Heart Flashcards
What is the size of the heart compared to a common object?
Slightly larger than a loosely clenched fist
What type of blood does the right side of the heart receive?
Poorly oxygenated (venous) blood
What is the function of the left side of the heart?
Receives well-oxygenated (arterial) blood and pumps it into the aorta
What are the two main phases of the cardiac cycle?
- Diastole (ventricular relaxation and filling)
- Systole (ventricular contraction and emptying)
What produces the ‘lub’ and ‘dub’ heart sounds?
Snapping shut of one-way valves during heart contractions
What are the three layers of the heart chamber walls?
- Endocardium
- Myocardium
- Epicardium
What is the primary component of the heart’s wall?
Myocardium
What motion do the ventricles produce during contraction?
Wringing motion
What is the fibrous skeleton of the heart?
A framework of dense collagen forming fibrous rings and trigones
What are the functions of the fibrous skeleton of the heart?
- Keeps orifices of valves patent
- Provides attachments for valve leaflets and myocardium
- Acts as an electrical insulator
What shapes the heart when viewed from the anterior or posterior?
Trapezoidal
What forms the apex of the heart?
Inferolateral part of the left ventricle
What forms the base of the heart?
Mainly the left atrium
What is the pulmonary trunk’s function?
Conducts low-oxygen blood to the lungs for oxygenation
What structures open into the right atrium?
- Superior vena cava (SVC)
- Inferior vena cava (IVC)
- Coronary sinus
Fill in the blank: The smooth part of the right atrium is known as the _______.
Sinus venarum
What separates the smooth and rough parts of the right atrial wall?
Sulcus terminalis
What is the oval fossa?
A depression in the interatrial septum, remnant of the oval foramen
What forms the largest part of the anterior surface of the heart?
Right ventricle
What is the conus arteriosus?
Arterial cone at the superior part of the right ventricle
What are trabeculae carneae?
Irregular muscular elevations in the right ventricle
What is the function of the right AV (tricuspid) orifice?
Allows blood to flow from the right atrium into the right ventricle
What thick muscular ridge separates the inflow part of the right ventricle from the outflow part?
Supraventricular crest
From which chamber does the inflow part of the right ventricle receive blood?
Right atrium
What is the location of the right AV orifice in relation to the sternum?
Posterior to the body of the sternum at the level of the 4th and 5th intercostal spaces
What structure surrounds the right AV orifice?
Fibrous ring of the fibrous skeleton of the heart
What prevents the dilation of the right AV orifice during varying blood pressures?
Fibrous ring
What is the function of the tricuspid valve?
Guards the right AV orifice
What prevents regurgitation of blood from the right ventricle back into the right atrium during ventricular systole?
Tricuspid valve cusps
How many papillary muscles correspond to the cusps of the tricuspid valve?
Three
What is the anterior papillary muscle’s origin?
Anterior wall of the right ventricle
What is the thickness comparison of the muscular part of the interventricular septum to the wall of the right ventricle?
Two to three times as thick
What is the septomarginal trabecula also known as?
Moderator band
What does the septomarginal trabecula carry?
Part of the right branch of the AV bundle
Where does blood enter the right ventricle from?
Posterior and inferior aspect
What is the U-shaped path blood takes through the right ventricle?
Changes direction about 140°
What is the location of the pulmonary valve?
At the apex of the conus arteriosus, at the level of the left 3rd costal cartilage
What structure forms most of the base of the heart?
Left atrium
How many pulmonary veins enter the left atrium?
Four (two superior and two inferior)
What feature indicates the floor of the oval fossa in the left atrium?
Semilunar depression in the interatrial septum
What is the thickness comparison of the left atrium wall to that of the right atrium?
Slightly thicker
What type of valve guards the left AV orifice?
Mitral valve
What structure does the left ventricle primarily form?
Apex of the heart
What is the primary function of the left ventricle?
Pumps oxygenated blood to the systemic circulation
What is the orientation of the aortic orifice in relation to the left ventricle?
Right posterosuperior part
What type of valve is the aortic valve?
Semilunar valve
What happens to the semilunar cusps during diastole?
