Cscs Terms - Chapter 1

Front 1

Motor Unit ( = Motor neuron + fibers it innervates)

Back 1

Basic functional unit of neuromuscular system

Front 2

Epimysium

Back 2

Covers the body's 430+ skeletal muscles

Front 3

Tendons

Back 3

Attach muscles to bone

Front 4

Bone periosteum

Back 4

Aspect of bone to which tendons attach

Front 5

Fasciculi

Back 5

Groups of muscle fibers (up to 150)

Front 6

Perimysium

Back 6

Covers fasciculi

Front 7

Endomysium

Back 7

Covers each muscle cell

Front 8

Sarcomere

Back 8

Smallest contractile unit of skeletal muscle

Front 9

T-Tubules

Back 9

Perpendicular with sarcoplasmic reticulum, and is continuous with sarcolemma(covering the cell); allowing action potential(electrical nerve impulse) to arrive simultaneously throughout

Front 10

Sliding-filament Theory

Back 10

Actin filaments (outer) slide in on Myosin filaments -> pulls Z-line to center of sarcomere -> muscle shortens

Front 11

Acetylcholine

Back 11

Neurotransmitter released by Action Potential, resulting in muscle excitement

Front 12

Type I Fiber

Back 12

Slow Twitch (develops force and relaxes slowly)

Front 13

Type IIa / IIb Fibers

Back 13

Fast Twitch (develop force and relax rapidly)

Front 14

Recruitment

Back 14

Process which varies number of Motor Units activated in order to increase force production

Front 15

Actin

Back 15

Thin Myofilament, arranged outside of Myosin sections in a double-helix structure

Front 16

Myosin

Back 16

Thick Myofilament, arranged in lines between sections of Actin. Cross-bridges from this myofilament allow the two to touch

Front 17

Golgi Tendon Organ (GTO's)

Back 17

Activate when muscle is placed under tension and mitigate excessive force by causing muscle to relax

Front 18

Sarcopenia

Back 18

Reduction in muscle size and strength due to inactivity and aging

Front 19

A-band

Back 19

Corresponds with the alignment of Myosin filaments (dark in color)

Front 20

I-band

Back 20

Corresponds with the areas in two adjacent sarcomeres that contain only Actin filaments (light in color)
Decreases during contraction

Front 21

Z-line

Back 21

In middle of I-band and appears as a thin, dark line running longitudinally through the I-band
During contraction, it is pulled toward center of sarcomere

Front 22

H-zone

Back 22

Area in center of sarcomere where only Myosin filaments are present. During contraction, it decreases as Actin slides over Myosin

Front 23

SA Node

Back 23

Normally initiates the heart's electrical impulse