Muscular System Flashcards
myology
scientific study of muscles
skeletal muscle
attached primarily to bone, striated and voluntary
cardiac muscle
most of the heart, striated and involuntary
smooth muscle
walls of hollow internal organs, blood vessels, stomach, non-striated, involuntary
functions of muscle tissue
- produce body movements 2. stabilize body positions 3. store and move substances within the body 4. generate heat
tendon
"”pick up sticks”” (panty hose) fascia, stretched beyond muscle as connective tissue attaches muscle to bone
muscle fascicle
groups of 10 to 100 or more muscle fibers, arranged in bundles
muscle fiber (cell)
1 ““pick up stick”” each muscle is a separate organ composed of hundreds of long, cylindrical cells, lie parallel to one another. contains myofibrils
myofibrils
"”piece”” threads in sarcoplasm, extends lengthwise. contain the myofilaments
myofilaments
what thick and thin filaments are called, contractile proteins
thick filament- myosin
2 golf clubs twisted together, produce power stroke
thin filament- actin
twisted helix, binding site for myosin
thin filament- tropomyosin
covers the myosin head-binding site on actin in relaxed muscle
thin filament- troponin
once bound to calcium, drags tropomyosin away from the binding sites
sarcomere
describes the arrangement of the above myofilaments. compartments where think and thick filaments are arranged. basic functional unit of the muscle cell
sarcoplasm
muscle fiber cytoplasm
the sliding filament mechanism
describes a muscle contraction. the length of the filaments do not change, filaments overlap, shortening the sarcomere as the muscle contracts.
sarcoplasmic reticulum
a fluid filled cavity around each myofibril that stores calcium via the calcium pump
calcium
in relaxed muscle, calcium is stored in the sarcoplasmic reticulum. when released starts the filaments sliding (contracts)
what must happen for a muscle to contract?
motor neuron, action potential, acetylcholin is released, release of calcium, calcium released from sarcoplasmic reticulum, calcium binds to troponin
ATP
energy source that makes all this happen
how does muscle fiber relax?
action potential stops, acetylcholine stops, calcium chambers close, calcium pump removes the remaining calcium, myosin heads no longer can bind, muscle will now relax
origin of muscle
attachment to tendon to stationary bone
insertion of muscle
attachment of other tendon to movable bone
belly of muscle
fleshy portion of muscle between the tendons
muscles of facial expression
originate in the bones of skull and insert into the skin
frontal belly
scalp anteriorly
occipital belly
scalp posteriorly
orbicularis oris
closes and protrudes the lips. shapes the lips during speech
zygomaticus (major and minor)
muscles for smiling
levator labii superioris
raises upper lip
depressor labii inferioris
depresses lower lip
buccinator
major cheek muscle
platysma
draws lower lip inferiorly, depresses mandible
orbicularis oculi
closes eye
intrinsic of eyeball
muscles that would originate and insert inside the eye
extrinsic of eyeball
outside the eye. fastest contracting and most precisely controlled skeletal muscles of the body.
superior rectus
eyeball superiorly
inferior rectus
eyeball inferiorly
lateral rectus
eyeball laterally
medial rectus
eyeball medially
superior oblique
rotate eye on axis
inferior oblique
rotate eye on axis
muscles that move the mandible
muscles of mastication
masseter
elevates the mandible as in chewing
temporalis
elevates and retracts mandible as in chewing
muscles that move the tongue
need for chewing, swallowing
extrinsic of tongue
outside the tongue, moves the entire tongue
intrinsic of tongue
inside the tongue, alter the shape of the tongue
placement of hyoid bone
in the neck, between mandible & larynx, doesn’t articulate with any other bone
sternocleidomastoid
flex cervical/neck area, flex head and rotate head to side
semispinalis capitis
acting together, extend head, singly, rotate head to side
splenius capitis
acting together, extend head. singly rotate head to same side
tendionous intersections
anterior surface of the rectus abdominis is interrupted by 3 transverse fibrous bands of tissue
linea alba
(white line) tough, fibrous band extends from the xiphoid process of the pubic symphysis
rectus abdominis
flexes vertebral column, lumbar and compresses abdomen
external oblique and internal oblique
acting together, flexes vertebral. singly, latterly flexes vertebral column
transversus abdominis
compresses abdomen
muscles in anterolateral abdominal wall superficial to deep
external oblique, internal oblique, transversus abdominis
diaphragm
dome shaped, most important muscle that powers breathing. results in inhalation
intercostals
breathing muscles, between the ribs
external intercostals
inhalation
internal intercostals
exhalation
muscles of pelvic floor
pelvic diaphragm, stretches from pubis to the coccyx and one lateral wall to the other
levator ani and coccygeus and ischiococcygeus
supports and maintains position of pelvic viscera
muscles of the perineum
inferior to the pelvic diaphragm
external urethral sphincter
expels last drop of urine and semen
external anal sphincter
keeps anal canal and anus closed
pectoralis minor
(anterior,deep) abducts scapula and rotates it downward
serratus anterior
