Chapter 8; Bio 210 (Muscles) Flashcards Preview

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Flashcards in Chapter 8; Bio 210 (Muscles) Deck (42):
1

Muscular System

responsible for movement of the body (Only skeletal muscle)

2

Skeletal Muscle 6 functions

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

3

Myofibrils

contractile level of muscle contraction
-made of smaller units called myofilaments

4

Actin (thin) and Myosin (thick) are

protein filaments (myofilaments) that form Sacromeres

5

Sacromeres

join end to end to form Myofibrils

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Z lines

boundaries of a sacramere [_____]

7

A band

dark band inside Z lines [_____

8

I band

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

9

H Zone

where the myofilaments don't over lap (in the middle)
[_{}___ H zone ___{}_]

10

***Phases of Contraction***

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

11

NMJ

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

12

Motor Neurons

nerve cells with axons that connect nervous system to muscular system

13

T Tubule (Transverse tubule)

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

14

Sacrolemma

plasma membrane of skeletal muscle

15

Terminal cisterns of the SR

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

16

SR

sacroplasmic reticulum

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Triad

region where cisterns border a T tube

18

Endomysium

areolar connective tissue surrounds EACH muscle fiber (

19

Perinysium

wraps several sheather muscle fibers (surrounds fascicles)

20

Epimysium

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

21

Tendon

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

22

***NMJ Process***

-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

23

Neuron and Muscle Cell

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

24

Motor Unit

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

25

Synaptic Cleft

space between muscle fibers and the neuromuscular junction

26

ACh

acetylcholine => a neurotransmitter within many mitochondria and axon terminals

27

Action Potential

ACh ( K+ or Na+)

28

Sliding Filament Theory

-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)

29

Order of Filament Theory

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

30

Prime Mover (agonist)

the prime mover is the muscle used to accomplish a stimuli

31

Antagonist

the tricep brachii when extending after flexion of the bicep brachii

32

Synergist

aid the action of the agonist

33

Fixator

hold a skeletal place in position when using muscle

34

Origin of muscle

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

35

Insertion Point of muscle

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

36

Points

medial origin and lateral insertion
(non appendenges)

37

Twitch Contraction

single muscle fiber to single stimulus

38

4 Factors of Muscle Contraction

Motor Unit Recruitment
Frequency of Stimulus
Muscle Tone
Lenght Tension

39

Isotonic Contraction

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

40

Isometric Contraction

muscle prevented from changing length even though tension is increasing

41

Atrophy

muscles lack of activity (cast on)

42

Hypertrophy

building muscle