Chapter 8; Bio 210 (Muscles)

Question 1

Muscular System

Answer 1

responsible for movement of the body (Only skeletal muscle)

Question 2

Skeletal Muscle 6 functions

Answer 2

1- produce movement
2-maintain posture
3-functioning of internal organs
4-guard entrances and exits in body
5-body temperature
6-nutrient reserves

Question 3

Myofibrils

Answer 3

contractile level of muscle contraction

-made of smaller units called myofilaments

Question 4

Actin (thin) and Myosin (thick) are

Answer 4

protein filaments (myofilaments) that form Sacromeres

Question 5

Sacromeres

Answer 5

join end to end to form Myofibrils

Question 6

Z lines

Answer 6

boundaries of a sacramere [_____]

Question 7

A band

Answer 7

dark band inside Z lines [_____

Question 8

I band

Answer 8

light band between z line and a band [{}____{}]

Question 9

H Zone

Answer 9

where the myofilaments don’t over lap (in the middle)

[{}___ H zone ___{}]

Question 10

Phases of Contraction

Answer 10

Resting
Excitation (action potential down t tubule excites it)
Excitation/ Contraction Coupling (Ca ions binds with tropin and removes tropamyosin exposing active site)
Contraction (thin slides past thick)
Resting

Question 11

NMJ

Answer 11

junction between an axon and a motor neuron and a muscle fiber is nueromuscular junction

Question 12

Motor Neurons

Answer 12

nerve cells with axons that connect nervous system to muscular system

Question 13

T Tubule (Transverse tubule)

Answer 13

at each junction of A and I bands the sacrolemma indents (tube that holds in multiple myofibrils)

Question 14

Sacrolemma

Answer 14

plasma membrane of skeletal muscle

Question 15

Terminal cisterns of the SR

Answer 15

where the T tube runs between then branches off into tubules of SR

Question 16

SR

Answer 16

sacroplasmic reticulum

Question 17

Triad

Answer 17

region where cisterns border a T tube

Question 18

Endomysium

Answer 18

areolar connective tissue surrounds EACH muscle fiber (

Question 19

Perinysium

Answer 19

wraps several sheather muscle fibers (surrounds fascicles)

Question 20

Epimysium

Answer 20

bounds together fascicles and sheaths the ENTIRE muscle (dense irregular connective tissue)

Question 21

Tendon

Answer 21

provides durability and space to the muscles (pass over a joint and provide protection from bone)`

Question 22

NMJ Process

Answer 22

• Axons branch off to the muscle with Terminal Branches
• Together the neuron and all stimulated muscle fibers make up a ‘Motor Unit’
• The neuron and muscle fibers don’t touch (synaptic cleft)
• Action Potential is released from axon terminals into the cleft
• The ACh diffisues and binds with recpetors on the sacrolemma
• Once joined with ACh, the permeability of sacrolemma changes
• Ion channels open depolarizing the sacrolemma and contraction occurs

Question 23

Neuron and Muscle Cell

Answer 23

only TWO kinds of cells in body that can propagate action potentials

Question 24

Motor Unit

Answer 24

ALL stimulated fibers and axons (can be more than one neuromuscular junction)

Question 25

Synaptic Cleft

Answer 25

space between muscle fibers and the neuromuscular junction

Question 26

ACh

Answer 26

acetylcholine => a neurotransmitter within many mitochondria and axon terminals

Question 27

Action Potential

Answer 27

ACh ( K+ or Na+)

Question 28

Sliding Filament Theory

Answer 28

• Calcium ions diffuse from the sacroplasmic reticulum (inside of the T tubule) into the sacroplasm.
• Calcium ions released from SR bind to troponin molecules
• Troponin molecules bind to G actin molecules are released
• Topomyosin moves and exposes the active sites on G actin
• Active sites are exposed on G actin molecules, heads of myosin bind to them forming cross bridges (EXPOSURE OF ACTIVE SITES)
• Initiates (POWER STROKE) which slides the actin past the myosin filament
• ATP binds to the myosin head causing it to detach from actin (CROSS BRIDGE RELEASE)
• Myosin head splits ATP into ADP and P which Phosphate remains attached to myosin head (BREAKDOWN OF ATP)
• Myosin head returns to resting position and energy is stored in head (RECOVERY STROKE)

Question 29

Order of Filament Theory

Answer 29

EXPOSURE OF ACTIVE SITES
HINGE STROKE (once myosin binds)
POWER STROKE
CROSS BRIDGE RELEASE
BREAKDOWN OF ATP
RECOVERY STROKE

Question 30

Prime Mover (agonist)

Answer 30

the prime mover is the muscle used to accomplish a stimuli

Question 31

Antagonist

Answer 31

the tricep brachii when extending after flexion of the bicep brachii

Question 32

Synergist

Answer 32

aid the action of the agonist

Question 33

Fixator

Answer 33

hold a skeletal place in position when using muscle

Question 34

Origin of muscle

Answer 34

point of attachment of a muscle when NO movement occurs when the muscle contracts

Question 35

Insertion Point of muscle

Answer 35

point of attachment of a muscle where movement DOES occur when the muscle contracts (towards the origin point)

Question 36

Points

Answer 36

medial origin and lateral insertion

non appendenges

Question 37

Twitch Contraction

Answer 37

single muscle fiber to single stimulus

Question 38

4 Factors of Muscle Contraction

Answer 38

Motor Unit Recruitment
Frequency of Stimulus
Muscle Tone
Lenght Tension

Question 39

Isotonic Contraction

Answer 39

muscle tension changes muscle length

• cocentric- muscle lengthens picking up
• eccentric- muscle tension remains the same while muscle lengthens

Question 40

Isometric Contraction

Answer 40

muscle prevented from changing length even though tension is increasing

Question 41

Atrophy

Answer 41

muscles lack of activity (cast on)

Question 42

Hypertrophy

Answer 42

building muscle