Muscles Part 1

Question 1

Muscle Tissue is derived from

Answer 1

Mesoderm

Question 2

Three types of muscle tissue

Answer 2

Skeletal
Cardiac
Smooth

Question 3

Skeletal Muscle Tissue contains

Answer 3

40% of body mass
multi-nucleated cells
quick twitch, short contractions

Question 4

Cardiac Muscle Contains

Answer 4

cells are short and branched
striations
intercalted discs
intermediate twitch

Question 5

Smooth Muscle Tissue Contains

Answer 5

Lack striations
Slow twitch
long contrations

Question 6

Functions of Skeletal Muscle Tissue

Answer 6

Produces Skeletal Movement
Maintains Body Posture and Positon
Supports Soft Tissues
Guards Entrances and Exits
Maintains body temperature
Provides Nutrient Reserves

Question 7

A Single Skeletal Muscle is composed of

Answer 7

Large bundles called fascicles

Question 8

Fascicles are composed of

Answer 8

Numerous Muscle Cells also called Muscle Fibers

Question 9

Muscle Fiber is composed of

Answer 9

Myofibrils

Question 10

Myofibrils are composed of

Answer 10

Two Contractile proteins called myofilaments

Question 11

Myosin

Answer 11

Thick Myofilaments

Question 12

Actin

Answer 12

Thin myofilaments

Question 13

Sarcomeres

Answer 13

Myocin and Actin are arranged in an overlapping pattern creating hundreds to thousands of these

Question 14

Epimysium

Answer 14

Dense Layer of Collagen Fibers surrounds the entire muscle
Separates Muscle from surrounding tissues and organs
Connected to Deep Fascia

Question 15

Perimysium

Answer 15

Fibrous layer that divides muscle fibers into a series of bundles called fascicles
Possesses blood vessels, nerves, collagen and elastic fibers

Question 16

Endomysium

Answer 16

Delicate connective tissue that surrounds individual skeletal muscles/fibers

Question 17

Tendon

Answer 17

End of skeletal muscles collagen fibers merge into this

Question 18

Aponeurosis

Answer 18

Broad sheet at end of muscles, anchor to bone

Question 19

Cytoplasm of a muscle cell is called

Answer 19

Sarcoplasm

Question 20

Myogobin

Answer 20

Large amounts in muscle cells
Important protein in storage of oxygen

Question 21

Plasma Membrane of a muscle cell is called

Answer 21

Sarcolemma

Question 22

Transverse Tubules (T tubules)

Answer 22

Invaginations of the sarcolemma that extend deep into the sarcoplasm at right angles to cells surface
Allow electrical impulses generated at the surface to travel into the cell’s interior

Question 23

Sarcoplasmic Reticulum (SR)

Answer 23

Similar to smooth ER of other cells
Forms tubular network surrounding each myofibril
Membrane contains ion pumps that move Calcium from cytosols into the ER

Question 24

Calsequestrin

Answer 24

Protein located in the SR that calcium ions bind to

Question 25

Triad

Answer 25

One T-Tubule that has a terminal cisterna on either side

Question 26

Terminal Cisterna

Answer 26

Tubules of SR that are enlarged and form chambers to store calcium ions

Question 27

Sarcomere

Answer 27

Functional/contractile unit of skeletal muscle Resting length of about 2 um Composed of specific arrangements of myofilaments of actin and myosin

Question 28

A Band

Answer 28

Dense region of sarcomere that contains overlapping thick (myosin) and thin (actin) filaments

Question 29

I Band

Answer 29

Either side of A band Only contains thin filaments (actin)

Question 30

H Band

Answer 30

In the middle of the A- Band Only contains Thick filaments (myosin)

Question 31

M Line

Answer 31

Located in Middle of H band Anchors central portion of each thick filament

Question 32

Z Lines

Answer 32

Mark Boundary between adjacent sarcomeres

Question 33

Actinins

Answer 33

Located in Z line Proteins Anchor thin filaments of adjacent sarcomeres

Question 34

Numbers 1-5

Answer 34

1 - Muscle Fiber Nucleus 2 - Motor Neuron Axon 3 - Axon Branches 4 - Motor Neuron Endplate 5 - Myofibril of muscle fiber

Question 35

Numbers 6-10

Answer 35

6 Synaptic Cleft 7 Folded Sarcolemma 8 Acetylcholine 9 Mitochondria 10 Synaptic Vesicles

Question 36

Thin Filaments of Actin are composed of

Answer 36

F-Actin Filamentous Actin G-Actin Globular Actin Nebulin Tropomyosin Troponin

Question 37

F-Actin

Answer 37

Filamentous - Twisted strand composed of two rows of 300-400 individual molecules of G-Actin

Question 38

G-Actin

Answer 38

Globular Rounded, compact molecule of protein that possesses an active site where one myosin molecule can bind

Question 39

Nebulin

Answer 39

Long strand of protein that extends along the F-Actin strand in the cleft between the rows of G-Actin molecules Helps stabilize the F-Actin strands

Question 40

Tropomyosin

Answer 40

Double-stranded protein that covers over the active sites of the G-Actin in a resting muscle. Prevents interaction of actin and myosin

Question 41

Troponin

Answer 41

Three globular subunits, strategically placed along tropomyosin

Question 42

Action of Calcium biding to Troponin

Answer 42

Troponin changes shape which causes tropomyosin to swivel, revealing active site on G-Actin so myosin and actin can form a cross bridge

Question 43

Myosin

Answer 43

Myosin Molecules - pair of myosin subunits twisted around each other Tail portion connected to a free head portion Tail and Free head connected by hinge that allows head to swivel Single filament has about 300 molecules twisted together - tails point to M Line, heads arranged in a spiral facing the thin filaments At core is a thick elastic filament of Tintin which recoils after stretching

Question 44

Synaptic Terminals

Answer 44

Axon of each motor neuron branches to form numerous cellular extensions