Cardiac Week 1 Flashcards
Topic 1: Anatomy - Q1: What are the contents of the thoracic cavity?
A: Mediastinum: Contains the heart, thymus, trachea, esophagus, and major vessels. Pleural Cavities: Contain the lungs and pleural membranes. [cite: 1, 2]
Topic 1: Anatomy - Q2: What are the boundaries and divisions of the mediastinum?
A: Boundaries : Superior: Thoracic inlet. Inferior: Diaphragm. Anterior: Sternum. Posterior: Vertebral column. Lateral: Pleural cavities. Divisions : Superior mediastinum, and inferior mediastinum (further divided into anterior, middle, and posterior). [cite: 3, 4]
Topic 1: Anatomy - Q3: What are the contents of each division of the mediastinum?
A: Superior Mediastinum: Thymus, great vessels, trachea, esophagus, thoracic duct, vagus and phrenic nerves. Inferior Mediastinum: Anterior : Fat, lymph nodes, thymic remnants. Middle : Heart, pericardium, roots of great vessels, phrenic nerves. Posterior : Esophagus, descending aorta, azygos veins, thoracic duct, sympathetic trunks. [cite: 5, 6, 7, 8]
Topic 1: Anatomy - Q4: Describe the structure, blood supply, and innervation of the pericardium.,
A: Structure : Fibrous Pericardium: Outer layer that protects and anchors the heart. [cite: 9, 10] Serous Pericardium: Divided into parietal and visceral layers with a pericardial cavity containing lubricating fluid. [cite: 11] Blood Supply : Pericardiophrenic artery, branches of bronchial and esophageal arteries. [cite: 12] Innervation : Phrenic nerve, vagus nerve, and sympathetic trunks. [cite: 12]
Topic 1: Anatomy - Q5: What are the functions of the pericardium?
,A: Protects the heart. Reduces friction with pericardial fluid. [cite: 13, 14] Prevents overdistension of the heart. Anchors the heart in place. [cite: 14]
Topic 1: Anatomy - Q6: Describe the structure and great vessels of the heart.
A: Structure : Four chambers (right atrium, right ventricle, left atrium, left ventricle), valves (tricuspid, mitral, pulmonary, aortic), and layers (endocardium, myocardium, epicardium). [cite: 15] Great Vessels : Superior and inferior vena cava. Pulmonary arteries and veins. Aorta. [cite: 15, 16]
Topic 1: Anatomy - Q7: Describe the branches and distribution of the coronary arteries.
A: Right Coronary Artery : Branches into right marginal artery and posterior interventricular artery, supplying the right atrium, right ventricle, and parts of the left ventricle and interventricular septum. [cite: 17, 18] Left Coronary Artery : Branches into the circumflex artery and anterior interventricular artery (LAD), supplying the left atrium, left ventricle, and anterior interventricular septum. [cite: 19]
Topic 1: Anatomy - Q8: Explain the direction of blood flow in the heart.
,A: Deoxygenated blood: Body → Right atrium → Right ventricle → Lungs. [cite: 20, 21, 22] Oxygenated blood: Lungs → Left atrium → Left ventricle → Body. [cite: 21, 22]
Topic 1: Anatomy - Q9: Compare the structure of the right and left sides of the heart.
A: Right Side: Thinner walls, pumps deoxygenated blood to the lungs (low pressure). [cite: 23, 24, 25] Left Side: Thicker walls, pumps oxygenated blood to the body (high pressure). [cite: 24, 25]
Topic 2: Clinically Relevant Anatomy - Q1: Describe the location and position of the heart and its chambers.
A: Location : In the thoracic cavity, within the mediastinum, posterior to the sternum and resting on the diaphragm. [cite: 26, 27] Orientation : Apex points downward, forward, and to the left (at 5th intercostal space). [cite: 28]
Topic 2: Clinically Relevant Anatomy - Q2: Describe the location and position of the major vessels.
A: Aorta: Ascends, arches over the heart, descends into the thorax and abdomen. [cite: 29, 30, 31] Pulmonary Trunk: Exits the right ventricle and splits into pulmonary arteries. [cite: 31] Superior/Inferior Vena Cava: Drain blood into the right atrium. [cite: 31]
Topic 2: Clinically Relevant Anatomy - Q3: Identify the relevant areas for palpation in the cardiovascular system.
A: Carotid artery (neck). Radial/ulnar arteries (wrist). [cite: 32, 33] Apical impulse (5th intercostal space). Femoral and popliteal arteries. [cite: 33]
Topic 2: Clinically Relevant Anatomy - Q4: Identify the sites for auscultation of the heart.
