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.
What initiates formation of the interatrial septum?
What is peculiar of the ostium primum?
Continued growth of the septum primum enables its ________.
What creates the ostium secundum?
Growth of the endothelium-covered septum primum toward the endocardial cushions initiates formation of the interatrial septum but the ostium primum maintains atrial continuity.
Continued growth of the septum primum enables its fusion with the endocardial cushions but apoptosis of fibroblasts and endothelial cells in the upper portion of the septum creates the ostium secundum.
What creates the foramen ovale?
What becomes the valve of the foramen ovale?
What and when is the fossa ovale created. Where is the fossa ovale located anatomically?
the septum secundum forms but its failure to close the ostium secundum creates the foramen ovale.
Inferior part of the septum primum becomes the valve of the foramen ovale.
Increased left atrial pressure after birth presses the valve against the septum secundum and creates the fossa ovale in the interatrial septum.
Fusion of the ______ and _______ endocardial cushions also forms the _________ portion of the interinterventricularventricular septum that joins what portion and for what purpose?
Fusion of the anterior and posterior endocardial cushions also forms the small membranous portion of the interventricular septum that joins its muscular portion to close the inter ventricular foramen.
Why does ASD cause hypertrophy of the right atrium and ventricle and dilation of the pulmonary trunk?
Compensations for the left to right shunt of blood.
How can the resulting left-to-right shunt cause pulmonary hypertension and lead to heart failure?
Increased volume and pressure will lead to left sided hypertrophy and dilatation. The increase on Venous SV can lead to Pulmonary HTN. With time the right side of the heart will be inefficient—> cardiac failure.
What is VSD with Eisenmenger syndrome?
Eisenmenger syndrome refers to any untreated congenital cardiac defect with intracardiac communication that leads to pulmonary hypertension, reversal of flow, and cyanosis.
The previous left-to-right shunt is converted into a right-to-left shunt secondary to elevated pulmonary artery pressures and associated pulmonary vascular disease.
Development of the syndrome represents a point at which pulmonary hypertension is irreversible (changes is tissue cannot be reversed) and is an indication that the cardiac lesion is likely inoperable
If left unchecked, increased pulmonary blood flow and/or elevated pulmonary arterial pressure can result in remodeling of the pulmonary microvasculature, with subsequent obstruction to pulmonary blood flow. This is commonly referred to as pulmonary vascular obstructive disease (PVOD).
The PVOD will lead to a reversal of blood flow- right to left.
Why do ASD and VSD accompany tricuspid atresia?
Tricuspid atresia involves obliteration of the right atrioventricular orifice and characterized by the absence or fusion of the tricuspid valves.
ASD and VSD accompany tricuspid atresia because with the fusion of tricuspid valves those openings allow for mixing of blood.
What forms the ridged cardiac muscle portions of the right and left ventricles?
What forms the smooth outflow tracts of both ventricles and what becomes the trunks arteriosus?
Ridged cardiac muscle portions of the right and left ventricles are formed by the proximal portion of the bulbus cordis (green) and the primitive ventricle (blue), respectively.
Smooth outflow tracts of both ventricles are formed by the midportion (aka conus cordis) of the bulbus cordis and its distal portion becomes the truncus arteriosus.
Aortic sac and pulmonary trunk are derived from what?
Bilateral pairs of _______ develop on the _______ walls of the conus cordis and ___________ (i.e., the conal and truncal cushions).
What cells migrate into the OUTFLOW tract to form the bilateral (term from above)?
Aortic sac and pulmonary trunk are derived from the truncus arteriosus
Bilateral pairs of cushions develop on the interior walls of the conus cordis and proximal truncus arteriosus (i.e., the conal and truncal cushions).
Neural crest cells migrate into the outflow tract to form the bilateral cushions.
What joins to form the left and right conotruncal ridges?
What creates the spiral aorticopulmonary septum?
Describe the function of the septum.
the ipsilateral conal and truncal cushions join to form the left and right conotruncal ridges that twist around each other and fuse to create the spiral aorticopulmonary septum.
Septum separates the left ventricular outflow tract and aortic sac from the right ventricular outflow tract and pulmonary trunk.
Three ________ form on the pulmonary side of the septum and envision three similar leaflets form on the aortic side of the septum to create the cusps of the pulmonary and aortic valves.
valvular leaflets
What causes Tetralogy of Fallot and what are the four characteristic cardiovascular alterations?
