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BIO 112 - I GOT THIS!!! > Chapter 9 - Muscles > Flashcards

Chapter 9 - Muscles Flashcards

(60 cards)

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1
Q

There are 3 types of muscle tissue in the muscular system. What are they?

A

Skeletal muscle, cardiac muscle, smooth muscle

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2
Q

Skeletal Muscle

A

Attached to bones of skeleton

voluntary (consciously controlled)

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3
Q

Cardiac Muscle

A

makes up most of the wall of the heart

involuntary (non-consciously controlled)

responsible for pumping action of the heart

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4
Q

Smooth Muscle

A

found in walls of internal organs, such as those of digestive tract

Involuntary (non-consciously controlled)

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5
Q

Skeletal Muscles facts

A

Over 600 skeletal muscles in the body

Attached to bones, and skin of face

Under conscious control
(voluntary)

Are organs of the muscular system

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6
Q

Skeletal muscles are composed of:

A

Skeletal muscle tissue
Nervous tissue
Blood
Connective tissues

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7
Q

Connective tissue coverings over skeletal muscles:
F.A.T.

A

Fascia, Tendon, Aponeurosis

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8
Q

Fascia

A

Thin covering of connective tissue around a muscle

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9
Q

Tendon

A

Cord-like mass of connective tissue that connects muscle to a bone

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10
Q

Aponeurosis

A

Sheet-like mass of connective tissue that connects a muscle to bone, skin, or another muscle

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11
Q

Connective tissue in and closely surrounding a muscle:

A

Epimysium: surrounds whole muscle; lies beneath fascia

Perimysium: surrounds fascicles within a muscle.

Endomysium: surrounds muscle fibers (cells) within a fascicle

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12
Q

Skeletal muscle fiber (cell):
(I don’t really know how to break this slide up)

A

Multinucleated
Sarcolemma: Cell membrane of muscle fiber
Sarcoplasm: Cytoplasm of muscle fiber

Many myofibrils:
Long, parallel structures that run down fiber
Consist of thin actin filaments and thick myosin filaments
Sarcomeres: Units that connect end-to-end, to make up myofibrils

Sarcoplasmic reticulum (SR): Endoplasmic reticulum of muscle; stores calcium

Transverse (“T”) tubule: Relays electrical impulses to the SR

Triad: Unit consisting of 1 T tubule and 2 SR cisternae

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13
Q

Myofibrils consist of…?

A

Sarcomeres connected end to end

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14
Q

Striation Pattern is made by…?

A

arrangement of myofilaments in myofibrils

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15
Q

A sarcomere consists of these structures:

A

I band: Light band; composed of thin actin filaments

A band: Dark band; composed of thick myosin filaments with portions overlapped with thin actin filaments

H zone: Center of A band; composed of thick myosin filaments

Z line (Z disc): Sarcomere boundary; in center of I band anchors filaments in place

M line: Center of sarcomere and A band; anchors thick filaments

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16
Q

I Band

A

Light band; composed of thin actin filaments

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17
Q

A Band

A

Dark band; composed of thick myosin filaments with portions overlapped with thin actin filaments

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18
Q

H Zone

A

center of A band; composed of thick myosin filaments

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19
Q

Z Line (Z Disc)

A

sarcomere boundary; in center of I band anchors filaments in place

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20
Q

M Line

A

center of sarcomere and A band; anchors thick filaments

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21
Q

Thick filaments:

A

Composed of myosin protein

Heads form cross-bridges with thin filaments

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22
Q

Thin Filaments

A

Composed of actin protein

Associated with troponin and tropomyosin, which prevent cross-bridge formation when muscle is not contracting

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23
Q

Contraction of a skeletal muscle fiber:

A

Requires interaction from several chemical and cellular components

Results from a movement within the myofibrils, in which the actin and myosin filaments slide past each other, shortening the sarcomeres

Muscle fiber shortens and pulls on attachment points

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24
Q

Neuromuscular Junction (NMJ):