A: Aortic valve: Right 2nd intercostal space. Pulmonary valve: Left 2nd intercostal space. Tricuspid valve: Left 4th intercostal space near sternum. [cite: 34, 35] Mitral valve: Left 5th intercostal space, midclavicular line. [cite: 35]
Topic 3: Cardiac Cycle - Q1: What are the phases of the cardiac cycle?
A: Atrial Systole : Atria contract, filling the ventricles. [cite: 36] Ventricular Systole : Isovolumetric contraction (pressure builds, valves closed). [cite: 36, 37] Ventricular ejection (blood exits via semilunar valves). [cite: 37] Diastole : Isovolumetric relaxation (pressure drops). Ventricular filling (passive flow). [cite: 37]
Topic 3: Cardiac Cycle - Q2: Describe the relationship between blood volume
A: Blood moves from high-pressure to low-pressure areas. Valves prevent backflow (AV valves into atria; semilunar valves into ventricles). [cite: 38, 39]
Topic 4: The Heart as a Pump - Q1: Describe the structure of the myocardium.
A: Composed of cardiac muscle cells (cardiomyocytes) . [cite: 40, 41, 42] Arranged in spiral or circular bundles for contraction efficiency. [cite: 41, 42] Contains intercalated discs (gap junctions and desmosomes) for synchronized contraction. [cite: 42]
Topic 4: The Heart as a Pump - Q2: Describe the structure and function of cardiomyocytes.
A: Cylindrical, striated muscle cells with a central nucleus. Rich in mitochondria for high energy demands. [cite: 43, 44] Interconnected by intercalated discs, allowing electrical and mechanical continuity. [cite: 44]
Topic 4: The Heart as a Pump - Q3: Explain cardiac output and its determinants.
A: Cardiac Output (CO) = Heart Rate (HR) × Stroke Volume (SV). [cite: 45] Determinants: Heart rate (sympathetic and parasympathetic regulation). [cite: 45, 46] Stroke volume (preload, afterload, and contractility). [cite: 46]
Topic 4: The Heart as a Pump - Q4: Discuss the factors affecting venous return.
A: Muscle pump action. Intrathoracic pressure changes (respiration). [cite: 46, 47] Venous valve function. Blood volume and venous tone. [cite: 47]
Topic 5: A Closer Look at Valves - Q1: Discuss the anatomy and histology of the atrioventricular and semilunar valves.
A: Atrioventricular (AV) Valves : Tricuspid (right), Mitral (left). [cite: 47, 48, 49] Supported by chordae tendineae and papillary muscles . [cite: 48, 49] Semilunar Valves : Pulmonary (right ventricle), Aortic (left ventricle). [cite: 49] Pocket-like cusps prevent backflow. [cite: 49]
Topic 5: A Closer Look at Valves - Q2: Discuss the physiology and function of the atrioventricular and semilunar valves.
A: AV valves: Prevent backflow from ventricles to atria during systole. [cite: 50, 51] Semilunar valves: Prevent backflow from arteries into ventricles during diastole. [cite: 51]
Topic 5: A Closer Look at Valves - Q3: What generates heart sounds?
A: S1 (“lub”): Closure of AV valves at the start of systole. [cite: 52, 53] S2 (“dub”): Closure of semilunar valves at the start of diastole. [cite: 53]
Topic 5: A Closer Look at Valves - Q4: Explain the consequences of insufficient valvular function.
A: Regurgitation: Backflow of blood due to incomplete valve closure. Stenosis: Narrowing of valve, increasing resistance to flow. [cite: 54]
Topic 6: Cardiac Conduction Pathway - Q1: Identify the structures involved in the cardiac conduction pathway.
A: Sinoatrial (SA) node. Atrioventricular (AV) node. [cite: 54, 55, 56] Bundle of His. Right and Left Bundle Branches. Purkinje fibers. [cite: 56]
Topic 6: Cardiac Conduction Pathway - Q2: Describe the spread of electrical activity across the heart.
A: SA node initiates impulse → spreads to atria → AV node delays conduction → travels via Bundle of His and bundle branches → Purkinje fibers stimulate ventricles. [cite: 56, 57]
Topic 6: Cardiac Conduction Pathway - Q3: Discuss the functions of the SA node, AV node, and Purkinje fibers
A: SA node: Pacemaker, initiates electrical impulses (~60–100 bpm). [cite: 58, 59] AV node: Delays conduction to allow atrial contraction. [cite: 59] Purkinje fibers: Ensure rapid conduction for coordinated ventricular contraction. [cite: 60]
Topic 7: Excitation-Contraction Coupling - Q1: Describe the phases of an action potential in cardiomyocytes.
