Quiz 3 - Heart Flashcards Preview

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Flashcards in Quiz 3 - Heart Deck (81):


-2 ear-like appendages that are attached to the atria
-do not serve any significant function
-developmental remnants of the primitive atrium



-grooves that separate parts of the heart


coronary sulcus

-groove between the atria and ventricles


interventricular sulcus

-groove between the right and left ventricles


interatrial septum

-internal separation between the atria
-AV node is here!


interventricular septum

-internal separation between the ventricles
-has both muscular and membranous parts


right atrium receives blood from which three sources?

-SVC, IVC, coronary sinus


RA: crista terminalis

-ridge that separates the smooth part of the RA (derived from the sinus venosus) from the rough part of the right atrium (the primitive atrium in the embryo)


RA: pectinate muscles

-comb-like muscular ridges found on the wall of part of the RA and within the left auricle


RA: fossa ovalis

-an oval-shaped depression on the interatrial septum of the RA that marks the location of the foramen ovale (opening between RA and LA) that was present in the fetus


RA: openings

-for the SVC, IVC, coronary sinus


RA: tricuspid valve

-lies between RA and RV.
-3 cusps anchored to papillary muscles in the RV called "chorae tendineae"


papillary muscles

-contract during systole to put tension on the chordae tendineae of the RV
-hold the valve cusps in a closed position to prevent backflow
-these muscles DO NOT contract to open the valve!


right ventricle receives blood from what?

-the RA thru the tricuspid valve


RV: trabeculae carneae

-muscular bundles on the walls of the ventricles


RV: papillary muscles

-attached to AV valve cusps via chordae tendineae, which hold the valve closed during systole and prevent backflow.
-these muscles DO NOT contract to open the valve!


RV: septomarginal trabecula (moderator band)

-a band of muscle that has conductive tissue that connects the interventricular septum to the anterior papillary muscles and the anterior wall of the right ventricle
-the right bundle branch leaves the septum thru this band!


RV: conus arteriosus (aka "infundibulum")

-the smooth outflow tract of the RV leading up to the pulmonary valve.


RV: pulmonary (semilunar) valve

-valve between the conus arteriosus of the RV and the pulmonary trunk (artery).
-3 cusps, each of which has a central nodule vital for valve closure
-pulmonary valves are PASSIVELY opened during systole
-when the ventricle relaxes, blood falls down the outflow tract and collects in the sinuses of the semilunar valve. As the sinuses fill, the nodules of the three cusps meet and form the shape of an inverted pyramid; this prevents the cusps from descending further and keeps the valve closed.


left atrium receives oxygenated blood from where?

-the lungs via 4 pulmonary veins


LA: pectinate muscles

-comb-like muscular ridges found on the wall of part of the RA and within the left auricle.


LA: valve of foramen ovale

-a piece of tissue on the interatrial septum of the left atrium that is a remnant of the primitive interatrial septum in the embryo (septum primum).
-typically, the valve is completely fused with the interatrial wall, but sometimes incomplete fusion occurs and a small opening might be present in the interatrial septum (called patent foramen ovale)


LA: openings

-for the four pulmonary veins


LA: mitral (bicuspid) valve

-between LA and LV
-2 cusps


left ventricle receives blood from?

-LA thru mitral valve


LV: trabeculae carneae

-muscular bundles on the walls of the ventricles


LV: papillary muscles

-same as in RV; attached to AV valve cusps via chordae tendineae that hold the valve closed during systole


LV: aortic (semilunar) valve

-between LV and aorta
-consists of 3 cusps with nodules.
-works in the same way as the pulmonary semilunar valves
-when blood collects in the sinuses of these valves, it flows into the coronary arteries (thus the coronary arteries fill during ventricular relaxation)


left ventricular hypertrophy (LVH)

-hypertrophy refers to an increase in the size of cells
-LVH can be a normal process (i.e. in response to athletic training) but it can also be pathological
-some pathological etiologies of LVH include hypertension, aortic stenosis/obstruction, and cardiomyopathy


base of the heart

-comprised of the LA, small portion of the RA, and the proximal pars of the great veins (vena cava and pulmonary veins)


apex of the heart

-points anterioinferior (anterior and to the left)
-part of the left ventricle
-lies deep to the 5th intercostal space


