Musculoskeletal System Flashcards
Slow, Oxidative Fibers (Type 1) mitochondria, capillaries, myoglobin content, and glycogen content
Mitochondria: Numerous
Capillaries: Numerous
Myoglobin content: High (red fibers)
Glycogen content: Low
Fast, Oxidative-Glycolytic Fibers (Type 2a) mitochondria, capillaries, myoglobin content, and glycogen content
Mitochondria: Numerous
Capillaries: Numerous
Myoglobin content: High (red fibers)
Glycogen content: Intermediate
Fast, Glycolytic Fibers (Type 2b) mitochondria, capillaries, myoglobin content, and glycogen content
Mitochondria: Sparse
Capillaries: Sparse
Myoglobin content: Low (white fibers)
Glycogen content: High
Slow, Oxidative Fibers (Type 1) rate of fatigue, speed of contraction, and major locations
Rate of fatigue: Slow
Speed of contraction: Slow
Major location: Postural muscles of back
Fast, Oxidative-Glycolytic Fibers (Type 2a) rate of fatigue, speed of contraction, and major locations
Rate of fatigue: Intermediate
Speed of contraction: Fast
Major location: Major muscles of legs
Fast, Glycolytic Fibers (Type 2b) rate of fatigue, speed of contraction, and major locations
Rate of fatigue: Fast
Speed of contraction: Fast
Major location: Extraocular muscles
Red fibers
Well vascularized and have lots of myoglobin, which stores oxygen. Myoglobin is an iron- and oxygen-storage protein found in cardiac and skeletal muscle.
Red fibers contract slowly and resist fatigue.
White fibers
Low in myoglobin; they contract quickly, but tire easily.
Three different motor units in the human body
Type 1, type 2a, type2b
Type 1 motor unit
Highly fatigue resistant, has a lower activation threshold, contains fewer muscle fibers, and has low force generation during contraction.
Type 2 motor unit
Resistant to fatigue, has a higher activation threshold, and the force produced is higher compared to type 1
Type 2b motor unit
Fatigable, has a high activation threshold, innervates the most muscle fibers, and generates the greatest force during contraction
The structural unit of a muscle is a _______
muscle fiber
The functional unit of a muscle, consisting of a motor neuron and the muscle fibers it controls, is a _______
motor unit
Fascia
A band or sheet of connective tissue, that attaches, encloses, and separates muscles and other internal organs. It interpenetrates and
surrounds the muscles, bones, nerves, and blood vessels of the body.
How is fascia classified?
Fascia is classified by layer as superficial fascia, deep fascia, and visceral or
parietal fascia, or by its function and anatomical location.
Deep fascia
Associated with, bone (periosteum and endosteum), cartilage (perichondrium), blood vessels (tunica externa), muscles (epimysium, perimysium, and endomysium), nerves (epineurium, perineurium, and endoneurium)
High density of elastin fiber for extensibility and resilience
Fascia function
Often surrounds groups of muscles, forming compartments.
Fasciae also reduce friction between muscles and blood vessels and nerves.
Muscle functions (broad sense)
Prime mover or agonist, fixators, synergist, antagonist
Prime mover or agonist
The main muscle responsible for producing a specific movement of the body (e.g., concentric contraction).
Fixators
Steady the proximal parts of a limb while movements are occurring in distal parts.
Synergist
Complements the action of prime movers—for
example, by preventing movement of the intervening joint when a prime mover passes over more than one joint.
Antagonist
A muscle that opposes the action of a prime mover. As a prime mover contracts, the antagonist progressively relaxes, producing a smooth movement.
Functions (narrow sense)
Flexors and extensors, abductors and adductors
What muscles shorten the most during contraction?
When muscles contract, the fibers shorten to about 70% of their resting length. Muscles with a long parallel fascicle arrangement shorten the most, providing considerable range of movement at a joint, but are not powerful.
Muscle power
Muscle power increases as the total number of muscle cells increases. Therefore, the shorter, wide pennate muscles that “pack in” the most fiber bundles shorten less but are most powerful.
