Questions and Answers
What lever class has the fulcrum situated between the force and the load?
Which element is important in directly triggering contraction?
Calcium (Ca++)
Identify the muscle that has the arrow pointing to it.
Diaphragm muscle
Thin and thick filaments are organized into functional units called ________.
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Cardiac muscles differ from skeletal muscles in that they contain ________.
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Which connective tissue surrounds the entire muscle and separates it from surrounding tissues?
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What are the types of striated muscle?
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Which types of muscle are involuntary?
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Smooth muscle is responsible for what movements?
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A ring-like band of muscle made of smooth muscle that will stop the flow of contents from one organ to another is known as what?
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How do muscles help control glucose levels in the bloodstream?
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What does excitability of the muscles mean?
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Which function of muscle is best described as helping to maintain posture and preventing unwanted movements?
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Muscles have the ability to shorten. This is known as?
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Is the return to an original shape after being stretched known as?
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Is the ability to stretch without tearing known as?
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Aerobic respiration is the type of energy creation that will give the muscle about two minutes of energy only.
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Between skeletal muscle, cardiac muscle, and smooth muscle, the smooth muscle has the lowest adenosine triphosphate (ATP) demands due to the latch-bridge mechanism.
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Which of the following is a function of smooth muscle?
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What is the function of cardiac muscle?
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Only __________ muscles are under __________ control, such as blinking your eyes.
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The neurotransmitter used at the neuromuscular junction is?
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Skeletal muscle fiber is considered to be multinucleated.
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What is the fixed point of a lever system that the movement is applied to known as?
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What is the functional contractile unit of the myofibril where muscle tension is produced?
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The connection formed between actin and myosin is known as what?
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Which regulatory protein binds calcium to initiate muscle contraction?
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Titin sits between the M-line and Z-lines of the sarcomere and acts as a spring for actin filaments, attaching to the Z-line.
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During muscle contraction, the sarcomere shortens and the H-zone grows in size.
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What are the main contractile proteins of the thick and thin filaments in a sarcomere called?
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Which layer of connective tissue surrounds each muscle fiber?
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What happens to the I-band when the sarcomere contracts?
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The two contractile proteins, actin and myosin, are the main myofilaments that form the sarcomere.
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Study Notes
Muscle Types and Function
- First-Class Lever: Fulcrum positioned between the force and load.
- Agonist Support: Synergist muscles assist agonists in movement.
- Prime Mover for Head Flexion: Sternocleidomastoid muscle is responsible.
- Diaphragm Muscle: Primary muscle involved in respiration.
Muscle Contraction Mechanism
- Calcium (Ca++): Essential element for triggering muscle contraction.
- Sarcomeres: Functional units comprised of thin and thick filaments.
- Intercalated Discs: Unique feature of cardiac muscles not present in skeletal muscles.
- Muscle Surrounding Tissue: Epimysium encases entire muscle and separates it from adjacent tissues.
- Striated Muscle Types: Includes skeletal and cardiac muscles.
Muscle Control and Characteristics
- Involuntary Muscles: Cardiac and smooth muscles; operate without conscious control.
- Smooth Muscle Function: Moves contents through organs like the small intestine.
- Sphincter Muscles: Control flow between organs by contracting to close passageways.
- Muscle Extensibility: Ability to stretch without injury.
- Muscle Glycogen Utilization: Skeletal muscles manage glucose levels by storing glycogen.
Muscle Properties
- Excitability: Muscle cells create electrical currents through ion uptake.
- Stabilization: Muscle contractility helps maintain posture.
- Elasticity: Muscles return to original shape post-extension.
- Electrical Excitability: Changes in resting membrane potential due to ion exchange.
Muscle Fiber Organization
- Types of Muscle Fiber: Skeletal fibers are long, thin, multinucleated, and voluntary.
- Cardiac Muscle: Found strictly in the heart, has intercalated discs for synchronized contractions.
- Smooth Muscle in Blood Vessels: Regulates blood flow and pressure.
Contraction Terms and Mechanisms
- Peristalsis: Smooth muscle contraction for food movement in the digestive tract.
- Cross-Bridge Formation: Interaction between actin and myosin during contraction.
- AChE (Acetylcholine Esterase): Enzyme that breaks down ACh at the neuromuscular junction.
- Tetanus: Continuous muscle contraction due to high-frequency stimulation.
Naming Skeletal Muscles
- Muscle Naming Conventions: Based on location, size, shape, action, and number of origins.
- Agonist: Main muscle responsible for a particular movement.
- Muscle Attachment Points: Origin is fixed points, while insertion is the movable end.
Muscle Actions and Synergists
- Major and Minor Muscles: "Major" indicates the largest and most active muscle in a pair.
- Skeletal Muscle actions: Includes movements like extending the forearm (triceps brachii) and flexing the vertebral column (rectus abdominis).
- Synergists in Muscle Action: Support the primary mover during contractions (e.g., pectoralis major for arm movements).
Muscle Disorders and Function
- Myasthenia Gravis: Autoimmune disorder disrupting neuromuscular transmission leading to muscle weakness.
- Duchenne Muscular Dystrophy: Genetic disorder resulting in muscle tissue degeneration and replacement with fat.
Energy and Muscle Maintenance
- ATP Production: Muscle fibers predominantly utilize aerobic respiration for sustained energy.
- Thermoregulation: Muscle contractions produce heat as by-products of ATP production during physical activity.
- Latch-Bridge Mechanism: Allows smooth muscle to sustain contractions with minimal energy usage.
Muscle Structure Insights
- Sarcomere Structure: Actin and myosin overlap within the A-band, while I-bands shorten during contraction.
- Calcium's Role: Initiates muscle contraction by binding to troponin, causing tropomyosin shifts to expose actin binding sites.
- Connective Tissue: Endomysium surrounds each muscle fiber, while Z-line defines the boundaries of each sarcomere.### Muscle Contraction and Sarcomere Structure
- Actin and myosin are the primary contractile proteins that form the sarcomere.
- Hydrolysis of ATP does not cause conformational changes in the head region of actin.
- Troponin and tropomyosin are regulatory proteins associated with actin and myosin.
- Myomesin serves as the structural protein in the M-line of the sarcomere.
- Titin acts as a spring for actin filaments, connecting to the Z-line and providing elastic properties.
- During muscle contraction, the sarcomere shortens, and the H-zone does not increase in size; it actually decreases.
Nervous System Structure
- Neurons are the fundamental units of the nervous system responsible for information transmission and processing.
- Dendrites are branch-like extensions that receive signals from other neurons or sensory receptors.
- Axons are the main output structures transmitting electrical signals away from the neuron's cell body.
- Synapses are specialized junctions for communication between neurons or with target cells.
Myelin Sheath
- The myelin sheath is produced by Schwann cells in the peripheral nervous system and oligodendrocytes in the central nervous system.
Action Potentials and Ion Channels
- Voltage-gated channels open in response to changes in membrane potential, generating action potentials.
- Saltatory conduction, occurring along myelinated axons, enhances the speed of action potentials.
Organization of the Nervous System
- The nervous system consists of two main divisions: Central Nervous System (CNS) and Peripheral Nervous System (PNS).
- Integration of postsynaptic potentials from multiple presynaptic neurons characterizes spatial summation.
Additional Neuroglial Functions
- Astrocytes are crucial for maintaining the blood-brain barrier and regulating the extracellular environment of neurons.
- Graded potentials refer to small, localized changes in membrane potential that vary in amplitude.
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Description
Review of BIOS252 week 1 and 2 covering levers, agonist, synergist, and prime movers in head flexion. Test your knowledge with this quiz!
