nervous system Flashcards
nervous system
complex system of nerve cells that carries information to and from the brain and spinal cord to muscles, organs, and glands with the body
serves 3 principal functions
sensory input
integration
motor output
sensory neurons
bring in info from the outside world and send it to the spinal cord
chemoceptors
smell and taste
mechanoreceptor
touch, pressure, stertch
photoreceptors
light
thermoreceptors
heat
nociceptors
pain
auditory receptors
sound
alges
pain
analgesic
motor output
the brain decides to act and sends signals to muscles and/or glands with instructions on what to do
sensory neurons
eyes, ears and other sense organs
connector/interneurons
connect various neurons within the brain and spinal cord
motor
carry impulses from the brain and spinal cord to muscles and glans
the nervous system is divided into ___ main parts
2
central nervous system (CNS)
brain and spinal cord
peripheral nervous system (PNS)
all other nerves in the body
central nervous system
consists of brain and spinal cord which are protected by the skeletal system
3 meningeal layers of the CNS
dura mater - tough, outer layer
arachnoid - middle, less dense, web like appearance
pia mater - innermost, thin, compact
brain contains about ___ neurons
85-100,000,000,000 neurons
the brain
protected by many layers
canine and feline brains
not as developed as primates
mature at a faster rate
from birth
spinal cord
extension of the brain that is encased in the vertebrae
sensation recieved by sensory nerves transmitted to
spinal cord
transmitted either go to brain or to motor nerves where it
produces an action
PNS
all the nervous tissue in your body that isnt your brain or spinal cord
PNS is divided further into other categories based on
function
sensory division
picks up stimuli and communicates this info to the brain
afferent - signal is traveling toward the brain
motor division
sends info from the brain to the muscles and glands
efferent - signal is travelling away from the brain to muscle and gland
somatic nervous system
allows for voluntary control of muscles
autonomic
involuntary control of muscles
heartbeat, breathing, digestion
sympathetic division
gets the body excited (fight or flight)
parasympathetic division
helps the body to calm down and relax
signal pathway step by step
sensory neurons use sensory input to bring information to the body
the signal travels up the pathway toward the spinal cord (afferent)
from spinal cord up to the brain (interneurons)
the brain process that info (integration) and decides what to do
if action is to be taken, motor output sends a signal tto the target muscles or glands using motor neurons (efferent)