5 surfaces of the heart

1. anterior (sternocostal) surface
2. posterior surface
3. right (pulmonary) surface
4. left (pulmonary) surface
5. inferior (diaphragmatic) surface


first surface: anterior (intercostal) space

-the portion of the heart facing anteriorly
-comprised primarily of the RV
-lies directly posterior to the sternum and costal cartilages


second surface: posterior surface

-base of the heart
-consists of LA and the part of the RA that receives the SVC and IVC


third surface: right (pulmonary) surface

-comprised of the RA
-in contact with the right lung


fourth surface: left (pulmonary) surface

-comprised of the LV and left auricle
-in contact w/ the left lung


fifth surface: inferior (diaphragmatic) surface

-in contact w/ diaphragm
-comprised of RV and LV


3 borders of the heart

can be seen on a chest x-ray

1. right border
2. left border
3. inferior border


first border: right border

-the right "edge" of the heart
-comprised of the SVC, RA, and IVC


second border: left border

-the left "edge" of the heart
-comprised of aortic arch, left auricle, LV


third border: inferior border

-b/w the sternocostal and diaphragmatic surfaces
-comprised of RV and LV (apex)


point of maximum impulse (PMI)

-refers to the area of the chest wall closest to the heart during systole
-typically in the 5th intercostal space at the midclavicular line (corresponding to the apex of the heart)
-displacement of the PMI can be indicative of hypertrophy or cardiomyopathy


coronary circulation

-provides blood to the heart
-the coronary arteries, veins, and their branches travel in grooves on the surface of the heart (i.e. coronary and interventricular sulci)


the R and L coronary arteries branch from ____

the ascending aorta


R coronary artery

-emerges from the ascending aorta at the tip of the right auricle
-it travels in the coronary sulcus between the RA and RV


3 important branches of the RCA

1. SA nodal artery
2. marginal artery
3. posterior interventricular artery

*also normally supplies the AV node via a small AV nodal branch


L coronary artery

-originates from the ascending aorta posterior to the pulmonary trunk
-almost immediately bifurcates into 2 branches


2 branches of the LCA

1. anterior interventricular branch (left anterior descending aka LAD); travels in the anterior interventricular sulcus and supplies mainly the LV
2. circumflex artery; travels in the coronary sulcus on the left side of the heart and terminates before reaching the posterior interventricular sulcus.


small anastomoses between the coronary arteries

-not sufficient to nourish the tissue if a major branch becomes occluded


myocardial infarction (MI) aka heart attack

-death of heart tissue due to lack of blood flow


venous blood from the heart tissue is collected by the ______

-cardiac veins
-most cardiac veins terminate in the coronary sinus


coronary sinus

-a sac-like structure on the posterior side of the heart that empties into the right atrium


great cardiac vein

-originates near the apex of the heart and travels in the anterior interventricular sulcus with the anterior interventricular artery (LAD).
-then enters the coronary sulcus and travels with the circumflex artery to the posterior side of the heart before merging with the coronary sinus


middle cardiac vein

-travels in the posterior interventricular sulcus with the posterior interventricular artery
-terminates in the coronary sinus


small cardiac vein

-travels with the marginal branch of the right coronary artery
-enters the coronary sinus near the IVC


anterior cardiac veins

-very small
-transmit blood from the RV directly into RA (i.e. not thru the coronary sinus)


SA node

-specialized cardiac muscle cells that initiate the electrical impulse responsible for cardiac contraction
-found at the anterior part of the junction between the RA and the SVC
-supplied by the RIGHT coronary artery (sinuatrial nodal artery)


AV node

-conveys the electrical impulse from the atria to the ventricles
-located in the interatrial septum near the opening of the coronary sinus and the tricuspid valve
-supplied by the RIGHT coronary artery (atrioventricular nodal artery)


AV bundle of His

-transmits impulse from the AV node to the ventricles
-travels in the membranous part of the interventricular septum then divides into two branches (one per ventricle)
-supplied by the LEFT coronary artery (anterior interventricular artery)


