Anatomy Exam 1 Flashcards
sternal angle
represents the joint between the manubrium and body of the sternum
superior and inferior mediastina demarcation and what is contained within.
an imaginary transverse plane from the sternal angle to the disc at T4/T5 demarcates the superior and inferior mediastina, which contain all the thoracic viscera except the lungs.
Discuss the three subdivisions of the inferior mediastinum.
inferior mediastinum is subdivided into the middle mediastinum that contains the heart, the anterior mediastinum between the heart and the sternum, and the posterior mediastinum between the heart and vertebrae T5 to T12.
Define the pericardium
Discuss the layers to the pericardium and wha they line.
pericardium is a closed sac that covers the heart and beginning of the great vessels.
Parietal layer of the serous pericardium forms a membranous lining of the outer fibrous pericardium and becomes the visceral layer of the serous pericardium when it reflects onto the beginning of the great vessels and the heart.
Define the pericardial cavity and what it contains and function.
Pericardial cavity is a potential space between the opposing parietal and visceral layers of the serous pericardium.
Cavity normally contains a thin fluid film to allow frictionless contractions of the heart.
At the beginning of the great vessels what layer(s) are continuous with them?
What layer(s) fuses with the diaphragm?
continuity of the parietal and visceral layers of the serous pericardium at the beginning of the great vessels
Fibrous pericardium fuses with the diaphragm
What are common causes of mediastinal widening typically discovered in chest radiographs?
Any structure in the mediastinum may contribute to pathological widening.
- Observed after trauma resulting from a head-on collision. This may produce hemorrhage into the mediastinum from lacerated great vessels (aorta/VC)
- Malignant lymphoma (cancer of lymphatic tissue) produces massive enlargement of mediastinal lymph nodes and widening of mediastinum.
- Hypertrophy of the heart (Venous return greater than CO—> heart failure) —> widening of the inferior mediastinum.
Why can cardiac tamponade be fatal and how is pericardiocentesis normally performed?
Cardiac tamponade is heart compression by fluid (air, fluid, blood) outside of the heart but inside the pericardial cavity. The increased pressure compromises the SV—> CO—> circulation fails.
A WIDE-BORE needle may be inserted through the LEFT 5th or 6th ICS near the STERNUM.
Anatomically where is the heart located?
What partially covers the anterior surface of the heart?
Discuss the right and left ventricle space occupation of the anterior surface of the heart.
Heart resides obliquely two-thirds to the left of the midsternal line
Anterior surface is partially covered by the sternum and costal cartilages.
Right ventricle forms two thirds of the anterior surface and the left ventricle occupies the other third that includes the apex of the heart.
What forms the posterior aspect of the heart?
What forms the diaphragmatic surface of the heart?
Base of the heart occupies its posterior aspect and is formed mainly by the left atrium.
Left ventricle forms two thirds of the diaphragmatic (inferior) surface of the heart and the right ventricle occupies the other third.
How are isolated dextrocardia and dextrocardia associated with situs inversus distinguished?
Dextrocardia is the apex misplaced to the right instead of the left.
Dextrocardia is associated with mirror image positioning of the great vessels and arch of the aorta.
The aforementioned anomaly may be part or a general transposition of the thoracic and abdominal viscera and chambers- situs inversus. Lower incidence of cardiac defects and heart usually functions fine.
The aforementioned anomaly also may only be associated with the heart- isolated dextrocardia. The congenital anomaly is complicated by severe cardiac anomalies such as transpositions of the great arteries.
What forms of the right/inferior/left/superior border of the heart?
What emerges from the anterior aspect of the superior border of the heart?
Discuss the function and location of the cardiac auricles.
Right atrium is between the SVC and IVC and forms the right border of the heart
Right ventricle forms the inferior border, and the left ventricle forms the left border.
Both atria form the superior border of the heart and the pulmonary trunk, aorta, and SVC emerge from its anterior aspect.
Right and left auricles are pouch-like projections from the atria that increase atrial capacity and overlap the ascending aorta and pulmonary trunk, respectively.