A: Resting Membrane Potential: Stable potential before excitation. Depolarization: Sodium influx rapidly increases voltage. Plateau Phase: Calcium influx sustains contraction. [cite: 60, 61, 62] Repolarization: Potassium efflux restores resting potential. [cite: 62]
Topic 7: Excitation-Contraction Coupling - Q2: How do these electrical events correlate to mechanical heart functions?
A: Depolarization triggers contraction. [cite: 62, 63] Plateau phase corresponds to sustained contraction for blood ejection. [cite: 63] Repolarization allows relaxation and filling. [cite: 63]
Topic 7: Excitation-Contraction Coupling - Q3: What triggers cardiac myocyte contraction?
A: Action potential opens voltage-gated calcium channels → calcium influx triggers sarcoplasmic reticulum calcium release → actin-myosin interaction → contraction. [cite: 63, 64]
Topic 7: Excitation-Contraction Coupling - Q4: Describe the characteristics of ventricular action potential.
A: Longer duration (~200 ms). [cite: 65, 66] Plateau phase due to calcium influx, important for sustained contraction. [cite: 66]
Topic 7: Excitation-Contraction Coupling - Q5: Describe the characteristics of pacemaker action potential.
A: Spontaneous depolarization (automaticity). [cite: 66, 67] No true resting potential. Key ions: Sodium, potassium, calcium. [cite: 67]
Topic 8: Autonomic Control of the Cardiac Conduction Pathway - Q1: Discuss cardiac innervation and conduction pathway.
A: Sympathetic nerves: Increase heart rate and contractility. Parasympathetic (vagus) nerves: Decrease heart rate. Autonomic control influences conduction speed and rhythm. [cite: 68, 69]
Topic 8: Autonomic Control of the Cardiac Conduction Pathway - Q2: Describe the role of the sympathetic nervous system in cardiac conduction.
A: Releases noradrenaline . [cite: 70, 71] Increases SA node firing rate, conduction velocity, and force of contraction. [cite: 71]
Topic 8: Autonomic Control of the Cardiac Conduction Pathway - Q3: Describe the role of the parasympathetic nervous system in cardiac conduction.
A: Releases acetylcholine . [cite: 72, 73] Slows SA node firing, reduces heart rate, and prolongs conduction time. [cite: 73]
Topic 8: Autonomic Control of the Cardiac Conduction Pathway - Q4: Enumerate the factors influencing the cardiac conduction pathway.
A: Autonomic nervous system activity. Hormones (e.g., adrenaline). Electrolyte levels (potassium, calcium). Drugs (e.g., beta-blockers, calcium channel blockers). [cite: 74, 75] Ischemia or infarction affecting conduction tissue. [cite: 75]
Are you able to describe the proper electrical conductance (in the correct order ) through the heart?
AV node -> SA node -> Bundle if his -> Bundle branches -> Purkinje fibers
b.
SA node -> AV node -> Bundle if his -> Purkinje fibers -> Bundle branches ->
c.
SA node -> AV node -> Bundle if his ->Bundle branches -> Purkinje fibers
This is the correct order of electrical conductance through the heart
d.
SA node -> AV node -> Bundle branches -> Bundle if his -> Purkinje fibers
SA node -> AV node -> Bundle if his -> Bundle branches -> Purkinje fibers
During your Emergency Medicine rotation, you see a patient where physical examination reveals ananxious, diaphoretic patient with unstable vital signs and hypoxemia. He denies any medical problemsbut admits to daily use of cocaine, including intranasal cocaine approximately 30 minutes ago. Thinking about some of the effects of cocaine use on the body, which of the following is true?
a.
QRS prolongation
b.
heart failure as a main issue
c.
decreased binding to Na channels
d.
increased Phase 0 depolarization
QRS prolongation
All cardiac valves are normally closed during which of the following phases of cardiac cycle?
a.
Ventricular filling
b.
Isovolumetric relaxation
Semilunar valves close after ejection and atrioventricular valves are still closed from the end of previous diastole
c.
Systolic ejection
d.
Atrial contraction
b.
Isovolumetric relaxation
In which structure of the nervous system would damage cause increased parasympathetic activity?
a.
Nucleus solitarius
b.
Cardiac decelerator centre
c.
Dorsal motor nucleus of the vagus
d.
Rostral ventrolateral medulla (RVLM)
d.
Rostral ventrolateral medulla (RVLM)
When describing the general phases of the cardiac myocyte action potential, which phase has rapiddepolarisation due to a transient increase of Na conductance into the cell?
a.
Phase 4
b.
Phase 2
c.
Phase 3
d.
Phase 1
e.
Phase 0
e.
Phase 0
Closure of the aortic and pulmonary valves produces which heart sound?
a.
S4
b.
S3
c.
S2
d.
