Autonomic nervous system Flashcards
(18 cards)
Where is the ANS integrated
In the hypothalamus- this is where the visceral motor nuclei originates
Explain the steps in which noradrenaline is biosynthesised and metabolised in the synapse
Tyrosine - DOPA by Tyrosine HYDROXYLASE
DOPA -Dopamine - by DOPA DECARBOXYLASE
Dopamine packaged into vesicles to make Noradrenaline - Dopamine BETA HYDROXYLASE.
Normal synaptic transmission; bind to adrengenic receptor
Taken up by glial cell and broken down by COMT
OR
Taken up by presynaptic cell and broken down by MOA-O
Explain the feature of adrenal gland
There’s no post ganglionic fibres to adrena gland in SNS- just one fibre straight to adrenal gland.
Secretes adrenaline straight into the bloodstream.
In SNS, there are 2 branches of post ganglionic fibres where does the other branch that doesn’t innervate major visceral tissues innervate
Blood vessels and erector pili and sweat glands
What types of receptors are found in each autonomic synapse
Preganglionic- ion channels- fast
Also present in adrenal gland.
Post ganglionic- G protein coupled receptors
Adrengenic or muscarinic
What does the autonomic nervous system control? What structures
Cardiac muscle
Smooth muscle
Internal organs
Skin
Explain steps of synthesis of adrenaline
Same as noradrenaline BUT
Noradrenaline converted to adrenaline in cytoplasm then packaged again into vesicles before being released.
Contrast the length of pre-ganglionic and post-ganglionic fibres in SNS and PNS
SNS
Pre- short; post- long
PNS
Pre- long ; post- short 9may be in organ already)
Explain steps in which ACh is made and its metabolism in synapse
Choline +Acetyl CoA converted into ACh by choline acetyl TRANSFERASE
Packaged into vesicles and exocytosis occurs
Binds to receptors
Products also taken up by glial cell; after ring broken down by AChesterase in the SYNAPSE
Choline taken up into presynaptic terminal by choline uptake protein.
Explain what controls blood vessel tone
SNS controls BOTH construction and dilation of blood vessels; using different adrengenic receptors.
Where are baroreceptors located
Large carotids
Describe the response of sympathetic and parasympathetic in the lungs and liver
Liver:
SNS- glucose relases; PNS- bile release
Lungs:
SNS- dilation; PNS- constriction.
Outline the neurotransmitter released at each autonomic synapse
Preganglionic synapse- ACh for both
Post ganglionic synapse
SNS: noradrenaline
PNS: ACh
Explain how the lung is regulated
No sympathetic neurones innervate gets the lung tissue; uses hormone _adrenaline.
Describe the micturition reflex.
Pressure in bladder detected;
More fibres sent down Parasympathetic pathway down to detrusor muscle in bladder causing to contract
Less sympathetic fibres sent (to internal sphincter muscle); doesn’t constrict so it relaxes
External sphincter muscle controlled by somatic nervous system
What adds layer of complexity to GI tract response in ANS
Enteric nervous system
What are the functions of the sympathetic and parasympathetic nervous system
Flight/flight
Rest and digest
What converts noradrenaline to adrenaline ?
What happens to the adrenaline secreted ?
Phenylethanol methyl transferase
Adrenaline (a HORMONE NOT neurotransmitter) diffuses into capillary and is transferred in the blood