In a radiographic cardiovascular silhouette what forms the right (3) / left (4) border of the heart.
Right brachiocephalic vein, SVC, and right atrium form the right border of the heart and the arch of the aorta, pulmonary trunk, left auricle, and left ventricle form the left border.
Discuss the formation of small and large aortic knobs in a radiographic silhouette.
“Aortic knob” = Arch of the aorta
Decreased flow into the aorta creates small “aortic knobs” in the silhouette and large “aortic knobs” result from increased left ventricular output.
Systemic circulation
Pulmonary circulation
Left atrium/ventricle and all its associated arteries and veins.
Right atrium/ventricle and all its associated arteries and veins and lungs.
Discuss the makeup of the right atrium wall.
Where is the oval fossa and the orifices for the IVC, SVC, and coronary sinus and their function.
Which orifice allows outflow into the right ventricle?
Interior anterior wall of the right atrium is ridged by cardiac muscle and the smooth posterior wall is formed mainly by the interatrial septum (i.e., the common wall between the right and left atria).
Oval fossa is in the septum and the orifices (openings) for the IVC, SVC, and coronary sinus that permit inflow into the atrium.
Right atrioventricular orifice allows outflow into the right ventricle
Discuss the makeup of the right ventricle.
Discuss the valve in the atrioventricular orifice.
interior wall of the right ventricle is ridged by cardiac muscle except its smooth outflow portion that leads to the pulmonary orifice and valve.
the three cusps of the tricuspid valve, which span the atrioventricular orifice, are connected to three papillary muscles that project into the ventricular lumen by the chordae tendineae.
Discuss the function of the papillary muscles.
Discuss the makeup of the pulmonary valve and its functions when it is open.
contraction of the papillary muscles at the onset of ventricular contraction tenses the chordae tendineae to insure tight closure of the valvular cusps and prevent retrograde flow into the right atrium.
Unidirectional outflow through the open pulmonary valve contains THREE cusps that LACK chordae tendineae attachments (i.e., the valve is simply forced open during ventricular contraction).
What is the causal relation with pulmonary HTN and the RV? What is a possible consequence from prolonged pulmonary HTN?
pulmonary hypertension (i.e., high blood pressure in the pulmonary arteries typically in response to an increased resistance to blood flow) requires the right ventricle to pump more forcefully.
Prolonged pulmonary hypertension creates right ventricular hypertrophy that can lead to cor pulmonale (i.e., progressive strain on the right ventricle causes its failure).
Why are shortness of breath and cyanosis during physical activity often the first symptoms of cor pulmonale?
Increased effort to breath will occur because not enough blood is being loaded with oxygen- also leading to cyanosis.
Discuss the makeup of the interior wall of the left atrium.
Discuss the location of the left atrium anatomically and its relation to its immediate posterior structure.
interior wall of the left atrium is uniformly smooth and contains orifices for the four pulmonary veins.
Left atrium, which lies immediately anterior to the esophagus which passes through the posterior mediastinum.
Discuss why the difference of the LV and RV exist.
Discuss the makeup of the interior wall of the left ventricle.
Discuss the makeup of the inter ventricular septum.
wall of left ventricle is 2-3 times thicker than the wall of the right ventricle because systemic arterial pressure is normally much higher than pulmonary arterial pressure.
Interior wall of the left ventricle is ridged by cardiac muscle except its smooth outflow portion leading to the aortic orifice and valve.
Interventricular septum is mostly muscular with a small membranous portion near the aortic and mitral valves.
What occurs during the onset of ventricular contraction in relation to the mitral valve?
Discuss the flow and makeup of the open aortic valve.
contraction of the two papillary muscles at the onset of ventricular contraction closes the two cusps of the mitral valve to prevent reverse flow through the atrioventricular orifice into the left atrium.
unidirectional outflow through the open aortic valve and recognize the three cusps of the aortic valve, like those of the pulmonary valve, LACK chordae tendineae attachments.
