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What are the primary functions of the cardiovascular system?
To transport blood throughout the body, delivering oxygen and nutrients while removing waste products.
Describe the location of the heart within the thoracic cavity.
The heart is located posterior to the sternum and between the lungs in the thoracic cavity.
What distinguishes arteries from veins in their functionality?
Arteries carry blood away from the heart, while veins bring blood toward the heart.
Identify the four chambers of the heart and their primary functions.
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Explain the importance of the sinoatrial (SA) node in cardiac function.
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What is the cardiac cycle and its significance in cardiovascular function?
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How do heart valves contribute to blood circulation?
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What function do capillaries serve in the cardiovascular system?
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Describe how the right side of the heart functions differently from the left side.
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What is the role of coronary vessels in heart function?
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What are some common cardiovascular diseases that affect heart function?
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Explain the significance of the refractory period in cardiac physiology.
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What factors can influence cardiac output?
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Identify the anatomical structures that control heart activity.
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What is the primary role of the pulmonary trunk in the cardiovascular system?
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Which valves are classified as semilunar valves, and where are they located?
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Explain the difference in blood carried by the pulmonary artery and pulmonary veins.
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What happens to deoxygenated blood as it flows through the cardiovascular system?
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Describe the role of the aorta in systemic circulation.
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What is the function of the tricuspid valve, and where is it located?
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Identify the effects of left ventricular impairment in congestive heart failure.
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What circulatory routes do the right and left sides of the heart serve?
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How does the heart's structure facilitate unidirectional blood flow?
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What key role do the pulmonary veins play in the cardiovascular system?
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What is the primary function of pulmonary circulation in the heart?
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Describe the role of the pericardium in relation to the heart.
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How does systemic circulation differ from pulmonary circulation?
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What connects the blood flow from the left ventricle to the systemic cells?
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Explain the anatomical relationship of the heart within the thoracic cavity.
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Which layer of the pericardium adheres directly to the heart?
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What is the significance of the pericardial cavity?
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Identify the path of blood flow from the right atrium to the lungs.
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What tissue composes the fibrous pericardium?
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How does deoxygenated blood return to the right atrium?
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What are the three layers that cover the heart?
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Describe the function of the pericardial cavity.
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Which structures are mainly visible from the anterior view of the heart?
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What is the role of the interventricular sulcus?
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What are the consequences of pericarditis if left untreated?
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Name the three layers of the heart wall and their primary characteristics.
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What is a distinguishing feature of the right atrium from a posterior view?
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Identify a clinical sign associated with pericarditis.
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What blood vessels are primarily visible from the posterior view of the heart?
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Where does the epicardium derive its cellular composition?
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What is the primary difference between cardiomegaly and hypertrophic cardiomyopathy?
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How does hypertrophic cardiomyopathy affect cardiac output?
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What cardiovascular conditions are commonly associated with hypertrophic cardiomyopathy?
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What are the two normal heart sounds, and what do they signify?
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How do valvular insufficiency and heart murmurs relate to each other?
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What role does the myocardium play in the heart's structure?
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How do the walls of the ventricles compare to those of the atria?
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What is the significance of the fossa ovalis in adult hearts?
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What is indicated by hypertrophic cardiomyopathy?
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Describe the function of the papillary muscles.
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What unique feature do the aortic and pulmonary semilunar valves have?
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What condition is described by cardiomegaly?
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How do tendinous cords function in relation to the heart valves?
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What distinct features do the left and right ventricles have?
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What is the primary role of the heart valves?
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What structural difference exists between the atrioventricular and semilunar valves?
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What role does the endocardium serve in the heart?
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How do age and disease affect heart valve elasticity?
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What anatomical feature separates the left and right atria?
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What is the resting membrane potential (RMP) of SA nodal cells?
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How does the parasympathetic nervous system influence the heart rate of SA nodal cells?
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What role do voltage-gated Ca2+ channels play during the depolarization of SA nodal cells?
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What is the function of the AV node if the SA node fails?
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How does the conduction rate of the action potential change as it passes through the AV node, and why is this significant?
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In what way do HCN channels facilitate the function of SA nodal cells?
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Describe the process through which K+ channels contribute to repolarization in SA nodal cells.
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What two key processes occur in cardiac muscle cells during a heartbeat?
