Muscle System Test Flashcards
voluntary muscles
-skeletal
involuntary muscles
- smooth
- cardiac
functions of the muscular system
-contraction (shortening) of the muscles allowing the body movement
sacromere
chains of tiny contractile units
where is the sacromere located in terms of the Z line
-sacromere is within the Z line
motor unit
one neuron and all the skeletal muscle cells it stimulates
calcium’s purpose in a muscle contraction
when calcium acts as a final trigger for contraction, because calcium binds to the regulatory proteins on the actin filaments, they change both their shape and their position on the thin filaments which exposes myosin binding sites for the myosin heads to attach
acetycholine
ACh=a chemical transmitter substance released by certain nerve endings
twitch contraction
when a single stimulus is delivered, and the muscle contracts and relaxes
tectonic contraction
a smooth, continuous contraction with relaxation
isotonic contractions
-“same tone” or tension
-the myofilaments are successful in their sliding movements (muscle shortens and movements occurs)
EX: bending the knee, rotating the arms, and smiling
isometric contractions
-“same measurement” or length
-the myosin filaments are “skidding their wheels”, and the tension in the muscle keeps increasing. they are trying to slide, but the muscle is pitted against some more or less immovable object
EX: when you try and lift 400-lb dress alone, and when you push against a wall with bent elbows the wall doesn’t move and the tricep moves isometrically
what muscle compresses the abdomen
rectus abdominus
flexion
a movement that decreases the angle of the joint and brings two bones closer together
extension
a movements that increases the angle, or distance, between two bones or two parts of the body
rotation
movement of a bone around its longitudinal axis
abduction
moving a limb away from the midline of the body
adduction
movement of a limb toward the midline of the body
circumduction
the proximal end of the limb is stationary, and its distal end moves in a circle (outlines a cone)
dorsiflexion
lifting the foot so that the superior surface approaches the shin (standing on your heels)
plantar flexion
depressing the foot (pointing toes)
inversion
turning the sole of the foot medially
eversion
turning the sole of the foot laterally
supination
when the forearm rotates laterally so the palm faces anteriorly and the radius and ulna are parallel
pronation
when the forearm rotates medially so the palm faces posteriorly so the ulna and radius form an X
opposition
action by which you move your thumb to touch the tips of your fingers on the same hand
prime mover
has the major responsibility for causing a particular movement
antagonist
muscles that oppose or reverse a movement
synergist
help prime movers by producing the same movement or by reducing undesirable movements
fixators
- specialized synergists
- they hold a bone still or stabilize the origin of a prime mover so all the tension can be used to move the insertion bone
how do you name muscles
- direction of muscle fibers
- relative size of muscle
- location of muscle
- number of origins
- location of the muscle’s origin or insertion
- shape of the muscle
- action of the muscle
muscle fatigue
when it is unable to contract even though it is still being stimulated
biceps branchii
powerful prime mover for flexion of the forearm and acts to supinate the forearm
biceps femoris
one of the three muscles that form the hamstring
deltoid
- injection site
- prime movers of arm abduction
frontalis
allows you to raise your eyebrows and wrinkle your forehead
gastrocnemius
prime mover for plantar flexion of the foot
iliopsoas
- fused muscle of the iliacus and psoas major
- prime mover of hip flexion
- acts to keep the upper body from falling backward when standing erect
orbicularis oris
closes the mouth and protrudes the lips
orbicularis oculi
allows you to close your eyes, squint, blink, and wink
pectoralis major
acts to adduct and flex the arm
rectus femoris
- one of the four muscles that make up the quadriceps
- extends the knee
- help to flex hip
- injection site
sartorius
acts as a synergist to bring out the cross-legged position
tibialis anterior
acts to dorsiflex and invert the foor
triceps branchii
- powerful prime mover of elbow extension
- antagonist of the biceps branchii
buccinator
- flattens the cheek
- listed as a chewing muscle
trapezius
- antagonists of the sternocleidomastoids
- can elevate, depress, adduct, and stabilize scapula
sternocleidomastoid
flex your neck or rotate head
Drugs affect on ACh
going to stop the contraction and it will not happen because the ACh will not bind and it needs to bind in order for the sodium channels to open and the ions to be released
Drugs affect on calcium not releasing
a contraction will not happen because the calcium cannot bind to the actin binding site
Drugs affect on promoting calcium release
this is going to increase the contractions (during labor) because there will be a lot of calcium binding to the actin binding site
Drugs affect on paralyzing nerve to the muscle
will not stimulate so there will be no irritability which is needed for a contraction
musculardystrophy
• bodycannotproducedystrophin(supports
musclefibermembrane
• muscleenlargesduetofat
• musclefibersdegenerate
• Duchennemostlymales,diagnosedat26yrs,
wheelchairbound,nocure
myastheniagravis
affectsadults,muscleweakness,droopyeyelids,difficulty
swallowing &talking
• duetoshortageofacetylcholinereceptors
• autoimmunedisease
• deathduetorespiratoryfailure