Define with a term a single heartbeat and how it occurs.
Describe a single heart beat in terms of diastole and systole.
the cardiac cycle represents a single heartbeat and results from synchronous pumping by the right and left atrioventricular chambers.
Each cycle includes filling of the relaxed ventricles (aka diastole) and emptying of the contracted ventricles (aka systole).
What occurs at the onset of diastole in terms of all four valves in the heart?
What action completes ventricular filling and concludes diastole?
at the onset of diastole, the pulmonary and aortic valves close and the mitral and tricuspid valves open.
Recognize atrial contraction completes ventricular filling and concludes diastole.
What reinforces the valvular cusps during the cardiac cycle?
rings of dense connective tissue surround the atrioventricular, pulmonary, and aortic orifices to reinforce the valvular cusps during the cardiac cycle.
Discuss the locations of the vertical position lines (5) of the anterior and posterior body.
imaginary vertical positions on the thoracic wall created by the midclavicular, midaxillary, and scapular lines (run parallel to the posterior median line and intersect the inferior angles of the scapula).
Use the anterior median (aka midsternal) line to extrapolate the positions of the bilateral parasternal lines.
How are ICS numbered and define their spacing.
Intercostal spaces (ICS) separate the ribs and costal cartilages from one another and are numbered according to the rib forming the superior border of the space.
Discuss the aortic/pulmonary/tricuspid/mitral valve auscultation sites.
parasternal lines in the RIGHT 2nd ICS is auscultation site for the AORTIC valve
parasternal lines in the LEFT 2nd ICS is the auscultation site for the PULMONARY valve
parasternal line in the left 4th ICS is the auscultation site for the tricuspid valve
parasternal line in the midclavicular line in the 5th ICS is the auscultation site for the mitral valve
Define valvular stenosis/insufficiency and their effects on blood flow.
What are the most common valvular abnormalities (2)?
valvular stenosis (narrowing) slows forward flow out of a chamber and valvular insufficiency (improper closure) allows reverse flow into a chamber.
Aortic valve stenosis and mitral valve insufficiency (prolapse) are the most common valvular abnormalities.
Discuss the causes of and define cardiac murmurs.
abnormal valves, septal defects between chambers, and anomalies of the great vessels create turbulent blood flow that causes cardiac murmurs (i.e., auscultatory sounds created during abnormal forward and reverse flow classified by their temporal relations to diastole and systole).
Why can left ventricular hypertrophy and dyspnea result from an aortic stenosis? Would the murmur be heard in diastole or systole?
Aortic stenosis causes extra work for the heart, resulting in LVH.
LVH —> Left sided cardiac failure allow for retrograde flow into the lungs and causing an overload of work on the lungs.
Heard in systole.
Why can pulmonary edema result from a mitral valve prolapse? Would the murmur be heard in diastole or systole?
With mitral valve prolapse (insufficiency) both leaflets extend back into LA during systole.
The increased retrograde flow will increase pressure inside the pulmonary veins leading to an efflux of blood into the lung interstitial space.
Heard in systole
Why can systemic edema result from a pulmonary valve stenosis and incompetence? Would the murmurs be heard in diastole or systole?
Pulmonary valve stenosis can lead to variable LV hypertrophy and overtime lead to left sided cardiac failure thus the VR will not match the VO of the LV and leading to retrograde flow into the Vena caves and downstream to the body. The increased retrograde flow will increase pressure inside the systemic veins leading to an efflux of blood into tissue interstitial space.
Pulmonary valve incompetence is when the valve does not close properly during diastole. During Diastole the high pressure blood after LV ejection will flow back into the LV and cause the above situation as well.
Murmur heard during diastole.
What is a collapsing pulse that results from an aortic valve insufficiency? Would the murmur be heard in diastole or systole?
Collapsing pulse- forcible impulse that rapidly diminishes. High pressure flow is being reduced after initial spike with the competing difference in pressure in the LV–> retrograde flow.
