Flashcards
Myology
Cards in this deck (89)
- 1What is Myology?The study of the structure, arrangement, and action of muscles
- 2What are the types of muscles?• Skeletal
• Visceral (smooth)
• Cardiac - 3What are the cellular characteristics of Skeletal muscles?Cells are long, cylindrical, striated, and multinucleate
- 4What are the cellular characteristics of Cardiac muscles?Cells are short, branched, and striated, usually with a single nucleus
Cells are interconnected by intercalated discs - 5What are the cellular characteristics of Visceral (smooth) muscles?Cells are short, spindle-shape, and non-striated, with a single, central nucleus
- 6Where are Skeletal muscles located?Attached to skeletal bones
- 7Where are Visceral (smooth) muscles located?Found in the walls of blood vessels and in digestive, respiratory, urinary, and reproductive organs
- 8Where are Cardiac muscles located?Found in the Heart
- 9What are the functions of Skeletal muscles?➢ Moves or stabilizes the position of the skeleton
➢ Guards entrances and exits to the digestive, respiratory, and urinary tracts
➢ Generates heat
➢ Protects internal organs - 10What are the functions of Visceral (smooth) muscles?➢ Moves food, urine and reproductive tract secretions
➢ Controls diameter of respiratory passageways
➢ Regulates diameter of blood vessels - 11What are the functions of Cardiac muscles?➢ Circulates blood
➢ Maintains blood (hydrostatic) pressure - 12What are the types of Skeletal muscles?➢ Parallel
o Strap-like
o Fusiform
o Radiate
o Quadrilateral
➢ Convergent
➢ Pennate
o Unipennate
o Bipennate
o Multipennate
➢ Circular - 13What are Parallel muscles?Muscle fibres run from one attachment of muscle to the skeleton to the other attachment
Good for large range of movement at joints - 14What are examples of the types of Parallel muscles?Strap-like
e.g. Sartorious
Fusiform
e.g. Biceps brachii muscle
Radiate (Triangular)
e.g. Trapezius
Flat (Quadrilateral)
e.g. Pronator quadratus - 15What are Convergent muscles?Muscles that converge onto one attachment site
e.g. Pectoralis Major and Minor - 16What are Pennate (Oblique) Muscles?Muscle fibres run oblique to line of pull of muscle
Good for Forceful contractions - 17What are examples of the types of Pennate muscles?Unipennate
e.g. extensor digitorum muscle
Bipennate
e.g. Rectus femoris muscle
Multipennate
e.g. Deltoid muscle - 18What are Circular Muscles? Give an example.Around entrances/exits
e.g. Orbicularis Oris muscle - 19What are the types of Skeletal Muscle attachments?➢ Tendon
➢ Aponeurosis
➢ Epimysium
➢ Raphe - 20What is a Tendon?A cord of fibrous tissue attaching muscle fibres to bone
- 21What is an Aponeurosis?A sheet of fibrous tissue attaching muscle fibres to bone
- 22What is an Epimysium?Attaches muscle directly to bone
- 23What is a Raphe?Muscle fibres attach directly to another muscle
- 24What does the Origin of a muscle mean?Refers to the fixed or stable end of a muscle
- 25What does the Insertion of a muscle mean?Refers to the free of movable end
- 26What are the factors for naming muscles?Name by:
➢ Size
➢ Length
➢ Shape
➢ Number of heads
➢ Location
➢ Action - 27What is an Isometric contraction? Give an example.Light contractions that increase the tension in the muscle without exerting enough force to move a body part
e.g. vertebral muscles maintaining posture - 28What are the types of Isotonic contractions? Give examples.Concentric
Muscle Shortens while contraction
Eccentric
Muscle lengthens while contracting (i.e. muscle is generating force but being stretched
e.g. Elbow flexion at 90o abduction - 29What is an Action in relation to muscles?Movement produced when a muscle contracts concentrically in isolation
- 30What can muscle actions help determine?➢ Site of attachments
➢ Type of joint
➢ Distance of line of force to joint and relationship (torque) - 31What is the function of muscle tissue?➢ Produce or Resist movement
➢ Provide stability
➢ Maintaining posture
➢ Generate heat
➢ Assist with venous return - 32What is Muscle Torque?Muscle torque refers to a force that tends to cause rotation
- 33How do you calculate Muscle Torque?Torque = Muscle Force (N) x Momentum (D)
D = perpendicular distance from joint axis to line of action of the force - 34What is an Accessory Structure?Tendon Sheaths
Tubular synovial sacs around a tendon. It permits the tendon to stretch and not adhere to the surrounding fascia
e.g. In the hand - 35What is the organisational function of Skeletal Muscles?➢ Skeletal muscle
➢ Muscle fibre
➢ Myofibril
➢ Myofilaments
o Tropomyosin
o Troponin
➢ Sacromere - 36What is a Skeletal Muscle?A muscle attached to the skeletal system
- 37What is a Muscle Fibre?A single muscle cell
- 38What are Myofibrils and what are their functions within muscle fibres?Any of the elongated contractile threads found in striated muscle cells
Made up of Sacromeres - 39What are Myofilaments and what are their functions within muscle fibres?Thick Filaments
Made up of many bonded units of Myosin
Myosin
A fibrous protein that forms (together with actin) the contractile filaments of muscle cells and is also involved in motion in other types of cell
Thin Filaments
Actin
Forms a helical structure that makes up the bulk of thin filament mass
Contains myosin-binding sites that allow myosin to connect to and move actin during muscle contraction - 40What is Tropomyosin?A long protein fibre that wraps around actin and covers the myosin binding sites on actin
- 41What is Troponin?Bound very tightly to tropomyosin to move it away from myosin binding sites during muscle contraction.