(anterior, saw-toothed) abducts scapula and rotates it upward. punching and pushing
trapezius
(posterior) located in the neck and upper back area. elevates scapula, extends head
pectoralis major
located in the upper chest. adducts and medially rotates arm at shoulder joint. crosses arms
latissimus dorsi
triangular muscle located in the middle and inferior part of back. draws arms inferiorly and posteriorly
deltoid
located over shoulder. abducts arm, flex and medially rotate and extend and laterally rotate at shoulder joint
rotator cuff muscles
strengthens and stabilizes the shoulder joint. supraspinatus, infraspinatus, teres minor, subscapularis
muscles that move the radius and ulna
most cause flexion and extension at the elbow which is a hinge joint
flexors
anterior surface of the rectus abdominis is interrupted by 3 transverse fibrous bands of tissue
biceps brachii
flexes forearm
brachialis
flexes forearm
brachioradialis
flexes forearm
extensors
posterior surface
triceps brachii
extends forearm
muscles that move the wrist, hand and fingers
are many and varies; located in the forearm
anterior compartment muscles
flexors
posterior compartment muscles
extensors
flexors retinaculum
over the palmar surface of the carpal bones
gluteus maximus
extends thigh at hip joint and laterally rotates thigh
gluteus medius
abducts thigh at hip joint and medially rotates thigh
gluteus minimus
abducts thigh at hip joint and medially rotates thigh
anterior (extensor) compartment
thigh extends the leg (at knee joint) and flexes the thigh (at hip joint)
quadriceps femoris
largest muscle in the body. composite of four separate muscles
rectus femoris
only one to flex thigh at hip joint
vastus lateralis
all extends leg a knee joint
sartorius
longest muscle in body. flexes leg at knee joint. rotates thigh at hip joint
semimembranosus
extends thigh at hip joint
anterior compartment (dorsiflex) - tibialis anterior
dorsiflexion of foot at ankle joint
pasterior compartment (plantar flexion) -gastrocnemius
plantar flexes foot at ankle joint
posterior compartment (plantar flexion) -soleus
plantar flexes foot at ankle joint
calcaneal (achilles) tendon
superficial muscles share this common tendon of insertion. strongest tendon of the body, inserts into the calcaneal bone of the ankle
posterior (flexor) compartment
thigh flexes the leg and extends the thigh
hamstrings
composite of three separate muscles
biceps femoris
all
semitendinosus
flexes leg at knee joint
isometric contractions
tension increases greatly without a change in muscle length
isotonic contraction
tension remains constant as muscle length decreases or increases
rigor mortis
state of rigidity after death, calcium ions leak from the sarcoplasmic reticulum. Myosin heads bind to actin that won’t detach from ATP absence. stuck for 24 hours then disintegrate.
twitch
brief contraction in motor unit in response to a single action potential in its motor neuron
muscle tone
at rest, small amount of tautness or tension due to weak, involuntary contractions of its motor units
hypotonia (flaccid paralysis)
loss of muscle tone, loose, flattened. muscles may atrophy and degenerate
hypertonia (spasticity)
increased muscle tone may become stiff or rigid
muscular atrophy
reduction in size
disuse
casting, bedridden
denervation
loss of nerve supply
cellular respiration
oxygen + glucose = ATP
botulism
a disease characterized by severe, potentially fatal paralysis of skeletal muscles, that results from the consumption of a bacterial toxin.
carpal tunnel syndrome
inflammation of the sheath that surrounds the flexor tendons of the palm and leads to nerve compression and pain.
compartment syndrome
Ischemia that results form accumulated blood and fluid trapped within limb muscle compartments formed by partitions of dense connenctive tissue
fibrosis
a process in which a tissue is replaced by fibrous connective tissue. Fibrosis makes muscles weaker and less flexible.
hernia
a condition involving an organ or a body part that protrudes through an abnormal opening in the wall fo a body cavity.
Intramuscular Injection (IM)
the administration of a drug by injectiong it into the mass of a large skeletal muscle.
ischemia
a deficiency of blood (‘‘blood starvation’’) in a body part due to compression of a regional vessels.
muscle cramps
prolonged, involuntary, painful mussular contrations.
muscular dystrophies
a varied collection of inherited diseases that produce progressive muscle weakness and deterioration.
myalgia
muscular pain; a common symptom of a wide variety of conditions and infections.
myasthenia gravis
a general muscular weakness that results from a reduction in the number of Ach receptors on the motor end plate
myoma
a benign tumor of muscle tissue
myositis
inflammation of muscle tissue
polio
a viral disease in which the destruction of motor neurons produces paralysis and atrophy of motor units.
rigor mortis
a state following death during which muscles are locked in the contracted position, which make sthe body extremely stiff.
sarcoma
a malignant tumor of mesoderm-derived tissue (muscle, bone or other ocnnective tissue).
strains
tears or breaks in muscles
tendinitis
inflammation of the conenctive tissue that surrounds a tendon.
tetanus
a disease caused by a bacterial toxin that results in sustained, powerful contractions of skeletal muscles throughout the body.