Revision Autonomic nervous system Flashcards
Central nervous system consists of
Brain, spinal cord
Peripheral NS consists of 3 types of nerves
Sensory nerves, motor nerves, autonomic nerves
Purpose of sensory nerves. What type of fibres
Touch, pain. From periphery (skin) TOWARDS spinal cord. Called Afferent fibres
Purpose of motor nerves
Voluntary control of skeletal muscle. AWAY from spinal cord to muscle: Somatic efferent system/fibres. Efferent means outward.
Purpose of autonomic nerves
Unconscious physiological control of organ system
Examples of medicines affecting CNS
Schizophrenia, depression, opioids
Medicines for PNS
Pain relief, muscle weakness, cardiovasuclar, GI, respiratory…
3 Divisions of autonomic nervous system
Sympathetic NS, Parasympathetic NS, Enteric NS
Use of sympathetic NS
Flight or flight
Use of parasympathetic NS
Rest and digest, stimulates visceral (internal organs) processes
Use of enteric NS
Local neuronal network that co-ords GI tract w imput from PNS and SNS
Anatomy from spinal cord to target tissue for sympathenic + parasympth NS
Pre-ganglionic neurone from CNS. A connection (synapse) made with second in a ganglion. To post-ganglionic neurone that innervates target tissue.
What is a ganglion
Group of nerve cell bodies
How can adrenaline be released from some pre-ganglionic SNS fibres
The pre-gang synapse with the adrenal medulla (inside adrenal gland above kidneys) which releases adrenaline
How many neurones for skeletal muscle
1 motor neurone from CSN to skeletal muscle
5 divisions of spinal cord and where in body
Medullary + cervical = Neck. Thoracic = Chest. Lumbar = Back. Sacral = Bottom end
Where do sympath pre-ganglionic neurones originate
Thoracic and lumbar of spinal cord
Are pre-gang neurones short or long in sympa vs parasympa
Sympa: Short. Parasympa: Long
What are paired PARAvertebral connections and their collective name (sympath)
Where pre-gang synapse on either side of the spinal cord. Many are in a line down CLOSE to spinal cord in the PARAvertebral chain.
What are unpaired PREvertebral ganglia and where
In front of spinal cord. Make connections to intestines, pelvic viscera (NOT symmetric)
3 types of connections where pre-gang synapse in (sympath)
Paired paravertebral, unpaired prevertebral gang, adrenal medulla
Examples of where postgang neurones go (sympath)
They are long so (paired) paravertebral: eyes, lungs, blood vessels, heart. Prevertebral: Liver, GI tracts etc
Where do parasympth pregang originate from
Medullary and sacral
Where are parasympathetic ganglia located in relation to target organs
Close to them. Far from spinal cord
What is the 10th cranial nerve
The vagus. Parasympathetic innervation of hear, lungs, upper GI tract.
What is the vascular shunt
Blood redistributed where blood vessels are constricted to GI, skin, brain but relaxted to skeletal muscle
3 main principal chemicals + their group
Acetycholine, Noradrenaline = Neurotransmitters. Adrenaline = Hormone
Acetylcholine acts on 2 types of receptors
Nicotinic receptors = Ligand gated ion channels superfamily (fast)
Muscarinic receptors = G protein couples receptors (flexible results)
What receptors does Noradren and adrenaline act on
Adrenoceptors = G protein couples receptors
How many adrenoceptors subtypes
5: α1, α2, β1, β2, β3
Use of acetylcholine
In all preganglionic neurones (parasym and sympa) in combo with nicotinic acetylcholic ion channel receptors.
In postgang PARAsympathetic neurones. Activates muscarinic receptors on target cells (G prot)
Main SYMPathetic mediators in postgang
Noradrenaline activating adrenoceptors (G prot)
What can be a result of circulating adrenaline in sympathetic
Both noradrenaline and adrenaline activate adrenoceptors! Eg lung bronchi where adrenaline is main stimulus
What is used in sympathetic innervation of sweat glands (exception)
Acetylcholine -> muscarinic receptors
Why does slabutamol activate adrenoceptors better in lungs than heart
Selective for β2-adrenoceptors in lung over β1-adr in heart!