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What is the average rate of action potential propagation at rest?
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What defines an ectopic pacemaker in the context of heart function?
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Explain the significance of the insulating characteristics of the fibrous skeleton in the conduction system of the heart.
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What role do Purkinje fibers play in the cardiac conduction system?
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Describe the purpose of a mechanical pacemaker in relation to heart rhythm.
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What is the average time taken for the depolarization and repolarization cycle in SA nodal cells?
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In what order do the cardiac muscle cells of the heart contract?
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What differentiates the depolarization mechanism of SA nodal cells from that of neurons?
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What happens during the propagation of an action potential in cardiac muscle cells?
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How do the Purkinje fibers contribute to the efficiency of ventricular contraction?
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What role do the sodium and potassium leak channels play in maintaining the resting membrane potential (RMP) of SA nodal cells?
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Describe the sequence of events that occurs within SA nodal cells when an action potential is generated.
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How does sympathetic innervation affect the heart's function according to the content provided?
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What is the functional significance of the conduction system in the heart?
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Explain how the parasympathetic innervation affects heart rate.
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What potential consequence can result from ischemic conditions affecting cardiac muscle?
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Define the term 'functional syncytium' in the context of heart chambers.
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What are baroreceptors and where are they located in relation to heart function?
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What membrane potential do SA nodal cells reach at threshold, and how is this achieved?
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Describe the process of depolarization in SA nodal cells.
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What factors contribute to the limited capability of cardiac muscle to use glycolysis?
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What is the influence of the cardioinhibitory center on the heart's conduction system?
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How do the Purkinje fibers contribute to cardiac function?
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Explain how the resting membrane potential (RMP) is affected during repolarization.
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What is the effect of clamped blood flow on cardiac muscle cells?
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What are the primary functions of the fibrous skeleton of the heart?
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How does coronary circulation differ from the blood flow through the heart chambers?
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Explain why coronary arteries are considered functional end arteries.
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What role does the anterior interventricular artery play in coronary circulation?
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What are the symptoms commonly associated with a myocardial infarction (MI)?
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What anatomical feature allows cardiac muscle cells to communicate and contract synchronously?
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Describe the composition and function of the coronary sinus.
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What structural differences distinguish cardiac muscle from skeletal muscle?
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How do gap junctions contribute to the function of the heart?
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What can cause valvular stenosis and its possible impact on the heart?
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What prevents action potentials from propagating directly from the atria to the ventricles?
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What is the significance of the right coronary artery in the heart's anatomy?
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Define 'functional syncytium' in the context of cardiac muscle.
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What is the role of myoglobin in cardiac muscle cells?
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Study Notes
Introduction to the Cardiovascular System
- Responsible for transporting blood to supply oxygen and nutrients to cells while removing waste products.
- Major components include the heart and blood vessels (arteries, capillaries, veins).
The Heart
- Positioned in the thoracic cavity, between the lungs and posterior to the sternum.
- Structured with several layers: epicardium (outer), myocardium (muscle layer), and endocardium (inner lining).
- Comprises four chambers: left and right atria, left and right ventricles, and features valves ensuring one-way blood flow.
Electrical and Mechanical Events
- SA node initiates the action potential that spreads through the heart's electrical conduction system.
- The cardiac cycle consists of the stages of contraction (systole) and relaxation (diastole).
- Electrocardiogram (ECG) measures electrical activity of the heart.
Cardiac Output
- Cardiac output is influenced by heart rate (number of beats per minute) and stroke volume (amount of blood ejected per beat).
- Factors affecting heart rate include autonomic innervation and hormones.
- Stroke volume can be affected by venous return, myocardial contractility, and afterload.
Anatomy of the Heart
- Divided into right (receives deoxygenated blood) and left sides (receives oxygenated blood).
- Right atrium collects blood from the body via venae cavae; right ventricle pumps it to the lungs for oxygenation.
- Left atrium receives oxygenated blood from the lungs via pulmonary veins; left ventricle distributes it to the body through the aorta.
Great Vessels
- Arteries and veins connect directly to the heart: aorta (oxygenated), pulmonary arteries (deoxygenated), and venae cavae (deoxygenated).
- Valves prevent backflow, ensuring efficient blood circulation through the heart's chambers.
