MMB [019] Muscle Function in Health and Diseases

Question 1

…..are low motor neurons

Answer 1

Alpha fibers

Question 2

True or false ?

A single motor neuron can innervate both types of muscle fibers

Answer 2

FALSE :

-Each motor neuron innervates only one kind of muscle fibers

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

Question 3

Concentric isotonic Contraction ?

Answer 3

Muscle shortens As lifting a load

Question 4

Eccentric isotonic Contraction ?

Answer 4

-Muscle lengthens while contracting

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

Question 5

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

Answer 5

Eccentric isotonic (lengthening)

Question 6

Def Muscle Fatigue

Answer 6

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

Question 7

The onset of muscle fatigue depends on ?

Answer 7

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

Question 8

Types of muscle fatigue ?

Answer 8

—A) Muscular fatigue

— B) Neuromuscular fatigue

—C) Central psychological fatigue

Question 9

Explain Muscular fatigue

Answer 9

—Depletion of energy stores inside the muscle (glycogen)

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

Question 10

Why lactic acid accumulation in muscles further complicate energy manifestation ?

Answer 10

↑ intracellular acidity inhibits the key enzymes in energy pathways

Question 11

Explain Neuromuscular fatigue :

Answer 11

— 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

Question 12

When does Neuromuscular fatigue accur ?

Answer 12

It occurs during fast-powerful activities

Question 13

Explain Central psychological fatigue

Answer 13

—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’

Question 14

A special type of muscle fibers ?

Answer 14

—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

Question 15

Which muscle fiber type is of larger diameter ?

Answer 15

White muscle fibers typII

Question 16

Answer 16

Question 17

Answer 17

Question 18

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

Answer 18

•Changes in their vascular supply & ATP synthesis capacity

•Changes in their diameter (CSA)

Question 19

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

Answer 19

I nitial strenth ,,,,, endurance

Question 20

What’s Myotonia ?

Answer 20

Genetic disease characterized by delayed muscle relaxation after voluntary contraction

Question 21

Explain Rigor mortis :

Answer 21

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.

Question 22

Why dead bodies become stiff ?

Answer 22

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.

Question 23

Cause of LMNL ?

Answer 23

Damage of

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

Question 24

3 major Effects of LMNL ?

Answer 24

1) Paralysis

2) Loss of all reflexes

3) Marked atrophy

Question 25

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

Answer 25

Ipsilateral

Question 26

Why are all reflexes lost in LMNL ?

Answer 26

due to interruption of reflex arc

Question 27

Effect of LMNL on muscle tone ?

Answer 27

Hypotonia or Atonia (flaccidity)

Question 28

Effect of LMNL on deep reflexes (stretch reflexes) ?

Answer 28

Hyporeflexia or Areflexia

Question 29

How does LMNL cause Marked atrophy of muscle ?

Answer 29

due to:

-Loss of trophic factors released from damaged nerve

Question 30

Fasciculation and Fibrillation are two conditions associated with….

Answer 30

LMNL

Question 31

What’s Fasciculation ?

Answer 31

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

Question 32

What’s Fibrillation and why does it happen ?

Answer 32

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

Question 33

Causes of UMNL ?

Answer 33

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

Question 34

Paralysis associated with UMNL ?

Answer 34

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

Question 35

Effect of UMNL on Muscle tone ?

Answer 35

Hypertonia

Question 36

Effect of UMNL on reflexes ?

Answer 36

Hyper-reflexia (Plantar reflex: positive Babinski sign)

Question 37

Effect of UMNL on muscle state ?

Answer 37

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

Question 38

what’s hemiplegics ?

Answer 38

one side paralysis

Question 39

quadriplegics ?

Answer 39

Paralysis of 4 limbs

Question 40

PROM therapy ?

Answer 40

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

Question 41

The main aim of mobility in PROM therapy ?

Answer 41

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

Question 42

Pathological factors that favor limitation of joint movement ?

Answer 42

➢ Oedema

➢ Trauma

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

Question 43

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

Answer 43

cross-section ,,

Question 44

CEREBRAL PALSY ?

Answer 44

• 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

Question 45

PhysioTherapy of CEREBRAL PALSY children ?

Answer 45

Cerebral palsy children need stretching of the spastic tight muscles

Question 46

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

Answer 46

➢ Walkers

➢ Crutches

➢ Canes

➢ Wheelchairs