Muscle Physiology 2

Question 1

Explain what reverse action is

Answer 1

• when the distal segment is fixed, so the origin moves towards the insertion (pull-up)

Question 2

Give an example of reverse action?

Question 3

What is passive insufficiency?

Answer 3

the inability of inactive components (passive tissues) in antagonist to stretch enough to allow full range of motion at joints by agonist

Question 4

What is active insufficiency

Answer 4

the inability of a muscle to shorten enough to cause full ROM simultanously as muscle passes over 2 or more joints–> involves active (contractile elements)

Question 5

What is tenodesis?

Answer 5

• when passive tension in a msucle expereineces passive insufficnecy that is significant enough to cause th etendon to pull on the bone (in the direction of the passive tension)
• if the bone is not free to move, damage to muscles occur
• it is a function of passive insufficiency, but it usually occurs in the presense of active insuffiency

Question 6

Give an example of tenodesis

Answer 6

• EX) in the finger muscles, due to passive and active insufficiency of finger extensor/flexor muscles, obsevre pulling of finger bones in the direction of passive tension

Question 7

What are the 3 classifications of muscle-produced-movements?

Answer 7

• Postural: holding still and fixating. SO that the body appears motionless, but is actailly making slight movements (stand up and close eyes.. slight sway feel)
• Ballistic: movement initiated by fast and forceful muscle actions, but continued by momentum (baseball swing)
• Tension: requires constant muscular contraction throughout the motor action (fast and slow)

Question 8

What are examples of slow and fast tension movements?

Answer 8

• Slow tension is when you are writing, the tension is maintained as you hold the pencil and move it across the page. (another example is weight lifting)
• Fast tension: a jab in boxing where you punch fast and hard (tension is maintained for the quick movement)

Question 9

How can our muscles grade/modulate force?

Answer 9

• the number of motor units contracting
• the frequency of the stimulation to the fibers
• Frequency of stimuation (summation wave)

Question 10

Describe the summation wave?

Answer 10

• if subsequent stimuli are sent before the previosu relaxation period is complete, a stronger contraction will result
• Each succesding contraction adds force to the previous contraction
• This process does have a limit. Occurs when there is a max overlap between crossbridging and no more tension is possible.

Question 11

What is the overall contractile force and what is it influenced by?

Answer 11

Peak/max force a muscle can generate
* muscle and fiber size (cross-sectional measurement): a larger muscle has more active muscle fibers and produces stronger contractions
* proportion of active fibers (more active = more crossbridging = stronger force)

Question 12

What influences a speed of a contraction?

Answer 12

• Physiological and anatomical makeup: more FG motor units, develop tension more quickly, ect
• Individual differnece
• Training in activities (sprint drills)

Question 13

What is endurance, and what is it influneced by?

Answer 13

Endurance is the ability of a muscle to exert a force, consistently and repetitively over a period of time

It is influenced by:
* Contractile force: muscle that is stornger can repeatedly contract for a longer period of time
* Circulorespiratory function: muscles have efficient circulation to supply fibers with oxygen and nutrients and clear waste products
* Nervous system function: continued repeated transmission of implues to muscle fibers

Question 14

What is muscle tone?

Answer 14

• Muscle tone is the tension in a muscle at rest. The quality that gives firmness and shape to muscles
• measure of a muscles resistance to stretching while in passive state
• The continued passive and active partial contractions of muscles in resting state help maintain posture and balance and help us “stay ready”

variation in tone:
- well conditioned muscles- good tone
- poor conditioned = poor tone (flabby)

Question 15

What are the types of abnormal tone and give an example

Answer 15

Hypertonia:
* excessivly high muscle tone, muscles are stiff and is difficult to overcome resistance and move
* rigidity, difficult to stretch muscle, tighness throughout

Hypotonia:
* low muscle tone making it difficult to recruit strength to move (sit to stand becomes difficult bc muslces are “less ready” to move

Question 16

How can we increase our strength and endurnace of our muscles?

Answer 16

• increased by training
• not all muscles react the same
• when muscle use ceases or lessens, muscle atrophy and weakness occurs
• strength relates to age
• strength differs on each side of the body and develops slower in women
• contactiel force varies with length

Question 17

What are the 2 general types of exercise?

Answer 17

• Aerobic: endurance exercise, prolonged exercise fueled by o2. Mostly SO fibes, increase body metabolism, increases cardiovascaklr function, produces leaner muscles
• Anaerobic: high intensity and shorter duraction, fueld by glycogen. Mostly FG and FOG, increases size of individual fibers, produces large muscles

Question 18

what 3 things are needed for most efficient motor actions?

Answer 18

• muscle strength
• muscle endurnace
• muscle flexibility

Question 19

What are 3 main effects of disease/injury?

Answer 19

1. Immobilization
2. Overuse
3. Aging

Question 20

What are the major symptoms of movement disorders?

Answer 20

• pain
• atrophy
• spasms/cramps
• hypertonicity or hypotonicicty

Question 21

What are myopathic disorders?

Answer 21

Diseases of the skeletal muscle, involving degeneration of muscle tissue leading to movement problems

• Muscular dystrophy
• Polio

Question 22

What are neuromuscular disorders?

Answer 22

Occur due to the interruption of the signal between the CNS and the muscles. Includes injury to peripheral nerves, axob, probelms at myoneural junction. The muscle is intact but the relay is damaged
* Peripheral nerve injury/infalmation
* Guillian Barre syndrom
* Myasthenia Graves

Question 23

What are neurological disorders?

Answer 23

Result from damage to the CNS
* CP
* CVA
* MS
* TBI

Question 24

Give exampls of disorders of connective tissue

Answer 24

• sprain: (pull/tear on ligament)
• strain (pull/tear on tendon)
• tendonitis
• bursitis
• rheumatoid diseases

Question 25

What are consequences to lack of movement

Answer 25

• atrophy: wasting of muscle tissue
• contracture: pathological shorteniing of a muscle when held ina fixed position, the muscle is NOT stretched or elongagted and assumes a new shorter position. It is described in terms of the direction of the shortened muscles