5a - Motor System & Action

Question 1

what are the 5 main major division of the CNS?

Answer 1

• spinal cord
• cerebellum
• brainstem
• diencephalon
• cerebral cortex

Question 2

the cerebrum consists of which 2 components?

Answer 2

• cerebral cortex

- subcortical structures

Question 3

def: a continuous layer of wrinkled grey matter that covers the cerebrum and is responsible for higher functions of the CNS

Answer 3

cerebral coretex

Question 4

def: the ridge of a wrinkle in the brain

Answer 4

gyrus

Question 5

def: the groove between the gyrus

Answer 5

sulcus

Question 6

what are the 3 subcortical structures?

Answer 6

1. hippocampus
2. amygdala
3. parts of the basal ganglia

Question 7

the hippocampus is in charge of…?

Answer 7

memory and navigation

Question 8

the amygdala is in charge of…..?

Answer 8

emotions and memory

Question 9

the diencephalon consists of which 3 structures?

Answer 9

1. thalamus
2. sub-thalamus
3. hypothalamus

Question 10

def: a collection of nuclei that relay and integrate information between the cerebral cortex and the peripheral senses, spinal cord, and brainstem. all the sensory info passes through here before reaching the cortex, interacts with the basal ganglia to modify movement

Answer 10

thalamus

Question 11

def: includes the subthalamic nuclei, is part of the basal ganglia

Answer 11

sub-thalamus

Question 12

the brain stem consists of which 3 components?

Answer 12

1. hindbrain
2. midbrain
3. reticular formation

Question 13

what are the 2 components of the hindbrain?

Answer 13

• pons

- medulla

Question 14

what are the 2 components of the midbrain?

Answer 14

• tectum

- tegmentum

Question 15

def: the main connections to the cerebellum

Answer 15

pons

Question 16

def: regulates body functions to allow life

Answer 16

medulla

Question 17

def: has a superior colliculi for eye movement control and an inferior colliculi related to the auditory system

Answer 17

tectum

Question 18

def: has a red nucleus that forms the descending tract known as the rubrospinal tract and a substania nigra which is part of the basal ganglia

Answer 18

tegmentum

Question 19

what is the spinal cord orginization?

Answer 19

1. cervical
2. thoracic
3. lumbar
4. sacral
5. coccygeal

Question 20

how many nerves are in each section of the spinal cord?

Answer 20

• cervical = 8
• thoracic = 12
• lumbar = 5
• sacral = 5
• coccygeal = 1

Question 21

what is the role of the cervical nerves?

Answer 21

control upper limb muscles

Question 22

what is the role of thoracic nerves?

Answer 22

control the muscles of the trunk and chest

Question 23

what is the role of lumbar nerves?

Answer 23

controls lower limb and lower back muscles

Question 24

what do cervical and lumbar enlargements do?

Answer 24

these regions contain the neural circuits responsible for controlling the arms and legs

Question 25

def: made up of cell bodies of neurons

Answer 25

grey matter

Question 26

def: made up of unmyelinated or myelinated axons of the neurons

Answer 26

white matter

Question 27

where are the sensory and motor components within the grey matter?

Answer 27

the sensory component is on the dorsal side | the motor component is on the ventral side

Question 28

what are the 4 types of neurons within the spinal cord

Answer 28

1. local interneurons 2. propriospinal neurons 3. projection neurons 4. motor neurons

Question 29

def: axons are confined to the same or adjacent spinal segment

Answer 29

local interneurons

Question 30

def: neurons whose axons reach distant spinal segments

Answer 30

propriospinal neurons

Question 31

def: neurons whose axons ascend to higher brain centers

Answer 31

projection neurons

Question 32

def: neurons whose axon exits the nervous system to innervate mucles

Answer 32

motor neurons

Question 33

______ _____ neurons (alpha motor neurons) execute movement and have a specific organization within the spinal cord

Answer 33

spinal motor neurons

Question 34

cell bodies of the alpha motor neuron are clustered in motor neuron _____ or motor nuclei

Answer 34

pools

Question 35

where within the spinal cord do the neurons that innervate distant muscles reside?

Answer 35

the distant muscles are connected to neurons on the lateral sides of the spinal cord, the same goes for close muscles

Question 36

what path does somatosensory information take from the peripheral nervous system to connect to the spinal cord

Answer 36

via the dorsal root

Question 37

what path does motor output take to go from the CNS to the PNS?

Answer 37

ventral roots

Question 38

the motor neuron and the muscle fibers it innervates are called?

Answer 38

a motor unit

Question 39

where are muscle fibers innervated ?

Answer 39

at their mid point

Question 40

T or F: the fibers of 1 motor units can vary in twitch speed

Answer 40

false, they are all the same speed

Question 41

def: muscle fibers that can exert strong and fast movements but fatigue quickly due to their mitochondria concentration

Answer 41

fast twitch

Question 42

def: muscle fibers that can work for longer periods of time without fatigue

Answer 42

slow twitch

Question 43

if there are fewer muscle fibers within the unit, there is _____ _____ _____ control in that limb

Answer 43

fine detail control

Question 44

what dictates the power of a movement?

Answer 44

the number of motor units recruited

Question 45

explain the nerve muscle synapse:

Answer 45

1. impulse propagates down axon of alpha motor neuron 2. the end of the axon spreads out into multiple synaptic boutons 3. synaptic boutons release Ach into junctional fold on the muscle endplate 4. the Ach binds to the receptor channel 5. channel opens allowing increased inflow of Na+ 6. positive feedback loop that leads to an action potential

Question 46

what are 3 ways the CNS can increase muscle force?

Answer 46

1. recruit different sized motor units 2. recruit more units 3. increase frequency of action potentials in alpha motor neuron

Question 47

more fibers recruited in a larger motor unit = ?

Answer 47

more tension

Question 48

what kind of relationship is there between motor units and muscle fiber tension?

Answer 48

summative relationship

Question 49

smaller motor units have _____ threshold for activation

Answer 49

lower

Question 50

sustained muscle contraction is when : ? (2)

Answer 50

- maximum muscle tension occurs | - action potential frequency is very high

Question 51

what are the 5 types of neural circuits?

Answer 51

1. divergence 2. convergence 3. serial processing 4. parallel processing 5. reverbation

Question 52

def: a mechanism for spreading stimulation to multiple neurone, sensory afferent neutron spreading info to different regions of spinal cord and brain

Answer 52

divergence

Question 53

def: providing input from multiple sources to 1 neutron, descending tracts converging onto alpha motor neuron

Answer 53

convergence

Question 54

def: circuit from 1 neutron to 1, stretch reflex

Answer 54

serial processing

Question 55

def: a mechanism in which neurons or pools process the same information simultaneously

Answer 55

parallel processing

Question 56

def: positive feedback loop

Answer 56

reverberation

Question 57

what is the difference between disynaptic and monosynaptic?

Answer 57

- 1 synapse vs 2 - disynaptic = one of the neurons that is connected in the pathways inhibits activation then connects to an alpha motor neuron

Question 58

def: muscle spindle feels unexpected stretch, the 1a afferent is connected to the alpha motor neurone of the units and it activates leading to the muscles connecting and thus increasing joint stability

Answer 58

monosynaptic stretch relfex

Question 59

def: causes a limb to pull away from a painful stimuli

Answer 59

withdrawal reflex

Question 60

what are the steps of the withdrawal reflex?

Answer 60

1. nociceptor gets activated and then diverges its signal into 3 paths