Circulatory Routes
- Pulmonary Circulation: Transfers deoxygenated blood from the right side of the heart to the lungs and back to the left side.
- Systemic Circulation: Distributes oxygenated blood from the left side of the heart to body tissues, returning deoxygenated blood to the right side.
Pericardium
- The heart is enclosed in a protective pericardium, composed of a fibrous outer layer and serous inner layers.
- The pericardial cavity contains serous fluid to reduce friction during heart contractions.
Common Cardiovascular Diseases
- Myocardial Infarction: Heart muscle damage due to blocked blood supply.
- Heart Murmurs: Abnormal blood flow sounds often indicating valve issues.
- Atherosclerosis: Buildup of plaque in arteries, leading to reduced blood flow.
- Circulatory Shock: Life-threatening condition from inadequate blood flow to the tissues.
Importance of Cardiovascular Health
- Maintaining a healthy cardiovascular system is crucial for overall health.
- Understanding heart anatomy and function aids in recognizing cardiovascular malfunctions and diseases.
Clinical Considerations
- Congestive Heart Failure: Impaired heart function leading to fluid buildup; systemic edema and pulmonary edema are clinical signs.
- Pericarditis: Inflammation of the pericardium; can lead to cardiac tamponade from fluid buildup.
Heart Anatomy
- Visible structures include the right and left atria, ventricles, major veins (SVC, IVC), and arteries (aorta, pulmonary trunk).
- Coronary vessels supply blood to the heart muscle and are located within the heart's sulci.
Sulci
- The heart features external grooves (sulci) separating chambers: coronary sulcus (atria from ventricles), anterior and posterior interventricular sulci (ventricles separation).
Heart Wall Layers
- The epicardium, myocardium, and endocardium each serve specific functions critical for cardiac mechanics and protection.### Layers of the Heart
- Myocardium: The thickest layer responsible for generating the pumping force for blood circulation.
- Endocardium: Innermost layer made of simple squamous epithelium (endothelium) and areolar connective tissue.
- Epicardium: The outermost layer protecting the heart.
Heart Structure
- Heart Chambers: Comprises four chambers: left atrium, right atrium, left ventricle, right ventricle; atria receive blood, ventricles pump blood.
- Ventricular Wall Thickness: Ventricles have thicker walls than atria; the left ventricular wall is approximately three times thicker than the right.
- Coronary Sinus: Empties deoxygenated blood into the right atrium.
Special Features
- Fossa Ovalis: Indicates the location of the fetal foramen ovale on the interatrial septum; marks where coronary sinus drains blood.
- Atrioventricular Openings: Enable blood flow from atria to ventricles; right atrioventricular opening contains the right AV valve.
Valvular Anatomy
- Heart Valves: Four valves, including right and left atrioventricular valves and aortic and pulmonary semilunar valves.
- Function of Valves: Prevent backflow during contraction; atrioventricular valves are connected to papillary muscles via tendinous cords.
Cardiovascular Conditions
- Cardiomegaly: Enlarged heart due to chamber size increase or wall thickening, often without specific cause.
- Hypertrophic Cardiomyopathy: Genetic disorder where heart walls thicken, decreasing cardiac output and causing potential for congestive heart failure.
Blood Flow Dynamics
- Coronary Circulation: Supplies the heart muscles with oxygenated blood and removes deoxygenated blood.
- Coronary Arteries: Include right coronary artery (branches into right marginal and posterior descending arteries) and left coronary artery (branches into left anterior descending and circumflex artery).
- Blood Flow: Primarily occurs during diastole; arteries collapse during systole, limiting flow.
Heart Sounds and Murmurs
- Heart Sounds: Two distinct sounds (S1, S2) associated with valve closure; crucial for assessing heart activity.
- Heart Murmurs: Abnormal sounds indicating issues like valve incompetence or stenosis.
Cardiac Muscle Structure
- Components: Striated, branched cells with one or two nuclei; connected by intercalated discs containing desmosomes and gap junctions.
- T-Tubules and SR: T-tubules extend to sarcoplasmic reticulum; lesser developed SR compared to skeletal muscle.
Electrical Conduction System
- Components: Includes SA node (pacemaker), AV node (relay for impulses), bundle of His, and Purkinje fibers for impulse transmission to ventricles.
