Chapter 10: Muscle Tissue Flashcards

1
Q

Three types of muscle

A

Cardiac
Smooth
Skeletal

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2
Q

What are some muscle similarities?

A

Excitability
Contractility
Elasticity

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3
Q

Muscle contraction depends on what two kinds of myofilaments

A

Actin and myosin

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4
Q

Microscopic appearance of skeletal muscle

A

Elongated
Multinucleate
Striated

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5
Q

Nervous system control of skeletal muscle

A

Voluntary nervous system
Somatic motor neurons

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6
Q

What are the functions of the skeletal muscles?

A

Moves the bones, maintains posture and body position, supports soft tissues, guards body entrances, and exits, maintains body temperature, and stores nutrients

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7
Q

Cardiac Muscle Microscopic appearance

A

Branching cells, single central nucleus , straited and joined to another muscle cell at the intercalated disc.

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8
Q

Nervous system control of cardiac muscle

A

Involuntary autonomic nervous system

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9
Q

Function of cardia muscle

A

pumps oxygen, nutrients throughout the body

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10
Q

Microscopic appearance of smooth muscle

A

Spindle-shaped, single central nucleus, no striations

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11
Q

Location of smooth muscles

A

Around hollow organs including blood vessels.

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12
Q

Origin

A

Attach to bone and does not move.

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13
Q

Insertion

A

Crosses a joint and attaches to bone. Insertion will move towards the origin.

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14
Q

When a muscle contracts, the _____ is pulled toward the _________.

A

Insertion
Origin

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15
Q

Levels of organization of Skeletal Muscle

A

Skeletal muscles, fascicles, muscle fiber, myofibrils, sarcomere.

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15
Q

Skeletal Muscle

A

organ
bundle of fascicles
contains epimysium

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16
Q

Fascicles

A

Bundle of fibers
contains perimysium

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17
Q

Muscle fiber

A

cell
Bundles of myofibrils.
Contains endomysium

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18
Q

Myofibrils

A

Repeating contractile units that are called sarcomeres

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19
Q

Sarcomeres

A

Organized unit of myofilaments.
Myosin and actin

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20
Q

A bands are ____
I bands are ______

A

dark
light

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21
Q

M line

A

Anchor for myofilaments, it is the horizontal line in the middle of the sarcomeres.

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22
Q

H band

A

The area where there is only myosin

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23
Q

A band or Zone of Overlap

A

Where both myosin and actin are

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24
Z lines
Separates the sarcomeres and marks the beginning of the end of a sarcomere
25
Titin
Stretchy protein that helps it pop back to its original position
26
I band
This is where it is only actin
27
Epimysium
surrounds the skeletal muscle
28
Perimysium
surrounds the fascicle
29
Endomysium
surrounds muscle fiber Blends into connective tissue attachments like tendon (cord-like) or aponeuroses (sheet-like)
29
Sites of muscle attachments
Bones Cartilage and connective tissue coverings
30
Thick Filaments
Myosin Each myosin molecule has a rod-like tail and two globular heads.
31
Thin Filaments
Actin Actin subunits contain an active site (which myosin heads attach to)
31
What two regulatory subunits does actin contain
Tropomyosin and troponin
32
Tropomyosin
covers the active site of actin, prevents myosin from attaching
33
Tropinin
Can bind to calcium, and when calcium attaches to troponin, it causes tropomyosin to shift away from the active sites on the actin.
34
Sarcolemma
Plasma membrane
35
T-Tubules
extended from sarcolemma into sarcoplasm. Carry electrical currents **action potential**from sarcolemma into the cell interior. Triggers contraction
36
Sarcoplasm
The cytoplasm of the muscle fibers.
37
Each myofibril is surrounded by ___________.
Sarcoplasmic Reticulum
38
How does calcium interact with troponin and affect tropomyosin?
When calcium binds to troponin, it causes tropomyosin to shift away from the active sites on the actin.
38
What does SR store?
Calcium
39
Acetylcholine
ACh is a chemical signal that will initiate muscle movement.
39
Neuromuscular Junction
A synapse between a neuron and a muscle cell.
39
Neurotransmitter
Chemical Sign
40
Sliding Filament Theory of Muscle contraction
The concept is that a sarcomere shortens as the thick and thin filaments slide past one another.
40
Synaptic Cleft
Narrow space between a somatic motor neuron and the motor end plate.
40
Recruitment
The process by which more and more motor neurons are activated.
40
Motor Unit
Consists of a single motor neuron and all the muscle fibers controls.
40
What are the two basic mechanisms by which the nervous system produces graded contractions?
*Varying the **number** of fibers that contract *Varying the **rate** at which fibers are stimulated
41
Rigor Mortis Occur
Muscles remain locked in a contracted state because there is no ATP for relaxation.
41
Action Potential
A propagated change in the membrane potential pf excitable cells in initiated by a change in the membrane permeability to sodium ions.
42
Twitch
Results from a single action potential in a motor neuron
43
How many phases does a single twitch have? and what are they?
Latent period Contraction phase Relaxation phase
44
Treppe
A stair-step increase in tension caused by repeated stimulations immediately after the relaxation phase. (Stimulus frequency <50/Sec) Seen in cardiac muscles
45
Wave summation
Increasing tension due to the summation of twitches. Caused by repeated stimulations before the end of the relaxation phase. (Stimulus >50/sec)
46
Tetanus
Maximum tension
47
Incomplete Tetanus
Muscle produces near-maximum tension. Caused by rapid cycles of contraction and relaxation
48
Complete Tetanus
Higher stimulation frequency eliminates the relaxation phase. Muscle is in continuous contraction. All potential cross-bridges form.
49
What are the two types of muscle contractions?
Isotonic and Isometric
50
Isotonic Contraction
Skeletal muscle changes in length. Resulting in motion.
51
Isotonic Concentric Contraction
Muscle tension > load resistance **Muscle shortens!**
52
Isotonic Eccentric Contraction
Muscle Tension < load (resistance) **Muscle elongates!**
53
Isometric contraction
Skeletal muscle develops tension that never exceeds the load. Muscle does not change length.
54
Anaerobic Metabolism
Breakdown of glucose in the absence of oxygen. Lead to build up of lactic acid. Causes muscle fatigue. Yields 2 ATP from one glucose
55
Aerobic Metabolism
Breakdown of glucose in the presence of oxygen. High yield- of approximately 36 ATP.
56
Slow Twitch
ATP broken down slowly Contract **slowly** Aerobic metabolism Store oxygen Rich blood supply **darker in color** Endurance- jogging, swimming, biking.
57
Fast Twitch
ATP broken down FAST Contract **quickly** Anaerobic metabolism Breaks down creatine-P for short bursts of energy. Poor blood supply **white in color** Fatigue quickly from lactic acid build-up. Power and high-intensity activity such as weight lifting
58
Strength or Resistance Training
The amount of actin and myosin and the number of sarcomeres within muscle fibers increases. The size of individual muscles increases. The number of muscle fibers does not increase.
59
Endurance or Aerobic Training
The number of blood vessels supplying muscles increases. Muscle fibers do not increase in size or number.
60
Do muscles pull or push?
Muscles ONLY pull, NEVER push.
61