Autonomic nervous system Flashcards
What is the CNS composed of?
brain and spinal cord
What is the peripheral nervous system composed of?
nerve cells carrying information to or from the CNS
Describe the input of the autonomic nervous system
input- neurons associated with interoceptors such as chemoreceptors,mechanoreceptors, thermoreceptors, nociceptors
Describe the output of the autonomic nervous system
-via motor neurons to
-cardiac muscle,smooth muscle,glands
-most organs have dual sympathetic and parasympathetis intervention
Describe the function of the ANS in the heart
-symp- HR and force increases
-para- HR and force decreases
Describe the function of the ANS in the iris
symp- pupil dilation
para-pupil constriction
Describe the function of the ANS in the salivary glands
symp-reduced saliva production
para-increased saliva production
Describe the function of the ANS in oral and nasal mucosa
symp-reduced mucus production
para-mucus production increased
Describe the function of the ANS in the lungs
symp-bronchial muscle relaxed
para-bronchial muscle contracted
Describe the function of the ANS in the stomach
symp- peristalsis reduced
para- gastric juice secreted, motility increased
Describe the function of the ANS in the intestines
symp-motility reduced
para-digestion increased, secretion and motility increased
Describe the function of the ANS in the kidney
symp-decreased urine secretion
para-increases urine secretion
Describe the structure of the SNS preganglionic neurons
-cell bodies in the lateral horns of grey matter in spinal cord of the:
-12 thoracic segment
-first 2-3 lumber segments of the thoracolumbar division
Describe the structure of the PSNS preganglionic neurons
cell bodies found in the nuclei od:
-four cranial nerves (III, VII, IX, X)
-lateral grey horns of the 2nd-4th sacral segments
-craniosacral division
Whats the difference between the preganglionic neurons and postganglionic neurons?
pre are short and post are long
Describe the structure of the sympathetic trunk ganglia
-lie in a vertical row alongside the vertabrae from skull to cocyx
-innervate organs above the diaphragm
Describe the structure of the collateral prevertebral ganglia
-lie in front of the vertebral column alongside abdominal muscles
-celiac ganglion
-superior and inferior mesenteric ganglion
-innervate organs below the diaphragm
Describe the parasympathetic ganglia structure
-located close to effector organs
-preganglionic axons are longer than sympathetic preganglionic fibres
List the key parts of synapses
-axon terminal
-synaptic vesicle
-transporter
-neurotransmitter
-synaptic cleft
-receptor
-postsynaptic neuron
Name the neurotransmitters in the ANS
-ACH
-Noradrenaline
List the neurotransmitters in the PSNS and the receptors
-ACH
-nicotinic receptors
-muscarinic receptors
-effector cells
List the neurotransmitters and receptors in the SNS
-ACH
-Noroadrenaline
-nicotinic receptor, adrenergic receptors,effector cells
-pre and post ganglion neuron
Describe what releases ACh
-both para and symp preganglionic neurons
-released by parasympathetic postganglion neurons and sympathetic postganglion neurons which innervate sweat glands
Describe the two types of ACh receptors
Nicotinic receptor
-symp and para ganglia
Muscarinic receptors
-plasma membrane of effector organs innervayed by PSNS
-membrane of sweat glands innervated by Symp postganglionic neurons
Describe Noraadrenaline
Noradrenaline= Norepinephrine
-released by symp postganglionic neurons
-acts at adrenergic receptors at effector organs
-broken down cathechol-o methyltransferase (COMT)
-two main group of adrenergic receptor- alpha and beta with subtypes
Describe the location and action of the adrenergic receptor a1
location-vascular smooth muscle
action-increased vascular smooth muscle contraction
Describe the location and action of the adrenergic receptor a2
location-CNS
action-decreased sympathetic outflow
Describe the location and action of the adrenergic receptor B1
location-cardiac cells
Action-increased HR, increased contractility, increased renin release
Describe the location and action of the adrenergic receptor B2
location-bronchiole smooth muscle, vascular smooth muscle
-action-bronchodilation,vasodilation
Describe the location and action of the adrenergic receptor B3
location-adipose tissue,bladder and gallbladder
action-increased lipolysis, relaxation of the bladder
Describe bronchodilator mechanisms
Beta 2 receptor agonist
-works on SNS
-Drug(sambutanol) binds to receptor
-receptor stimulates Gprotein to activate adenyl cyclase
-adenyl cyclase converts ATP to cAMP
-cAMP relases smooth muscle by:
-inhibits release of ca2+ from sarcoplasmic recticulum
-activates protein kinase A
-protein kinase A inactivates myosin light chain kinase-prevents actin-myosin interaction
-smooth muscle relaxation
Describe the bronchodilator mechanism at the muscarinic receptor
-ACh binds to muscarinic receptors
-receptors stimulate G protein to activate phospholipase C
-Phospholipase C stimulates production of inositol phosphate (IP3)
-IP3 binds to sarcoplasmic recticulum and stimulates release of Ca2+-contraction
-phospholipase C also leads to activation of myosin light chain kinase which causes a contraction
Describe the effects of anti cholinergic drugs in bronchodilator mechanisms
block the casacade reducing resting Paraympathetic bronchial tone resulting in bronchodilation
-ipratopium bromide-atrovent
