THE AUTONOMOUS NERVOUS SYSTEM Flashcards
autonomic nervous system
a division of the peripheral nervous system that controls involuntary physiological functions to maintain internal homeostasis and respond to stress
functions of the afferent nerve
carries sensory impulses to the CNS
functions of the efferent nerve
carries electrical signals from the CNS to the effector
the two main divisions or parts of the PNS
somatic NS
autonomic NS
the autonomic NS is divided into
the adrenergic( sympathetic system)
the cholinergic(parasympathetic system)
the motor neurons of the ANS operate via conscious control, true or false
false, they operate via subconscious control
functions of the motor neurons of the ANS
Innervate smooth muscle, cardiac muscle, internal organs & skin
Make adjustments to ensure optimal support for body activities, by carrying signals to their effectors
the motor neurons of the ANS have …………….. as most of their effectors
viscera
the unique property of somatic motor neurons
they are highly myelinated
axons of the ANS are described as a two neuron chain, true or false
true
similarities in properties of the preganglionic neurons of both the sympathetic and parasympathetic ANS
they are myelinated
similarities in properties of the postganglionic neurons of both the sympathetic and parasympathetic ANS
they are generally unmyelinated
which neurotransmitter do all somatic nerve cells release, what is the effect of this
ACh
there is stimulatory or excitatory effect
which neurotransmitter is released by the preganglionic neurons of the ANS
ACh
which neurotransmitter is released by the postganglionic neurons of the ANS
noradrenaline or ACh
what effect does noradrenaline have on it’s target cells
an inhibitory effect
preganglionic neurons
the first neurons in the two-neuron chain of the ANS
ganglia
a cluster of nerve cell bodies (neurons) located outside the central nervous system (CNS)
are adrenaline and noradrenaline considered neurotransmitters?
why
no, adrenaline is a hormone and noradrenaline is a neurotransmitter
because, adrenaline is released straight into the blood stream
effector organs of the SNS
skeletal muscle
Most visceral organs are innervated by both sympathetic and parasympathetic fibres, true or false
true
the innervation of the visceral organs by both sympathetic and parasympathetic fibres result to?
dynamic antagonisms that precisely control visceral activity, thereby leading to physiological antagonism
which ANS system causes vasodilation and are responsible for erection of the penis and clitoris
the parasympathetic system
which ANS system causes ejaculation of semen in males and reflex peristalsis in females
the sympathetic system
which ANS system keeps the body energy usage low
parasympathetic system
which ANS system keeps the body energy usage high
sympathetic system
what are some activities carried out in the parasympathetic division
Digestion
Defaecation
Diuresis:increased production or excretion of urine by the kidneys
which ANS system largely innervates the internal organs
the parasympathetic
neurotransmitter released by the preganglionic neurons parasympathetic division
ACh
neurotransmitter released by the postganglionic neurons of the parasympathetic division
ACh
function of the parasympathetic division of the ANS
responsible for the “rest and digest” functions, promoting activities that conserve and restore energy.
which ANS division (system) is the vagal nerve a major component of
the parasympathetic system
functions of the vagal nerve
stimulates digestive glands
Increases motility of smooth muscle of digestive tract
Decreases heart rate Causes bronchial constriction
where are the vagal nerves found
Visceral organs of thorax & abdomen
which ANS division innervates every part of the body
the sympathetic
which neurotransmitters are released by the preganglionic neurons of the sympathetic division
ACh
which neurotransmitters are released by the postganglionic neurons of the sympathetic division
noradrenaline
location of the adrenal glands
they sit on top of the kidneys
cholinergic receptors
Receptors that mediate responses to acetylcholine
adrenergic receptors
Receptors that mediate responses to adrenaline and noradrenaline
types of cholinergic receptors
muscarinic
nicotinic
types of adrenergic receptors
alpha and
beta
noradrenaline and adrenaline can both bind alpha and beta adrenergic receptors, true or false
true
the two forms of alpha adrenergic receptors
alpha1
alpha 2
some effects on the body when alpha 1 adrenergic receptors are stimulated
Ocular: mydriasis
Blood vessels: vasoconstriction
Male genitals: ejaculation
Bladder neck and prostate: contraction
some effects on the body when alpha 2 adrenergic receptors are stimulated
inhibition of norepinephrine release
contraction of smooth muscle
where are alpha 2 adrenergic receptors located
on the presynaptic terminal
alpha 2 receptors are located in both the CNS and the PNS, true or false
true
effects of stimulating beta 1 adrenergic receptors on the body
increased heart output, like increased heart rate and conduction
effects of stimulating beta 2 adrenergic receptors on the body
vasodilation
glycogenolysis
bronchodilation
smooth muscle relaxation
where is adrenaline synthesised, and stored
which organ metabolises it
in the adrenal medulla
in vesicles in the adrenal medulla
the liver
where is noradrenaline synthesized and stored
the presynaptic terminal
stored in vesicles
which receptors do noradrenaline bind to on the;
presynaptic neuron
postsynaptic neuron
alpha 2
alpha 1 or beta 1
what enzyme breaks down noradrenaline
monoamine oxidase(MAO)
Sympathomimetics
substances/ drugs that mimic or enhance the effects of the sympathetic nervous system
examples of Sympathomimetics
salbutamol
epinephrine
primary organs affected by b1 stimulation
heart
kidneys
primary organs affected by b2 stimulation
lungs
blood vessels
uterus
liver
which adrenergic receptors are stimulated by epinephrine
alpha and beta
examples of drugs that are beta blockers
propranolol
metoprolol
which between metoprolol and propranolol are;
selective beta 1 antagonists
non selective beta antagonists
metoprolol
propranolol
autonomic tone
Steady day-to-day influence exerted by the autonomic system.
usually only one ANS division provides the tone
