Anatomy Lab quiz 3

Question 0

Myofilaments

Answer 0

Composed of actin and myosin, contractile proteins

Responsible for shortening or contraction of muscle cells

Question 1

Skeletal muscle

Answer 1

Made up of large, long cylindrical cells sometimes called fibers
Contain myofibrils longitudinally arranged
-light (I) and dark (A) bands give the myofibrils a striped appearance
-myofibrils made up of even smaller threadlike myofilaments

Question 2

Sarcomeres

Answer 2

Actual contractile units of muscle
Extend from the middle of one I band (Z disk) to the middle of the next
Cross sections of the sarcomere in areas where thick and thin filaments overlap show that each thin filament is enclosed by three thick filaments and each thick filament is enclosed by six thin ones

Question 3

Transverse tubule

Answer 3

At each junction of the A and I bands, sarcolemma indents into the muscle cell forming this
These tubules run deep into the muscle cell between the cross Channels of the sarcoplasmic reticulum

Question 4

Triads

Answer 4

Regions where the SR terminal cisterns about a T tubule on each side

Question 5

Endomysium

Answer 5

Each muscle fiber is enclosed in this delicate areolar connective tissue sheath

Question 6

Perimysium

Answer 6

Several sheathed muscle fibers are wrapped by this collagenic membrane, forming a bundle of fibers called a fascicle

Question 7

Epimysium

Answer 7

A large number of fascicles are bound together by a substantially courser dense connective tissue (sheaths entire muscle)
Blends into the deep fascia (still courser sheets of dense connective tissue that bind muscles into functional groups, and into tendons)

Question 8

Tendons

Answer 8

Provide durability and conserve space
Can span bony projections
More tendons than fleshy muscle can pass over a joint
Support and bind muscle fibers
Provide a route for the entry and exit of nerves and blood vessels that serve the muscle fibers

Question 9

Neuromuscular or myoneural junction

Answer 9

Junction between a nerve fiber and a muscle cell

Question 10

Terminal boutons

Answer 10

Axon terminals
Axon of each motor neuron breaks into many branches called these
Each branch participates in forming a neuromuscular junction with a. Single muscle cell

Question 11

Motor unit

Answer 11

Together a neuron and all the muscle fibers it stimulates make up the motor unit
Do not actually touch, separated by a small fluid filled gap called the synaptic cleft