- 42What is a Sacromere?Repeating functional units within myofilaments, this is the smallest functional unit of the muscle fibre
- 43What is the structure of a muscle fibre?➢ Sarcoplasm
➢ Sarcolemma
➢ T-tubules
➢ Sarcoplasmic
➢ Mitochondria - 44What is Sarcoplasm?Cytoplasm inside the muscle fibre
Controls glycolytic enzyme concentration - 45What is a Sarcolemma and what is its function within muscle fibres?Cell membrane of muscle fibres
Acts as a conductor for electrochemical signals that stimulate muscle cells - 46What are T-tubules and what are their function within muscle fibres?Connect sarcolemma
Help carry electrochemical signals into the middle of muscle fibres - 47What is Sacroplasmic Reticulum and what is its function within muscle fibre?A membrane complex that forms a tubular network around each myofibril
Stores calcium ions for muscle contraction - 48What is a Mitochondria and what is its function within a muscle fibre?An enzyme responsible for energy-releasing chemical reactions
Break down sugars and provide energy in the form of ATP to active muscles - 49What are the structures of a Sarcomere?➢ A band (Dark)
➢ I band (Light)
➢ Z line
➢ H band
➢ M line - 50What does the A band (dark) of a Sarcomere refer to?Contains whole length of Myosin (thick) filaments and any actin overlap
- 51What does the I band (light) of a Sarcomere refer to?Contains Actin (thin) filaments without myosin overlap
- 52What does the Z line of a Sarcomere refer to?A line that joins adjacent sarcomeres (contain actin and myosin filaments)
- 53What does the H band of a Sarcomere refer to?The length of myosin without actin overlaps
- 54What does the M line of a Sarcomere refer to?A protein ring within H band that supports myosin
- 55What are the mechanisms of contraction?➢ Shortening model
➢ Sliding filament model
➢ Cross-bridge cycle - 56What is the first mechanism of contraction?I band (Actin filaments) shortens whilst the A band (Myosin filaments)
such that myosin heads pull the actin filaments towards centre of A band, detach from actin, and creates a power stroke to bind to the next actin molecule - 57What is the Sliding Filament Model?Myosin filaments stay still while actin filaments move or slide into the A band
Z lines move closer together - 58What is the Cross-bridge cycle of muscle contraction?A proposed mechanism that says filament sliding occurs by cyclical attachment and detachment of myosin to actin such that myosin heads pull the actin filaments towards centre of A band, detach from actin, and creates a power stroke to bind to next actin molecule
- 59What is the process of Muscular Contraction?I. Motor neurons release neurotransmitter chemicals at the Neuromuscular Junction (NMJ) that bond to the motor end plate of the sarcolemma
II. The motor end plate contains many ion channels that open in response to neurotransmitters and allow positive ions to enter the muscle fibre
III. Positive ions form an electrochemical gradient to form inside of the cell, which spreads throughout the sarcolemma and the T-tubules by opening even more ion channels
IV. Positive ions reach sarcoplasmic reticulum, Calcium ions release and allow flow into myofibrils
V. Calcium ions bind to troponin, changes shape and move to tropomyosin
VI. Tropomyosin moves away from myosin binding sites, allowing actin and myosin to bind together
VII. ATP molecules power myosin proteins to bend and pull on actin molecules closer to centre of sarcomere
VIII. Sacromere shortens and contracts, causing myofibrils to shorten muscle cell with great force
IX. Muscle continues contraction as stimulated by neurotransmitter - 60What is the process of Muscular Relaxation after contracting?I. When the motor neuron stops the realease of neurotransmitter, the process of contraction reverses itself
II. Calcium returns to sarcoplasmic reticulum
III. Troponin and tropomyosin return to rest
IV. Actin and Myosin prevent binding
V. Sacromeres return to enlongated resting state once the force of myosin pulling on actin has stopped - 61What are the types of muscular contractions?Isometric Contraction
Light contractions that increase the tension in the muscle without exerting enough force to move a body part
e.g. vertebral muscles maintaining posture
Isotonic Contraction
➢ Concentric
Muscle Shortens while contraction
➢ Eccentric
Muscle lengthens while contracting (i.e. muscle is generating force but being stretched - 62What are the factors influencing muscular contractions?➢ The number of motor units involved in contraction
➢ Amount of stimulus from the nervous system - 63What is a twitch contraction?A single nerve impulse of a motor neuron will cause a motor unit to contract briefly before relaxing
- 64What is a Temporal summation?Several signals from motor neurons within a short period of time, which increase the strength and duration of muscular contraction
- 65What is a Tetanus?Complete and lasting contraction where motor neuron provides many nerve impulses, up until nerve signal reduce or muscular fatigue
- 66What is meant by Muscle tone and its function for musculoskeletal functionability?A natural condition in which a skeletal muscle stays partially contracted at all times
