Chapter 8: Movement

Question 1

three categories of muscle

Answer 1

Smooth
Skeletal/Striated
Cardiac

Question 2

Smooth Muscle

Answer 2

controls digestive system and other organs

Question 3

Skeletal/Striated muscle

Answer 3

controls movements of the body in relation to the environment

Question 4

Cardiac Muscle

Answer 4

between other 2 categories with properties

Question 5

Need for antagonistic muscles

Answer 5

• important because there is no control to move the muscle in the opposite direction therefore you need another muscles to do that job
  ex) flexor and extensor

Question 6

fast muscles and conditions under which each is most useful

Answer 6

Fast twitch: fast contraction, fast fatigue

-anaerobic no O2 therefore fatigue quickly due to needed O2 for recovery (oxygen debt, sprinting)

Question 7

slow muscles and conditions under which each is most useful

Answer 7

• slow contraction
• no fatigue
• to not fatigue because they are aerobic (use O2)

Question 8

Proprioceptor

Answer 8

-receptor that detects position or movement of ta port of the body

Question 9

Proprioceptor in muscle

Answer 9

-detect stretch and tension of a muscle and sends messages to enable spinal cord to adjust its signals

Question 10

Muscle spindle

Answer 10

-receptor parallel to muscle that responds to stretch

Question 11

Golgi tendon organ

Answer 11

• responds to increase in muscle tension

- act as a brake against vigorous contraction

Question 12

roles of the primary motor cortex in the control of movement.

Answer 12

• elicits movement
• axons extend to brainstem and spinal cord which generate impulses that control muscles
• each spot does not control a specific muscle- they overlap

Question 13

role of posterior parietal cortex in the control of movement.

Answer 13

• planning movements
• keeps track of body position relative to the world
• controls aim

Question 14

role of supplementary motor cortex in control of movement

Answer 14

• planning and organizing rapid sequence of movements

- essential for inhibiting a habit when you need to do something else

Question 15

role of premotor cortex in control of movement

Answer 15

• most active right before a movement
• receives info about target that body is directing its movement towards and info about body’s current position and posture

Question 16

role of prefrontal cortex in control of movement

Answer 16

• active during a delay before a movement
• stores sensory info relevant to movement
• considers probable outcomes of possible movements

Question 17

implications of the timing of the readiness potential before the person is aware of making a decision

Answer 17

Readiness potential- produced by motor cortex before any voluntary movement

• on average 500ms before the movement
• brain activity responsible for the movement begins before the person’s conscious decision

Question 18

functions and cellular organization of the cerebellum

Answer 18

• contains more neurons than the rest of the brain combined
• motor structure (balance, coordination, timing, aim)
• help to tell if objects are same or different when in hands
• any sequence of rapid movements that require timing
• critical for certain aspects of attention

Question 19

organization of the cerebellum

Answer 19

• receives input from spinal cord + sensory systems from cranial nuclei and cerebral cortex
• neurons arranged in precise geometric pattern with multiple repetitions of same unit

Question 20

Purkinje Cells

Answer 20

-flat cells in sequential planes parallel to each other

Question 21

Parallel Fibres

Answer 21

-axons parallel to one another and perpendicular to planes of Purkinje Cells

Question 22

Action Potential Path in Cerebellum

Answer 22

• Action potential from parallel fibre excites 1 purkinje cell after another
• Purkinje cell transmits inhibitory message to cells in nuclei of cerebellum and vestibular nuclei in brainstem when it sends info to midbrain and thalamus

Question 23

Action Potential strength and distance in cerebellum

Answer 23

• depending on which and how many parallel fibres are active they might only stimulate 1st few Purkinje fibres or a long series
• more excited Purkinje= increase collective DURATION of response
• only 1st Purkinje= short message to target cells
• more than 1st= longer message to target cells

Question 24

Output of Purkinje cells

Answer 24

-timing of movement (onset and offset)

Question 25

Path in Cerebellum to brain

Answer 25

Parallel fibre -> Purkinje Cell (one after another) l l V V inhibitory message . vestibular nuclei in nuclei of cerebellum brain stem l l V V midbrain thalamus

