nervous system Flashcards
what are the functions of the nervous system
relays information around the body ensuring systems maintain homeostasis
generates reactions by sending info through network of nerves
controls, regulates and communicates info within the body
what are the 2 types of nervous system
central nervous system
peripheral nervous system
what does the CNS contain
Brian and spinal cord
what neuron’s are in the CNS
inter/ relay neurons
what does the PNS contain
motor and sensory neurons
function of PNS
relays info throughout the body
function of the CNS
receives sensory information, analyses it, formulates a response and sends info through motor neutrons to the effectors
what are the three types of neurons
relay
sensory
motor
what is the function of sensory neurons
transmits info from a receptor to the CNS
transmits info into the CNS via affrentt neurons
what is the function of relay neurons
situated in the spinal cord and transmits info within the CNS.
what Is the function of the motor neuron
transmits info from the CNS to an effector
conducts info from the brain and spinal cord to the effector
provides instruction to the body parts on how react to a stimulus
function of cell body in neuron structure
contains the nucleus
function of myelin sheath
insulates a neuron increasing speed of the nerve impulse
function of Schwann cell
provides the myelin sheath
function of node of ranvier
gaps within the myelin sheath
function of axon
transmits nerve impulses away from the cell body
function of dendrite
receives incoming impulses for the neurone
function of synaptic vesicle
contains neuro-transmitters
function of synaptic end bulb
ballon like structure at the distal portion of an axon
how many pairs of spinal nerves are there
31
where are the sodium and potassium channels located
nodes of ranvier
what happens when the neuron is polarised
not sending a signal, resting
outside membrane excess sodium
inside membrane excess of potassium
what happens when the neuron is depolarised
neuron receives a nerve impulse
sodium rushed inside of membrane becoming more positive ie depolarised
what needs to be met so the action potential is achieved
threshold
what occurs in repolarisation
sodium gates begin to close
potassium gates open to allow potassium to flow out of cell
electrical charges begins to be restored to resting value
what is the electrical charges resting value
-70mV
how long does depolarising and repolarising approx take
about 1 millisecond
how many pairs of nerves are connected to the brain
12
function of cranial nerves
transmit info fro sensory organs
control muscles/glands
approximately how many neurons and neurogila do we have in the brain
100 billion neurons
1 trillion neuroglia
what percentage of the bodies o2 does neurons and neurogilia require
20% with it being 2% of the body’s weight
