L1 Flashcards
What is the physical division of the NS?
Central vs peripheral
What is the functional division of the NS?
Somatic vs. autonomic
Where does the parasympa originate from the spine?
Cranio-sacral
Are para pre-gang neurons long or short? What does this say about where the ganglia are located?
PARA
Long pre-gang b/c synapse at ganglia that are at/near the target organ
Where do sympa pre-gang neurons originate from the spine?
Thoraco-lumbar
What NT do all pre-ganglionic neurons release?
ACh
What NT do para post-gang neurons release?
ACh = cholinergic neurons
What NT do somatic motor neurons release on to muscle?
ACh
What is the primary NT released by sympa post-gang neurons? Which NTs are sometimes released by these neurons?
NE
Big sites of action: heart, resp tract, blood vessels, bladder
Sometimes D or ACh
Which NT is released to stimulate the adrenal medulla? Which NTs can the adrenal medulla release into the blood in response?
Stim = ACh Release = NE or E
Describe ACh synthesis:
- Where
- Transporters
- Enzymes
- Choline uptake into cholinergic nerve terminal
- ACoA (made in mitochondria) + choline –> ACh
ChAT enzyme - ACh into vesicles
Which transporter moves choline into the nerve terminal? Which transporter moves ACh into vesicles?
CHT = into term VAT = into vesicle
What process causes exocytosis of ACh vesicles?
Neuron AP
Opens voltage gated Ca2+ channels
↑ [Ca2+] –> vesicle fusion
Which enzyme degrades ACh back into choline & acetate inactivating it?
AChE = acetylcholinesterase
Explain the 5 steps of NE synthesis in the nerve terminal.
- Tyrosine uptake
- Tyrosine –> DOPA
- Tyrosine hydroxylase
- RATE LIM STEP - DOPA –> dopamine
- Dopamine –> vesicles
- Dopamine –> NE
- Dopamine beta hydroxylase
Which transporter moves dopamine into vesicles?
VMAT
How is NE’s action the synapse terminated?
- Diffusion
2. Reuptake into terminal via NET
What enzyme coverts NE –> EPI in the adrenal medulla?
Phenyl-ethanol-amine-N-methyl-transferase
What is the action of cocaine vs amphetamine in the adrenergic nerve terminal?
Cocaine - stop NE reuptake
Amphetamine - increase non-vesicular release of NE (NE that was cytosolic)
What molecules are you looking for if you assay the blood for catecholamine metabolites?
Meta-nephrine & nor-metanephrine
Which enzyme converts NE/E –> normeta/metanephrine?
COMT
What molecules are you looking for if you assay the urine for catecholamines?
VMA
MHPG
What enzyme converts normeta/metanephrine –> VMA & MHPG?
MAO = mono-amine oxidase
What are the 2 types of cholinergic (ACh) receptors?
Nicotonic - Nn & Nm
Muscarinic - M1-3
Are nicotinic receptors ion channels or GCPRs?
Ion channels - bind ACh, open Na/K channel
Are muscarinic receptors ion channels or GCPRs?
GCPRs
M1 & 3 = Gq
M2 = Gi = inhibitory via ↓PKA
What do Gq receptors do?
Activate phospholipase -> IP3 -> ↑[Ca2+] -> activate PKC
Where do you find Nn receptors? What is the response if they bind ACh?
Nn = neuronal
@ ganglia & adrenal medulla
+ ACh : EPSP –> AP –> release catecholamines
Is Nn transmission 1:1?
NO - think about it, its on a ganglia!
Need temporal or spatial summation to reach threshold
Where do you find Nm receptors? What is the response if bind ACh? Is transmission 1:1?
Nm = muscular!
@ NMJ
+ ACh: end plate potential –> AP in muscle –> contract
YES 1:1
Where do you find M1 receptors? What happens if they bind ACh?
@ Autonomic ganglia
Late EPSP in ganglia
Where do you find M3 receptors? What happens if they bind ACh?
Smooth muscle, glands, endothelium
Fxn = contraction, secretion
Where do you find M2 receptors? Fxn if bind ACh?
@ HEART
Parasympa at heart = rest (Gi)
↓Contractility
Slower pacemaker = ↓HR
What are the 3 types of adernergic/dopaminergic receptors? Are they all ion receptors or GCPRs?
Alpha - 1 & 2
Beta - 1, 2, 3
D1
ALL GCPRs
Where do you find alpha1 receptors? What happens when binds NE?
Vascular smooth muscle - contract
Intestines - relax
Liver - glycogenolysis & gluconeogenesis
Where do you find alpha2 receptors? What happens at each location when NE binds?
Pancreas beta cells
Platelets
Nerve endings - ↓transmitter release
Vasc smooth muscle - contract
Where do you find beta1 receptors? What happens when bind NE?
Heart - ↑HR, contractility
J-g apparatus - ↑renin release = water retention
Where do you find beta2 receptors? Effects of binding NE?
Pulmonary smooth muscle - bronchodilation (relax)
Liver - ↑glycogenolysis
Skeletal muscle - ↑K uptake
Where do you find beta3 receptors? Effects of binding NE?
Adipose cells - ↑lipolysis
Where do you find dopamine receptors? Effects of binding NE?
Vasc smooth muscle - dilate = ↑blood flow at coronary, renal, and mesenteric plexi
What is an autoreceptor vs heteroreceptor?
Autoreceptor = pre-synaptic receptor for uptake of that neuron's own NT to terminate action (alpha 2) Heteroreceptor = presynaptic receptor for OTHER agents (neuromodulators)
What is a quantum?
Amt of ACh stored in 1 synaptic vesicle
Referenced for transmission at NMJ
What is a mini end plate potential?
Spontaneous release of 1 quanta into the synaptic cleft
Describe what can happen when ACh is release at a ganglia for transmission - which receptors may be activated and what would happen due to each?
Nn - fast EPSP
M1 - slow EPSP via K+ channel closing
M2 - IPSP
What 4 variables does the sympathetics control for the heart?
- TPR
- HR
- Contractility
- Venous tone (preload)
How does para influence the heart?
HR - directly decreases
What is the baroreceptor reflex for blood pressure regulation?
High BP
↑baroreceptor firing
↓sympa –> dilate vasc smooth muscle to ↓preload
↑para = dominate heart tone anyways
Does sympathetic innervation of the dilator muscle cause miosis or mydriasis?
DILATION = mydriasis
Does para innervation of the constrictor muscle cause miosis or mydriasis?
MIOSIS = constriction