Heard during diastole
Discuss the route/supply of the left coronary artery
SHORT left coronary artery (LCA) bifurcates into the circumflex artery and anterior interventricular artery (aka left anterior descending artery or LAD).
the arteries mainly supply the left atrium, most of the left ventricle, and the ANTERIOR two-thirds of the interventricular septum, including the AV bundle “bundle of His”.
Discuss the route/supply of the right coronary artery
LONG right coronary artery (RCA) generates the marginal artery and posterior interventricular artery.
Determine the arteries mainly supply the right atrium, SA node, AV node, most of the right ventricle, and the POSTERIOR third of the interventricular septum.
Which vein accompanies the LAD?
Where do all the coronary veins empty into? And said term drains into _____.
Great cardiac vein accompanies the LAD.
ALL the coronary veins empty into the coronary sinus
Sinus drains into the right atrium.
Why are the coronary arteries perfused during diastole rather than systole?
Back flow of blood is due to recoil of the elastic aorta. With the aortic valve closed during diastole the blood is allowed to pass into the coronary arteries.
Discuss the locations of the SA node, AV node, AV bundle, and right and left bundle branches.
- SA node in the right atrial wall adjacent to the SVC orifice
- AV node in the interatrial septum
- AV bundle “bundle of His” in the membranous portion of the interventricular septum
- Right and left bundle branches in the walls of the ventricles
What electrically initials the impulses for heart contraction?
Discuss the route of serial conduction and what this allows for.
SA node is the pacemaker that initiates the impulses for contraction.
Serial conduction of the impulses through both atria, the AV node, AV bundle “bundle of His”, and bundle branches enables synchronous contractions of the bilateral atrioventricular pumps.
How does the moderator band contribute to the efficiency of right ventricular contraction?
The moderator band is a curved muscular bundle that traverses the right ventricular chamber from the inferior part of the IVS to the base of the anterior papillary muscle.
It carries part of the right branch of the AV bundle creating a “short cut” across the chamber which facilitates conduction time, allowing coordinated contraction of the anterior papillary muscle.
How do the consequences differ after a heart block and bundle branch block?
A heart block is the occlusion coronary arteries and/or their branches that supply different parts of the conduction system–> causing disturbances in the cardiac muscle contraction.
Note: Cardiac muscle can contract independently and does not need an electrical impulse. Although without areas of the conduction system being perfused the rate of contraction for the ventricles is much slower and they contract independently of the SA node (if spared). The non-perfused areas of the conduction system die off and the signal from the SA node will no longer reach the ventricles.
A bundle branch block is due to damage of the actual bundle branches (primary effect). The conduction system continues downward through the unaffected bundle branch and there is a normally timed systole for that particular ventricle. The impulse then spreads to the other ventricle via myogenic (muscle propagated) conduction producing an asynchronous contraction.
What forms the cardiac plexus (2)?
Discuss the functions of the aforementioned parts of the cardiac plexus on heart rate when they synapse with the SA node.
Postsynaptic sympathetic fibers of the cardiopulmonary splanchnic nerves and presynaptic parasympathetic fibers of vagus nerves form the cardiac plexus.
Synapsing with the SA node the sympathetic fibers accelerate heart rate and the parasympathetic fibers return the rate to its basal level.
some peripheral projecting fibers from the _____ at ______ coursing in the _______ rami of spinal nerves ________ enter the _______ communicating rami and accompany the ___________ nerves to the heart.
Define the peripheral projecting fibers ( ______ fibers) function.
some peripheral projecting fibers from the DRG at C5-T5 coursing in the anterior rami of spinal nerves C5-T5 enter the white communicating rami and accompany the cardiopulmonary splanchnic nerves to the heart.
These afferent fibers convey pain from the heart into the CNS and are called visceral sensory fibers.
Define referred pain.
Where/how is referred pain from the heart most commonly felt? Relate the spinal nerves responsible for this as well.
visceral pain (i.e., pain from an organ) is defined as referred pain.
