MUSCLE SYSTEM

Question 1

CARDIAC MUSCLE CHARACTERISTICS

Answer 1

-strations
-usually has a single nucleus
-branching cells
-joined to another muscle cell at an intercalated disc
-involuntary
-found only in the heart

Question 2

SKELETAL MUSCLES FUNCTIONS

Answer 2

-produce movements
-maintains posture
-stabilize joints
-generates heat

Question 3

MICROSCOPIC ANATOMY OF SKELETAL MUSCLES

Answer 3

-sarcolemma//specialized plasma membrane
-myofibrils// long organelles inside muscle cell
-smooth endoplasmic reticulum// surrounds myofibril

Question 4

THE NERVE STIMULUS & ACTION POTENTIAL

Answer 4

-skeletal muscles must be stimulated by motor neuron(nerve cell) to contract
-motor unit- one motor neuron & the skeletal muscles cells stimulated by the neuron
5-

Question 5

NEUROMUSCULAR JUNCTION

Answer 5

-association site of axon terminal of the motor neuron & muscle

Question 6

SYNAPTIC CLEFT

Answer 6

-gap between nerve & muscles
-nerve & muscle do not make contact
-area between nerve & muscle is filled with interstitial fluid

Question 7

5 GOLDEN RULES OF SKELETAL MUSCLE

Answer 7

1- few exceptions, but all skeletal muscles cross at least 1 joint
2- Typically, the bulk of skeletal muscle lies proximal to the joint crossed
3- all skeletal muscles have at least 2 attachments: the origin & insertion
4- skeletal muscles can only pull; they never push
5- during contraction, a skeletal muscle insertion moves toward origin

Question 8

TYPES OF MUSCLES

Answer 8

PRIME MOVER
-muscles with major responsibility for a certain movement
ANTAGONIST
-muscle that opposes or reverses a prime mover
SYNERGIST
-muscle that AIDS a prime mover in movement & helps prevent rotation
FIXATOR
-stabilizes the origin of prime mover

Question 9

NAMING SKELATAL MUSCLES

Answer 9

-by direction of muscle fibers
-relative size
-location of muscle(temporalis)
-by number of origins
(tricep)
-by location of origin + insertion (sterno or on the sternum)
-by the shape (deltoid = triangular)
-by action- flexor & extensor

Question 10

ABDUCTION & ADDUCTION

Answer 10

-abduction// moving closer to midline of body
-adduction// moving farther

Question 11

DORSIFLEXION & PLANTAR FLEXION

Answer 11

-dorsiflexion// pointing foot upwards toward shin
-plantar flexion// pointing toes to the floor

Question 12

INVERSION & EVERSION

Answer 12

-inversion// turn sole of foot medially
-eversion// turn sole of foot laterally

Question 13

SUPINATION & PRONATION

Answer 13

-supination// turn hands to face anteriorly
-pronation// turn hands to face posteriorly