AV bundle branches

-right and left branches emerge from the AV bundle at the junction of the membranous and muscular parts of the interventricular septum
-conduct the impulse along the muscular part of the septum
-the right bundle branch leaves the septum via the septomarginal trabecula (moderator band!)
-supplied by the LEFT coronary artery (anterior interventricular artery)


Purkinje fibers

-terminal branches of the right and left bundle branches
-form a plexus in the ventricular wall (between the endo- and myocardium)
-spread the impulse of the cardiac conduction system across the ventricles


what happens if the conduction tissue is deprived of blood (i.e. by CAD)?

-the atria and ventricles can become desynchronized
-called an AV block
-there are a variety of causes, severities, and clinical outcomes
-most common mechanisms of AV block is fibrosis or sclerosis of the conduction system, resulting in progressive impairment

***results in a WIDE QRS COMPLEX ON ECG!!!!


how are visceral nerves in the thorax distributed to their targets?

-by traveling in plexuses that surround the thoracic viscera


cardiac plexus

-surrounds the aortic arch and the anterior surface of the tracheal bifurcation
-efferent branches from this plexus supply the heart
-there are also afferent neurons from the heart traveling in the cardiac plexus


sympathetic neurons that supply the heart

-cardiac nerves (increase HR and contractility)
-preganglionic neurons have cell bodies in the lateral horn of the upper thoracic levels of the spinal cord (T1-T5) and their axons enter the sympathetic chain
-once in the chain, many neurons ascend to the cervical region (due to the fact that the heart was more superior during development) and synapse in the cervical sympathetic ganglia
-other neurons stay at the same level and synapse in the upper thoracic sympathetic ganglia
-postganglionic neurons leave the sympathetic chain as cardiac nerves, and enter the cardiac plexuses to travel to the heart


parasympathetic neurons that supply the heart

-vagus nerves (decrease HR)
-preganglionic neurons have their cell bodies in the brainstem (remember vagus is a cranial nerve) and their axons travel in the vagus nerves to the thorax
-the vagus nerves give off cardiac branches that enter the cardiac plexus to reach the heart
-the cardiac branches synapse with postganglionic neurons in parasympathetic ganglia in the cardiac plexus on in the wall of the heart


visceral afferents

-visceral afferent neurons in the cardiac plexuses carry pain sensations from the heart and are important for reflexes
-pain fibers generally travel back to the CNS with the sympathetic cardiac nerves
-reflex fibers generally travel with the cardiac branches of the vagus nerves
-these neurons sense changes in BP and the chemical content of blood

(chemo- and baroreceptors in the aortic arch follow parasympathetics of CN X back to brain; visceral afferents from pain follow sympathetics back to T1 to T4 levels of CNS)


pain from the heart is typically due to _____-

ischemia (tissue damage)


pain from the heart is often felt where?

-in the skin of the chest and left arm
-example of "referred pain" - the brain misinterprets the source of afferent neurons (the brain thinks the neurons are coming from the skin rather than the viscera)


the anterior (sternocostal) surface of the heart is predominantly _______



the posterior surface of the heart is composed of ____

LA, RA, SVC/IVC portions


the LV alone makes up the majority of the ______

left pulmonary surface


the apex of the heart, which corresponds to the PMI, is found where on a healthy pt?

-5th I/C space, midclavicular line


the apex of the heart is part of the _______



atria and ventricles separated externally by _____

coronary sulcus


RA receives blood from _____

coronary sinus


T/F: the internal surface of the RA is only partially covered by pectinate muscles?



T/F: the valve between the coronary sinus and the RA is called the tricuspid?

false: there is no functioning valve b/w the coronary sinus and the RA


the aortic semilunar valve cusps close at the end of systole because:

backwards flow of aortic blood fills the valve sinuses


anterior interventricular branch (left anterior descending aka LAD)

-branch of the LCA
-occlusion or aneurysm of this is known as the "widowmaker"
-it is the primary source of blood to the LV and if the LV becomes ischemic, all cells of the body, including the heart, become starved of O2.


most cardiac veins terminate:

in the coronary sinus