This statement is not quite correct in a biomechanical sense.
Muscle origin
The origin is usually the proximal end of the muscle, which remains fixed.
Muscle insertion
The insertion is usually the distal end of the muscle, which is movable.
Types of skeletal muscle contraction
Reflexive contraction, tonic contraction, and phasic contraction
Reflexive contraction
A type of skeletal muscle contraction automatic and not voluntarily controlled—for example, respiratory movements of the diaphragm. Muscle stretch evokes reflexive contraction produced by tapping a tendon with a reflex hammer.
Tonic contraction
A type of skeletal muscle contraction which is a slight contraction (muscle tone) that does not produce movement or active resistance but
gives the muscle firmness, assisting the stability of joints and the maintenance of posture.
Phasic contraction
A type of skeletal muscle contraction.
Two types of phasic contraction: Isometric and isotonic
Isometric contractions
A type of phasic contraction where the muscle length remains the same—no movement occurs but muscle tension is increased above tonic levels (e.g., the deltoid holds the arm in abduction).
Force = Mass
Isotonic contraction
A type of phasic contraction where the muscle changes length to produce movement.
Two types:
Concentric contraction: Muscle shortening, Force > Mass
Eccentric contraction: Muscle lengthening/relaxation of a contracted muscle, Force < Mass
Muscular hydrostat
A biological machine
consisting mainly of muscles with no skeletal support.
Ex. human pharynx (throat), elephant trunk
Joint classification
Joints can be classified as synarthroses or diarthroses.
Diarthroses (synovial joints)
Joints that allow free
movement of the attached bones, such as knuckles, knees, and elbows.
Synarthrosis
Permits only limited movement.
Synostoses, syndesmoses, and symphyses
Synostoses
A type of synarthroses joint that allows essentially no movement between bones. In older adults synostoses unite the skull bones, which in children and young
adults are held together by sutures.
Syndesmoses
A type of synarthroses joint that joins bones by dense connective tissue only. E.g., the interosseous ligament of the inferior tibiofibular joint and the posterior
region of the sacroiliac joints.
Symphyses
A type of synarthroses joint that have a thick pad of fibrocartilage between the thin articular cartilage covering the ends of the bones. Examples include
intervertebral discs and the pubic symphysis.
Diarthroses (synovial joints) components
Articular capsule: Composed of fibrous layer and synovial membrane.
Synovial membrane lines the capsule and produces synovial fluid. Continuous with a ligament inserting into the periosteum of both bones;
Joint cavity containing synovial fluid lubricant
Rheumatoid arthritis
Chronic inflammation of the
synovial membrane of the joint causes thickening of
this connective tissue and stimulates the macrophages to release collagenases and other
hydrolytic enzymes.
Articular Cartilage
Proteoglycan aggregates bound to hyaluronan
form a hydrated megacomplex that acts as a biomechanical spring. This spring distributes forces evenly through the cartilage, and also causes movement of water within the cartilage.
When pressure is applied a small amount of water is forced out of the cartilage matrix into the synovial fluid. When pressure is released
water is attracted back into the interstices of the matrix. Such movements of water occur constantly with normal use of the joint, and are also important for nutrition of the cartilage, and for gas and metabolite exchange.
Intervertebral Disc
The disc consists of
concentric layers of fibrocartilage that form the annulus fibrosus, which surrounds the nucleus
pulposus.
The intervertebral discs function primarily as shock absorbers within the spinal column and allow greater
mobility within the spinal column.
Herniated Disc
Within an intervertebral disc, collagen loss or other degenerative changes in the annulus fibrosus are often accompanied by
displacement of the nucleus pulposus, a condition variously called a slipped or herniated disc. This occurs most frequently on the posterior region of the intervertebral disc where there are fewer collagen bundles.
Carpal tunnel syndrome
Results from any lesion that significantly reduces the size of the carpal tunnel or, more commonly, increases the size of some of the structures (or their coverings) that pass through it (e.g., inflammation of the synovial sheaths).
Force generated by a muscle is proportional to its ________
cross-sectional area
(the number of fibers
being fired).
