week 3 control of movement and CNS Flashcards
function of the nervous system
coordinate systems internally and externally and control environment
what are the 3 divisions of the nervous system
somatic, special, visceral
what is the sensory division of the ns
afferent fibres sending impulses from receptors to the cns
what is the motor divison
efferent fibres transmitting impulses from sna to effectors
what is the peripheral ns
outside the cns
what does motor output do
initiates and transmits information to effectors from cns
the sensory nervous system is output or input
input
what is somatic sensory
input from ears, eyes ,skin
what is efferent
going away - to the organs
what does the sensory nervous system do
detect stimulus inputs from receptors
what is somatic sensory
eyes , ears, skin
what is visceral sensory
sensory input for the organs- nonconscious
what is motor division
efferent fibres impulses from cna to effectors
what is motor output
initiating and transmitting information from effectors to cns
what is somatic motor
voluntary and controlled - effectors skeletal muscle
what is autonomic motor control ouput
cardiac involuntary information - cardiac and bp - smooth muscle
what is an axon
carries electrical messages
what is the myelin sheath
layer of swann cells which help propagation of nerve conduction
what is the nodes called in meylin sheath
raniver
what is a synapse
a contact point between the axon and dendrite - send neurotransmitters from one nerve to another
what is a dendrite
the structures in which attach to the axons for transmission
what is resting membrane potential
the negative resting charge and different between inside and outside the cell
what is polarised
negative
what is depolarized
positive
what is hyperpolarized
extra positive
what is the resting negative charges for resting membrane potential in cell
-5 to 100mv
what’s the resting membrane potential for neurons
-45 to -75
why is the resting potentail always negative
sodium is higher outside and potassium is higher outside
what is resting membrane determined by
permeability and difference in NA and K
what is the permeability regulated by
proteins - allowing channels to open and or close
what happens when the channels open for sodium and potassium
the gradients will go from low to high concentration- changing resting membrane potential
at rest what channels are open
potassium
which channels are closed at resting membrane potential
sodium
what is constantly leaving the cell causing a negative charge
K
atp is used to minitor that what moving in and out the cell
Potassium
how many pottasium moving in
2
how many sodium moving in membrane potential
3
when does action potential occur
when a strong enough stimulus depolarized the cell
what does ap do for membrane potential
opens channels of sodium changing the cell to positive and depolarizing the cell
what is repolarizing
the cell returns to the original resting membrane potential - negative with more sodium on the outside and potassium inside and sodium channels close
the gates open means what is formed
action potential and then it can be stimulated again
what is the all or none law with axons
the conduction of nerve cannot go back when left
what is synaptic transmission
chemical messenger released from presynaptic membrane, causing depolarization
neurotransmitter scan be what 2 types
inhibitory and or exhibitory
what can excitatory postsynaptic potential promote
depolarization in 2 ways
what are the 2 types of depolarisation promotion
temporal summation and spatial summation
what is temporal summation
rapid repetitive excitation from a single excitatory presynaptic neuron
what is spatial summation
summing from EPSP FROM several different presynaptic neurons
what does inhibitory signals cause
hyperpolarization
Neurons with more negative membrane potential tend to resist what more
depolarization
what is joint proprioception for
helping understand where the body is and how t move it as well as receive information
what are free nerve endings for
touch pressure sensory
what are golgi tendons for
in joint ligaments - monitors force development
mechanical input examples
pressure or length of muscle
examples of information proprioception picks up
joint angle, length, tension
what do muscle spindles do
respond to changes in the muscle length preventing overstretching
what do muscle spindles consist of
extrafusal muscles
what are gamma motor neurons
stimulate the intrafusal fibres to contact the extrafusal fibers using an alpha motor neuron
what is the stretch reflex
causes reflex reaction to prevent overstretching
how does the stretch reflex occur
Spindles stimulate the spinal cord where sensory and motor neurons initiation contraction stopping overstretching
what do spindles help maintain
regulation of movement and posture
golgi tendons prevent
too much force
stimulation og GTO results in what
reflex relax of muscle
what signals help work with GTO
inhibitory and alpha motor neurons
gto can vary depending on what
strength
how does GTo action occur
sensory neurons and AP sent to spinal cord and all 3 types of neurons with alph moto cause muscle relaxation
inhibition of alpha motor neurons = what
relaxed tendons
msucle contraction is a response to what
ap in the spinal cord
what are muscle chemoreceptors sensitive to
changes in chemicals - H+ ions and CO2 + K
What do chemoreceptors do
inform CNS about metabolic muscular activity
a motor unit is with what
the muscle fibres it innervates
motor neurons are found where
in the spinal cord
what is a low ratio of innervation ratio and why is it small
finer movements - 23/1
what is an example of big innervation ratio and why
gross movements - 1000/1
what muscle fiber is recruited first
1
cerebrum and cerebral cortex is used for what
movement organization and storage of experience and recepting sensory information
what does the brainstem do
CV function, locomotion and muscle tone, posture and information receiving from sense
cerebellum is control of movement and
integration of sensory information
brain stem sections 3 are
pons, medulla ob. mid brain
what does midbrain do
connects pons and cerebral hemisphere and controlls response, movement and hearing
what does the medulla ob. do
autonomic function and relays signals from brain to spinal cord and helps movement
what does pons do
involved in sleep and autonomic function - also relays cerebellum and cerebrum
what is the dorsal root neurons
sensory
what is the ventral root neurons
innervate the spinal cord / motor
what is spinal tuning
the intrinsic neural network which helps refine movement after receiving stimulus
where does the withdrawal reflex occur
reflex arc - contraction of muscle through spinal cord
how does the withdrawl reflex occur
the sensory neurons from pain conduct ap to spinal cord
excitatory interneurons and alpha neurons innervate flexor muscle