They snap closed to prevent blood return
What are the three semilunar cusps of the pulmonary valve?
Anterior, right, and left
The edge of each semilunar cusp is thickened in the region of contact, forming what?
Lunule
What happens when the left ventricle forces the cusps apart?
The cusps are forced apart by the left ventricle.
What are the nodules and lunules in relation to the semilunar valves?
The nodules and lunules meet in the center when the valve closes.
What is the lunule in the context of heart valves?
The lunule is the thickened edge of each cusp in the region of contact.
What is the significance of the aortic and pulmonary sinuses?
They prevent the cusps from sticking to the wall of the vessel.
Where is the mouth of the right coronary artery located?
In the right aortic sinus.
Where is the mouth of the left coronary artery located?
In the left aortic sinus.
Is there an artery that arises from the posterior aortic sinus?
No, no artery arises from the posterior aortic (noncoronary) sinus.
What do the blood vessels of the heart primarily comprise?
The coronary arteries and cardiac veins.
How do the endocardium and some subendocardial tissue receive oxygen and nutrients?
By diffusion or microvasculature from the chambers of the heart.
Where are the blood vessels of the heart typically located?
Embedded in fat, just deep to the epicardium.
What influences the blood vessels of the heart?
Both sympathetic and parasympathetic nerves.
What is the typical pattern of distribution for coronary arteries?
The RCA anastomoses with the circumflex branch of the LCA.
What does the right coronary artery (RCA) supply?
Right atrium, SA and AV nodes, posterior part of IVS.
What is the function of the posterior interventricular artery?
Supplies right and left ventricles and posterior third of IVS.
What is the origin of the left coronary artery (LCA)?
Left aortic sinus.
What does the left coronary artery (LCA) supply?
Most of left atrium and ventricle, IVS, and AV bundles.
Fill in the blank: The right coronary artery arises from the _______.
right aortic sinus.
True or False: The RCA typically provides most blood to the conducting tissue of the heart.
True.
What is meant by dominance of the coronary arterial system?
Defined by which artery gives rise to the posterior interventricular branch.
What percentage of people have RCA dominance?
Approximately 67%.
What does the terminal branch of the RCA supply?
The diaphragmatic surface of the heart.
What is the cardiac plexus?
A network supplying the heart, located on the anterior surface of the bifurcation of the trachea, posterior to the ascending aorta and pulmonary trunk
Contains both sympathetic and parasympathetic fibers, as well as visceral afferent fibers.
What types of fibers are found in the cardiac plexus?
Sympathetic, parasympathetic, and visceral afferent fibers
Visceral afferent fibers are responsible for reflexive and nociceptive functions.
Where do the sympathetic presynaptic fibers originate?
Superior five to six thoracic segments of the spinal cord
These fibers are part of the sympathetic nervous system.
Where are the cell bodies of postsynaptic sympathetic fibers located?
Cervical and superior thoracic paravertebral ganglia of the sympathetic trunks
These fibers are involved in sympathetic innervation to the heart.
How do postsynaptic sympathetic fibers reach the heart?
They travel across cardiopulmonary splanchnic nerves and the cardiac plexus
They end in the SA and AV nodes and connect with parasympathetic fibers on coronary arteries.
What is the primary function of sympathetic innervation to the heart?
Increase heart rate, force of contractions, and blood flow through coronary vessels
These actions support increased activity, such as during stress.
What is the role of parasympathetic innervation in heart function?
Slows the heart rate
It is activated after stress or increased activity.
What is the origin of the presynaptic fibers for parasympathetic innervation?
Vagus nerves
These fibers are crucial for regulating heart rate.
Where are the postsynaptic parasympathetic cell bodies located?
In the atrial wall and interatrial septum near the SA and AV nodes, and along the coronary arteries
This location is critical for effective parasympathetic regulation.
True or False: The cardiac plexus is only composed of sympathetic fibers.
False
It contains sympathetic, parasympathetic, and visceral afferent fibers.
Fill in the blank: The cardiac plexus has both _______ and parasympathetic fibers.
sympathetic
This allows it to regulate heart function in different states.
