Muscle

Question 1

Actin

Answer 1

• linear polymers of globular actin (G-actin) subunits

- occur as microfilaments in cytoskeleton and as thin filaments used in contraction

Question 2

Myosin

Answer 2

• motor protein chains that intertwine forming long tail and pair of heads
• approx 250=thick filament

Question 3

Titin

Answer 3

stabilizes position of myosin and actin and returns stretched muscles to their resting length

Question 4

2 Structural Muscle Groups

Answer 4

Striated

Non-Striated

Question 5

Striated Muscle Types

Answer 5

Skeletal Muscle

Cardiac Muscle

Question 6

Non-Striated Muscle Types

Answer 6

Smooth Muscle

Question 7

3 Functional Muscle Groups

Answer 7

Skeletal Muscle
Cardiac Muscle
Smooth Muscle

Question 8

Smooth Muscle

Answer 8

• small cells with single nucleus
• not arranged in sarcomeres
• contraction initiated by electrical or chemical signals controlled by autonomic NS

Question 9

Skeletal Muscle

Answer 9

• many nuclei in same fiber

- very long cells (~80cm)

Question 10

Cardiac Muscle

Answer 10

• striated, small cells with single nucleus

- controlled buy internal pacemaker (involuntary)

Question 11

Fascicles

Answer 11

bundle of fibres surrounded by perimysium

Question 12

Myofibers

Answer 12

multinucleated single muscle cell that make up a fascicle

Question 13

Myofibril

Answer 13

elongated contractile threads containing actin and myosin that make up a myofiber

Question 14

Epimysium

Answer 14

outmost layer of fibrous elastic tissue that covers the entire muscle

Question 15

Endomysium

Answer 15

areolar connective tissue covering individual fibres

Question 16

A Bands

Answer 16

thick myosin filaments (dark bands) which are bisected by the M Line, marking the centre of the myosin filament

Question 17

H Zones

Answer 17

central area of sarcomere where myosin contracts and shortens

Question 18

M Line

Answer 18

attachment site for thick filaments in middle of A Band

Question 19

I Band

Answer 19

thin actin filament (light bands) that are bisected by thick dark line known as Z Disc

Question 20

Sarcomere

Answer 20

• region between two successive Z Discs

- each possess two T Tubules

Question 21

Sarcolemma

Answer 21

membrane that continues within a skeletal muscle finer as T Tubules

Question 22

Transverse (T) Tubules

Answer 22

long hollow areas that go across myofibril, permits things to travel in and out of cell and depolarization from nerve signal

Question 23

Sarcoplasmic Reticulum

Answer 23

primarily stores calcium, signals cause release, form meshwork around each myofibril

Question 24

Terminal Cisternae

Answer 24

enlarged areas of SR that surround T Tubles

Question 25

Triade

Answer 25

structure formed by T Tubule flanked by two terminal cisternae

Question 26

Titin

Answer 26

• large, hooked protein where the actin filament attaches to the Z discs
• helps anchor myosin in place so that the filament does not slide too far

Question 27

Tropomyosin

Answer 27

component of thin filament that inhibits contraction by blocking interaction between actin and myosin

Question 28

Acetylcholine

Answer 28

neurotransmitter released by nerve cells to activate skeletal muscles

Question 29

Muscle Spindles

Answer 29

monitor elongation and rate of elongation of muscle

Question 30

Golgi Tendon

Answer 30

monitors stretch and rate of stretch of tendon

Question 31

Intercalated Disc

Answer 31

gap junctions that are found at the junction of two myocardial cells that allows the conductivity of electrical signals between cells