terminate as Purkinje fibers
Myogenic activity in the ____________node initiates the cardiac cycle.
sinu-atrial
The rate, force and output of the resulting cardiac contractions are modulated by _____________ and ___________.
autonomic nerves and ganglion cells.
Which structurs are innervated by autonomic nerves and ganglion cells?
Nodal tissues
Conduction bundles and termination fibers
Coronary vessels
Atrial and ventricular musculature
How do sympathetics act on the heart? What about parasympathetics?
Sympathetics
- Accelerates heart and dilates the coronary arteries
Parasympathetics
- Slows the heart and constricts the coronary arteries
What are the preganglionic and postganglionic fibers that innervate the heart?
Vagal cardiac nerves: Pregagnlionic parasympathetic fibers
Sympathetic cardiac nerves: Postganglionic fibers
The cardiac branch of the superior cervical sympathetic ganglion is entirely _________ (afferent/efferent).
Efferent
Autonomic cardiac nerves supply the heart by way of the _________.
Cardiac plexus
Where is the cardiac plexus located?
On the posterior surface of the aortic arch and pulmonary trunk/arteries, immediately anterior to the bifurcation of the trachea.
Coronary plexus
Extensions of the cardiac plexus along the coronary arteries
Pulmonary plexus
Vagal and sympathetic fibers that innervated the bronchial tree and visceral pleura
Where is the largest group of cardiac ganglia located?
Near the SA and AV nodes
NOTE: Smaller groyps are located int he upper part of the left atruym, the interatrial septum, and the junctions of atria and auricles
Which parts of the heart are devoid of cardiac ganglia?
- Right atrial free wall
- Atrial appendages
- Trunk of the great vessels
- Most of the ventricular myocardium
NOTE: The majority of neurons in cardiac ganglia are local circuit neurons which synapse only on other ganglion cells
What are the branches of the right coronary artery? What does each branch supply?
Posterior descending artery
- Posterior 3rd of the interventricular septum
Right marginal artery
- Supplies branches to both surfaces of the right ventricle
What are the branches of the left coronary artery? What does each branch supply?
Anterior interventricular artery (left anterior descending artery)
- Anterolateral myocardium
- Apex
- Interventricular septum (anterior 2/3rd)
Circumflex artery
- Posterolateral left ventricle
- Anterolateral papillary muscle.
The circumflex artery gives rise to _____________ arteries.
Left marginal
The proxumal parts of large coronary artery branches are not connected by large collaterals to other branches. However, more distally along each branch anastomotic conenctions of various calibers join with neighboring branches. What is the significance of this?
Allows for some bidirectional flow between main branches
NOTE: These anastomoses are generally not sufficient to provide colateral pathways around sudden large coronary blockages
There are three cardiac veins that make up the coronary sinus. What are they and where do they drain?
Great cardiac vein
- Drains into the right atrium
Middle cardic vein
Small cardiac vein
- mostly drain into the right atrium and ventricle
When is coronary blood flow the greatest?
During ventricular diastole, especially for the left coronary artery
The period of time that begins with contraction of the atria and ends with ventricular relaxation is known as the __________.
cardiac cycle
The period of contraction that the heart undergoes while it pumps blood into circulation is called ______.
systole.
The period of relaxation that occurs as the chambers fill with blood is called ________.
diastole.
What are the phases of the cardiac cycle?
1st Diastole
1st Systole
2nd Diastole
2nd Systole
NOTE: 1st and 2nd diastole occur at the same time and 1st and 2nd systole occur at the same time
What occurs during the 1st Diastole?
1st Diastole period
- Atria and ventricles are relaxed
- AV valves are open.
- Impulses from the SA node travel to the AV node and the AV node send signals that trigger both atria to contract.
- As a result of the contraction, the right atrium empties its contents into the right ventricle.
What occurs during the 1st systole?
1st systole
- At the beginning of the first systole period, the right ventricle is filled with blood passed on from the right atrium.
- The ventricles receive impulses from Purkinje fibers, which carry electrical impulses to the ventricles causing them to contract.
- AV valves close and the semilunar valves (pulmonary and aortic valves) open.
- Ventricular contraction causes oxygen-depleted blood from the right ventricle to be pumped to the pulmonary artery.
- The pulmonary artery carries oxygen-depleted blood along the pulmonary circuit to the lungs.
What occurs during the 2nd diastole?
2nd Diastole Period
- The semilunar valves close and the atrioventricular valves open.
- Oxygenated blood from the pulmonary veins fills the left atrium.
- The SA node contracts again triggering both atria to contract. Atrial contraction causes the left atrium to empty its contents into the left ventricle.
What occurs during th 2nd systole period?
2nd systole period
- AV valves close and the semilunar valves open.
- The ventricles receive impulses and contract.
- Oxygenated blood in the left ventricle is pumped to the aorta
- The aorta branches out to provide oxygenated blood to all parts of the body through systemic circulation.
- After its tour through the body, oxygen-depleted blood is returned to the heart via the venae cavae.
Primary heart field gives rise to
Inflow tracts
Left ventricle
Secondary heart field gives rise to
Inflow tracts
Right ventricle
The right horn of the embryonic sinus venosus contributes to the _______ and the left horn forms the __________.
Right atrium; coronary sinus
Ventricle of primitive heart tube mainly becomes the ________ ventricle
Left
Bulbus cordis forms the ______
Infundibulum
_________ is to the right of the septum primum.
Septum secundum
Antrioventriclar endocardial cushions grow together and fuse to form the ________.
Interventricular septum
After AV endocardial cushions fuse, endocardial mesenchyme projects from around AV orifices and down into ventricular cavities to initiate ____________ development.
AV valve
Aortic and pulmonary valves initially develop in the _______________, and only later gain attachments of the semilunar leaflets across the ventricular border.
Myocardial outflow tract (truncus
_________________ are paired proliferative centers hoining SHF and pronephric field. They give rise to epicardial cells as well as to myocardial cells for the venous pole of the heart.
Pro-epiicardial tissues
Epicardial cells migrate over surface of heart to form a mesothelium that then generates __________.
Mesenchymal cells
____________ arise by vaculogenesis of sub-epicardial mesenchyme which forms trunks that fuse with the base of the aorta.
Coronary arteries
The _______ develop by sprouting from the coronary sinus.
Coronary veins
Tetralogy of Fallot
A combination of four congenital abnormalities. The four defects include a ventricular septal defect (VSD), pulmonary valve stenosis, a misplaced aorta and a right ventricular hypertrophy.
Common arterial trunk results from failure of _________ to fuse.
Spiral septum cushions
Transposition of arterial trunks
Aorta connects to RV
PT to LV
Double outlet ventricle
Both PT and aorta arise from RV
