Podcast
Questions and Answers
What is NOT a distinguishing property of cardiac muscle cells?
What is NOT a distinguishing property of cardiac muscle cells?
Which of the following components of intercalated discs is primarily responsible for preventing cell separation during contraction?
Which of the following components of intercalated discs is primarily responsible for preventing cell separation during contraction?
What is the primary function of gap junctions in cardiac muscle cells?
What is the primary function of gap junctions in cardiac muscle cells?
Which feature is NOT characteristic of the cardiac cycle?
Which feature is NOT characteristic of the cardiac cycle?
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What advantage does a closed circulatory system provide?
What advantage does a closed circulatory system provide?
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What is the primary role of the pulmonary circuit in the cardiovascular system?
What is the primary role of the pulmonary circuit in the cardiovascular system?
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During which phase of the cardiac cycle do the atrioventricular (AV) valves close?
During which phase of the cardiac cycle do the atrioventricular (AV) valves close?
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What causes the characteristic heart sounds that can be heard during a heartbeat?
What causes the characteristic heart sounds that can be heard during a heartbeat?
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Which of the following statements about the stages of the cardiac cycle is true?
Which of the following statements about the stages of the cardiac cycle is true?
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What is the primary function of coronary circulation?
What is the primary function of coronary circulation?
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Study Notes
Human Anatomy - Heart
- Course register code: 498185
- Lecturer: Dr Lucy Smyth
- Email: [email protected]
- Topics covered will include heart location, structure (gross and micro anatomy), function (cardiac cycle), and the heart conduction system
- The cardiovascular system contains the heart, blood vessels, and blood
Heart Location
- Located in the thoracic cavity
- More specifically, the mediastinum region of the thorax
Heart Structure
- The heart has four chambers: two atria and two ventricles
- Gross Anatomy: External features of the heart
- Micro Anatomy: Microscopic detail, including cardiomyocytes (myocytes / cardiac muscle cells)
- Layers of the heart wall include the endocardium, myocardium, and epicardium (visceral pericardium).
Cardiac Muscle Cells (Myocytes / Cardiocytes)
- Features: single centrally located nucleus, branching structure, numerous mitochondria
- Other features: Abundant myoglobin reserves, myofibrils for contraction, intercalated discs for connection with other cells
Intercalated Discs
- Composed of adherens junctions, desmosomes, and gap junctions
- Support synchronized contraction of cardiac tissue
Adherens Junctions
- Anchoring sites for actin
- Connect sarcomeres together
Desmosomes
- Prevent cell separation during contraction
- Bind intermediate filaments to join cells together
Gap Junctions
- Allow action potentials to spread between cardiac cells
- Permit ion passage between cells
T-Tubules
- Deep invaginations of the cell plasma membrane
Heart Function (Cardiac Cycle)
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The heart's job is to pump blood.
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Systole: Contraction phase
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Diastole: Relaxation phase
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The cycle involves the movement of blood through the cardiac chambers, controlled by atrioventricular (AV) valves and semilunar valves
Cardiac Cycle Stages
- Atrial and ventricular diastole
- Atrial systole, ventricular diastole
- Ventricular systole, atrial diastole
Heart Valves
- AV valves: Tricuspid and mitral valves
- Semilunar valves: Pulmonary and aortic valves
- Valve closing creates heart sounds ("lub-dub") essential for one-way blood flow
Two Circulatory Circuits
- Pulmonary circuit: Right heart to lungs to left heart
- Systemic circuit: Left heart to body to right heart
Coronary Circulation
- Blood flow through vessels supplying the heart muscle
- Includes main coronary arteries: left main coronary artery, left circumflex coronary artery, left anterior descending coronary artery, right coronary artery, right marginal coronary artery, posterior interventricular artery
Pathologies
- Atherosclerosis: Narrowed artery lumen due to plaque buildup
- Heart attack: Blockage in coronary artery leading to damaged heart tissue
- Treatments: Percutaneous transluminal coronary angioplasty (PTCA), coronary artery bypass surgery (CABG)
Conduction System
- Composed of autorhythmic fibers (pacemaker cells and conduction fibres)
- Components: Sinoatrial (SA) node, atrioventricular (AV) node, Bundle of His, Bundle branches, Purkinje fibers
- ECG can detect pathologies in conduction system
Fetal Circulation
- Oxygen supplied from maternal blood
- Structures: Ductus arteriosus, foramen ovale, ductus venosus
- Structures close after birth
Congenital Heart Defects
- Atrial septal defect (ASD): Hole between atria
- Ventricular septal defect (VSD): Hole between ventricles
- Patent ductus arteriosus (PDA): Duct remains open after birth
12 Lead ECG
- Electrocardiogram (diagnostic tool for heart conditions)
- Electrode placement: V1-V6
- ECG trace: P wave, QRS complex, T wave
- Patterns reveal heart's electrical activity
- Used to diagnose conduction system disorders
Practise Questions
- Available for further study
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Description
Explore the structure and function of the heart in this quiz covering its location, anatomy, and the cardiac cycle. Dive into both gross and micro anatomy, understanding chamber structures, and the heart's conduction system. Perfect for anyone studying human anatomy with a focus on the cardiovascular system.
