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Biology 108 > Chapter 6 Muscular System > Flashcards

Chapter 6 Muscular System Flashcards

(51 cards)

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1
Q

Muscles

A

Responsible for all types of body movement

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2
Q

3 types of muscle

A

Skeletal

Cardiac

Smooth

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3
Q

Muscle charactoristics

A

skeletal and smooth are elongated

contraction is due to movement of microfilaments

myo and mys refers to muscle

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4
Q

Skeletal Muscle

A

attached by tendons

cells are multinucleated striated,

have visible banding voluntary

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5
Q

connective tissue wrappings

A

cells surrounded and bundled by connective tissue

Endomysium

Perimysium

Epimysium

Fascia

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6
Q

Endomysium

A

encloses a single muscle finber

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7
Q

Perimysium

A

wraps around a fascicle (bundle) of muscle fiber

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8
Q

Epimysium

A

covers entire skeletal muscle

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9
Q

Fascia

A

on the outside of the epimysium

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10
Q

Skeletal muscle attachments

A

epimysium blends into tendons

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11
Q

Tendons

A

cord like structures that connect muscle to bone

mostly collogen fibers

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12
Q

Smooth muscle chacteristics

A

lack striations

spindle shaped cells

singel nucleus

involuntary

mainly in wall of hollow organs

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13
Q

Cardiac muscle characteristics

A

Striations

usually single nucleus branching cells

joined by intercalated disc

involuntary

found only in heart

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14
Q

Muscle functions

A

produce movement

maintain posture

stabilize joints

generate heat

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15
Q

Skeletal muscle fiber

A

thin elongated cylindrical cell with rounded ends

extends length of muscle

sarcolemma

transverse tubules

myofibrils

sarcoplasmic reticulum

striation pattern

sarcomere

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16
Q

Sarcolemma

A

plasma membrane

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17
Q

transverse tubules

A

invaginations of sarcolemma

entend all through fiber

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18
Q

myofibrils

A

bundle of contractile proteins

think filament-myosin

thin filament-actin

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19
Q

sarcoplacsmic reticulum

A

modified ER

sacs and tubes that surround each myofibril

stores Ca+2

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20
Q

striation pattern

A

due to arrangement of thin and thick fibers

A band: dark think filament

I band: thin filament anchored to Z lines

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21
Q

Sarcomere

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A

contractile unit of muscle

segment of myofirbril between 2 Z lines

22
Q

Sarcomere organization

myosin

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A

myosin

2 twisted proteins with globular heads (cross bridges) projecting outwards

myosin cross bridge head has ATPase enzymes

energy released cocks myosin head to prepare for binding wtih actin

23
Q

thick filaments

Study These Flashcards
A

composed of many myosin molecules

located in center of sarcomere

24
Q

Actin

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A

double stranded helical molecule

each actin monomer has binding site for myosin

troponin and tropomyosin are regulatory proteins found on thin filament

25
thin filament
actin is the main protein anchored to the Z disc
26
H zone
region in the center of "A" band that contains only myosin at rest
27
M line
proteins that hold myosin molecules in place
28
Excitability
ability to receive and respond to a stimulus
29
Contractabillity
ability to shorten when an adequate stimulus is received
30
Extensibility
ability of muscle cells to be stretched
31
Elasticity
ability to recoil and resume resting length after stretching
32
muscle contraction
skeletal muscles must be stimulated by a motor neuron to contract
33
Motor unit
one motor neuron all of skeletal muscles cells are stimulated by that neuron
34
Neuromuscular Junction
connection between axon terminal of the motor neuron and muscle
35
Motor Neuron
Axon terminal contains the synaptic vesicles vesicles contain neurotransmitters transmitters are chemicals taht transmit signal from neuron to next cell
36
Motor End Plate
folded region of the sarcolemma under the axon terminal contains Ach receptors
37
Synaptic Cleft
gap between nerve and muscle filled with interstitial fluid
38
transmission of Nerve Impulse to Muscle
Nerve impulse reaches axon terminals of motor neuron synaptic vesicles release acetylcholine (ACh) ACh diffuses across cleft and binds to receptors on motor end plate sarcolemma becomes permeable to Na+ Na+ rushes into the cell generating an action potential action potential travels on sarcolemma and stimulates muscle fiber to contract
39
sliding filament theory
muscle contraction involves the shortening of all the sarcomeres within a muscle fiber
40
sliding filament theory
myosin pulls the thin filaments intothe center of the sarcomere thin filaments slide past the think filaments
41
Main events in skeletal muscle contraction
once stimulated an action potential travels along sarcolemma down t-tublules causes SR to release Ca+2 Ca+2 binds to troponin troponin and tropomyosin move exposing binding site for myosin on actin myosin cross bridge binds to actin phosphate and SDP are released from cross bridge myosin cross bridge changes and pulls actin in (power stroke) new ATP binds to myosin and cross bridge detaches from actin ATP is hydrolysed and energy is used to "cock" myosin head so it is ready to bind with actin cross bridge cycle continues if ATP and Ca+2 are present
42
Skeletal muscle Relaxation
ACh is degraded muscle fiber is no longer stimulated Ca+2 is pumped back into the SR new ATP causes cross bridge to detach from actin Troponin-tropomyosin move so tropomyosin covers myosin binding site on actin muscle fiber relaxes ATP is hydrolysed and energy is used to "cock" myosin cross bridge ready for further stimulation
43
Contraction of Skeletal muscle
All or None not all fibers may be stimulated during same interval different combinations may give different responses graded responses different degrees of contraction strength
44
contractoin graded responses
frequency of stimulation number of motor units being stimulated at one time
45
Energy for contraction
stored ATP only 4-6 secons is stored other pathways to produce ATP
46
Direct Phosphorylation of ADP
muscle cells store CP (high energy molecule) CP supplies are exhausted in less than 15 seconds
47
Anerobic glycolysis and lactic acid formation
occurs when O2 is limited or absent produces 2 ATP and lactic acid not as efficient but fast about 40 seconds of energy
48
Aerobic Respiration
Main source of ATP can provide hours of energy
49
Cell oxygen source
blood hemoglobin in RBC carries oxygen from lungs Myoglobin found in skeletal muscle temporary storage site for oxygen
50
muscle fatigue
Muscle unable to contract even with a stimulus
51
muscle fatigue causes
build up of lactic acid lack of ATP depletion of muscle glycogen stores lack of acetylcholine

Biology 108 (38 decks)

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