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).