S1
c.
S2
Which of the following best describes the structure of the myocardium?
a.
Connective tissue providing elasticity to the heart chambers
b.
Striated muscle tissue arranged in a branching pattern
c.
Smooth muscle tissue that contracts involuntarily
d.
A single layer of epithelial cells lining the heart chambers
b.
Striated muscle tissue arranged in a branching pattern
The repolarization phase of the cardiac action potential depends upon which type of channels?
a.
Sodium potassium pumps
b.
Potassium channels
c.
Fast sodium channels
d.
Slow calcium channels
e.
Both fast sodium channels and slow calcium channels
b.
Potassium channels
In terms of anatomical relations, which of the following is correct?
a.
The lung is inferior to the heart
b.
The diaphragm is superior to the mediastinum
c.
The apex of the heart is anterior to its base
d.
Sternum is superior to the heart
e.
The aorta is superficial to the sternum
c.
The apex of the heart is anterior to its base
Which of the following structures separates the diaphragmatic surface of the heart from the base?
a.
The coronary sulcus
b.
The right ventricle
c.
The left atrium
d.
The anterior interventricular groove
e.
The posterior interventricular groove
a.
The coronary sulcus
Which of the following best describes the histological structure of the atrioventricular valves?
a.
Composed mainly of dense connective tissue with a central core of endocardium
b.
Characterized by a thin layer of endothelial cells overlying a thick myocardial layer
c.
Contains a fibrous skeleton that provides attachment sites for cardiac muscle
d.
Composed of three parts: collagen with some elastic fibres leaflets; fine, strong fibrous ligaments and papillary muscles
e.
Predominantly made of cardiac muscle tissue for enhanced contractility
d.
Composed of three parts: collagen with some elastic fibres leaflets; fine, strong fibrous ligaments and papillary muscles
The T wave of the electrocardiogram occurs during which phase of the cardiac cycle?
a.
Isovolumetric relaxation
b.
Rapid ventricular ejection
c.
Atrial systole
d.
Reduced ventricular ejection
e.
Isovolumetric contraction
d.
Reduced ventricular ejection
ECG Wave Cardiac Cycle Phase Event
P wave Atrial systole Atrial depolarization
QRS complex Isovolumetric contraction & rapid ventricular ejection Ventricular depolarization & onset of systole
T wave Reduced ventricular ejection Ventricular repolarization
End of T wave Isovolumetric relaxation Completion of repolarization, onset of diastole
Which of the following is true when differentiating between the pacemaker (SA, AV node) and non-pacemaker (cardiac muscle) AP?
a.
AP Cardiac muscle can occur in cardiac muscles other than SA & AV
b.
AP Cardiac muscle driven by funny current Na channels
c.
AP Cardiac muscle has three phases
d.
AP SA Node has no automaticity
a.
AP Cardiac muscle can occur in cardiac muscles other than SA & AV
AP SA Node
-AP Cardiac muscle
Occur in pacemaker cells
-Occur in cardiac muscles other than SA and AV
Driven by funny current Na channels
-Driven by stimulus, no funny current
Unstable RMP (-50 to -90 mV)
-Stable RMP -90 mV
Only 3 phases
-4 phases
Automaticity is possible
-No automaticity
Feature Pacemaker AP (SA, AV Nodes) Non-Pacemaker AP (Cardiac Muscle)
Location SA node, AV node Atria, ventricles, Purkinje fibers
Resting Membrane Potential Unstable (~-60mV, drifts up) Stable (~-90mV)
Phase 4 (Initiation) Driven by funny current (If, Na⁺) Maintains resting potential
Depolarization (Phase 0) Ca²⁺ influx (L-type channels) Na⁺ influx (fast sodium channels)
Phases Three phases (4, 0, 3) Five phases (4, 0, 1, 2, 3)
Repolarization (Phase 3) K⁺ efflux K⁺ efflux
Automaticity Present (spontaneous depolarization) Absent (requires stimulus)
Which of the following regarding anatomy of the heart is true?
a.
The apex is formed by the right ventricle
b.
The ascending aorta is entirely outside the pericardial sac
c.
The right atrium is posterior to the left atrium
d.
The right coronary artery supplies art of left ventricle
e.
The left coronary artery supplies right atrium
d.
The right coronary artery supplies part of left ventricle
When the left ventricular stroke volume is 40 ml/beat and the heart rate is 80 beats/minutes, thecardiac output is?
Select one:
a.
2 Litres/minute
b.
5 Litres/minute
c.
6 Litres/minute
d.
3.2 Litres/minute
e.
4.5 Litres/minute
d.
3.2 Litres/minute
Cardiac output= SV X HR. 40 x 80= 3.2 L/min
