MMB [019] Muscle Function in Health and Diseases Flashcards

1
Q

…..are low motor neurons

A

Alpha fibers

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2
Q

True or false ?

A single motor neuron can innervate both types of muscle fibers

A

FALSE :

-Each motor neuron innervates only one kind of muscle fibers

  • either (slow oxidative = red muscle fibers) or (fast glycolytic = white muscle fibers)
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3
Q

Concentric isotonic Contraction ?

A

Muscle shortens As lifting a load

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4
Q

Eccentric isotonic Contraction ?

A

-Muscle lengthens while contracting

-contractile activity resists stretch = lengthening contraction
AS lowering a load to the ground

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5
Q

Which type of isotonic Contractions is Most likely to cause muscle injury ?

A

Eccentric isotonic (lengthening)

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6
Q

Def Muscle Fatigue

A

It is the temporary decrease in muscle force of contraction due to previous contractile activity

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7
Q

The onset of muscle fatigue depends on ?

A

—1) Duration & intensity of contractile activity
— 2) Type of muscle fiber, some muscle fibers resists fatigue

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8
Q

Types of muscle fatigue ?

A

—A) Muscular fatigue

— B) Neuromuscular fatigue

—C) Central psychological fatigue

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9
Q

Explain Muscular fatigue

A

—Depletion of energy stores inside the muscle (glycogen)

— lactic acid accumulation with ↑ intracellular acidity  inhibition of the key enzymes in energy pathways

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10
Q

Why lactic acid accumulation in muscles further complicate energy manifestation ?

A

↑ intracellular acidity inhibits the key enzymes in energy pathways

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11
Q

Explain Neuromuscular fatigue :

A

— It is due to depletion of Acetyl choline (Ach) stores at the motor end plate as the rate of Ach release is more than its rate of synthesis

—It occurs during fast-powerful activities

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12
Q

When does Neuromuscular fatigue accur ?

A

It occurs during fast-powerful activities

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13
Q

Explain Central psychological fatigue

A

—Occurs when CNS no longer adequately activates the motor neurons supplying the working muscles

‘Athlete’s performance is not only dependent on the physical state of his muscles, but also, upon the will to win “ability to overcome psychological fatigue’

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14
Q

A special type of muscle fibers ?

A

—There is another type of skeletal muscle fibers called fast oxidative (type IIa)

—It has combined features from both fiber types and rare in human

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15
Q

Which muscle fiber type is of larger diameter ?

A

White muscle fibers typII

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16
Q
A
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17
Q
A
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18
Q

2 types of changes can be induced by training in muscle fibres:

A

•Changes in their vascular supply & ATP synthesis capacity

•Changes in their diameter (CSA)

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19
Q

hypertrophied muscle is better for ….
(initial strenth/endurance) but not for ….. (initial strenth/endurance)

A

I nitial strenth ,,,,, endurance

20
Q

What’s Myotonia ?

A

Genetic disease characterized by delayed muscle relaxation after voluntary contraction

21
Q

Explain Rigor mortis :

A

A condition that occurs after death due to ATP depletion

Without ATP, Ca ++ pumps are not functioning&raquo_space; ca ++ remains free in intercellular space&raquo_space; The exposed active sites on actin attract myosin cross bridges, which attach but are not able to detach&raquo_space; The body becomes stiff due to these bound myosin cross bridges&raquo_space; Muscle will remain rigor until the cellular proteins begin to breakdown usually within 24 – 48 hours.

22
Q

Why dead bodies become stiff ?

A

Muscles Without ATP, Ca ++ pumps are not function&raquo_space; The exposed active sites on actin attract myosin cross bridges, which attach but are not able to detach&raquo_space; The body becomes stiff due to these bound myosin cross bridges&raquo_space; Muscle will remain rigor until the cellular proteins begin to breakdown usually within 24 – 48 hours.

23
Q

Cause of LMNL ?

A

Damage of

AHCs (poliomyelitis) or α motor neuron (Diabetes Mellitus, alcoholism)

24
Q

3 major Effects of LMNL ?

A

1) Paralysis

2) Loss of all reflexes

3) Marked atrophy

25
Q

Paralysis associated with LMNL is (ipsi/contra lateral),,,, and is localized to a muscle or muscle group

A

Ipsilateral

26
Q

Why are all reflexes lost in LMNL ?

A

due to interruption of reflex arc

27
Q

Effect of LMNL on muscle tone ?

A

Hypotonia or Atonia (flaccidity)

28
Q

Effect of LMNL on deep reflexes (stretch reflexes) ?

A

Hyporeflexia or Areflexia

29
Q

How does LMNL cause Marked atrophy of muscle ?

A

due to:

-Loss of trophic factors released from damaged nerve

30
Q

Fasciculation and Fibrillation are two conditions associated with….

A

LMNL

31
Q

What’s Fasciculation ?

A
  • Jerky contraction of a group of muscle fibers due to pathological discharge of injured motor neuron
  • Felt & seen
32
Q

What’s Fibrillation and why does it happen ?

A
  • Contraction of an individual muscle fiber due to denervation hypersensitivity (sensitivity to circulating Ach)
  • Felt & not seen
33
Q

Causes of UMNL ?

A

Lesion from the cortex to AHCs or cranial nerve nuclei except cranial nerves (I, II, VIII) may be vascular lesion

34
Q

Paralysis associated with UMNL ?

A

Wide spread may be hemiplegia (one-sided paralysis) on the opposite side of the body

35
Q

Effect of UMNL on Muscle tone ?

A

Hypertonia

36
Q

Effect of UMNL on reflexes ?

A

Hyper-reflexia (Plantar reflex: positive Babinski sign)

37
Q

Effect of UMNL on muscle state ?

A

No wasting due to presence of hypertonia, besides muscle can contract reflexly

38
Q

what’s hemiplegics ?

A

one side paralysis

39
Q

quadriplegics ?

A

Paralysis of 4 limbs

40
Q

PROM therapy ?

A

Passive Range Of Mobility , the dr moves the patient passively because he can’t do it himslef

41
Q

The main aim of mobility in PROM therapy ?

A

to prevent the deposition and shrinkage of the connective tissue which is normally laid in any immobilized limb

42
Q

Pathological factors that favor limitation of joint movement ?

A

➢ Oedema

➢ Trauma

➢ Impaired circulation (Age is associated with progressive decrease of circulation and therefore more restriction of motion)

43
Q

Muscle strength depends on the ….of a muscle and on the motor unit recruitment

A

cross-section ,,

44
Q

CEREBRAL PALSY ?

A

• This is a neurological disorder affecting motor coordination and movement.

• It is caused by an insult to the CNS of the fetus which can be during pregnancy or during delivery or early months after delivery

• The muscles become spastic and tight and it can be accompanied by different affection of other CNS areas as speech centre and hearing or visual centres

45
Q

PhysioTherapy of CEREBRAL PALSY children ?

A

Cerebral palsy children need stretching of the spastic tight muscles

46
Q

Some CP patients require special training programs for standing and for mobility :

A

➢ Walkers

➢ Crutches

➢ Canes

➢ Wheelchairs