Chapter 2 Basic Exercise Science: Muscular System

Question 1

What is the muscular system?

Answer 1

A series of muscles that moves the skeleton.

Question 2

What is the composition of muscle fibers?

Answer 2

1) Outer layer=epimysium (deep fascia)
2) Perimysium wraps each fasicle
3) Endomysium (inside of the perimysium), made up of individual muscle fibers

Question 3

What is the epimysium?

Answer 3

A layer of connective tissue that is underneath the fascia and surrounds the muscle

Question 4

What is the perimysium?

Answer 4

The connective tissue that surrounds fascicles.

Question 5

What is the endomysium?

Answer 5

The deepest layer of connective tissue that surrounds individual muscle fibers.

Question 6

What role does connective tissue play in a muscle?

Answer 6

They allow the forces generated by the muscle to be transmitted from the contractile components of the muscle to the bones, creating motion.

Question 7

How is a tendon formed?

Answer 7

By each layer of connective tissue that extends the length of the muscle.

Question 8

What are tendons?

Answer 8

Connective tissues that attach muscle to bone and provide an anchor for muscles to produce force

Question 9

What is a sarcomere?

Answer 9

The functional unit of muscle that produces muscular contraction and consists of repeating sections of actin and myosin.

Question 10

What is neural activation?

Answer 10

The contraction of a muscle generated by neural stimulation. The communication link between the nervous system and muscular system

Question 11

How are ligaments and tendons similar?

Answer 11

They both have poor vascularity that leaves them susceptible to slower repair and adaptation

Question 12

What is the composition of muscle fibers?

Answer 12

They are encased by a plasma membrane (sarcolemma) and contain cell components such as cellular plasma (sarcoplasm), nuclei and mitochondria, and myofibrils

Question 13

What are myofibrils?

Answer 13

A cell within a muscle fiber that contains actin (thin filaments) and myosin (thick filaments)
myofilaments that are the contractile components of muscle tissue

Question 14

What two protein structures are important to muscle contraction?

Answer 14

Tropomyosin: located on the actin filament and blocks myosin binding sites on the actin filament keeping myosin from attaching to actin when the muscle is in a relaxed state
Troponin: located on the actin filament plays a role in muscle contraction by providing binding sites for calcium and tropomyosin when a muscle needs to contract

Question 15

What is a motor unit?

Answer 15

A motor neuron and all of the muscle fibers it innervates

Question 16

What are neurotransmitters?

Answer 16

Chemical messengers that cross the neuromuscular junction (synapse) to transmit electrical impulses from the nerve to the muscle

Question 17

What is the neuralmuscular junction?

Answer 17

The point where the motor neuron meets an individual muscle fiber. Usually a small gap between the nerve and muscle fiber (synapse)

Question 18

What is the process that takes place before neurotransmitters are released?

Answer 18

Electrical impulses (action potentials) are transported from the central nervous system down the axon of the neuron, once it reaches the end of the axon (axon terminal) neurotransmitters are released

Question 19

What is the sliding filament theory?

Answer 19

1) Sarcomere shortens as a result of z-lines moving closer together
2) Z-lines converge as myosin heads attach to the actin filament and asychronously pulling (power strokes) the actin filament across the myosin resulting in shortening of muscle fibers