TOF is the most frequent occurring abnormality of the contruncal region. TOF is due to an unequal division of the conus resulting from anterior displacement of the contruncal septum.
Displacement of the septum produces:
1. a narrow RV outflow region- pulmonary infundibular stenosis
- VSD
- overriding aorta that arises directly above the septal defect
- RVH due to increased pressure for the ventricle to pump through the narrow RV outflow region.
Which septal malformation causes the transposition of the great vessels, and why is it the leading cause of death in neonates with cyanotic heart disease?
Conotruncal septum fails to follow its normal spiral course and runs straight down.
Decreased oxygen saturation of blood.
What are the main tributaries of the bilateral sinus horns?
What transports oxygenated blood from the placenta and nutrients from the temporary yolk sac into the sinus horns.
What drains the body of the embryo?
the umbilical, vitelline, and common cardinal veins are the main tributaries of the bilateral sinus horns.
Umbilical vein and vitelline vein transport oxygenated blood from the placenta and nutrients from the temporary yolk sac into the sinus horns (cardinal veins drain the body of the embryo)
Bilateral sinus horns initially deliver _____ returns to the _______.
What shifts venous return toward the right sinus horn?
What forms the smooth interior portion of the right atrial wall?
What becomes the coronary sinus?
Bilateral sinus horns initially deliver equal returns to the sinus venosus
Left-to-Right venous shunt shifts venous return toward the right sinus horn.
Expanded right sinus horn forms the smooth interior portion of the right atrial wall
Diminished left sinus horn becomes the coronary sinus.
What completes the formation of the uniformly smooth interior wall for the LA.
Angiogenic ingrowths from the four pulmonary veins into the left atrium completes the formation of its uniformly smooth interior wall.
Discuss the three layer of heart wall
Three layers of the heart wall include the thick myocardium with bundles of myoblast-derived myocytes, lined internally by the endocardium and covered externally by the epicardium.
What acts as a shock absorber for the heart?
What cover the epicardial fat?
Coronary vessels and the cardiac plexus permeate within fatty tissue of the epicardium that acts as a shock absorber for the heart.
Mesothelium (i.e., the visceral layer of the serous pericardium) covers the epicardial fat.
Endocardium consists of what tissue type and is lined by what tissue type?
What specific of the lined tissue type?
endocardium consists of dense connective tissue lined by endothelium, which is the only tissue directly exposed to the circulating blood (i.e., endothelial antithrombogenicity inhibits blood coagulation to maintain regular flow through the chambers).
Valvular cusps contain a core ___________.
Discuss what facilities valvular stability.
Valvular cusps contain a core of dense connective tissue
Continuity of the connective tissue with the rings of dense connective tissue surrounding the cardiac orifices facilitates valvular stability.
Which element of the conducting system is depicted in the membranous portion of the interventricular septum?
AV bundle “bundle of His”
How after invading the endocardium, can streptococcal bacterial infections in children and adolescents be life-threatening?
The most serious complication is an effect on endocardium covering valves (ulceration, scarred; deformed) of the left side of the heart- mitral insufficiency and aortic stenosis may result.
Inflammation fo all three layers of the heart can also occur.
During bending of the elongating heart tube, (cell type) wrap around the ventricular lumens in a helical fashion.
during bending of the elongating heart tube, myocytes wrap around the ventricular lumens in a helical fashion (i.e., ventricular contraction is analogous to “wringing water from a wet towel” to maximize cardiac output).
Discuss the muscle cell type facets the contribute to the sliding filament mechanism.
What provides the energy required to sustain the cardiac cycle?
myofibrils, myofilaments, and cross striations enable myocytes to contract via the sliding filament mechanism.
Dense capillary network (i.e., each myocyte has its own capillary) and vast population of mitochondria in the sarcoplasm provide the energy required to sustain the cardiac cycle
Function (anatomical and physiological) of intercalated discs/desomosomes.
adjacent myocytes are joined by intercalated discs
Discs contain gap junctions to enable rhythmic contractility of the entire myocardium and desmosomes to prevent disruption of the myocytes during systole.
What peculiar of all myocytes?
Why is the SA node the cardiac pacemaker?
