16 Questions
What is the main cause of the contraction of cardiac muscle (systole)?
Closing of voltage gated Ca+2 channels
What is the process that results in the return of ions to their previous resting state in cardiac muscle?
Repolarization
What causes hyperpolarization in cardiac muscle?
Influx of anions (Cl– ions) through chloride channels
What does the refractory period refer to in excitable membranes?
The amount of time it takes for a membrane to be ready to respond to a second stimulus
From where does the cardiac electric impulse originate in the heart?
SA node (Pacemaker)
What role does the AV node play in the heart's conductive system?
Allows passage of the electric impulse slowly (AV nodal delay)
What is responsible for transmitting the cardiac electric impulse from the AV node to the right and left ventricles?
Right and left bundle branches
What is the final step in the heart's conductive system?
Purkinje fibers distributing impulse to all cells
What is the primary characteristic of the cardiac muscle?
Auto-rhythmicity
Which cells in the heart can generate action potential spontaneously?
SA node and AV node
What is the normal pacemaker of the heart?
SA node
What factor can cause an increase in heart rate (↑HR)?
Sympathetic stimulation
During which phase of action potential does depolarization occur?
Phase 0
What causes a large influx of sodium ions inside the cardiac cell during depolarization?
Opening of voltage-gated sodium channels
Which type of stimulation can lead to a decrease in heart rate (↓HR)?
Parasympathetic stimulation
What is the primary function of the SA node in the heart?
Generating action potential spontaneously
Test your knowledge of the components and characteristics of the cardiovascular system, including the heart, blood vessels, and blood circulation. Explore the automatic, rhythmic, excitable, conductive, and contractile features of the cardiac muscle.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