➢ Provides a slight tension on the muscle to prevent damage to the muscle and joints from sudden movements
➢ Helps maintain the body’s posture - 67What are the characteristics of Slow fibres of Skeletal Muscle Tissues?Small cross-sectional diameter
Low Tension
Slow contraction speed
High Fatigue Resistance
Coloured Red
High Myoglobin content
Dense Capillary supply
Many mitochondria
Low glycolytic enzyme concentration - 68What are the characteristics of Fast fibres of Skeletal Muscle Tissues?Large cross-sectional diameter
High tension
Fast contraction speed
Low fatigue resistance
Coloured White (deoxidised)
Low Myoglobin content
Scarce Capillary supply
Few mitochondria
High Glycolytic enzyme concentration - 69What are the characteristics of Intermediate fibres of Skeletal Muscle Tissues?Intermediate cross-sectional diameter
Intermediate tension
Fast contraction speed
Intermediate fatigue resistance
Coloured Pink
Low Myoglobin content
Intermediate capillary supply
Some Mitochondria
High Glycolytic enzyme concentration - 70What is Myotendinous Junction (MTJ)?The site of connection between tendon and muscle
The force generated by muscle contraction is transmitted from intracellular contractile muscle proteins to the extracellular connective tissue proteins of the tendon - 71Describe the gross characteristics of Myotendinous Junction (MTJ).➢ Is a potential site of weakness (injury prone)
➢ The muscle cell membrane (sarcolemma) is folded into finger-like projections to increase inter-surface area for force transmission
➢ Perimysium of the muscle is continuous with collagen fibres of the tendon
➢ Receives sensory information on muscle length (spindles), tension (golgi organs) and pain - 72What is the normal blood and nerve supply of the Myotendinous Junction?The MTJ receives blood supply from the muscle, and is considered hypo-vascular, meaning it's deficient in blood vessels
- 73Describe the histological characteristics of the Myotendinous Junction (MTJ).Tendon collagen fibrils are set within deep processes that are formed on the surface of the muscle cells.
components of extracellular matrix of MTJ include:
➢ laminin
➢ Integrin
➢ Vinculin
➢ fibronectin
➢ Talin
Enable a strong connection between the muscle actin filaments and the tendon collagen fibers - 74What are the types of actions by muscles?➢ Agonist
➢ Antagonist
➢ Stabiliser
➢ Synergist - 75What is an Agonist?Muscle producing desired movement contracting either concentrically (action) or eccentrically
➢ Prime movers
e.g. Anterior Deltoid in Glenohumeral joint Flexion
➢ Assistant movers
e.g. Triceps Bachii assist Extension of Glenohumeral joint - 76What is an Antagonist?Muscle which must relax (i.e. not contracting) to allow desired movement to occur
e.g. Triceps Brachii in Elbow joint Flexion - 77What is a Stabiliser? Give an example.Muscle that supports a body part so that another muscle will have a firm base from which to act
e.g. Posterior Deltoids in Glenohumeral joint Flexion - 78What is a Synergist? Give an example.Muscle that eliminates an undesired movement that would otherwise be produced by the movers
e.g. Pronator Teres is synergist in Supinated Elbow joint Flexion - cancels out Bicep brachii Supination - 79What is a Spurt muscle and what is its role in joint movement?Origin far from moving joint
Greater motion vector - Mobility
Rotational > Translational - 80What is a Shunt muscle and what is its role in joint movement?Origin close to moving joint
Greater compressive force - Stability
Translational > Rotational - 81What is a Fulcrum?A thing that plays a central or essential role in an activity, event, or situation
- 82What is the moment arm?line from elbow joint out at perpendicular angle
changes throughout movement - 83What are the concepts of muscle recruitment?• Effect of load
• Effect of speed
• Effect of joint position
• Laws and Principles - 84What is the effect of Load in muscle recruitment?Increasing load = increase in activation of muscle, doesn’t necessarily affect movement pattern
Loaded = all muscles
Unloaded = just spurt muscles - 85What is the effect of Speed in muscle recruitment?Increasing speed = decreases stability of joint
= more likely to injure - 86What is the effect of Joint position in muscle recruitment?Changing joint position changes gravity effects and therefore muscles used in actions
- 87What are the Laws and Principles in muscle recruitment?Muscles are recruited in such a way that synergistic activity is minimised
Muscles do not work in isolation - 88What are the factors in determining the main agonist?• Joint position
• Minimising synergist activity
• Large Cross-sectional areas
• Uni/ Bi/ Poly-articular based on what movement desired - 89What is an example of joint position affecting muscle recruitment?Elbow joint flexion, whilst radioulnar joints are supinated = less recruitment of Biceps brachii
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- Anatomy (Topic 1 - General Anatomy & Physiology) Flashcards on Myology, created by Jack Henderson on 20/04/2018.
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