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.
Pacemaker cells lack a distinct plateau phase.
615
views
Ch. 17 The Cardiovascular System I: The Heart
Amerman2nd EditionHuman Anatomy & PhysiologyISBN: 9780136873822
Non è quello che usi tu?Cambia libro di testoScegli un libro di testo diverso
TOC.tableOfContents
- Ch. 1 Introduction to Anatomy and Physiology26
- Ch. 2 The Chemistry of Life38
- Ch. 3 The Cell55
- Ch. 4 Histology47
- Ch. 5 The Integumentary System30
- Ch. 6 Bones and Bone Tissue36
- Ch. 7 The Skeletal System40
- Ch. 8 Articulations19
- Ch. 9 The Muscular System36
- Ch. 10 Muscle Tissue and Physiology29
- Ch. 11 Introduction to the Nervous System and Nervous Tissue28
- Ch. 12 The Central Nervous System42
- 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 Heart30
- Ch. 18 The Cardiovascular System II: The Blood Vessels43
- Ch. 19 Blood32
- Ch. 20 The Lymphatic System and Immunity45
- 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
Amerman2nd EditionHuman Anatomy & PhysiologyISBN: 9780136873822Non è quello che usi tu?Cambia libro di testo
Capitolo 17, Problema 6
How do pacemaker cardiac muscle cells differ from contractile cardiac muscle cells? What is autorhythmicity?
Guida verificata passo dopo passo1
Pacemaker cardiac muscle cells, also known as autorhythmic cells, are specialized cells in the heart that generate and conduct electrical impulses to initiate and regulate the heartbeat. Contractile cardiac muscle cells, on the other hand, are responsible for the mechanical contraction of the heart to pump blood.
Pacemaker cells differ from contractile cells in their ability to spontaneously depolarize without external stimulation. This property is called autorhythmicity, which allows pacemaker cells to set the rhythm of the heart independently of nervous system input.
Autorhythmicity is achieved through the unique ion channel dynamics in pacemaker cells. These cells have 'funny' sodium channels (If channels) that open during hyperpolarization, allowing a slow influx of sodium ions, which gradually depolarizes the cell membrane.
In pacemaker cells, once the membrane potential reaches a threshold, voltage-gated calcium channels open, leading to a rapid influx of calcium ions and the generation of an action potential. This differs from contractile cells, which rely on external stimulation to depolarize and contract.
Contractile cardiac muscle cells have a stable resting membrane potential and require action potentials from pacemaker cells or neighboring contractile cells to depolarize. Their primary role is to generate force for pumping blood, while pacemaker cells focus on initiating and regulating the electrical activity of the heart.
Risposta video verificata per un problema simile:
Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.
Concetti chiave
Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.
Pacemaker Cells
Pacemaker cells, primarily located in the sinoatrial (SA) node of the heart, are specialized cardiac muscle cells responsible for initiating and regulating the heartbeat. Unlike contractile cells, they have the unique ability to generate spontaneous action potentials due to their unstable resting membrane potential, which allows them to automatically trigger heart contractions.
Video consigliato:
6:36
Comparing Action Potentials in Pacemaker and Contractile Cells
Contractile Cardiac Muscle Cells
Contractile cardiac muscle cells, found throughout the heart, are responsible for the actual contraction and pumping of blood. These cells respond to the electrical signals generated by pacemaker cells, leading to coordinated contractions. They contain myofibrils and are structured to facilitate strong contractions, ensuring effective blood circulation.
Video consigliato:
6:36Comparing Action Potentials in Pacemaker and Contractile Cells
Autorhythmicity
Autorhythmicity refers to the ability of certain cardiac cells, particularly pacemaker cells, to generate rhythmic electrical impulses without external stimulation. This intrinsic property is crucial for maintaining a consistent heart rate and rhythm, allowing the heart to function autonomously and adapt to the body's varying demands for blood flow.
Video consigliato:
8:47Pacemakers: Molecular Physiology
Pratica correlata
Domanda del libro di testo
Mr. Watson has been diagnosed with mitral insufficiency, or a malfunctioning mitral valve, which causes the valve to not close properly. Predict the signs and symptoms you might expect from a disease of this valve. What would happen to the patient's stroke volume and cardiac output? Explain. What might help improve his cardiac output?
703
views
Domanda del libro di testo
A newer drug, ivabradine, lowers the heart rate by blocking the nonselective HCN cation channels. Why would this action decrease the heart rate? Would this drug have an effect on pacemaker cells, contractile cells, or both? Explain.
780
views
Domanda del libro di testo
An experimental toxin makes the refractory period of cardiac muscle cells equal in length to that of skeletal muscle fibers. Predict the consequences of this toxin.
765
views
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.
646
views
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.
973
views