the nervous system Flashcards
functions of the nervous system
together with the endocrine (hormonal system) - it controls all bodily functions and maintains homeostasis
components of nervous system
brain, spinal cord and vast network of peripheral nerves
homeostasis
how the body maintains balance between bodily systems to ensure they will operate efficiently and effectively
when the body needs to increase the activity of a particular function, the nervous system will send a series of stimulatory messages or impulses to accelerate the rate at which this function
same process with slowing down - sends suppressing or inhibitory messages
sensory input
stimuli is delivered to brain via series of nerves
sensory neurons that detect stimuli monitor a wide variety of areas like temperature, light and sound
interpretation
sensory input is converted into electrical signals called nerve impulses that are transmitted back to the brain. it is here that the signals are consolidated to create sensations, thoughts, decisions, and memories
CNS
Central Nervous System = brain and spinal cord
PNS
Peripheral Nervous System = all nerves outside brain and spinal cord
starts with 31 pairs of nerves from spinal cord and through intervertebral space - carry electrical signals to and from every cell in the body
nerves connect with adjacent nerves via microscopic junctions called ‘synpases’ - means adjacent nerves can communicate with each other via a ‘neurotransmitter’
separated into a ‘sensory division’ and ‘motor division’
sensory division
delivers information about things like touch, pressure and body position to the CNS for analysis and interpretation
motor division
sends motor signals towards the bodily tissues like glands, organs, blood vessels and skeletal muscles. can be voluntary or involuntary
motor output
once the sensory information has been processed by the CNS, nerves are recruited to voluntarily contract the skeletal muscles (or involuntarily if a reflex)
integration of the CNS and PNS
whilst they are separate systems they are part of an integrated system that deliver
- sensory input to the CNS
- interpretation and analysis of the input
- motor output, a appropriate to the sensory information
somatic division
controls skeletal muscles and some sensory organs
also referred to as ‘voluntary motor system’
also mediates involuntary reflex actions the patella tendon knee jerk.
autonomic division
controls all involuntary actions
further classified as stimulatory or inhibitory where the activity of the target organ/tissue is increased or decreased respectively.
those messages which stimulate tissues to increase their activity are classified as ‘sympathetic’, whereas those messages which are inhibitory are classified as ‘parasympathetic’
stages of integration of central and peripheral divisions of nervous system
look at diagram pg 91
structure of a motor neuron
nucleus = info about movement stored
‘motor learning’ / ‘muscle memory’ = the process by which information is stored in these cells
receive incoming chemical messages from adjacent nerves at their dendrites. this electrical info is then transmitted through the cell body and along the nerves axon until it reaches the terminal end of nerve cell.
it is at the terminal end that the nerve releases the chemical ‘neurotransmitter’, which passes across the synapse to stimulate the dendrites of the nerve in sequence
