nervous system 7 Flashcards
what type of muscle cells are affected by the involuntary system
smooth muscle cells and cardiac muscle cells
how is the involuntary system different from the somatic nervous system?
axons travel from the CNS and pass the chemical message onto a second axon which reaches the cardiac/smooth muscle tissue
what is the point where the first nerve cell in the autonomic pathway passes the message onto the second nerve cell called?
the ganglion
what does the middle point between the two axons contain?
the ganglia contain a lot of nerve cell bodies
what are the first part of the pathway called?
PREGANGLIONIC NEURONS
what are the nerve cells that travel from the ganglion to the muscle tissue called?
POSTGANGLIONIC NEURONS
what are the 2 divisions of the autonomic nervous system called?
the SYMPATHETIC and PARASYMPATHETIC nervous systems
what does the somatic system involve?
the sympathetic nervous system involves relatively SHORT preganglionic axons and LONGER postganglionic axons.
(o)——–< (o)——————<
what does the parasympathetic system involve?
the parasympathetic nervous system involves relatively LONG preganglionic axons and short postganglionic axons
(o)———————–< (o)——<
what does the sympathetic motorneurones release (2) ?
preganglionic neurone releases ACh at the ganglion
postganglionic neurone releases noradrenaline (NA) at the target tissue
(few rare cases where postganglionic axon realises ACh at target tissue e.g. sweat glands)
what do the parasympathetic motorneurones release? (2)
preganglionic nuerone releases ACh at the ganglion, postganglionic nuerone releases ACh at the target tissue
what is the difference between the effects of the sympathetic and parasympathetic nervous system?
parasympathetic: effects are targeted ( can pinpoint specific organs and tissues )
sympathetic: effects are widespread ( when this system is activated it tends to affect all the tissues and organs it controls, global activation)
why are the sympathetic effects the way that they are? (2)
RELEASE OF HORMONES FROM THE ADRENAL GLANDS.
some sympathetic preganglionic fibers supply the control the release of noradrenaline and adrenaline directly into the circulation (producing widespread effects)
DIVERGENCE : each sympathetic preganglionic neurone sends branches to many sympathetic postganglionic nueorns ; thus the effects are amplified.
what type of processes are the sympathetic and parasympathetic involved with?
parasympathetic: involved with ANABOLIC processes (i.e. those concerned with saving and storing energy)
sympathetic: involved with CATABOLIC processes (i.e. those involved with the usage of energy ) e.g. increased heart rate, decreased digestive system activity. also associated with the ‘fight - or - flight’ response
what is the term for when relevant organs are supplied by both divisions of the autonomic nervous systems?
DUAL INNERVATION
