Podcast
Questions and Answers
What is the primary characteristic of smooth muscle classified as single unit or visceral muscle?
What is the primary characteristic of smooth muscle classified as single unit or visceral muscle?
What role does glycolysis play in muscle metabolism?
What role does glycolysis play in muscle metabolism?
Which energy pathway is primarily used by muscles during prolonged, moderate exercise like marathons?
Which energy pathway is primarily used by muscles during prolonged, moderate exercise like marathons?
In the context of muscle contractions, what does the term 'motor recruitment' refer to?
In the context of muscle contractions, what does the term 'motor recruitment' refer to?
Signup and view all the answers
Which of the following best explains the sliding filament mechanism during muscle contraction?
Which of the following best explains the sliding filament mechanism during muscle contraction?
Signup and view all the answers
What initiates the contraction cycle in smooth muscle fibers?
What initiates the contraction cycle in smooth muscle fibers?
Signup and view all the answers
Which type of muscle contraction occurs when a muscle changes length while generating force?
Which type of muscle contraction occurs when a muscle changes length while generating force?
Signup and view all the answers
What happens during the refractory period of muscle contraction?
What happens during the refractory period of muscle contraction?
Signup and view all the answers
What effect does wave summation have on muscle tension?
What effect does wave summation have on muscle tension?
Signup and view all the answers
During smooth muscle contraction, which process is responsible for the binding of myosin to actin?
During smooth muscle contraction, which process is responsible for the binding of myosin to actin?
Signup and view all the answers
Study Notes
Smooth Muscle
- Single-unit (visceral) smooth muscle: Muscle fibers contract as a coordinated unit, found in visceral organs.
- Multi-unit smooth muscle: Individual muscle fibers are innervated by a motor neuron, allowing for precise control, found in the eyeballs and other locations requiring fine motor movements.
- Function: Visceral organs (e.g., stomach, intestines) vs. precise movements (e.g., eye movements).
Energy for Skeletal Muscle Contraction
- Glycolysis: Breaks down glucose to pyruvate, then lactate (lactic acid buildup lowers pH, hindering contraction). Provides ATP anaerobically (without oxygen).
- Creatine phosphate (CP): Muscle fibers can generate ATP using CP stores until glycogen stores are depleted.
- Aerobic respiration: Slowest ATP production method, breaks down fatty acids, amino acids, and glucose, utilizing oxygen (aerobic) and occurs during rest.
- Energy during exercise: During exercise, muscle relies more on glucose for energy.
Stimulating Skeletal Muscle
- Electro Myography (EMG): Used to record muscle activity.
- Resting membrane potential: The electrical difference across the muscle cell membrane at rest.
- Refractory period: Brief period after a stimulus where the muscle cannot respond to another stimulus.
- Myogram: A graph of muscle tension over time.
- Latent period: Delay between stimulation and contraction.
- Contraction period: Period where the muscle shortens.
- Relaxation period: Period where the muscle returns to its original length.
- Internal tension: Force generated within the muscle.
- External tension: Force exerted outside the muscle.
Factors Affecting Muscle Tension
- Wave summation: Increased muscle tension from successive stimuli.
- Motor unit recruitment: Gradually activating more and larger motor units to produce stronger contraction.
Sliding Filament Mechanism
- Steps: Z discs move closer, I bands shorten, zones of overlap widen, H zones narrow, A band width remains constant.
Muscle Contraction Types
-
Isotonic contraction: Muscle changes length and moves a load.
- Concentric: Muscle shortens.
- Eccentric: Muscle lengthens.
- Isometric contraction: Muscle develops tension without changing length.
Smooth Muscle Contraction
-
Mechanism:
- Calcium-calmodulin complex formation.
- Myosin light-chain kinase (MLCK) activation.
- Cross-bridge phosphorylation.
- Cross-bridge binding to actin.
- Cross-bridge cycling.
- Relaxation: Requires dephosphorylation.
- Latch state: Smooth muscle can maintain contraction with relatively low energy use.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz covers the distinctions between single-unit and multi-unit smooth muscle, including their functions and locations. It also addresses the energy mechanisms of skeletal muscle contraction, exploring glycolysis, creatine phosphate, and aerobic respiration. Test your understanding of muscle physiology and energy production.
