Neuro - Chapter 9

Front 1

__________ is the use of sensory information to prepare for movement.

Back 1

Feedforward

Front 2

__________ is the use of sensory information during or after the movement to make corrections either to the ongoing movement or to future movements.

Back 2

Feedback

Front 3

In people with complete loss of somatosensation below the neck, joint movements are ___________ & fast movements are ___________.

Back 3

joint mvmnts are: not well synchronized

fast mvmnts: decomposed (only 1 jt is moved at a time; to simplify control by eliminating interaction of torques)

Front 4

T/F_ Well-learned movements like walking and eating, normally require little conscious attention.

Back 4

TRUE. (Thats why sometimes we drive or walk somewhere and we dont know how we got there :)

Front 5

Well-learned/ automatic movements need little conscious attention but require continous integration (unconscious) of ________, __________, and _________ information with motor processing.

Back 5

visual
somatosensory
vestibular

Front 6

Loss of any of the 3 senses integral to automatic movement results in?

Back 6

ease and gracefullness of movement are affected

Front 7

What is the sequence of events in a motor act? (Hint: starts with a decision to do something)

Back 7

Decision (anterior part of frontal lobe) --> Motor planning areas --> Control circuits (cerebellum & basal ganglia) --> Descending motor pathways --> Lower motor neurons --> Skeletal Muscles

Front 8

T/F_ Voluntary movement is controlled from the bottom up (muscle to SC to brain).

Back 8

FALSE. From the top down (brain to SC to muscle)

Front 9

LMNs directly innervate _____________.

Back 9

skeletal muscle fibers

Front 10

UMNs are ________________.

Back 10

neurons whose axons travel in the descending tracts

Front 11

Descending tracts are clasified as ___________, ___________________, and ___________.

Back 11

postural/gross movement tratcs, fine movement & limb flexion tracts, and nonspecific UMN tracts.

Front 12

The postural/gross movement tracts control _________.

Back 12

automatic skeletal muscle activity

Front 13

Fine movement & limb flexion tracts control _____________.

Back 13

movements of the limbs and face

Front 14

What do Nonspecific UMNs do?

Back 14

facilitate all LMNs

Front 15

What areas of the brain constitute the motor control circuits? (2)

Back 15

cerebellum & basal ganglia

Front 16

What do the control circuits do in motor activity?

Back 16

they adjust activity in the descending tracts, resulting in excitation or inhibition of the LMN. (thus, they partially determine motor contraction)

Front 17

The plasma membrane of a muscle cell is called ___________.

Back 17

sarcolemma

Front 18

The sarcolemma has projections that extend into the muscle called _______________ which are adjacent to the __________ __________.

Back 18

T-tubules

sarcoplasmic reticulum

Front 19

Sarcoplamsic reticulums are storage sacs for what ion?

Back 19

Ca++

Front 20

What neurotransmitter is required to bind to receptors and depolarize the sarcolemma?

Back 20

ACh

Front 21

What is the sequence of excitation of a muscle cell by a neuron?

Back 21

ACh binds to sarcolemma --> sarcolemma depolarizes --> induces depolarization of T-tubules --> the change in electrical potential elicits release of Ca++ from sarcoplasmic reticulum --> Ca++ bind to receptors inside muscle fibers --> muscle contraction is initiated. :)

Front 22

Myofibrils consist of proteins arranged in __________.

Back 22

sarcomeres

Front 23

__________ are the functional units of muscle.

Back 23

sarcomeres

Front 24

The structural proteins of the sarcomere are _______, ______, and ______.

Back 24

Z line, M line, and titin

Front 25

The contractile proteins of the sarcomere are ________, _______, _________, and __________.

Back 25

myosin, actin, tropomyosin and troponin

Front 26

_________ forms the thick filaments which have specialized projections called ____________.

Back 26

myosin, crossbridges

Front 27

________ is the primary component of thin filaments.

Back 27

Actin

Front 28

In the resting muscle, most binding sites on actin are partially covered by _____________ preventing myosin from binding.

Back 28

tropomyosin

Front 29

__________ maintains the blocking position of tropomyosin.

Back 29

troponin

Front 30

________ needs to bind to troponin to cause a conformational change that pulls tropomyosin away from the crossbrigde binding sites allowing a muscle contarction to happen.

Back 30

Ca++

Front 31

Myosin heads
a) push themselves medially over actin on the center of the sarcomeres
b) pull actin medially towards the center of the sarcomere
c) pull tropomyosin & troponin toward the center of the sarcomere

Back 31

B-) pull actin toward the center of the sarcomere.

***Repeated attachment, swiveling and detachment produces the contraction.

Front 32

the amount of tension generated by a contracting muscle depends on ____________.

Back 32

the length of the sarcomeres. (when a sarcomere is at optimal length, it generates maximal tension).

Front 33

Resistance to stretch is called __________.

Back 33

stiffness

Front 34

T/F _ A stiff muscle generates less resistance to stretch than a normal muscle.

Back 34

FALSE. generates MORE resistance

Front 35

Active stiffness is initiated by ________________.

Back 35

neural signals: UMN firing and reflexes

Front 36

Intrinsic stiffness is produced by _____________.

Back 36

weak crossbridge attachments

Front 37

Passive stiffness arises primarily from _____________.

Back 37

resistance provided by titin.

***titin is a protein that maintains the position of myosin relative to actin, and prevents the sarcomeres from being pulled apart.

Front 38

When healthy, innervated muscle is continous immobilized in a shortened position for a prolonged period of time, sarcomeres ________________.

Back 38

sarcomeres disappear from the ends of myofibrils.

***the loss of sarcomeres is a structural adaptation to the shortened position so that the muscle can generate optimal force at the new resting length.

Front 39

If a muscle is immobilized in a lengthened position _________________.

Back 39

new sarcomeres will be added.

Front 40

___________ _________ is the amount of stiffness in resting muscle.

Back 40

muscle tone

Front 41

How is muscle tone assessed?

Back 41

PROM

Front 42

Normal resistance to stretch is produced by? (2)

Back 42

weak binding of myosin & actin, and titin.

Front 43

In relaxed standing, muscles have only _____________ & __________ stiffness.

Back 43

passive & intrinsic

Front 44

If a muscle is stretched after s prolonged period of immobility, the resistance of the muscle to stretch is _____________.

Back 44

increased.

***When a muscle remains immobile, weak actin-myosin bonds continue to form which increases stiffness.

Front 45

Stiffness increases after immobilization and briefly following ____________.

Back 45

a prolonged contraction

Front 46

A muscle contraction elicited by stretch of the spindle is called ______________.

Back 46

stretch reflex

Front 47

Cocontraction (the simultaneous contraction of anatgonists) can ____________ (increase or decrease) stiffness.

Back 47

increase

Front 48

The stretch shortening cycle consists of _____________.

Back 48

an eccentric contraction immediatley followed by a concentric contraction

Front 49

The stretch shortening cycle is used for _______________.

Back 49

to generate maximum muscle force