Muscle Pt 6 (SM reflexes/hypertrophy/atrophy)

Question 1

What are 3 types of skeletal muscle adaptations?

Answer 1

1. Hypertrophy / atrophy
2. Increase in ATP synthesizing capacity
3. Nueral adaptations

Question 2

T/F there is a constant remodeling of muscle mass

Answer 2

True

Question 3

The constant remodeling of muscle mass is controled by protein ___ & ___

Answer 3

protein synthesis & degragation

Question 4

If you want to increase Muscle mass, protein synthesis must ___ degragation. How can this be done? which method is most common?

Answer 4

synthesis > degragation
1. hypertrophy = increase in diameter of already present muscle fiber = MOST COMMON
2. hyperplasia = increase in # of muscle fibers (via splitting) (u can’t make new muscle fibers via myosatellite cells, that only occurs during development) = unlikly

Question 5

Satellite cells vs. myosatellite cells

Answer 5

1. satellite = can cause regeneration of damaged muscle fiber by donating nuclius
2. myosatellite = can create new muscle fibers in developent phase

Question 6

Hytrophy is a skeletal mass adaptation that ___ muscle mass

Answer 6

increases muscle mass

Question 7

What is hypertrophy? What is it’s result?

Answer 7

hypertrophy = overload in stimulas
Causes = muscle fibers to expand outward setting off myogenic events that lea to increase in size of sarcomere & # of contraclile proteins

Question 8

In hypertrophy, # of muscle fibers . . . and # of myofibers within the one muscle fiber . . .

Answer 8

muscle fiber = remain constant
myofibril (myofiber?) within fiber= increases

Question 9

Expain the 3 myogenic events that lead to hypertrophy . . .

Answer 9

1. Increase in size/# of proteins (actin/myosin) = increase # of myofibrillar proteins
2. increased # of sarcomeres = increase myofibrils
3. increased sarcoplasmic storage (glycgen)

in humans = hypertrophy can’t be caused by an increased # of muscle fibers

Question 10

In which muscle type does hypertrophy occur fastest?

T1 or T2

Answer 10

Type 2 muscle is more succeptible to hypertrophy

Question 11

If you want to decrease muscle mass via atrophy = protein ___ must exceed ___

Answer 11

atrophy = mass decrease
protein degragation > synthesis

Question 12

What is atrophy?

Answer 12

Mechanism to reduce muscle mass that can be triggered by multiple stimulas

Don’t use it = lose it

Question 13

What are some causes of atrophy (decrease in muscle mass?)

Answer 13

1. Dissuse (immobalization, bedrest, unloading = no gravity)
2. Food deprivation
3. Muscle wasting due to chronic disease (Cachexia)

Question 14

Muscle mass is naturally effected by age = it ___ muscle mass. How does it do this?

Answer 14

age = decrease muscle mass
muscle mass replacedd with adipocyte tissue

Question 15

What are 3 myogenic events that lead to atrophy?

Answer 15

1. loss of nucleus
2. decreased amount of myofibril proteins (actin/myosin)
3. decrease in myofiber cross-section area

Question 16

ALS and Muscular dystrophy are examples of skeletal muscle __

Answer 16

atrophy
1. ALS = nueromuscular disorder = decrease use of muscle fiber
2. Muscular dystrophy = mutation that causes your fibers to easily break (non fixable)

Question 17

Voluntary skeletal muscle movement starts in the ____ —> sends signal to __/__ motr neurons –> signal sent to muscle = contraction

Answer 17

signal made in primary motor cortex –> upper motor nueron –> lower motor nueron –> muscle fiber = contraction

Question 18

Involuntary skeletal muscle movement occures via sensory nuerons which return a signal to spinal cord = alter lower motor nueron acticity

Answer 18

True

Question 19

Involuntary skeletal muscle movement occures at the __ lvl & voluntary movment a the __ lvl

Answer 19

involintary SM = spinal cord level
voluntary = primary cortex level

Question 20

The sensory recepotrs associated with involantary SM movement can respond to stimulus in 2 ways . . .

Answer 20

1 .stimulus says contraction is needed = spinal cord sends signal to CNS to activate motor nuerons for muscle fibers
2. stimulus senses relaxation is needed = input activates inhibitaory interneurons in the CNS which stop activty in motor neuron –> relaxation

Question 21

T/F activation/inhibitin of skeletal muscle can ONLY occur via input from brain (CNS / primary cortex)

Answer 21

False
Activation/inhibition can also occur in response to sesory receptors in spinal cord that don’t rely on brain input

Question 22

What are the 4 components of skeletal muscle reflexes?

Answer 22

1. sensory receptors
2. integrating center
3. efferent neurons
4. effectors

Question 23

Monosynaptic reflex vs polysynaptic reflex

Answer 23

monosynaptic = 1 sensory nueroun directly connecting onto the motor nueron in spinal cord [motor nueron joining with only 1 sensor]
polysynaptic = 1+ sensory nueron can attach to motor nueron (with use of interuerons) [motor nueron joins with 1+ sensores] = excitatory / inhibitory

synapse = connection of sensory nuerons onto somatic motor nueron

Question 24

What are the primary sensory receptors that cause skeletal muscle reflexes?

Answer 24

Proprioceptors

give info to CNS about position of limbs in space & effort exerted by SM

Question 25

What are the 3 important parts of proprioceptors?

Answer 25

1. Muscle spindle
2. Golgi tendon organ
3. Joint receptor s

Question 26

Found in propioceptors

Explain Muscle spindles

Answer 26

function: respond to changes in muscle legnth
stretch receptor
Info carried = send info to CNS about muscle length & their changes

Question 27

Muscle spindles repsond to ___ due to being __ receptors

Answer 27

respond to muscle length change due to strech receptors

Question 28

T/F Muscle spindles only activate when they sense a change in muscle length

Answer 28

False = they are tonically active, always on lookout for change = this impacts your resting muscle tone

Question 29

not 100%%% sure

What effect do muscle spindle cause?

Answer 29

if they sense change in muscle length –> they alter amount of contraction poduced

Question 30

What is the muscle spindle reflex?

Answer 30

the addition of a load sretches muscle & spindles = creating a reflex contraction
{muscle streched = spindle creates a contraction to offset load displacement)

Question 31

What 2 parts make up muscle spindles?

Answer 31

1. sensory nuerons wrapped around intrafusal muscle fibers
2. gamma motor nueron (starts contraction in response to length change)

Question 32

proprioceptor

What 2 parts make up the golgi tendon organ

Answer 32

1. sensory nueron interwoven among collagen fiber
2. connective tissue capsule

Question 33

What stimulus do golsi tendon organs respond to?

Answer 33

changes in muscle tension

Question 34

What do goli tendon organs do?

Answer 34

sense tension change –> control force within muscle & stability around joints

Question 35

What is the tendon golgi reflex?

Answer 35

protect the muscle from extra heavey loads by causing muscle to relax and drop load

Question 36

Are golgi tendons tonically active?

Answer 36

No

Question 37

What are joint receptors within propioreceptors

Answer 37

found in capsules and ligaments around joints & are activated by mechanical distortion that accompanies change in position of bone

sense change in position of bones

Question 38

What is reciprocal inhabition

Answer 38

when stimulus of sensory receptors lead to contraction of one muscle and inhibition in the antigonisitic muscle

Question 39

What are flexion reflexes? Name an example?

Answer 39

flexion reflex = pull limbs away from painful stimuli
Ex. Crossed extensor reflex= a flexion reflex in one line causes extension in the opposite limb (coordination of reflex = maintain balance)