Nervous System Flashcards
What two Afferent divisions are there?
Somatic sensory (skeletal muscle responding to walking or input from olfactory receptor)
Visceral sensory (dealing with internal environment stimuli)
What are the two division in the Visceral Motor neurone pathway?
Parasympathetic and Sympathetic
What are the Parasympathetic pathway results on body?
Lungs constrict
Bladder contraction
Liver release more bile
Effects of the sympathetic pathway on the body?
Liver increases glucose release
Bladder relaxation
Lungs dilate
Where do the Visceral Motor nuclei originate?
Hypothalamus
Ganglionic fibres in parasympathetic system?
Made of two neurons:
Ganglions closer to tissues
Long Pre ganglionic - Ganglion - short post ganglionic - effector organ
What is the arrangement of Ganglionic fibres in the sympathetic system?
Ganglions closer to spinal cord
Short pre ganglionic fibres - ganglion - long post ganglionic fibres - effector
What are Sympathetic trunks?
Long chains running parallel to the spinal cord, lots of sympathetic nerves synapse at those chains allowing for mass activation of neurons. = coordinated response
e.g. heart rate increases and lungs dilate simultaenously
What is the one exception to the two neuron arrangement in ANS?
The sympathetic innervation of the adrenal gland
Only one sympathetic nerve, no post ganglion
What NT do parasympathetic pre-ganglionic and post-ganglionic nerves release? (into synapse)
Acetylcholine
What NT do sympathetic pre-ganglionic fibres and post-ganglionic fibres release? (into synpase)
Acetylcholine
Noradrenaline
respectively
How does low blood pressure cause low inhibition of the sympathetic pathway? ( dis inhibition )
Low blood pressure sensed by baroreceptors which normally keep sympathetic NS suppressed, the sensory info relayed to the brain is reduced.
Leads to reduced inhibition of sympathetic NS increasing it. Increases heart rate.
What is the enteric nervous system?
(ENS) is a quasi autonomous part of the nervous system controls gut without brain.
If there are no sympathetic nerves innervating lung tissue, how is bronchodilation achieved?
The sympathetic NS affects the adrenal glands which release hormone adrenaline that causes this effect.
What is the micturition reflex?
When the bladder gets full there is pressure build up. The sympathetic system which keeps the internal sphincter closed relaxes and is switched off and the parasympathetic system contracts the Detrusor muscle so is switched on.
What type of receptor would you want at automonic ganglia?
Nicotinic acetylcholine Ion Channel receptor. fast one for quick neuronal transmission
(also used by sympathethic nerves innervating adrenal medulla)
Where can G-protein coupled receptors be found?
Receptors respond to ACh released by post-ganglionic fibres, and muscarinic receptors in tissues and adrenergic receptors responding to noradrenaline.
Precursors for acetylcholine?
Choline and Acetyl CoA converted by choline acetyl transferase
Precursors for Noradrenaline?
Tyrosine converted to DOPA by tyrosine hydroxylase, DOPA converted to dopamine by DOPA decarboxylase.
Dopamine packaged into vesicles with enzyme dopamine beta hydroxylase to release Noradrenaline
Noradrenaline metabolism and uptake?
Uptake 1 protein into presynaptic neuron or uptake 2 protein into glial cells
monoamine oxidase in neuron and another enzyme in glial cells metabolise.
Adrenaline being released by adrenal glands?
Noradrenaline from vesicle converted to adrenaline in cytoplasm by phenylethanol methyl transferase. exocytosis from nerve releases adrenaline and diffuse into capillaries.
Which receptor responds to neurotransmitter release from parasympathetic postganglionic fibres?
Muscarinic Acetylcholine
Which receptor responds to neurotransmitter release from sympathetic postganglionic fibres?
Adrenergic receptors - to Noradrenaline or adrenaline
What do Nicotinic receptors respond to?
Present within all autonomic ganglia - ion channel linked