Purkinje fibers comprise what?
all myocytes inherently contract spontaneously
SA node is the cardiac pacemaker because spontaneous contraction of its modified myocytes occurs at the fastest rate.
Modified myocytes called Purkinje fibers comprise the bundle branches that reside in the ventricular endocardium.
- From text, pp. 89: Can myocytes readily regenerate after myocardial infarction?
No. No satellite cells are associated with these cells.
Why are myocytes stretched in patients with dilated cardiomyopathy and why can the disease be fatal?
Mutations exist in the cytoskeletal proteins that disrupt intercalated disc morphology by dissociating junctions between myocytes and disruption myofibrillar organization and contractile function.
These disruptions lead to enlargement of one or more chambers and thinning of ventricular walls–> weakened ability to pump.
Discuss the wall profile (layers) of the aorta.
Wall of the aorta consists of an inner tunica intima (analogous to the endocardium), a thick tunica media (analogous to the myocardium), and an outer tunica adventitia (analogous to the epicardium without a mesothelium).
Discuss the role of the tunica media of the aorta during both phases of the cardiac cycle.
Concentric layers (laminae) of elastic fibers in the tunica media of the aorta distend during systole and passively recoil during diastole thereby enabling continuous blood flow during both phases of the cardiac cycle.
Describe the vasa vasorum, where it resides, supply.
distinct nutritive microvessels designated the vasa vasorum reside in the connective tissue of the tunica adventitia to supply the adventitia of the aorta and outer portion of the media (i.e., the diffusion distance is too great from the vessel lumen).
Does the wall of the pulmonary trunk resembles that of the aorta?
Yes.
Both great vessels can accommodate the systolic surge and continuously deliver blood into the arteries
Which tissue abnormality characterizes Marfan syndrome?
Connective tissue disorder causes by molecular defects in the FNN1 gene—> encodes the glycoprotein fibrillar-1. This extracellular protein is a component of microfibrils, which serves as scaffolds for elastic fiber deposition.
What is an aortic aneurysm and why does Marfan syndrome increase its susceptibility?
abnormal localized dilation in the weakened wall of an artery. Marfan syndrome weakens the arterial wall.
There is Density of the vasa vasorum in the _________.
What augments tonic contraction of the helical layers of smooth muscle in the tunica media and why?
Density of the vasa vasorum in the thick tunica adventitia of the SVC.
Tensile strength of the adventitia augments tonic contraction of the helical layers of smooth muscle in the tunica media to restrict overdistension of the SVC.
What assists blood flow in the IVC against gravity into the right atrium.
tonic contraction of the longitudinally organized smooth muscle in the tunica adventitia of the IVC assists blood flow against gravity into the right atrium.
Why is the vasa vasorum more extensive in the SVC (and IVC) than in the aorta?
Vasa vasorum would be more abundant in large veins, as partial oxygen pressure and osmotic pressure is lower in veins. This would lead to more vasa vasorum needed to supply the vessels sufficiently.
Aortic sac is derivative of ?
Pairs of aortic arches arise from the aortic sac and terminate in the ______.
aortic sac is a derivative of the truncus arteriosus and generates the left and right dorsal aortae.
- dorsal aortae.
Discuss the reason behind the paired arch numbering.
Which arches disappear?
the paired arches are numbered I, II, III, IV, and VI because the fifth pair regress.
Aortic arches I and II also disappear.
What separates the aortic sac and pulmonary trunk?
What does the aortic sac form?
Aorticopulmonary septum
Aortic sac forms the ascending aorta and the proximal portion of the arch of the aorta that generates the brachiocephalic artery.
What forms the right and left common carotid arteries, the right subclavian artery, and the left subclavian artery?
Bilateral 3rd aortic arches
Right 4th aortic arch
Left 4th aortic arch continues the arch of the aorta
What completes the arch of the aorta and continues as the descending aorta?
Right dorsal aorta disappears beyond the ______.
the left dorsal aorta
Right subclavian artery.
What forms the right and left pulmonary arteries?
What forms the ductus arteriosus to join the left pulmonary artery with the arch of the aorta?
What forms the ligament arteriosum and when does that occur?
Bilateral 6th aortic arches
Left 6th aortic arch
Obliteration of the ductus arteriosus after birth.
Define correction of the aorta and where it occurs (location).
coarctation of the aorta is an abnormal narrowing of the descending aorta (either preductal or postductal) that obstructs blood flow to the inferior part of the body.
