The Nervous System: Structure Flashcards
What does it take for an organism to behave? (simple organism)
- register the environment (magnetic fields)
- transform of signals (experience internal change)
- generate appropriate responses (this is key for behaviour)
What is it good for?
- to interact flexibly with environment
What goes on in a complex organism?
- attaches to cell membrane of specific receptor cell
- chemical change inside cell causes more in other cells (nerve impulse along neural pathways)
- eventually results in activation of output systems
What goes on in a simple cell organism ?
E.g. Plants (no NS)
- molecule attaches itself to cell membrane
- chemical change at membrane= cascade inside cell
- results in specific behaviour (such as change in direction for more food)
What is the direction of signal transfer? for a small number of neurons
same direction, down pathway
What is the direction of signal transfer? for a network
not one direction as NS is a network so all different directions
What is the simplest form of a NS?
Uncentralised: have no nerve centre that controls activity of groups of other neurons and actions of distant body parts
What form does a complex NS have?
PNS and CNS seperated. Functionally it is more hierachially organised and specialised to direct communication between neurons and body parts
What can we do without a brain?
- Monosynaptic connection: knee jerk reflex
- receptors inside muscle fibre get stretched and triggers reflex (repeats) - Polysynaptic reflex arc: complex processing in spinal cord
- receptor + effector in different places, shows simple forms of learning
- several synapses between sensory + motor neuron - learning (walking)- only in response to stimulation e.g. cats walking even when connection is cut (spinal cord is useful)
Which organism can learn to change their behaviour?
Complex (animals)
Which organism can produce specific behaviours that correspond exactly to specific stimulation?
Simple (plants)
