Transcript autonomic nervous system

AUTONOMIC NERVOUS SYSTEM
by : dr.Miyko P
By : dr. Miyko Prastyawan
Somatic vs. Autonomic




Voluntary
Skeletal muscle
Single efferent neuron
Axon terminals release
acetylcholine.
 Always excitatory
 Controlled by the cerebrum
 Involuntary
 Smooth, cardiac muscle;
glands
 Multiple efferent neurons
 Axon terminals release
acetylcholine or
norepinephrine
 Can be excitatory or inhibitory
 Controlled by the homeostatic
centers in the brain – pons,
hypothalamus, medulla
oblongata
Somatic vs. Autonomic
Autonomic Nervous System
Sympathetic
 “Fight or flight”
 “E” division: Exercise,
excitement, emergency,
and embarrassment.
Parasympathetic
 “Rest and digest”
 “D” division: Digestion,
defecation, and
diuresis.
 Maintains normality of
body functions.
Exceptions to the Rule
Exception to the dual innervation rule:
Sweat glands and blood vessel smooth muscle
are only innervated by sympathetic and rely
strictly on up-down control.
Exception to the antagonism rule:
 S & P work cooperatively to achieve male sexual
function.
 Parasympathetic is responsible for erection.
 Sympathetic is responsible to ejaculation.
ANS Structure
Both ANS divisions share the same general
structure.
Autonomic pathways always consist of 2
neurons in series.
(Somatic only have 1 neuron)
They synapse in an autonomic ganglion
outside the CNS.
The 1st neuron in the autonomic pathway is
the preganglionic neuron,
• Cell body in CNS,myelinated, and projects to
the autonomic ganglion.
While the 2nd neuron is the postganglionic
neuron.
• Cell body in autonomic ganglion,
unmyelinated, and projects to the effector
(tissue target).
Sympathetic vs. Parasympathetic
Structural Differences
The Differences
Asal dari SSP
Sympathetic
T1 - L2
(thoracolumbar)
Parasympathetic
Brainstem,
S2 - S4
(craniosacral).
Letak ganglion autonom Paravertebral –
(dimana neuron pre dan in sympathetic
post-sinaps bertemu)
Chain.
Dekat jaringan target
Panjang serabut
preganglionic
Pendek
Panjang
Panjang serabut
postganglionic
Panjang
Pendek
Sympathetic Outflow
Sympathetic vs. Parasympathetic
Receptor/NT Differences:
The Differences
Sympathetic
Parasympathetic
Neurotransmitter di
sinapsis (dari neuron
postganglionic)
Norepinephrine
(adrenergic
neurons)
Acetylcholine
(cholinergic
neurons)
Tipe reseptor
neurotransmitter di
sinapsis target.
Alpha dan Beta
Muscarinic
Neurotransmitter di
Ganglion
Acetylcholine
Acetylcholine
Receptor di
Ganglion
Nicotinic
Nicotinic
Cholinergic Receptors
Acetylcholine can act on two types of receptors:
Muscarinic Receptors
• Junction between parasympathetic
postganglionic neuron and target tissue.
Nicotinic Receptors (always excitatory)
• Neuromuscular junctions of skeletal muscles.
• Autonomic ganglia of both Sympathetic and
Parasympathetic paths (between preganglionic
and postganglionic neurons).
Adrenergic Receptors
Sympathetic nervous system only
• Neurotransmitter: Norepinephrine from
sympathetic postganglionic neuron.
• Hormones from adrenal medulla:
norepinephrine and epinephrine.
Adrenergic Receptors
Alpha receptors: stimulation in vascular smooth
muscle causes vasoconstriction.
• Alpha receptor blockers are medicines used to
lower blood pressure by inhibiting constriction of
blood vessels.
Beta Receptors
• Stimulation on cardiac muscles causes an
increased heart rate.
• Stimulation on bronchial smooth muscles in
lungs causes broncho-dilation (easier to breath).
Sympathetic vs. Parasympathetic
Effects:
In the following tables, note the effects of the
sympathetic and parasympathetic nervous
systems on various body organs.
Try to deduce why the divisions cause these
particular actions.
Target Organ
Parasympathetic
Effects
Sympathetic
Effects
Mata (iris)
Stimulates constrictor
muscles. Pupil
constriction.
Stimulates dilator
muscles. Pupil
dilates.
Mata (otot silier)
Stimulates. Lens.
accommodates –
allows for close vision.
No innervation
Kelenjar Ludah
Watery secretion.
Mucous secretion.
Kelenjar Keringat
No innervation.
Stimulates sweating
in large amounts.
(Cholinergic)
Kandung Empedu
Stimulates smooth
muscle to contract
and expel bile.
Inhibits gallbladder
smooth muscle.
Target Organ
Parasympathetic
Effects
Sympathetic
Effects
Errector Pili
No innervation
Stimulates
Otot jantung
Decrease HR
increase HR and force
of
contraction.
Pembuluh darah
koroner
Constricts
Dilates
Urinary Bladder;
Urethra
Increase urination
decrease urination
Paru2
Contricts bronchiole
(small air passage)
smooth muscle.
Dilates bronchioles.
Kelenjar lacrimal
Increase tears
No innervation
Target Organ
Parasympathetic
Effects
Sympathetic Effects
Ginjal
No innervation.
Releases the enzyme
renin which acts to BP.
Pembuluh darah
No innervation
Constricts most blood
vessels and increases
BP.
Exception: dilates blood
vessels serving skeletal
muscle.
Koagulasi darah
No effect.
Increase coagulation
rate.
Organ pencernaan
increase peristalsis and decrease glandular and
enzyme/mucus
muscular
secretion.
activity.
Liver
increase Glycogen
synthesis
from glucose
increase glucose from
breakdown of glycogen
Target Organ
Parasympathetic
Effects
Sympathetic
Effects
Mental Activity
No innervation.
increase alertness.
Penis
Vasodilates penile
arteries. Erection.
Smooth muscle
contraction.
Ejaculation.
Vagina; Clitoris
Vasodilation.
Erection.
Vaginal reverse
peristalsis.
Uterus
Depends on stage of
the cycle.
Depends on stage
of the cycle.
Endocrine
Pancreas
Stimulates insulin
secretion.
Inhibits insulin
secretion.
Metabolisme sel
No effect.
increase metabolic
rate.
Jaringan adiposa
No effect.
Stimulates fat
breakdown.
Homeostatic Imbalances of the
ANS: Hypertension
May result from
overactive
sympathetic
vasoconstriction
Homeostatic Imbalances of the
ANS: Raynaud’s Disease
Exaggerated
vasoconstriction
in hands or feet.
Brought on by
cold or emotional
stress.
Causes cyanosis in
hands or feet.
Hirschsprung’s Disease
Congenital
abnormality where the
distal colon does not
have parasympathetic
innervation.
 1 case per 5,000 live
births.
 No peristalsis leads to
congenital megacolon
 Need permanent
colostomies.
Hirschsprung’s Disease