- From double arch of the aorta and Figure B1.32 (C), pp. 174 (COA): Why might surgery be required if the right dorsal aorta fails to disappear?
a
- From Figure 13.39 (A), pp. 189 (ME): Why is neonatal surgery required to correct preductal coarctation of the aorta?
a
- From Figure B1.34, pp. 175 (COA): With postductal coarctation, which arteries typically create a compensatory collateral circulation and why can notable pulsations occur in the intercostal spaces?
a
- From patent ductus arteriosus (PDA), pp. 189 (ME): Why can a patent ductus arteriosus create the cascade of pulmonary hypertension, right ventricular hypertrophy, and cor pulmonale in premature infants?
a
Anterior and posterior cardinal veins drain into the ______.
What veins are the main tributaries of the sinus horns?
Intraembryonic common cardinal vein.
Common cardinal vein and the extra-embryonic vitelline and umbilical veins
What veins become the internal jugular veins?
Which vein contributes to the transformation of the common cardinal vein into the SVC?
Bilateral anterior cardinal veins
Left brachiocephalic vein
What obliterates most branches of the posterior cardinal veins?
What forms the azygos vein?
IVC is mainly formed by (3) veins.
Intraembryonic left-to-right venous shunt
the remaining proximal portion of the right posterior cardinal vein
coalescence of the renal, gonadal, and common iliac veins
How does oxygenated blood in the umbilical vein bypasses the liver?
Blood from the IVC flows through the foramen ovale in the interatrial septum into the left atrium.
via the ductus venosus to enter the IVC.
Blood from the SVC flows from the right atrium into the right ventricle but is mostly diverted from the pulmonary trunk via _______.
Why is there severe resistance to blood flow into the lungs?
the ductus arteriosus into the aorta (i.e., swallowed amniotic fluid collapses the pulmonary vessels and the resulting high pulmonary vascular resistance severely resists blood flow into the lungs).
What occurs a few minutes after birth concerning the ductus venous and the umbilical arteries/veins?
the ductus venosus becomes the ligamentum venosum and the umbilical arteries and umbilical vein concurrently close.
Discuss what occurs after birth with the foramen ovale and when does it close (fuse) forming what?
Increased left atrial pressure after birth presses the valve of the foramen ovale against the septum secundum and their fusion, which typically occurs between the 8th month and 12th month postnatally, forms the fossa ovale in the interatrial septum.
- From Figure 13.50, pp. 197: Why does left atrial pressure increase and right atrial pressure decrease when a newborn begins to breathe?
a
- From Figure 13.16 (G), pp. 173: Why might crying create cyanotic periods in neonates but not in one-year old infants?
a
distension of the ______ fiber laminae in the tunica media of the aorta and pulmonary trunk accommodates the systolic surge and passive recoil of the laminae during diastole maintains _______ flow in the systemic and pulmonary circulations.
Branches of the aorta and pulmonary trunk are called?
elastic, continuous
muscular arteries.
(few/multiple) circular layers of ______ muscle occupy the tunica media of muscular arteries in the systemic circulation.
Why are arterial lumens are partially constricted?
multiple, smooth
Postsynaptic sympathetic fibers continuously activate some of the muscle fascicles (i.e. normal tonic contraction of the smooth muscle).
Tonic contraction (reduces/increases) blood pressure and flow velocity into the microcvascular arterioles, capillaries, and venules.
What are the terminal branches of the muscular arteries?
What further protects the delicate capillary networks?
Reduces
Arterioles
Tonic contraction of the HELICALLY arranged arteriolar smooth muscle
Additional local activation of the arteriolar smooth muscle causes vasoconstriction (i.e., synchronized contraction of the entire tunica _____) and blood flow into the capillaries is significantly (reduced/increased).
Regulation of CAPILLARY blood flow is based on
media
local tissue needs (e.g., when jogging vasoconstriction in the digestive tract diverts blood to the limbs).
despite relatively less smooth muscle in the tunica media of the pulmonary arteries and arterioles, tonic contraction sufficiently reduces blood pressure and flow velocity into the pulmonary capillaries.
Informational
- From Clinical Point, pp. 186 (EH): What mechanisms mainly lead to hypertension?
a
Thin venular walls consist of (cell type) surrounded by (cell type).