What does contraction distance and rate of shortening depend on?
The number of sarcomeres. The contraction distance depends on the number of
sarcomeres. However, the number of sarcomeres
does not affect the contraction time of the muscle—each sarcomere contracts in the same unit of time.
Parallel muscles
Generate greater velocity but less force, because of smaller cross-sectional area.
But both parallel and pinnate muscles produce approximately the same amount of power.
P = W/t = F * d/t = F * V
Pinnate muscles
Have more force, less velocity.
But both parallel and pinnate muscles produce approximately the same amount of power.
P = W/t = F * d/t = F * V
Movement of a hinge joint is _______
uniaxial
Articular cartilage does not have a ___________
perichondral covering
Which has higher muscle tension (force generated), isometric contraction or isotonic contraction?
Isometric contraction
The breast meat of a chicken is very white in color, whereas the breast meat of a wild duck is dark red. Why is the reason or reasons for this difference?
The difference reflects both function and the effects of breeding. Ducks fly long distances and so the meat has a higher percentage of Type I fibers, whereas chickens don’t fly much and their breast muscle is mainly Type IIb. A second reason is that chickens are bred to have “whiter” white meat.
Which type of muscle fibers experience the most rapid fatigue?
Fast glycolytic (type 2b)
An entire skeletal muscle is enclosed within a thick layer of dense connective tissue called the _________
Epimysium
Muscles perform different classes of functions. A ________________ steadies the proximal parts of a limb while movements happens distally.
fixator
The distance that a muscle contracts depends on ____________
The arrangement (parallel, pinnate, etc) and length of the muscle fibers.
Deltoid muscle has a ______ structural type
Multipennate
Sartorius muscle has a ______ structural type
Thin parallel
Biceps brachii muscles have a ______ structural type
Fusiform
Extensor digitorum longus muscles have a ______ structural type
Unipennate
Orbicularis oris muscle has a ______ structural type
Circular
Rectus femoris muscle has a ______ structural type
Bipennate
Pectoralis major muscle has a ______ structural type
Convergent
Rectus abdominis muscles have a ______ structural type
Quadrate
External oblique muscles have a ______ structural type
Flat parallel muscle with aponeurosis
Omohyoid muscle has a ______ structural type
Digastric
Supination of the wrist
During the motion of supination, the joint between the humerus and ulna maintains its position, while the head of the radius rotates on the distal condyle of the humerus.
Reversed prompt
Mitochondria: Numerous
Capillaries: Numerous
Myoglobin content: High (red fibers)
Glycogen content: Low
Slow, Oxidative Fibers (Type 1) mitochondria, capillaries, myoglobin content, and glycogen content
Reversed prompt
Mitochondria: Numerous
Capillaries: Numerous
Myoglobin content: High (red fibers)
Glycogen content: Intermediate
Fast, Oxidative-Glycolytic Fibers (Type 2a) mitochondria, capillaries, myoglobin content, and glycogen content
Reversed prompt
Mitochondria: Sparse
Capillaries: Sparse
Myoglobin content: Low (white fibers)
Glycogen content: High
Fast, Glycolytic Fibers (Type 2b) mitochondria, capillaries, myoglobin content, and glycogen content
Reversed prompt
Rate of fatigue: Slow
Speed of contraction: Slow
Major location: Postural muscles of back
Slow, Oxidative Fibers (Type 1) rate of fatigue, speed of contraction, and major locations
Reversed prompt
Rate of fatigue: Intermediate
Speed of contraction: Fast
Major location: Major muscles of legs
Fast, Oxidative-Glycolytic Fibers (Type 2a) rate of fatigue, speed of contraction, and major locations
Reversed prompt
Rate of fatigue: Fast
Speed of contraction: Fast
Major location: Extraocular muscles
Fast, Glycolytic Fibers (Type 2b) rate of fatigue, speed of contraction, and major locations
Reversed prompt
Well vascularized and have lots of myoglobin, which stores oxygen. Myoglobin is an iron- and oxygen-storage protein found in cardiac and skeletal muscle.