A

A type of synapse

Also called a myoneural junction

Site where an axon of motor neuron and skeletal muscle fiber interact

Skeletal muscle fibers contract only when stimulated by a motor neuron

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25
Parts of a Neuromuscular Junction:
Motor neuron: Neuron that controls skeletal muscle fiber Motor end plate: Specialized folded portion of skeletal muscle fiber, where fiber binds to neurotransmitter Synaptic cleft: Space between neuron and muscle fiber, across which neurotransmitter travels Synaptic vesicles: Membrane-bound sacs containing neurotransmitters Neurotransmitters: Chemicals released by motor neuron to deliver message to muscle fiber
26
Acetylcholine (ACh) is...?
...the neurotransmitter Nerve impulse causes release of ACh from synaptic vesicles ACh binds to ACh receptors on motor end plate ACh causes changes in membrane permeability to sodium and potassium ions, which generates a muscle impulse (action potential) Impulse causes release of calcium ions from SR, which leads to muscle contractio
27
Order of events in Cross-bridge Cycling:
Myosin head attaches to actin binding site, forming cross-bridge Myosin cross-bridge pulls thin filament toward center of sarcomere ADP and phosphate are released from myosin New ATP binds to myosin Linkage between actin and myosin cross-bridge break ATP splits Myosin cross-bridge goes back to original position, ready to bind to another binding site on actin
28
When neural stimulation of muscle fiber stops, what happens?
Acetylcholinesterase (enzyme) rapidly decomposes ACh remaining in the synapse. Muscle impulse stops when ACh is decomposed. Stimulus to sarcolemma and muscle fiber membrane ceases. Calcium pump moves Troponin-tropomyosin complex again covers binding sites on actin. Myosin and actin binding are now prevented. Muscle fiber relaxes.
29
What are the 2 Phases of Cellular Respiration?
Anaerobic & Aerobic
30
Anaerobic Phase
Glycolysis Occurs in cytoplasm Produces little ATP
31
Aerobic Phase
Citric acid cycle and electron transport system Occurs in the mitochondria Produces the most ATP Myoglobin stores extra oxygen in muscles
32
Myoglobin stores what?
Extra Oxygen in Muscles
33
Muscle Fatigue is what?
the Inability to contract muscle
34
What are common causes of muscle fatigue?
Decreased blood flow Ion imbalances across the sarcolemma Loss of desire to continue exercise Accumulation of lactic acid (controversial)
35
What is a Muscle Cramp?
Sustained, involuntary muscle contraction May be caused by changes in electrolyte concentration in extracellular fluids in the area
36
Heat Production
Heat is a by-product of cellular respiration in active cells Muscle cells are major source of body heat More than half the energy released in cellular respiration becomes heat; less than half is transferred to ATP Blood transports heat throughout body core
37
Muscle tone (tonus)
Continuous state of partial contraction in resting muscles
38
What are the 3 types of Contractions?
Concentric Eccentric Isometric
39
Concentric Contraction
muscle contracts with force Greater than resistance and shortens (curling a dumbbell, pulling it higher)
40
Eccentric Contraction
Muscle contracts with force less than resistance and lengthen (lowering the dumbbell after a bicep curl, pulling it lower)
41
Isometric Contraction
muscle contracts but does not change length
42
Compared to skeletal muscle fibers, smooth muscle fibers are?
Shorter Single, centrally located nucleus Elongated with tapering ends Myofilaments randomly organized Lack striations Lack transverse tubules Sarcoplasmic reticulum (SR) not well developed
43
What are the 2 types of smooth muscle?
Multi-Unit smooth muscle Visceral smooth muscle
44
Multi-unit Smooth Muscle:
Cells are less organized Function as separate units Fibers function independently Iris of eye, walls of blood vessels Stimulated by neurons, hormones
45
Visceral Smooth Muscle
Single-unit smooth muscle; cells respond as a unit Sheets of spindle-shaped muscle fibers Fibers held together by gap junctions Exhibit rhythmicity Conduct peristalsis Walls of most hollow organs More common type of smooth muscle
46
Smooth muscle contraction resembles skeletal muscle contraction in these ways...
Interaction between actin and myosin Both use calcium and ATP Both are triggered by membrane impulses
47
Smooth Muscle Contraction is different from skeletal muscle contraction in these ways...
Smooth muscle lacks troponin; uses calmodulin instead Two neurotransmitters affect smooth muscle: Acetylcholine (Ach) and norepinephrine (NE)
48
Cardiac Muscle:
Located only in the heart Striated muscle cells Muscle fibers joined together by intercalated discs Fibers branch, contain a single nucleus Network of fibers contracts as a unit (syncytium) Self-exciting and rhythmic Longer refractory period than skeletal muscle No sustained or tetanic contractions
49
Skeletal muscles generate many different types of body movements Action of a muscle depends mainly on these factors...?
Type of joint it is associated with Way muscle is attached on both side of the joint
50
One end of a skeletal muscle is more _____ and the other end is more _______?
Fixed & Movable
51
Origin means?
less movable end
52
Insertion means?
more movable end
53
When a muscle contracts, what happens?
Insertion is pulled toward origin
54
True or False A muscle can have more than one origin or insertion
TRUE
55
Most skeletal muscle function in groups. Roles of muscles in performing certain actions include...?
agonist prime mover synergists antagonist
56
Agonist
muscle that causes an action
57
Prime Mover
agonist primarily responsible for movement (in some cases, the terms "agonist" and "prime mover" are used interchangeably)
58
Synergists
muscles that assist agonist/prime movert
59
Antagonist
muscles whose contraction causes movement in the opposite direction of the prime mover
60
Lifespan Changes
Myoglobin, ATP, and creatine phosphate decline, starting in the 40s Connective tissue and adipose cells replace some muscle tissue By age 80, almost half of muscle mass has atrophied Muscle strength decreases, and reflexes become slower Exercise helps to maintain muscle mass and function

BIO 112 - I GOT THIS!!! (13 decks)

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