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Muscular System Flashcards

1
Q

muscle tissue types

A

skeletal
cardiac
smooth

muscles = organs → have all four basic tissue types: muscle, nerve, connective, vasculature)

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2
Q

excitability

A

ability to respond to stimulation from NS

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3
Q

contractility

A

ability to shorten and pull (bone)

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4
Q

extensibility

A

ability to contract over different lengths
contraction at rest or while stretched

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5
Q

elasticity

A

ability to regain original length

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6
Q

characteristics of skeletal muscle

A

somatic structures = under voluntary control (sympathetic innervation)
innervated by spinal nerves + cranial nerves
contractile organs - attach directly or indirectly onto bones
contraction produces motion of the body

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7
Q

functions of skeletal muscle

A

produce movement at joints via tendons or muscle fibres
maintain posture + body position
support soft tissues
regulate orifices (sphincters)
maintain body temperature

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8
Q

structure of skeletal muscle

A

organ → fascicle → fibre → myofibril → sarcomere
(organ → fibre are covered with connective tissue sheath)

muscle covered by epimysium
fascicle covered by perimysium
fibre covered by endomysium

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9
Q

structure of muscle fibre

A

muscle cell
contains myofibrils, nuclei, mitochondria, sarcoplasm (cytoplasm)
membrane = sarcolemma

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10
Q

myofibrils

A

surrounded by sarcoplasmic reticulum + t-tubules
contain sarcomeres

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11
Q

sarcomere

A

basic contractile unit of muscle
intedigitation of thick and thin filaments
boundaries = Z lines (pair)
centre = M line

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12
Q

H band

A

middle of sarcomere
contains only thick filaments (myosin)

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13
Q

I bands

A

margin of sarcomere (near Z lines)
contains only thin filaments (actin)

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14
Q

A band

A

zone of overlap
contains both thin and thick filaments

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15
Q

muscle contraction

A

depolarization of sarcolemma → spreads through t-tubules
release of Ca2+ from SR = cross-bridging between thick and thin filaments → pivoting of myosin heads towards M line

width of I band + H band decreases
width of A band remains constant

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16
Q

nerve stimulation

A

each muscle fibre is innervated by a motor neuron
neuron fires → signals fibre to contract

contraction is all or none = fibre either contracts or doesn’t

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17
Q

motor unit

A

motor neuron + fibres it innervates
(all muscle cells controlled by single motor neuron)

amount of muscle tension depends on number of motor units stimulated

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18
Q

slow twitch fibres

A

red - lots of mitochondria + myoglobin
narrow diameter
resistant to fatigue = sustained contraction (less powerful)
aerobic metabolism produces ATP

ex. calf: soleus muscle has higher proportion of slow fibres = enlarged in marathon runner

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19
Q

fast twitch fibres

A

white - less myoglobin
large diameter
rapid contraction → powerful
fatigue easily
anaerobic glycolysis produces ATP

ex. calf: gastrocnemius muscle has higher proportion of fast fibres = enlarged in sprinter

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20
Q

parallel muscles

A

fascicles run parallel to long axis of muscle
most common muscle type
large force exerted because all fascicles pull in same direction = only one action

ex. rectus abdominus (flat band), biceps brachii (spindle-shaped)

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21
Q

spindle shaped muscle

A

parallel muscle with tendon at either end
central portion = belly
during contraction → belly widens and muscle shortens

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22
Q

convergent muscles

A

fan-shaped
fascicles originate over wide area but converge at common attachment site
direction of pull can change by varying which fascicles contract
less force exerted because not all fascicles pull in same direction

ex. pectoralis major, trapezius

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23
Q

circular muscles

A

fibers are arranged concentrically around opening → form sphincters
contraction reduces diameter of opening

ex. orbicularis oculi (eye) + oris (mouth)

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24
Q

pennate muscles

A

tendons run through body of muscle
fascicles form oblique angle relative to tendon
contain more muscle fibres than parallel muscle of same size = generate more force

