Podcast
Questions and Answers
What is the primary difference in structure between skeletal muscle and smooth muscle?
What is the primary difference in structure between skeletal muscle and smooth muscle?
What is the duration of the refractory period in skeletal muscle action potential?
What is the duration of the refractory period in skeletal muscle action potential?
What is the function of the sarcoplasmic reticulum in the skeletal muscle contraction cycle?
What is the function of the sarcoplasmic reticulum in the skeletal muscle contraction cycle?
What is the term for the amount of blood ejected by a ventricle per beat?
What is the term for the amount of blood ejected by a ventricle per beat?
Signup and view all the answers
What is the correct sequence of events in the skeletal muscle contraction cycle?
What is the correct sequence of events in the skeletal muscle contraction cycle?
Signup and view all the answers
What is the term for the basic contractile unit of muscle fiber?
What is the term for the basic contractile unit of muscle fiber?
Signup and view all the answers
What is the duration of the action potential in cardiac muscle?
What is the duration of the action potential in cardiac muscle?
Signup and view all the answers
What is the term for the wave of ventricular depolarization on an ECG?
What is the term for the wave of ventricular depolarization on an ECG?
Signup and view all the answers
Study Notes
Skeletal Muscle vs. Smooth Muscle Anatomy
- Skeletal muscle: Multinucleated fibers, striated, and organized into sarcomeres and myofibrils, with components including epimysium, perimysium, endomysium, and fascicles
- Smooth muscle: Single nucleus per cell, non-striated, with dense bodies instead of sarcomeres, and organized into sheets or bundles found in walls of hollow organs
Action Potential in Cardiac vs. Skeletal Muscle
- Skeletal muscle action potential: Short duration (~2 ms), short refractory period (~5 ms), and all-or-nothing propagation
- Cardiac muscle action potential: Long duration (~200-300 ms), long refractory period (~250 ms), and graded propagation influenced by autonomic nervous system
Skeletal Muscle Contraction Cycle
- Excitation: Action potential arrives at neuromuscular junction
- Calcium release: Sarcoplasmic reticulum releases Ca2+
- Cross-bridge formation: Ca2+ binds to troponin, exposing binding sites on actin
- Power stroke: Myosin heads pivot, pulling actin filaments
- Detachment: ATP binds to myosin heads, causing them to release actin
- Resetting: ATP is hydrolyzed, resetting myosin heads
Sarcomere and Muscle Contraction/Relaxation
- Sarcomere: Basic contractile unit of muscle fiber
- Contraction: Actin and myosin filaments slide past each other, shortening the sarcomere
- Relaxation: Calcium ions are pumped back into the sarcoplasmic reticulum, actin and myosin filaments return to resting position
ECG and Cardiac Physiology
- ECG: Electrocardiogram
- P Wave: Atrial depolarization
- QRS Complex: Ventricular depolarization
- T Wave: Ventricular repolarization
Cardiac Terms and Regulation
- Stroke Volume (SV): Amount of blood ejected by a ventricle per beat, regulated by preload, contractility, and afterload
- Cardiac Output (CO): Total volume of blood pumped by the ventricle per minute, calculated by CO = SV x Heart Rate (HR)
- End-Diastolic Volume (EDV): Volume of blood in the ventricle at the end of diastole, affected by venous return and filling time
- End-Systolic Volume (ESV): Volume of blood remaining in the ventricle after systole, affected by contractility and afterload
- Preload: Degree of stretch of cardiac muscle fibers at the end of diastole, influenced by venous return
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Compare and contrast the anatomy of skeletal and smooth muscles, including structure, organization, and components. Learn about the differences between these two types of muscles.
