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Biology anatomy/physiology > GENERAL MUSCLE CHARATERISTICS > Flashcards

GENERAL MUSCLE CHARATERISTICS Flashcards

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1
Q

What is the energy that powers actin and myosin in muscle contraction?

A

ATP

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2
Q

What is the initial source of energy used to replenish ATP?

A

Creatine Phosphate

- includes a high-energy phosphate bond

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3
Q

How is creatine phosphate synthesized?

A
  • when sufficient amounts of ATP are present, creatine phosphate is formed by an enzyme in the mitochondria called “creatine phosphokase”
  • creatine phosphate stores excess energy in its high-energy bonds
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4
Q

What does creatine phosphate do once ATP is decomposed to ADP?

A
  • creatine phosphate cannot directly supply energy, so it transfers one of its phosphate bonds to ADP to convert it back to ATP
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5
Q

What happens when creatine phosphate can no longer supply sufficient energy to ATP?

A
  • muscle starts to use glycolysis to replenish energy
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6
Q

What are the sources of oxygen required for the aerobic reactions in cellular respiration?

A
  • oxygen is delivered to the muscle fibers thru blood flow, where it is carried by hemoglobin in the red blood cells
  • oxygen can also be stored in the muscle fibers temporarily when bound to myoglobin
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7
Q

What are the different types of contractions?

A
  • isotonic: muscle contracts and changes length; equal force

- isometric: muscle contracts but does not change length; change in force

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8
Q

What is concentric/eccentric isotonic contraction?

A
  • concentric: shortening contraction

- eccentric: lengthening contraction

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9
Q

what are the 3 different types of muscle fibers?

A
  • slow-twitch fibers (type II)
  • Fast-twitch glycolytic fibers (type IIb)
  • fast-twitch fatigue resistant fibers (type IIa)
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10
Q

What are the general characteristics of slow-twitch fibers? (type II)

A
  • always oxidative
  • resistant to fatigue
  • red fibers
  • abundant myoglobin
  • good blood supply
  • many mitochondria
  • slow ATPase activity; slow to contract
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11
Q

What are the general characteristics of fast-twitch glycolytic fibers (type IIb)

A
  • anaerobic respiration (glycolysis)
  • white fibers (less myoglobin)
  • poorer blood supply
  • fewer mitochondria than slow-twitch
  • more SR than fast-twitch
  • susceptible to fatigue
  • fast ATPase activity; contracts rapidly
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12
Q

What are the general characteristics of fast-twitch resistant fibers? (type IIa)

A
  • intermediate twitch fibers
  • intermediate oxidative capacity
  • intermediate amount of myoglobin
  • pink fibers
  • resistant to fatigue
  • rapid ATPase activity
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13
Q

What type of contraction happens when someone pushes against a wall but the muscles do not lengthen/shorten

A
  • isometric contraction
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14
Q

What type of contraction happens when someone flexes their bicep?

A
  • isotonic
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15
Q

What are the primary characteristics of fast-twitch fibers?

A
  • primarily glycolytic (prone to fatigue)

- or primarily oxidative (fatigue resistant)

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16
Q

What are the primary characteristics of slow-twitch fibers?

A
  • are oxidative and always resistant to fatigue
17
Q

Where are white fibers (fast-twitch) found?

A
  • certain hand muscles, muscles in the eye

- contract rapidly and are more susceptible to fatigue

18
Q

What is a threshold stimulus?

A
  • is the degree of stimulus that elicits an action potential in a single muscle fiber or single neuron
19
Q

What is the difference between fast-twitch fibers and slow twitch?

A
  • fast twitch: contract more rapidly due to the presence of more extensive SR and faster ATPase activity, and are more dependent on glycolysis and therefore are prone to fatigue
  • Slow twitch: slower to react but have many mitochondria and myoglobin and are therefore more able to produce ATP aerobically and are therefore more resistant to fatigue
20
Q

What are the general characteristics of smooth muscle?

A
  • shorter
  • single, centrally located nucleus
  • elongated with tapering ends
  • myofilaments randomly organized
  • lack striations
  • lack transverse tubulse
  • SR not well developed
21
Q

What are the general characteristics of multiunit smooth muscle?

