Transcript Autonomic Nervous System

Autonomic Nervous
System
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Aims of session
• To review the basic structure and
function of the Autonomic Nervous
System (ANS)
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Objectives
Learners should be able to:
1. Describe the basic structure and general
functions of the sympathetic and
parasympathetic divisions of the autonomic
nervous system
2. Describe the fight’/’flight’ responses and
cooperative effects of the sympathetic and
parasympathetic sysyem on different
organs.
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Nervous System Divisions
Anatomical division of
Nervous system
Central Nervous System
(Brain, Spinal Cord)
Encased in the Cranium and
vertebral column
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Peripheral Nervous
System
(Nerve connections
between
the CNS and body
organs/tissues )
allows nerve connections between the
CNS and the organs and tissues of the
body i.e. the nerve trunks, plexus and
nerve fibres
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Nervous System - Physiology
Physiological division
of the nervous system
Somatic
Voluntary and
Conscious Mechanisms
E.G Skeletal
muscle and
joint
movement
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Autonomic
Involuntary Control Mechanisms
Sympathetic and
Parasympathetic
Regulating:
Cardiorespiratory ,
Gastrointestinal,
Genitourinary
Reproductive ,
Integumentary
Neurological ,
Endocrine systems
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Ganglia- e.g..
Part of the nervous system that carries out its functioning automatically i.e. without
conscious control. With such organs and tissue are able to function in either a
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decreased
or increased manner in order to maintain homeostasis
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Ganglion
A mass of nerve cell bodies
RECAP Dorsal root ganglia – sensory nerves connect CNS with
PNS
Autonomic Ganglia
Autonomic ganglia -clusters of neurones and a junction
between autonomic nerves originating from the CNS and
autonomic neurones serving peripheral target organs.
CNS to ganglia = Preganglionic
Ganglia to effector organ = Postganglionic
Many sympathetic and parasympathetic ganglions run from the
top to the bottom of the spine.
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Physiological Similarities and Differences
Parasympathetic
Myelinated /
Distribution Neurotransmitter Function
nerve type
Unmyelinated
Preganglionic
Myelinated
CNS to
Ganglion
Acetylcholine
Postganglionic
Unmyelinated.
Throughout
body
acetylcholine.
Sympathetic
Myelinated /
Distribution
nerve type
Preganglionic
Unmyelinated
Myelinated
Postganglionic
Unmyelinated.
(normally)
returns body
to normal
state after a
fight/flight
Neurotransmitter Function
(normally)
CNS to
Ganglion
Throughout
body
Acetylcholine
Fight’ or ‘Flight’
response
Noradrenaline.
Postganglionic fibres i.e. between the Ganglion and target tissue ganglion)
Preganglionic fibres i.e. between the CNS and the ganglion anglionic fibres i.e. between the Ganglion and target tissue ganglion)
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What
What
would
would
bebe
happening
happening
to to
thean
Gut
wall
arteriole
with with
parasympathetic
sympathetic nerve
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Sympathetic Inhibitory and
Excitatory Functions
2 types of receptors to Sympathetic nerve
excitation - Alpha and Beta
Adrenaline excites both alpha and beta
receptors equally
Noradrenaline excites mainly alpha receptors.
There are also subtypes of each – more of this later on
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Autonomic Nervous System Effects
Structure
Sympathetic Stimulation
Parasympathetic Stimulation
Iris (eye muscle)
Pupil Dilation
Pupil Constriction
Salivary Glands
Saliva production reduced
Saliva production increased
Oral/Nasal
Mucosa
Mucus production reduced
Mucus production increased
Heart
Heart rate and force
increased
Heart rate and force decreased
Lung
Bronchial muscle relaxed
Bronchial muscle contracted
Stomach
Peristalsis reduced
Gastric juice secreted; motility
increased
Small Intestine
Motility reduced
Digestion increased
Large Intestine
Motility reduced
Secretions and motility increased
Liver
Increased conversion of
glycogen to glucose
Reduction in conversion of glycogen
to glucose
Kidney
Decreased urine secretion
Increased urine secretion
Adrenal medulla
Noradrenaline and
adreanaline secreted
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Secretion of Adrenaline and
noradrenalin
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Wall relaxed
Wall contracted
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Major Organ Responses to Autonomic Impulses
Organ
Heart
Arteries
Sympathetic Stimulation
Parasympathetic Stimulation
Increased heart rate beta1 (& beta2)
Decreased heart rate
Increased force of contraction beta1
(& beta2)
Decreased force of contraction
Increased conduction velocity
Decreased conduction velocity
Constriction (alpha1)
Dilation
Dilation
Dilation (beta2)
Veins
Constriction (alpha1)
Dilation (beta2)
Bronchial muscle contraction
Lungs
Bronchial muscle relaxation (beta2)
Increased bronchial gland secretions
Decreased motility (beta2)
Increased motility
Gastro
Intestinal
Contraction of sphincters [email protected]
(alpha)
Relaxation of sphincters
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Major Organ Responses to Autonomic Impulses
Organ
Sympathetic Stimulation
Parasympathetic Stimulation
Glycogenolysis (beta2 & alpha)
Liver
Gluconeogenesis (beta2 & alpha)
Glycogen synthesis
Lipolysis (beta2 & alpha)
Kidney
Bladder
Uterus
Eye
Renin secretion (beta2)
Detrusor relaxation (beta2)
Detrusor contraction
Contraction of sphincter (alpha)
Relaxation of sphincter
Contraction of pregnant uterus
(alpha)
Relaxation of pregnant and nonpregnant uterus (beta2)
Dilates pupil (alpha)
Constricts pupil
Increased lacrimal gland
secretions
Submandibular Viscous salivary secretions (alpha)
& parotid
glands
Skin
Pilomotor muscles contract
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Sweat glands secrete
slightly
Watery salivary secretions
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