Thin venular walls consist of endothelium surrounded by loose connective tissue.
Discuss the role of SCATTERED smooth muscle fibers in the tunica media and bundles of collagen fibers in the tunica ADVENTITIA.
Overdistension of the muscular veins is restricted by scattered smooth muscle fibers in the tunica media and bundles of collagen fibers in the tunica adventitia that provide tonic contraction and tensile strength, respectively.
What forms the bicuspid valves of the muscular veins of the limbs?
Bicuspid valves formed by infoldings of the tunica intima characterize the muscular veins of the limbs.
- From Clinical Point, pp. 181: How do varicose dilations usually occur in the veins of the limbs?
a
superior mediastinum is above ______.
Discuss the thymus (location) and what makes it difficult to identify in the cadaver?
the imaginary transverse plane between the sternal angle and disc at T4/T5.
Thymus is the most superficial structure (i.e., closest to the skin) in the superior mediastinum
Thymus’s progressive involution after puberty makes it difficult to identify in the cadaver.
What unites to form the SVC
SVC receives all venous blood from where?
Bilateral brachiocephalic veins unite to form the SVC.
superior to the diaphragm EXCEPT from the heart.
the ascending aorta is covered by what?
What are the branches of the ascending aorta (2)?
the pericardium
left and right coronary arteries.
arch of the aorta and proximal portion of the brachiocephalic artery are protected by the ______.
Discuss the route of the arch of the aorta, posteriorly.
Sternal manubrium.
Arch of the aorta passes posteriorly to become the descending aorta that resides posterior to the esophagus in the posterior mediastinum
Discuss the route of the left and right recurrent laryngeal nerves
Where does the Left recurrent laryngeal nerve arises from and discuss its course superiorly.
loop under the arch of the aorta
loop under the right subclavian artery
Left vagus nerve adjacent to the ligamentum arteriosum and courses superiorly alongside the trachea toward the larynx.
- From Lung Cancer and Mediastinal Nerves pp. 125: Why can paralysis of the left vocal cord and resulting hoarseness be caused by an aneurysm of the arch of the aorta?
a
After generating the recurrent laryngeal nerves, the vagus nerves contribute to the _____.
Cardiac plexus
Discuss the course of the esophagus and descending aorta.
The esophagus closely associates with the (part of heart).
Esophagus and descending aorta course through the superior and posterior mediastina.
Left atrium that forms the posterior aspect of the heart.
- From Figure 1.65 (A), pp. 161: Why can dysphagia and pulmonary hypertension result from mitral valve stenosis?
a
in the diaphragm, the esophageal hiatus resides at vertebrae _____ and the aortic hiatus resides and vertebrae _____.
Thoracic duct and azygos vein also traverse the _____.
- T10
- T12
- Aortic hiatus.
Thoracic duct returns lymph from the _______ to the ______.
Lower limbs, pelvis, abdomen, left side of the thorax, left upper limb, and left side of the head and neck to the LEFT venous angle at the junction of the LEFT internal jugular and LEFT subclavian veins (i.e., the origin of the left brachiocephalic vein).
Smaller right lymphatic duct returns lymph from the ______ to the _________.
Right upper limb and the right side of the thorax, head, and neck to the right venous angle.
Discuss the azygos vein (drains) and provides collateral pathway between the ____ and _____.
drains blood from the walls of the thorax and abdomen and empties into the SVC, provides a collateral pathway between the IVC and SVC.
- From Alternate Venous Routes to the Heart pp. 176 and Figure 1.74 (B), pp. 171: How do alternate venous pathways to the right atrium differ after obstruction of the SVC superior to the entrance of the azygos vein and after obstruction of the IVC superior to the origin of the azygos vein?
a
What allows the IVC to ascend from the abdomen into the thorax? What level of vertebra is this?
How and what facilitates the formation of the canal opening?
Caval opening in the diaphragm at vertebra T8
when the arcs of the horseshoe-shaped heart tube merge into a single tube, the sinus venosus remains embedded in the septum transversum
Bilateral sympathetic trunks are on the ______ of the ______ vertebrae.
______ communicating rami from spinal nerves _____ convey ____synaptic sympathetic fibers to the _______ ganglia of the sympathetic trunks.
Bilateral sympathetic trunks on the bodies of the thoracic vertebrae.
White, T1-L2, pre-, paravertebral
