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What are the effects of the plateau phase of the contractile cell action potential?
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Ch. 17 The Cardiovascular System I: The Heart
Amerman3rd EditionHuman Anatomy & PhysiologyISBN: 9780138247201, 9780138247928, 9780138201814
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TOC.tableOfContents
- Ch. 1 Introduction to Anatomy and Physiology24
- Ch. 2 The Chemistry of Life37
- Ch. 3 The Cell54
- Ch. 4 Histology46
- Ch. 5 The Integumentary System30
- Ch. 6 Bones and Bone Tissue36
- Ch. 7 The Skeletal System40
- Ch. 8 Articulations19
- Ch. 9 The Muscular System35
- Ch. 10 Muscle Tissue and Physiology29
- Ch. 11 Introduction to the Nervous System and Nervous Tissue28
- Ch. 12 The Central Nervous System41
- Ch. 13 The Peripheral Nervous System41
- Ch. 14 The Autonomic Nervous System and Homeostasis31
- Ch. 15 The Special Senses39
- Ch. 16 The Endocrine System42
- Ch. 17 The Cardiovascular System I: The Heart28
- Ch. 18 The Cardiovascular System II: The Blood Vessels43
- Ch. 19 Blood32
- Ch. 20 The Lymphatic System and Immunity41
- Ch. 21 The Respiratory System27
- Ch. 22 The Digestive System27
- Ch. 23 Metabolism and Nutrition7
- Ch. 24 The Urinary System39
- Ch. 25 Fluid, Electrolyte, and Acid-Base Homeostasis39
- Ch. 26 The Reproductive System10
- Ch. 27 Development and Heredity5
Amerman3rd EditionHuman Anatomy & PhysiologyISBN: 9780138247201, 9780138247928, 9780138201814Non è quello che usi tu?Cambia libro di testo
Capitolo 17, Problema 8b
Mark the following statements as true or false. If a statement is false, correct it to make a true statement.
Pacemaker cells lack a distinct plateau phase.
Guida verificata passo dopo passo1
Step 1: Understand the role of pacemaker cells in the heart. Pacemaker cells are specialized cardiac cells responsible for generating and regulating the heart's rhythmic contractions. They are found in the sinoatrial (SA) node and atrioventricular (AV) node.
Step 2: Review the action potential phases of pacemaker cells. Unlike contractile cardiac cells, pacemaker cells have a unique action potential that includes three phases: Phase 4 (spontaneous depolarization), Phase 0 (rapid depolarization), and Phase 3 (repolarization).
Step 3: Recall that pacemaker cells do not have a distinct plateau phase. The plateau phase (Phase 2) is characteristic of contractile cardiac cells, where calcium influx balances potassium efflux, maintaining a prolonged depolarization. Pacemaker cells lack this phase because their action potential is designed for rhythmic firing rather than sustained contraction.
Step 4: Evaluate the statement provided. The statement 'Pacemaker cells lack a distinct plateau phase' is true based on the physiology of pacemaker cells.
Step 5: If the statement were false, the correction would involve clarifying that pacemaker cells do not exhibit a plateau phase due to their unique action potential designed for automaticity rather than contraction.
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Pacemaker Cells
Pacemaker cells are specialized cardiac cells responsible for initiating and regulating the heartbeat. They generate electrical impulses that trigger heart contractions, primarily located in the sinoatrial (SA) node. Unlike other cardiac cells, pacemaker cells have an unstable resting membrane potential, allowing them to spontaneously depolarize and set the rhythm of the heart.
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6:36
Comparing Action Potentials in Pacemaker and Contractile Cells
Plateau Phase
The plateau phase is a characteristic part of the action potential in cardiac muscle cells, particularly in ventricular myocytes. It is marked by a prolonged depolarization due to the influx of calcium ions, which helps prevent tetany and allows the heart to fill with blood before contracting again. Pacemaker cells do not exhibit this plateau phase, as their action potentials are shorter and primarily driven by different ionic currents.
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Percorso guidato
03:21Phases of Mitosis
Action Potential
An action potential is a rapid change in membrane potential that occurs in excitable cells, such as neurons and muscle cells, including those in the heart. In cardiac cells, the action potential consists of several phases, including depolarization, plateau, and repolarization. Understanding the differences in action potentials between pacemaker cells and other cardiac cells is crucial for comprehending their distinct roles in heart function.
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03:53Action Potential
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Domanda del libro di testo
How do pacemaker cardiac muscle cells differ from contractile cardiac muscle cells? What is autorhythmicity?
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Domanda del libro di testo
Mark the following statements as true or false. If a statement is false, correct it to make a true statement.
Open sodium ion channels cause hyperpolarization in pacemaker cells, which triggers HCN channels to open and begins a new action potential.
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Domanda del libro di testo
Mark the following statements as true or false. If a statement is false, correct it to make a true statement.
The plateau phase in contractile cells is due to the influx of calcium ions through calcium ion channels.
688
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Domanda del libro di testo
Mark the following statements as true or false. If a statement is false, correct it to make a true statement.
The rapid depolarization phase of the contractile cell action potential is due to the opening of voltage-gated potassium ion channels.
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Domanda del libro di testo
Cardiac muscle cells are joined by structures called:
a. T-tubules.
b. tight junctions.
c. sarcoplasmic reticulum.
d. intercalated discs.
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