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Bio 168 (2020) > chapter 10 > Flashcards

chapter 10 Flashcards

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Biology 101 flashcards
1
Q

a primary tissue type divided into:

                - Skeletal Muscle
                - Cardiac Muscle
                - Smooth Muscle
A

Muscle Tissue

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2
Q
  • Includes only skeletal muscles (organs)

* Is not all muscle, only skeletal muscle bc all of the other muscle types belong to other systems

A

The Muscular System

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3
Q
  • Muscle tissue (muscle cells or fibers)
  • Connective tissues
  • Nerves
  • Blood vessels

(this combination is necessary to make a functional skeletal muscle organ; which will shorten.) Shortening will allow you to move those bones relative to each other.

A

Skeletal Muscle Structures

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4
Q
  1. Produce skeletal movements
  2. Maintain body position (postural muscles)
  3. Support soft tissues
  4. Guard body openings
  5. Maintain body temperature
A

Functions of Skeletal Muscles

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5
Q

Muscles have 3 layers of connective tissues… what are they?

A

Epimysium
Perimysiun
Endomysium

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6
Q
  • a dense irregular connective tissue that is dominated by collagen fibers.
  • Allows you to tie everything within the organ together,
  • serves as a barrier for things that are trying to invade the organ)
A

Epimysium

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7
Q
  • Exterior collagen layer
  • Connected to deep fascia
  • Separates muscle from surrounding tissues
  • Outermost most surface of the muscle organ
A

Epimysium

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8
Q
  • Holds the muscle fascicles together
  • (Areolar connective Tissue)
  • this form of loose connective tissue has enough collagen/elastic fibers to keep the fascicles where they need to be so they’re not sliding around within the muscle organ
A

Perimysium

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9
Q
  • Surrounds muscle fiber bundles (fascicles)
  • Contains blood vessel and nerve supply to fascicles
  • Between and around the muscle fascicles
A

Perimysium

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10
Q
  • Within the muscle fascicle,
  • surrounds the individual muscle fiber,
  • holds the muscle fiber within its fascicle relative to its neighbors so that it doesn’t slide around,
  • primary purpose is to hold things to the muscle fiber, maintains important vital connections (neurons, stem cells, blood vessels,)
A

Endomysium

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11
Q
  • Surrounds individual muscle cells (muscle fibers)
  • Contains capillaries and nerve fibers contacting muscle cells
  • Contains satellite cells (stem cells) that repair damage
  • Within the fascicles
  • innermost
A

Endomysium

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12
Q

• Muscles have extensive vascular systems that:
– supply large amounts of oxygen
– supply nutrients
– carry away wastes

A

Blood vessels

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13
Q

Immature muscle cell

A

myoblast

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14
Q

Skeletal muscle cells

A

fibers

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15
Q
  • Are very long
  • Develop through fusion of mesodermal cells (myoblasts)
  • Become very large
  • Contain hundreds to thousands of nuclei
A

Skeletal Muscle Fibers

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16
Q
  • The cell membrane of a muscle cell
  • Surrounds the sarcoplasm (cytoplasm of muscle fiber)
  • A change in transmembrane potential begins contractions
  • Lets you signal
A

Sarcolemma

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17
Q

a signal that can travel across the sarcolemma and T Tubules (membrane)

A

Action Potential or Muscle impulse

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18
Q
  • Transmit action potential/muscle impulse through cell
  • Allow entire muscle fiber to contract simulataneously
  • Have same properties as sarcolemma
  • Network of tubes
  • Passes message to myofibrils
A

Transverse Tubules (T tubules)

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19
Q
  • Lengthwise subdivisions within muscle fiber
  • Made up of bundles of muscle protein filaments (myofilaments)
  • Myofilaments are responsible for muscle contraction (shortening)
A

Myofibrils

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20
Q

made of the protein actin

A

Thin filaments

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21
Q

made of the protein myosin
• Contain twisted myosin subunits
• Contain titin strands that recoil after stretching

A

Thick filaments

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22
Q
  • A membranous structure surrounding each myofibril
  • Helps transmit action potential to myofibril (the myofibril doesn’t understand the message that the sarcolemma & T tubules sent) SR helps translate the message to contract
  • Similar in structure to smooth endoplasmic reticulum
  • Forms chambers (terminal cisternae) attached to T tubules
  • Stores/release calcium ions and when the timing is right, it puts the calcium ions back into storage
A

Sarcoplasmic Reticulum

23
Q

Is formed by 1 T tubule and 2 terminal cisternae

A

A Triad

24
Q
  • Concentrate Ca2+ (via ion pumps)
  • Release Ca2+ into sarcomeres to begin muscle contraction
  • (Stores calcium), when the signal arrives, (releases calcium), when the signal is gone, (put calcium back into storage) (SR
A

