Chapter 8: Movement Flashcards Preview

Brain And Behavior > Chapter 8: Movement > Flashcards

Flashcards in Chapter 8: Movement Deck (41):
1

Muscles

Composed of fibers; each fiber is innervated by one motor neuron

2

Smooth muscle

internal organs, long, thin cells

3

Skeletal/striated muscle

main movers, long cylindrical fibers with stripes

4

cardiac muscle

heart; fused fibers contract together

5

Motor Unit

smallest functional unit

6

Neuron meets fiber at ?

Neuromuscular junction

7

Antagonistic muscles work in concert

Flexors vs Extensors

8

Myasthenia Gravis

autoimmune disorder; antibodies against ACh receptors

9

Symptoms of Myasthenia Gravis

progressive weakness, rapid fatigue of skeletal muscles

10

Physiological Basis of Myasthenia Gravis

fewer ACh receptors, morphological changes at synapse, action of Acetycholinsterase

11

Mammalian Muscles

Fast-twitch fibers and slow-twitch fibers

12

Fast-twitch fibers

contract and relax rapidly, anaerobic (no oxygen), fatigue rapidly, generate greatest force, (ex sprinting)

13

Slow-twitch fibers

longer contraction time, aerobic (oxygen), resistant to fatigue, generate much less force (walking)

14

Proprioceptors

Sensitive to position and movement of muscles; detect muscular stretch and tension; allows spinal cord to adjust signal

15

Two primary types of proprioceptors

Muscle spindles and golgi tendon organs

16

Muscle Spindles

parallel to muscle, senses stetch; muscle stretched -> signal motor neuron in spinal cord --> muscle contraction; negative feedback --> stretch causes contraction; stimulates Stretch reflex (knee-jerk)

17

Golgi Tendon organs

in tendons (connects muscles to bone), senses tension; vigorous muscle contraction --> signal spinal cord inhibitory interneurons --> inhibit motor neuron (inhibits contraction); negative feedback --> tension causes muscle relaxation; protects against vigorous contraction

18

Reflexes

consistent, automatic response to stimulu; allied reflexes occur together/ elicit each other

19

Ballistic movements

executed as a whole; cannot be corrected/not sensitive to feedback

20

Central Pattern Generators

neural mechanisms that generate rhythmic motor patters (wet dog shake, wing flapping in birds)

21

Major motor areas in FOREBRAIN

Cortex, basal ganglia

22

Major motor areas in MIDBRAIN

Substantia Nigra; Red Nucleus; Reticular Formation

23

Major motor areas in HINDBRAIN

Cerebellum, Reticular formation, vestibular nucleus

24

Primary Motor Cortex

coordinated movements in several muscles leading to specific outcome

25

Posterior Parietal Cortex

coordinating movement through environment based on visual input

26

prefrontal cortex

involved in planning movement

27

premotor cortex

involved in planning movement

28

supplementary cortex

involved in preparation for rapid sequences of movement

29

Dorsolateral Tract

carries axons from primary motor cortex and red nucleus to spinal interneurons controlling spinal motor neurons; THEN cross over to contralateral side at pyramids in ventral portion; THEN courses down dorsolateral portion of white matter of spinal cord; THEN controls movement of distal limbs (hands,fingers,toes)

30

Ventromedial Tract

Carries axons from primary motor cortex, axons from vestibular nucleus, tectum, reticular formation; THEN synapse on spinal interneurons controlling spinal motor neurons; THEN come axons cross, some dont, providing bilateral innervation; THEN courses down ventromedial portion of white matter of spinal cord; controls proximal limbs and axial musculature (neck, shoulders, trunk)

31

Motor functions of cerebellum

contains more neurons than rest of structures of brain combined; involved in: control of rapid eye movement, timing, establishment of new motor programs

32

Caudate Nucleus

primary input area; receives info from sensory areas of thalamus and cortex; receives important dopaminergic projection from substantia nigra in midbrain

33

putamen

same function

34

globus pallidus

primary output area; sends info to thalamus, which sends info to motor and prefrontal cortex, also midbrain

35

role of basal ganglia

organization of action sequences into chunks; inhibition of specific motor responses

36

Parkinson's disease

degeneration of the dopaminergic neurons in the substantia nigra projecting to the caudate nucleus and putamen

37

symptoms of parkinson's disease

rigidity; muscle tremors; slow movements; sometimes cognitive deficits; difficulty initiating movement; sometimes depression

38

frequency of parkinson's disease

1/100 above age 50

39

Causes of Parkinson's disease

early onset has genetic component; possible environmental influence

40

Treatment for Parkinson's disease

L-dopa: crosses blood-brain barrier, where its absorbed by neurons and can increase dopamine production; cant restore degenerated neurons; effectiveness declines as disease progresses

41

Other possible treaments

Antioxidant drugs - decrease further damage; dopaminergic agonists - can cross blood-brain barrier; glutamate or adenosine antagonists; inactivating electrical stimulation of globus pallidus; neurotrophins - promote growth and survival of neurons; drugs that decrease apoptosis; fetal tissue transplants; drugs that block calcium channels abundant in elderly brains; drugs that stimulate cannabinoid receptors