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

Chapter 9 - Muscles Flashcards

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Biology 101 flashcards
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
Q

Parts of a Neuromuscular Junction:

A

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
Q

Acetylcholine (ACh) is…?

A

…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
Q

Order of events in Cross-bridge Cycling:

A

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
Q

When neural stimulation of muscle fiber stops, what happens?

A

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
Q

What are the 2 Phases of Cellular Respiration?

A

Anaerobic
&
Aerobic

30
Q

Anaerobic Phase

A

Glycolysis
Occurs in cytoplasm
Produces little ATP

31
Q

Aerobic Phase

A

Citric acid cycle and electron transport system

Occurs in the mitochondria

Produces the most ATP

Myoglobin stores extra oxygen in muscles

32
Q

Myoglobin stores what?

A

Extra Oxygen in Muscles

33
Q

Muscle Fatigue is what?

A

the Inability to contract muscle

34
Q

What are common causes of muscle fatigue?

A

Decreased blood flow

Ion imbalances across the sarcolemma

Loss of desire to continue exercise

Accumulation of lactic acid (controversial)

35
Q

What is a Muscle Cramp?

A

Sustained, involuntary muscle contraction

May be caused by changes in electrolyte concentration in extracellular fluids in the area

36
Q

Heat Production

A

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
Q

Muscle tone (tonus)

A

Continuous state of partial contraction in resting muscles

38
Q

What are the 3 types of Contractions?

A

Concentric

Eccentric

Isometric

39
Q

Concentric Contraction

A

muscle contracts with force Greater than resistance and shortens

(curling a dumbbell, pulling it higher)

40
Q

Eccentric Contraction

A

Muscle contracts with force less than resistance and lengthen

(lowering the dumbbell after a bicep curl, pulling it lower)

41
Q

Isometric Contraction

A

muscle contracts but does not change length

42
Q

Compared to skeletal muscle fibers, smooth muscle fibers are?

A

Shorter

Single, centrally located nucleus

Elongated with tapering ends

Myofilaments randomly organized

Lack striations

Lack transverse tubules

Sarcoplasmic reticulum (SR) not well developed

43
Q

What are the 2 types of smooth muscle?

A

Multi-Unit smooth muscle

Visceral smooth muscle

44
Q

Multi-unit Smooth Muscle:

A

Cells are less organized

Function as separate units

Fibers function independently

Iris of eye, walls of blood vessels

Stimulated by neurons, hormones

45
Q

Visceral Smooth Muscle

A

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
Q

Smooth muscle contraction resembles skeletal muscle contraction in these ways…

A

Interaction between actin and myosin

Both use calcium and ATP

Both are triggered by membrane impulses

47
Q

Smooth Muscle Contraction is different from skeletal muscle contraction in these ways…

A

Smooth muscle lacks troponin; uses calmodulin instead

Two neurotransmitters affect smooth muscle: Acetylcholine (Ach) and norepinephrine (NE)

48
Q

Cardiac Muscle:

A

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
Q

Skeletal muscles generate many different types of body movements
Action of a muscle depends mainly on these factors…?

A

Type of joint it is associated with

Way muscle is attached on both side of the joint

50
Q

One end of a skeletal muscle is more _____ and the other end is more _______?

A

Fixed
&
Movable

51
Q

Origin means?

A

less movable end

52
Q

Insertion means?

A

more movable end

53
Q

When a muscle contracts, what happens?

A

Insertion is pulled toward origin

54
Q

True or False

A muscle can have more than one origin or insertion

A

TRUE

55
Q

Most skeletal muscle function in groups. Roles of muscles in performing certain actions include…?

A

agonist

prime mover

synergists

antagonist

56
Q

Agonist

A

muscle that causes an action

57
Q

Prime Mover

A

agonist primarily responsible for movement (in some cases, the terms “agonist” and “prime mover” are used interchangeably)

58
Q

Synergists

A

muscles that assist agonist/prime movert

59
Q

Antagonist

A

muscles whose contraction causes movement in the opposite direction of the prime mover

60
Q

Lifespan Changes

A

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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