Red fibers contract slowly and resist fatigue.
Red fibers
Reversed prompt
Low in myoglobin; they contract quickly, but tire easily.
White fibers
Reversed prompt
Type 1, type 2a, type2b
Three different motor units in the human body
Reversed prompt
Highly fatigue resistant, has a lower activation threshold, contains fewer muscle fibers, and has low force generation during contraction.
Type 1 motor unit
Reversed prompt
Resistant to fatigue, has a higher activation threshold, and the force produced is higher compared to type 1
Type 2 motor unit
Reversed prompt
Fatigable, has a high activation threshold, innervates the most muscle fibers, and generates the greatest force during contraction
Type 2b motor unit
Reversed prompt
muscle fiber
The structural unit of a muscle is a _______
Reversed prompt
motor unit
The functional unit of a muscle, consisting of a motor neuron and the muscle fibers it controls, is a _______
Reversed prompt
A band or sheet of connective tissue, that attaches, encloses, and separates muscles and other internal organs. It interpenetrates and
surrounds the muscles, bones, nerves, and blood vessels of the body.
Fascia
Reversed prompt
Fascia is classified by layer as superficial fascia, deep fascia, and visceral or
parietal fascia, or by its function and anatomical location.
How is fascia classified?
Reversed prompt
Associated with, bone (periosteum and endosteum), cartilage (perichondrium), blood vessels (tunica externa), muscles (epimysium, perimysium, and endomysium), nerves (epineurium, perineurium, and endoneurium)
High density of elastin fiber for extensibility and resilience
Deep fascia
Reversed prompt
Often surrounds groups of muscles, forming compartments.
Fasciae also reduce friction between muscles and blood vessels and nerves.
Fascia function
Reversed prompt
Prime mover or agonist, fixators, synergist, antagonist
Muscle functions (broad sense)
Reversed prompt
The main muscle responsible for producing a specific movement of the body (e.g., concentric contraction).
Prime mover or agonist
Reversed prompt
Steady the proximal parts of a limb while movements are occurring in distal parts.
Fixators
Reversed prompt
Complements the action of prime movers—for
example, by preventing movement of the intervening joint when a prime mover passes over more than one joint.
Synergist
Reversed prompt
A muscle that opposes the action of a prime mover. As a prime mover contracts, the antagonist progressively relaxes, producing a smooth movement.
Antagonist
Reversed prompt
Flexors and extensors, abductors and adductors
Functions (narrow sense)
Reversed prompt
When muscles contract, the fibers shorten to about 70% of their resting length. Muscles with a long parallel fascicle arrangement shorten the most, providing considerable range of movement at a joint, but are not powerful.
What muscles shorten the most during contraction?
Reversed prompt
Muscle power increases as the total number of muscle cells increases. Therefore, the shorter, wide pennate muscles that “pack in” the most fiber bundles shorten less but are most powerful.
This statement is not quite correct in a biomechanical sense.
Muscle power
Reversed prompt
The origin is usually the proximal end of the muscle, which remains fixed.
Muscle origin
Reversed prompt
The insertion is usually the distal end of the muscle, which is movable.
Muscle insertion
Reversed prompt
Reflexive contraction, tonic contraction, and phasic contraction
Types of skeletal muscle contraction
Reversed prompt
A type of skeletal muscle contraction automatic and not voluntarily controlled—for example, respiratory movements of the diaphragm. Muscle stretch evokes reflexive contraction produced by tapping a tendon with a reflex hammer.
Reflexive contraction
Reversed prompt
A type of skeletal muscle contraction which is a slight contraction (muscle tone) that does not produce movement or active resistance but
gives the muscle firmness, assisting the stability of joints and the maintenance of posture.
Tonic contraction
Reversed prompt
A type of skeletal muscle contraction.
Two types of phasic contraction: Isometric and isotonic
Phasic contraction
Reversed prompt
A type of phasic contraction where the muscle length remains the same—no movement occurs but muscle tension is increased above tonic levels (e.g., the deltoid holds the arm in abduction).
