aos 1 : nervous systems and neutrons Flashcards
nervous system
a network of neurons that coordinate actions and transmit signals between different parts of the body, it consists of 2 divisions; Central NS & peripheral NS.
brain
responsible for memory, attention, concentration, language, spatial skills
spinal cord
3 major functions;
- transmits sensory information from PNS to brain
- transmits motor information from brain to PNS enabling movement
- reflex arc
sensory neurons
aka afferent neurons, send sensory info (from environment) from sense organs (skin receptors, eyes, ears etc) to the brain via the spinal cord (central NS) for further processing
motor neurons
aka efferent neurons, sends motor info (originating in primary motor cortex) via spinal cord to skeletal muscles in PNS enabling voluntary movement.
interneurons
can only be found in the CNS; they integrate information with other neurons ie. sensory and motor
dendrites
are the branched projections of neurons that receive input from other neurons
synapse
a junction that permits a neutron to pass on a chemical signal to another cell
neurotransmitters
chemicals which allow transmission of signals from 1 neutron to another
soma
the cell body which contains most of the cells genetic material
axon
a long projection of a neutron that conducts electrical impulses away from the soma
PNS
contains all the neurons outside the CNS
CNS
division of the NS which processes and interprets incoming information, stores memories, sends out neural information that initiates actions; made up of brain and spinal cord
somatic NS
a division of the PNS, responsible for voluntary movement & transmission of sensory information to CNS
autonomic NS
division of PNS which connects CNS to visceral muscles, which keeps vital organs going with conscious thought
visceral muscles
muscles that regulate the internal organs (without conscious thought) eg. heart, lungs
skeletal muscles
muscles attached to bones, which require a command from the brain (motor cortex) to move
sympathetic NS
a division of the autonomic NS which prepares the body for action, by increasing the body physiological arousal when the organism is under threat
parasympathetic NS
a division of the PNS which counterbalances the effects of the sympathetic NS and maintains an optimum level of functioning during low stress times
homeostasis
a steady internal body environment, that is maintained by the parasympathetic NS during low stress times
myelin
a white fatty substance that protects the axon and enhances the transmission of the electrical impulse
neurons
the core components of the NS
receptors
the structures on the dendrites neurons that recognise and bind specific neurotransmitters
neurohormone
similar to a neurotransmitter but it can be released into the bloodstream or in the brain via a presynaptic neuron
glutamate
the most abundant excitatory neurotransmitter in the CNS. it plays a key role in learning (LTP), memory, thinking and movement
GABA
the most abundant inhibitory neurotransmitter in the CNS. it regulates arousal, by counteracting the effects of glutamate
dopamine
a neurotransmitter that plays a key role in pleasure, reinforcement, movement, dependancy
inhibitory
when these types of neurotransmitters bind with postsynaptic neurons, they Arte less likely to fire an action potential
excitatory
when these types of neurotransmitters bind with postsynaptic neurons, they are more likely to fire an action potential
presynaptic
the sending neuron
postsynaptic
the receiving neuron
vesicles
storage sites of neurotransmitters that can be found in axon terminals