Referred pain from the heart is most commonly felt as a crushing sensation beneath the sternum with pain extending into the left upper limb (i.e., the heart is situated obliquely two-thirds to the left of the midsternal line and LEFT spinal nerves C5-T5 convey sensations from the sternum, the left side of the thoracic wall, and the left upper limb).
In the PREsomite embryo what forms hemangioblasts?
What cells initiate the formation of the heart near the CRANIAL END of the neural plate?
in the presomite embryo, mesenchymal cells of the visceral mesoderm form hemangioblasts
Hemangioblast-derived endothelial cells initiate the formation of the heart near the cranial end of the neural plate.
Clusters of _______ cells organize around the _____ end of the neural plate into a ________-shaped _______ heart field.
Define vasculogenesis/angiogenesis.
Clusters of endothelial cells organize around the cranial end of the neural plate into a horseshoe-shaped primary heart field.
Vasculogenesis is the coalescence of endothelial cells into endothelium-lined tubes or vessels, and angiogenesis is the sprouting of new vessels from existing vessels.
Myocardial cells ( aka ____) are derivates of ________ that join what cells types in the ______ heart field?
__________ transforms the field into a ________-shaped endothelial tube covered by a layer of __________.
After closure of the neural tube, the CNS grows (direction) to extend over the _______ and future _________.
Myocardial cells (aka myoblasts) are derivatives of the visceral mesoderm that join the endothelial cells in the primary heart field.
Determine vasculogenesis transforms the field into a crescent-shaped endothelial tube covered by a layer of myoblasts.
After closure of the neural tube, the CNS grows cranially to extend over the heart tube and future pericardial cavity.
What occurs when the growing embryo bends craniocaudally and folds laterally?
Discuss the origins of the layers (3) of the pericardium.
when the growing embryo bends craniocaudally and folds laterally, the paired arcs of the crescent-shaped heart tube merge except at their caudal-most ends, which embed in the septum transversum (i.e., future central portion of the diaphragm).
Mesothelial cells and fibroblasts of the septum transversum migrate onto the surface of the heart tube to form the visceral and parietal layers of serous pericardium, and the fibrous pericardium, respectively.
What end of the heart tube is the outflow portion and it leads into what?
Dilatations along the craniocaudal axis of the tube form (4).
Cranial end of the heart tube is the outflow portion, shown here leading into one of the bilateral dorsal aortae.
Dilatations along the craniocaudal axis of the tube form the bulbus cordis (note the unlabeled left and right dorsal aortae extending from it), primitive ventricle, primitive atrium, and sinus venosus that receives the left and right sinus horns
What part of the heart tube moves and in what direction which places the developing chambers of the heart in their proper spatial relationships?
Discuss the function of the inter ventricular foramen.
Cranial end of the heart tube bends caudally and places the developing chambers of the heart in their proper spatial relationships.
Interventricular foramen connects the primitive left and right ventricles and although not shown the primitive left and right atria also remain connected.
What connects the atria and ventricles?
What forms the atrioventricular canal (3)? The Atrioventricular canal is derived from what?
What creates the right and left atrioventricular orifices?
a single atrioventricular canal connects the atria and ventricles
Anterior (superior), posterior (inferior), and lateral endocardial cushions that form in the atrioventricular canal are derived from the visceral mesoderm.
Fusion of the anterior and posterior cushions creates the right and left atrioventricular orifices.
What forms the cusps of the tricuspid and mitral valves?
thinning of the fused and non-fused endocardial cushions forms the cusps of the tricuspid and mitral valves at the right and left atrioventricular orifices, respectively.
Discuss the progression of the papillary muscles and chord tendinae with the onset of blood flow.
What covers the chordae tendineae and valvular cusps and lines the walls of the cardiac chambers?
after the onset of blood flow hollows out the ventricular surfaces of the valvular cusps and the muscular ventricular walls, growth of the papillary muscles and chordae tendineae secures their attachment to the valvular cusps.
Endothelium covers the chordae tendineae and valvular cusps and lines the walls of the cardiac chambers.