Force = Mass
Isometric contractions
Reversed prompt
A type of phasic contraction where the muscle changes length to produce movement.
Two types:
Concentric contraction: Muscle shortening, Force > Mass
Eccentric contraction: Muscle lengthening/relaxation of a contracted muscle, Force < Mass
Isotonic contraction
Reversed prompt
A biological machine
consisting mainly of muscles with no skeletal support.
Ex. human pharynx (throat), elephant trunk
Muscular hydrostat
Reversed prompt
Joints can be classified as synarthroses or diarthroses.
Joint classification
Reversed prompt
Joints that allow free
movement of the attached bones, such as knuckles, knees, and elbows.
Diarthroses (synovial joints)
Reversed prompt
Permits only limited movement.
Synostoses, syndesmoses, and symphyses
Synarthrosis
Reversed prompt
A type of synarthroses joint that allows essentially no movement between bones. In older adults synostoses unite the skull bones, which in children and young
adults are held together by sutures.
Synostoses
Reversed prompt
A type of synarthroses joint that joins bones by dense connective tissue only. E.g., the interosseous ligament of the inferior tibiofibular joint and the posterior
region of the sacroiliac joints.
Syndesmoses
Reversed prompt
A type of synarthroses joint that have a thick pad of fibrocartilage between the thin articular cartilage covering the ends of the bones. Examples include
intervertebral discs and the pubic symphysis.
Symphyses
Reversed prompt
Articular capsule: Composed of fibrous layer and synovial membrane.
Synovial membrane lines the capsule and produces synovial fluid. Continuous with a ligament inserting into the periosteum of both bones;
Joint cavity containing synovial fluid lubricant
Diarthroses (synovial joints) components
Reversed prompt
Chronic inflammation of the
synovial membrane of the joint causes thickening of
this connective tissue and stimulates the macrophages to release collagenases and other
hydrolytic enzymes.
Rheumatoid arthritis
Reversed prompt
Proteoglycan aggregates bound to hyaluronan
form a hydrated megacomplex that acts as a biomechanical spring. This spring distributes forces evenly through the cartilage, and also causes movement of water within the cartilage.
When pressure is applied a small amount of water is forced out of the cartilage matrix into the synovial fluid. When pressure is released
water is attracted back into the interstices of the matrix. Such movements of water occur constantly with normal use of the joint, and are also important for nutrition of the cartilage, and for gas and metabolite exchange.
Articular Cartilage
Reversed prompt
The disc consists of
concentric layers of fibrocartilage that form the annulus fibrosus, which surrounds the nucleus
pulposus.
The intervertebral discs function primarily as shock absorbers within the spinal column and allow greater
mobility within the spinal column.
Intervertebral Disc
Reversed prompt
Within an intervertebral disc, collagen loss or other degenerative changes in the annulus fibrosus are often accompanied by
displacement of the nucleus pulposus, a condition variously called a slipped or herniated disc. This occurs most frequently on the posterior region of the intervertebral disc where there are fewer collagen bundles.
Herniated Disc
Reversed prompt
Results from any lesion that significantly reduces the size of the carpal tunnel or, more commonly, increases the size of some of the structures (or their coverings) that pass through it (e.g., inflammation of the synovial sheaths).
Carpal tunnel syndrome
Reversed prompt
cross-sectional area
(the number of fibers
being fired).
Force generated by a muscle is proportional to its ________
Reversed prompt
The number of sarcomeres. The contraction distance depends on the number of
sarcomeres. However, the number of sarcomeres
does not affect the contraction time of the muscle—each sarcomere contracts in the same unit of time.
What does contraction distance and rate of shortening depend on?
Reversed prompt
Generate greater velocity but less force, because of smaller cross-sectional area.
But both parallel and pinnate muscles produce approximately the same amount of power.
P = W/t = F * d/t = F * V
Parallel muscles
Reversed prompt
Have more force, less velocity.
But both parallel and pinnate muscles produce approximately the same amount of power.
P = W/t = F * d/t = F * V
Pinnate muscles
