Module 3: The Autonomic Nervous System Flashcards
Where is glucose stored?
Liver
which nervous system does the ANS belong in?
PNS
what does the ANS control?
- visceral motor nerve fibers
e.g. smooth muscle, organs and glands
what are the 2 branches of the ANS?
- sympathetic
- parasympathetic
what is the purpose of the ANS?
to keep the body functioning in a healthy range (homeostasis)
what is the 5 step process of the ANS?
- stimulus: hot day
- receptor: detects heat
- input: sends to brain
- output: brain increases sweatign to cool body
- response: sweating cools body, back to homeostasis
what is the sympathetic division in charge of?
fight or flight: mobilises body to action
what is the sympathetic division activated by?
excercise, excitement, anxiety, fear, embarrassment, etc.
what as the effects of the sympathetic division being activated?
adrenaline release, heart rate increase, dry mouth, cold sweats, dialated pupils
how does the sympathetic division effect your body during excercise?
diverts blood away from gut and kidneys to skeleteal muscles an heart, dialates branchioles for more breathing, liver releases glucose for energy
What is the parasympathetic division in charge of?
keeps body energy low as possible
what is the effect of the parasympathetic division being activated?
urination, defecation, digestion, pupil constriction, reduced heart rate, reduced respiratory rate, glucose stored
what activates the parasympathetic division?
pleasure and relaxation
what is the anatomy of the neurons for the ANS?
2 neurons, pre and post ganglionic.
Preganglionic fiber is in the CNS and synapses with the post ganglionic fiber in the PNS
postganglionic axon travels to effector organ
what is the exception to the rule for 2 neurons in the ANS?
when the sympathetic division is innervating the adrenal medulla (gland on top of kidney) only 1 neuron and causes a release of adrenaline or noradrenaline
what are the 2 main neurotransmitters in the ANS?
- acetylecholine (ACh)
- noradrenaline/norepinephrine(US) (NA/NE)
which neurons release acetylecholine?
- all preganglionic neurons for both sympathetic and parasympathetic
- in the postgangionlinc neurons for the postganglionic only (except sweat glands)
what is the purpose of adrenaline and noradrenaline?
a hormone that produces a slower response to fight or flight responses.
which 2 receptors does acetlycholine bind to?
- nicotinic
- muscarinic
what does niotinic bind to?
ligand gated ion channels
why are they called nicotonic?
first thing that was found that they bind to: nicotine
are nicotinic receptors excitatory or inhibitory? what is the effect?
- excitatory
- cause Na+ channels to open and cause depolarisiation
where are nicotinic receptors found?
- all postganaglionic neurons
- adrenal medulla
- skeletal cells of somatic nervous system
are muscarinic recptors excitatory or inhibitory?
can be either, depends on the g-protein it couples to
where are muscarinic receptors found?
on organs in the parasympathetic and postganglionic neurons
also in sweat gland
what are the 2 classes of adrenergic receptors in noradrenaline nad adrenaline?
Alpha 1, Alph 2
Beta 1, Beta 2 and Beta 3
what are adrenergic receptors?
G protein coupled receptors
what is the effect of the adrenergic receptors?
depending on the receptor and cell type depends on the reaction e.g. noradrenaline binds of cardiac beta, which increases heart rate. adrenaline bind to bronchial beta 2 and dialates bronchi
which nervous system can we give drugs to make an effect on the body?
The ANS
do organs have 1 or 2 innervations from ANS?
2
what is tone in ANS?
when the parasympathetic and sympathetic are firing at the same time, to get control of a system
how does tone in the ANS affect the body?
it works precisely with visceral activity, normally 1 division dominating the other
what does it mean when the sympathetic division is dominant in the ANS?
it means you’re in the fight or flight state
which system in the ANS is faster?
Parasympathetic because it turns off first so the sympathetic division can start working
where is the ANS controlled?
bottom of the brain: hypothalamus and brain stem
what happens if there is brain damage in the hypothalamus and brain stem?
death, because your ANS won’t be working properly
does the spinal cord have any interation with the ANS?
Yes, urination and defection doesn’t go all the way to the brain
where are emotional responses activated?
Limbic system