Question 26

list the structures that comprise the basal ganglia

Answer 26

Caudate Nucleus Putamen Globus Pallidus

Question 27

Pathway of Basal Ganglia

Answer 27

``` Cerebral cortex l l V . V caudate . putamen nucleus l V globus pallidus l . l V . V . thalamus . midbrain l . V motor and prefrontal areas of cerebral cortex ```

Question 28

know the function of each and the general contribution of the whole system.

Answer 28

- output from globus pallidus to thalamus = inhibitory - neurons show a lot of spontaneous activity - caudate nucleus and putamen tell globus pallidus to stop inhibiting - basal ganglia selects a movement by stopping it being inhibited - very important for self initiated behaviours

Question 29

know the function of each and the general contribution of the whole system.

Answer 29

- output from globus pallidus to thalamus = inhibitory - neurons show a lot of spontaneous activity - caudate nucleus and putamen tell globus pallidus to stop inhibiting - basal ganglia selects a movement by stopping it being inhibited - very important for self initiated behaviours - have specialized cells for learning to stop and start a voluntary sequence of motions

Question 30

symptoms of Parkinson’s disease

Answer 30

- rigidity, muscle tremors, slow movements, difficulty initiating physical and mental activity, - slow on cognitive tasks such as imagining events or actions - loss of olfactory is early (first symptom) - depression - memory loss - not paralyzed or weak - difficulty with spontaneous movement

Question 31

immediate physiological cause of Parkinson’s disease

Answer 31

- gradual progressive death of neurons especially in substantia nigra - substantia nigra sends dopamine releasing axons to caudate nucleus and putamen - lose these axons and therefore lose dopamine

Question 32

genetic of Parkinson’s disease.

Answer 32

-genes have very small link

Question 33

environmental causes of Parkinson’s disease.

Answer 33

- exposure to toxins - MPTP chemical that body converts to MPP+ accumulates in and destroys neurons that release dopamine - exposure to hazardous herbicides and pesticides - people who smoke cigarettes and drink coffee have less of a chance of developing Parkinson's disease

Question 34

most common treatment for Parkinson’s disease and a problem with that treatment

Answer 34

-goal is to restore missing dopamine -L-dopa=precursor to dopamine is a main treatment for Parkinson's Problems with L-dopa -ineffective for some patients -does not prevent continued loss of neurons -unpleasant side effects (nausea, restlessness, sleep problems, low BP, repetitive movements, hallucinations, delusions)

Question 35

Other potential therapies for Parkinson's

Answer 35

- antioxidant drug to decrease further damage - drugs that directly stimulate dopamine receptors - drugs that inhibit glutamate or adenosine receptors - gene therapy : using virus to transfer into the brain a gene that increases dopamine synthesis - neurotrophins to promote survival and growth of remaining neurons - drugs that decrease apoptosis of remaining neurons - high frequency electrical stimulation of globus pallidus or subthalamic nucleus - possibility that transplanting brain tissue from aborted fetus would help

Question 36

describe the symptoms of Huntington’s disease

Answer 36

- severe neurological disorder - arm jerks, facial twitches, tremors spread to other parts of body and develop into writhing - tremors start interfering with walking, speech, and voluntary movements - limited ability to learn and improve new movements - depression, sleep disorders, memory impairment, anxiety, hallucinations, delusions, poor judgement, alcoholism, drug abuse, sexual disorders

Question 37

immediate physiological cause of Huntington’s disease

Answer 37

- gradual and extensive brain damage in caudate nucleus, putamen, globus pallidus, and cerebral cortex - genetic cause

Question 38

genetic cause of Huntington’s disease

Answer 38

- results from dominant gene on chromosome #4 - critical area of gene includes sequence of bases CAG which is repeated 11-24 times in most people, that repetition produces 11-24 glutamines - people with 35 CAG repetitions are considered safe - 36-38 repetitions might get it (probably not until old age) - 39+ repetitions are likely to get it - can predict whether a person will get it and when