- Functional Syncytium: Chambers function as a single unit due to coordinated contraction facilitated by intercalated discs.
Health Implications
- Coronary Heart Disease: Narrowing of coronary arteries due to plaque can lead to angina pectoris (chest pain) or myocardial infarction (heart attack).
- Symptoms of Myocardial Infarction: Severe chest pain, often radiating to arms, jaw; symptoms vary, especially in women.
Structural Support
- Fibrous Skeleton: Dense connective tissue that provides support, maintains valve structure, and insulates electrical signals between atria and ventricles.
Characteristics of Coronary Arteries
- Functionality: Not interconnecting; blood flow primarily occurs during heart rest phases.
- Critical Arteries: The anterior interventricular artery, known as the "widowmaker," is crucial for supplying the heart.
Cardiac Muscle Metabolism
- Respiration: Relies on aerobic cellular respiration facilitated by abundant mitochondria; contains myoglobin for oxygen storage.
- ATP Generation: Utilizes creatine kinase to produce ATP during muscle contraction.### Heart's Conduction System
- SA node serves as the heart's pacemaker, initiating the heartbeat.
- The electrical impulse travels through AV node, AV bundle, right and left bundle branches, and Purkinje fibers, causing heart contractions.
- Heart rate is modulated by autonomic nervous system input.
Regulation of Heart Rate
- Parasympathetic innervation via the vagus nerve reduces heart rate (cardioinhibitory effect).
- Sympathetic innervation increases both heart rate and force of contraction (cardioacceleratory effect).
Characteristics of Cardiac Muscle
- Cardiac muscle is vulnerable to ischemia, leading to failure.
- Unlike skeletal muscle, cardiac muscle has a limited ability to use glycolysis or accumulate oxygen debt.
Aerobic Cellular Respiration
- Cardiac muscle primarily relies on aerobic respiration for energy.
- Compromised blood flow can result in the death of cardiac muscle cells.
Innervation and Heart Activity
- The cardiac center, located in the medulla oblongata, regulates heart activity.
- Parasympathetic nerves decrease conduction through the SA and AV nodes without significantly affecting contraction strength.
SA Nodal Cells
- SA nodal cells are responsible for spontaneous action potentials, leading to heartbeats.
- Resting membrane potential (RMP) for SA nodal cells is approximately -60 mV.
Action Potential Generation
- SA nodal cells experience a sequence of events: threshold reaching, depolarization, and repolarization within about 0.8 seconds.
- During depolarization, calcium channels allow Ca2+ influx, altering the membrane potential positively.
Repolarization Phase
- Potassium (K+) exit through voltage-gated K+ channels returns the membrane potential to -60 mV.
- The process resets the RMP, ensuring consistent heart rhythm.
Autorhythmicity and Pacemaker Potential
- Autorhythmicity enables SA nodal cells to self-initiate action potentials without external stimuli.
- Pacemaker potential allows gradual accumulation of charge to reach the threshold for depolarization.
Conduction System and Propagation
- Action potentials propagate from the SA node through the AV node, AV bundle, and into Purkinje fibers, ensuring synchronized contractions.
- Insulating fibrous skeleton slows conduction, creating a controlled bottleneck effect.
Ectopic Pacemakers
- Ectopic pacemakers (other than SA node) can initiate heartbeats but do so at lower rates (20-50 BPM).
- A mechanical pacemaker can be used to regulate heartbeat when necessary.
Cardiac Conduction Pathway
- The conduction system consists of SA node, AV node, AV bundle, bundle branches, and Purkinje fibers.
- If the SA node fails, the AV node can take over as a pacemaker, maintaining a heart rhythm of 40-50 BPM.
Action Potential Events in Cardiac Muscle
- Cardiac cells propagate action potentials followed by contractions, first in the atria, then ventricles.
- The conduction delay at the AV node allows for efficient ventricular contraction, minimizing blood backflow into atria.
Mechanical Pacemaker Function
- Mechanical pacemakers deliver electrical impulses surgically implanted in patients to maintain appropriate heart rhythms.
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Description
Explore the important aspects of the cardiovascular system with a focus on the heart. This quiz covers the heart's location, anatomy, and components, providing insights into its crucial role in transporting blood throughout the body. Test your knowledge on heart functions and structures.