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25
unipennate
muscle fibers are on one side of tendon single plane pennation ex. extensor digitorum (forearm)
26
bipennate
muscle fibres are on both sides of tendon ex. rectus femoris (thigh)
27
multipennate
tendon branches with muscle ex. deltoid
28
naming: structure/shape of muscle
deltoideus = triangular maximus = large brevis = short
29
naming: specific region
carpi = wrist abdominis = abdomen
30
naming: attachment sites
sternocleidomastoideus = sternum, clavicle, mastoid process
31
naming: in relation to other muscles
profundus = deep superficialis = superficial
32
naming: action
flexor = flexion movement
33
production of movement
muscles: - attach on individual bones or soft tissue - usually cross at least one joint - pull a bone toward another so movement is produced at joint - stabilize a joint so others can produce movement
34
agonist
prime mover → major muscle to cause action contraction produces particular movement ex. biceps femoris flexes leg at knee joint
35
synergist
assists prime mover in performing action ex. semitendinosus (hamstring) also flexes leg at knee joint
36
antagonist
opposes movement of agonist ex. quadriceps femoris extends leg at knee joint
37
lever
rigid structure moves on fixed point (fulcrum = Fc) requires force to move a weight force generated by muscle contraction
38
first class lever
W - Fc - F increases range and speed of movement but requires larger force ex. head: Fc = atlanto occipital joint (not many examples)
39
second class lever
Fc - W - F increases force at expense of range and speed of movement ex. raising ankles: Fc = foot; F = soleus muscle + achilles tendon (not many examples)
40
third class lever
Fc - F - W increase range and speed of movement at expense of force ex. flexion of forearm: Fc = elbow; F = biceps brachii (attached to radius) most common in body
41
action vs function
ex. gluteus medius and minimus action = abduction of thigh at hip joint function = keep pelvis straight during walking
42
axial musculature
associated with axial skeleton: skull, vertebral column, ribs innervated by cranial or spinal nerves attachments on axial skeleton, associated organs, or soft tissue
43
functions of axial musculature
vision, mastication, facial expression, swallowing upright posture + movement of back support of abdominal + pelvic viscera respiration urination, defecation, parturition
44
groups of axial musculature
head + neck back thorax + abdominopelvic cavities pelvis + perineum
45
extraocular muscles
innervated by oculomotor, trochlear, and abducens nerves (CNs III, IV, VI) levator palpebrae superioris superior rectus medial rectus inferior rectus inferior oblique lateral rectus superior oblique
46
CN VI palsy
paralysis of right side lateral rectus = right eye can't move to the right
47
muscles of mastication
innervated by trigeminal nerve (CN V) - mandibular division (3) temporalis masseter medial pterygoid lateral pterygoid
48
biomechanics of mastication
lateral pterygoid = depressor of mandible to open mouth - pulls condyle of mandible anteriorly = move down + forward temporalis (pull up + back), masseter, medial pterygoid (pull up + forward) = elevation of mandible when closing mouth
49
muscles of facial expression
innervated by facial nerve (CN VII) orbicularis oculi orbicularis oris platysma occipitofrontalis buccinator
50
Bell's palsy
damage to facial nerve (CN VII) lesions typically at or beyond stylomastoid foramen = affect all ipsilateral motor branches ipsilateral upper and lower facial asymmetry = facial paralysis
51
pharyngeal muscles
innervated by vagus nerve (CN X) tensor + levator veli palatini superior constrictor middle constrictor inferior constrictor
52
tongue muscles
innervated by hypoglossal nerve (CN XII) control position of tongue palatoglossus styloglossus hyoglossus genioglossus
53
neck muscles
innervated by cranial or cervical nerves mylohyoid digastric (2 bellies) infrahyoids sternocleidomastoid longus capitis longus colli scalene muscles
54
biometrics of swallowing
1. contraction of mylohyoid and tongue muscles = floor of mouth tenses + elevation of hyoid bone 2. contraction of tensor and levator veli palatini muscles = tense + elevate soft palate to close gap between nose + mouth 3. elevation of larynx by many muscles = close airway 4. sequential contraction from top of constrictor muscles = push bolus into esophagus
