Chapter 1 Flashcards

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1
Q

Epimysium

A

the connective tissue that surrounds a skeletal muscle

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2
Q

Muscle fibers

A

combine to create a muscle

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3
Q

fasciculus or fascicle

A

a bundle of muscle fibers

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4
Q

perimysium

A

the connective tissue that surrounds a fasciculus

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5
Q

endomysium

A

connective tissue that separates adjacent fibers

surrounds each muscle fibers

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6
Q

sarcolemma

A

the plasma membrane that surrounds the muscle fiber . Receives and conducts stimuli in the form of electrical impulses or action potentials

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7
Q

cytoplasm

A

contains the cell’s energy sources (ATP, phosphoreatine, glycogen, and fat droplets), mitochondria (sites of aerobic ATP), and sacroplasmic reticulum

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8
Q

sacroplasmic reticulum

A
stores calcium and regulates muscle action by altering the intracellular calcium concentration.
transverse tubules (T-tubules)
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9
Q

T-tubules

A

channels that form openings in the sarcolemma of the muscle cell

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10
Q

Myofibrils

A

columnar protein structures that run parallel to the length of the muscle fiber.
A bundle of myofilaments (myosin and actin filaments)

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11
Q

Myosin and Actin filaments

A

Myosin-Thick
Actin-Thin
arranged in a regular pattern along lngth of myofibril, giving it a striped appearance

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12
Q

Tropomyosin

A

regulatory protein
rod-like protein that spans the length of seven G-actin proteins along the length of the actin filament
*Each end is attached to toponin

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13
Q

Troponin

A

Causes the movement of the tropomyosin when bound to calcium away from the myosin binding sites on actin, allowing the myosin head to attach and pull on the actin

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14
Q

Sarcomere

A

basic contractile unit of muscle, extends from z-line to z-line

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15
Q

H-zone

A

The area of A- band that contains myosin but no actin

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16
Q

M-line

A

a dark line in Middle of the H-zone that helps align adjacent myosin filaments

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17
Q

I-band

A

spans the distance between the ends of adjacent myosin filaments, lies partly ni each of two sarcolmeres

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18
Q

G-actin proteins

A

form the actin filament

*binding site for myosin head

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19
Q

Neuromuscular junction

A

where communication between the nervous and muscle systems occur

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20
Q

Sliding Filament Theory

A

Most widely accepted theory: muscle shortens or lengthens when the filaments (actin and myosin) slide past each other, without the filaments themselves changing in length.

  1. Action potential passes, releasing ACh at neruomuscular junction into the synaptic cleft between the axon terminal and muscle fiber
  2. ACh goes across synaptic cleft and binds with ACh receptors
  3. Leads to generation of action potential along the sarcolemma, and through T-tubules which triggers release of stored calcium
  4. calcium binds with troponin
  5. causes a change in shape of troponin, and tropomyosin moves
  6. myosin head attaches and pulls the actin filament toward the center of the sarcomere
  7. ATP molecule binds, and myosin head detaches from actin and ATPase splits the ATP molecule, energizing myosin head.
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21
Q

Concentric muscle action

A

when the amount of force produced by a muscle is greater than the external resistance acting in the opposite direction

22
Q

Eccentric muscle action

A

When the amount of force produced by a muscle is less than an opposing external resistance, and muscle lengthens even as it attempts to shorten

23
Q

Isometric (static) muscle action

A

when force of muscle and external resistance are equal. The muscle neither shortens or lengthens

24
Q

DOMS

A

Delayed-Onset muscle soreness that results from a combination of connective tissue and muscle tissue damage followed by an inflammatory reaction that activates pain receptors.

25
Q

Oxidative capacity

A

biochemical property of muscle fibers to produce ATP aerobically. Need fibers that have large and numerous mitochondria and are surrounded by a supply of capillaries

26
Q

Myoglobin

A

delivers oxygen from muscle cell membrane to mitochondria

27
Q

specific tension

A

fibers may differ in the amount of force they produce relative to their size

28
Q

Type I muscle fibers

A

Slow fibers: slow oxidative or slow twitch fibers.

*high oxidative capacity and are fatigue resistant, but they contract and relax slowly

29
Q

Type IIa

A

fast oxidative glycolytic (FOG

*moderate oxidative and anaerobic capacity which does allow some fatigue resistance

30
Q

Type IIx

A
fast glycolytic (FG)
*purely anaerobic and highly fatigable
31
Q

neurons

A

most basic unit of the nervous system

*nerve cell

32
Q

motor neurons

A

conduct impulses from central nervous system to muscle

33
Q

sensory or afferent neurons

A

carry impulses from periphery toward central nervous system

34
Q

synapse

A

site of communication between two neurons

*neuromuscular junction is a synapse

35
Q

Dendrites

A

projections from neuron cell body that receive the excitatory or inhibitory signals

36
Q

Muscle spindle

A

specialized to sense changes in muscle length

  • contains intrafusal fibers
  • myotatic or streth reflex
37
Q

Golgi Tendon Organ

A

protects muscle from injury by sending info to the spinal cord which causes relaxation of the acting muscle and stimulation of the antagonist muscle

38
Q

Motor unit

A

all fibers of a single motor unit are of the same muscle fiber type. The different muscle fiber types have distinct anatomical and physiological characteristics which determine their functional capacities

39
Q

Motor unit recruitment

A

vary the number of motor units and muscle fibers that are activated.

40
Q

rate coding

A

increase the firing rate of motor units already activated

41
Q

size principle of motor unit recruitment

A

motor units are recruited in a specific order.
First, type 1 is recruited, followed by IIa and then IIx.
Training allows more units to be recruited!

42
Q

Skeletal System

A

206 bones

axial: skull, vertebral column, sternum and ribs
appendicular: upper and lower limbs,

43
Q

Osteoclasts

A

breakdown bone

44
Q

Osteoblasts

A

simulate bone synthesis

45
Q

Cortical

A

compact bone

hard and dense found in outer layers of the shafts of the long bones

46
Q

Cancellous

A

trabecular bone
spongy bone, found in the interior area of long bones, the vertebrae, and head of the femur.
*Site of hematopoiesis, synthesis of blood cells

47
Q

Osteoporosis

A

weakening of bones

exercise and nutrition can help!

48
Q

Wolff’s law

A

bone will adapt in response to stresses placed on it

ex: running will increase bone density

49
Q

Tendons

A

Connect muscle to bone

50
Q

Ligaments

A

connect bones to bone

formed from collagen and elastin