A
  • muscle cells are well organized
  • function as separate units
  • found in irises of the eyes and large blood vessels
  • typically are stimulated by neurons or certain hormones
22
Q

What are the general characteristics of visceral smooth muscle?

A
  • composed of sheets of spindle-shaped cells held in close contact by gap junctions
  • the thick portion of each cell lies next to the adjacent cells
  • respond as a single unit
  • if one cell is stimulated, it might excite other adjacent cells
  • some displays a rhythmicity, which causes spontaneous repeated
    contractions
  • found in hollow organs such as the bladder, uterus, and digestive tract
23
Q

What is peristalsis?

A
  • rhythmic waves of muscular contraction in certain tubular organs
24
Q

What is vascular smooth muscle?

A
  • form of visceral smooth muscle

- found in the walls of many smaller blood vessels and plays a role in controlling blood flow and blood pressure

25
Q

What are the general characteristics of smooth muscle contraction?

A
  • doesn’t include troponin, and uses calmodulin instead
  • calmodulin binds to calcium ions released when the cell is stimulated, activating contraction
  • calcium needed for contraction diffuses into the cell from the extracellular fluid
26
Q

What special characteristics of visceral smooth muscle make peristalsis possible?

A
  • visceral smooth muscle is characterized by repetitive contractions, or rhythmicity, that transmits impulses from cell to cell via gap junctions
  • this enables peristalsis which is a wave of muscle contractions that moves the contents of tubular organs in a specific direction
27
Q

How is cardiac muscle similar to skeletal muscle?

A
  • both are striated
  • highly developed transverse tubules and SR
  • many mitochondria
  • their mechanisms of contraction are very similar
28
Q

How does cardiac muscle differ from skeletal muscle?

A
  • have less developed cisternae in their SR, so they store less calcium than skeletal muscle cells
  • contain larger transverse tubules; they bring in most of calcium through the extracellular fluid
  • only have one nucleus
  • connected by gap junctions in intercalated discs, and function as a unit
28
Q

How does cardiac muscle differ from skeletal muscle?

A
  • have less developed cisternae in their SR, so they store less calcium than skeletal muscle cells
  • contain larger transverse tubules; they bring in most of calcium through the extracellular fluid
  • only have one nucleus
  • connected by gap junctions in intercalated discs, and function as a unit
29
Q

What is the function of intercalated discs in cardiac muscle?

A
  • connects the ends of adjacent cardiac muscle
  • contain desmosomes that connect adjacent cells together, and gap junctions that provide passageways for ions
  • provide a mechanism for conducting the force of the contraction between the cells that make it possible the heart to contract as one unit
29
Q

What is the function of intercalated discs in cardiac muscle?

A
  • connects the ends of adjacent cardiac muscle
  • contain desmosomes that connect adjacent cells together, and gap junctions that provide passageways for ions
  • provide a mechanism for conducting the force of the contraction between the cells that make it possible the heart to contract as one unit
30
Q

What characteristics of cardiac muscle causes the heart to contract as a unit?

A
  • the transmission of impulses from cell to cell thru the gap junctions of the intercalated discs help the heart contract as a unit
31
Q

What two NT triggers smooth muscle?

A
  • ACh and norepinephrine (NE)
32
Q

What are the general characteristics of 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
  • self-exciting and rhythmic
  • longer refractory period than skeletal muscles
  • no sustained or titanic contractions
32
Q

What are the general characteristics of 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
  • self-exciting and rhythmic
  • longer refractory period than skeletal muscles
  • no sustained or titanic contractions
33
Q

What are the special characteristics of skeletal muscles?

A
  • striations: present
  • multiple nuclei
  • transverse tubule system is well developed
  • contracts and relaxes relatively rapidly
34
Q

What are the special characteristics of smooth muscle?

A
  • striations: absent
  • single nucleus
  • lacks transverse tubules
  • contracts and relaxes relatively slowly; some types are self-exciting and rhythmic
35
Q

What are the special characteristics of cardiac muscle?

A
  • striations: present
  • single nucleus
  • transverse tubules are well developed, intercalated discs connect cells
  • contracts as a unit, self-exciting, remains refractory until contraction ends

Biology anatomy/physiology (27 decks)

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