Cisternae

25
Q

(One unit of the myofibril and they exist because of how the thin and thick are organized)
• The contractile units of muscle
• Structural units of myofibrils
• Form visible patterns within myofibrils (thin/thick filaments)
(Responsible for the striations in the skeletal muscle/cardiac muscle slides)

A

Sarcomere

26
Q

• A striped or striated pattern within myofibrils:
– alternating dark, thick filaments (A bands) and light, thin filaments (I bands)
(are found in that cardiac muscle slide and skeletal muscle slide. 0

A

Muscle Striation

27
Q

– the center of the A band (The A band section)

– at midline of sarcomere

A

M Line

28
Q

– the centers of the I bands (the I band section)

– at 2 ends of sarcomere

A

Z Line

29
Q
  • The densest, darkest area on a light micrograph
  • Where thick and thin filaments overlap (interact)
  • Where the actual work of shortening is done
  • Most important part of the entire sarcomere
A

Zone of Overlap

30
Q
  • The area around the M line

* Apart of the A band that Has thick filaments (no thin filaments )

A

H Zone

31
Q
  • Are strands of protein
  • Reach from tips of thick filaments to the Z line
  • Stabilize the filaments
  • Prevents over stretching (proper alignment)
A

Titian

32
Q
  • Transverse tubules encircle the sarcomere near zones of overlap
  • Ca2+ released by SR causes thin and thick filaments to interact (contract)
A

Sarcomere Function

33
Q

– is 2 twisted rows of globular G actin
– the active sites on G actin strands bind to myosin
– looks like a pearl

A

F actin

34
Q

– holds F actin strands together
– hold the G’s together to make the F (it holds them together to make the (active site) to face outwards towards tropomyosin)

A

Nebulin

35
Q

– is a double strand
– prevents actin–myosin interaction
– (twisted rope)

A

Tropomyosin

36
Q

– a globular protein
– binds tropomyosin to G actin (moves Tropomyosin out of the way if it has calcium) No calcium means Tropomyosin sits on the active site and myosin and actin cannot interact.
– controlled by Ca2+

A

Troponin

37
Q
  • Ca2+ binds to receptor on troponin molecule
  • Troponin–tropomyosin complex changes
  • Exposes active site of F actin
A

Initiating Contraction

38
Q

– binds to other myosin molecules

A

tail

39
Q

– made of 2 globular protein subunits

– reaches the nearest thin filament

A

head

40
Q

• During contraction, myosin heads:
– interact with actin filaments, forming cross-bridges
– pivot, producing motion

A

Myosin Action

41
Q

– thin filaments of sarcomere slide toward M line
– between thick filaments
– the width of A zone stays the same
- Z lines move closer together

A

Sliding filament theory:

42
Q 
•	Neural stimulation of sarcolemma:
–	causes excitation–contraction coupling
•	Cisternae of SR release Ca2+:
–	which triggers interaction of thick and thin filaments
consuming ATP and producing tension
A

The Process of Contraction

43
Q

• Is the location of neural stimulation
• Action potential (electrical signal):
– travels along nerve axon
ends at synaptic terminal

A

The Neuromuscular Junction

44
Q
  • Releases neurotransmitter (acetylcholine or ACh)

* Into the synaptic cleft (gap between synaptic terminal and motor end plate)

A

Synaptic Terminal

45
Q

• Acetylcholine or ACh:
– travels across the synaptic cleft
– binds to membrane receptors on sarcolemma (motor end plate)
– causes sodium–ion rush into sarcoplasm
– is quickly broken down by enzyme (acetylcholinesterase or AChE)

A

The Neurotransmitter

46
Q
  • Generated by increase in sodium ions in sarcolemma
  • Travels along the T tubules
  • Leads to excitation–contraction coupling
A

Action Potential

47
Q 
•	Action potential reaches a triad:
–	releasing Ca2+
–	triggering contraction 
•	Requires myosin heads to be in “cocked” position:
loaded by ATP energy
A

Excitation–Contraction Coupling

48
Q
  1. Exposure of active sites
  2. Formation of cross-bridges
  3. Pivoting of myosin heads
  4. Detachment of cross-bridges
  5. Reactivation of myosin
A

5 Steps of the Contraction Cycle

49
Q

• As sarcomeres shorten, muscle pulls together, producing tension

A

Fiber Shortening

50
Q

• Depends on:
– duration of neural stimulus
– number of free calcium ions in sarcoplasm
– availability of ATP

A

Contraction Duration

51
Q
  • Ca2+ concentrations fall
  • Ca2+ detaches from troponin
  • Active sites are recovered by tropomyosin
  • Sarcomeres remain contracted until an outside force pulls muscle to original length
A

Relaxation

52
Q

• A fixed muscular contraction after death
• Caused when:
– ion pumps cease to function
– calcium builds up in the sarcoplasm

A

Rigor Mortis

53
Q

– as a whole, a muscle fiber is either contracted or relaxed

A

The all–or–none principal

Bio 168 (2020) (3 decks)

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