55
back muscles
transversospinal group - delicate adjustments at zygapophyseal joints of vertebrae extensors: (maintain upright posture) longissimus spinalis iliocostalis erector spinae
56
trunk muscles
intercostal muscles (3 layers) abdominal muscles: → can increase intra-abdominal pressure - rectus abdominis - external + internal obliques - transversus abdominis
57
respiration
contraction of intercostal muscles produces elevation of ribs increases volume of thoracic cavity synovial joint in front and back = allows movement of ribs contraction of diaphragm during inhalation → brings central tendon down to increase vol
58
diaphragm
separates thoracic + abdominal cavities chief muscle of respiration holes for inferior vena cava, esophagus, and aorta central tendon, muscle fibers, crura
59
pelvic muscles
coccygeus levator ani form the pelvic diaphragm provide support to pelvic viscera
60
perineal muscles
innervated by pudendal nerve external urethral sphincter external anal sphincter ischiocavernous bulbospongiosus
61
appendicular musculature
associated with appendicular skeleton (limb bones, shoulder + pelvic girdles) attachment on axial + appendicular skeleton
62
appendicular musculature - innervation
spinal nerves - form plexuses → branches of nerves leave plexus to innervate muscle compartments limb muscles are organized into compartments - each is innervated by specific nerve branch of a plexus
63
upper limb musculature
innervated by branches of brachial plexus (levels C5 to T1) (exception: trapezius - CN XI) major muscle groups: shoulder (pectoral girdle), arm, forearm, hand joints are designed for mobility rather than stability - positioning pectoral girdle - moving arm, forearm + hand, hand + digits
64
muscles moving pectoral girdle
trapezius levator scapulae rhomboids serratus anterior
65
force couple
muscles work together to complete a task not possible individually ex. scapular rotation requires trapezius (pulling up near acromion + pulling down near vertebral border) and serratus anterior (protraction)
66
muscles moving arm at shoulder joint
pectoralis major deltoideus latissimus dorsi rotator cuff muscles: - subscapularis - supraspinatus - infraspinatus - teres minor teres major
67
muscles moving forearm at elbow joint
biceps brachii brachialis brachioradialis triceps brachii
68
muscles moving hand at wrist joint
flexor carpi radialis plamaris longus flexor carpi ulnaris flexor retinaculum extensor carpi radialis longus + brevis extensor carpi ulnaris
69
muscles moving digits
flexor digitorum superficialis flexor pollicis longus flexor digitorum profundus extensor digitorum + extensor digiti minimi extensors + abductor for thumb 3 palmar interossei 4 lumbricals 4 dorsal interossei thenar muscles: adductor pollicis flexor pollicis brevis opponens pollicis abductor pollicis brevis
70
Carpal Tunnel Syndrome
carpal tunnel = 9 flexor muscle tendons, surrounded by carpal bones and flexor retinaculum + median nerve repetitive motion of flexor tendons can irritate their sheath coverings, leading to swelling and compression of median nerve in carpal tunnel
71
power vs precision grip
power grip = active contraction of digital flexor muscles in forearm ex. flexor digitorum profundus more force precision grip = active contraction of some short muscles found in hand ex. thenar muscles less force
72
lower limb musculature
innervated by branches of lumbosacral plexus (levels L2-S3) major muscle groups: hip (pelvic girdle), thigh, leg, foot joints are designed for stability (various degrees of mobility) locomotion, posture, balance - moving thigh, leg, foot + toes
73
muscles moving thigh at hip joint
gluteus maximus lesser gluteals: (stabilization of pelvis) - gluteus medius - gluteus minimus iliopsoas adductor muscle group
74
muscles moving leg at knee joint
quadriceps femoris: - 3 vasti - rectus femoris sartorius hamstring: - semitendinosus - semimebranosus - biceps femoris (long + short heads)
75
muscles moving foot at ankle joint
gatrocnemius soleus calcaneal tendon (Achilles) 2 peroneus (fibularis) muscles tibialis anterior
76
muscles moving toes
extensor digitorum longus extensor hallucis longus flexor digitorum longus flexor hallucis longus flexor digitorum brevis
77

Anatomy (14 decks)

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