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Questions and Answers
What lever class has the fulcrum situated between the force and the load?
What lever class has the fulcrum situated between the force and the load?
Which element is important in directly triggering contraction?
Which element is important in directly triggering contraction?
Calcium (Ca++)
Identify the muscle that has the arrow pointing to it.
Identify the muscle that has the arrow pointing to it.
Diaphragm muscle
Thin and thick filaments are organized into functional units called ________.
Thin and thick filaments are organized into functional units called ________.
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Cardiac muscles differ from skeletal muscles in that they contain ________.
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?
Which connective tissue surrounds the entire muscle and separates it from surrounding tissues?
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What are the types of striated muscle?
What are the types of striated muscle?
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Which types of muscle are involuntary?
Which types of muscle are involuntary?
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Smooth muscle is responsible for what movements?
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?
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?
How do muscles help control glucose levels in the bloodstream?
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What does excitability of the muscles mean?
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?
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?
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?
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?
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.
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.
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?
Which of the following is a function of smooth muscle?
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What is the function of cardiac muscle?
What is the function of cardiac muscle?
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Only __________ muscles are under __________ control, such as blinking your eyes.
Only __________ muscles are under __________ control, such as blinking your eyes.
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The neurotransmitter used at the neuromuscular junction is?
The neurotransmitter used at the neuromuscular junction is?
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Skeletal muscle fiber is considered to be multinucleated.
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?
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?
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?
The connection formed between actin and myosin is known as what?
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Which regulatory protein binds calcium to initiate muscle contraction?
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.
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.
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?
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?
Which layer of connective tissue surrounds each muscle fiber?
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What happens to the I-band when the sarcomere contracts?
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.
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!
