Exam 2 Flashcards
What is the function of the NS?
To coordinate and integrate body systems and maintain homeostasis
What comprises the CNS?
Brain and Spinal cord?
What comprises the PNS?
Nerves, part of the Somatic and Autonomic NS
Autonomic NS fx?
Innervates cardiac, smooth muscle and glands.
Somatic NS fx?
Innervates skeletal muscles (voluntary)
ANS is what kind of system?
2 neuron system: goes from spinal cord to synapse to another neuron that then goes to cardiac muscle, smooth muscle or glands
Where is the site of synapse?
Ganglion
What is a Ganglion?
Collection of nerve cell bodies in the peripheral NS that are located pre-ganglion or post-ganglion
Parts of the ANS?
Sympathetic and Parasympathetic
Sympathetic is also known as what and why?
Thoracolumbar division because pre-ganglionic neurons come out of the spinal cord T1-L2
Site where pre and post ganglionic neurons synapse in sympathetic response?
Ganglionic chain
Where is the ganglionic chain located?
Close to the spinal cord: pre-ganglionic = short, post-ganglionic = long (innvervate cardiac, smooth muscle and glands
What is the ratio of pre to post ganglionic in Sympathetic response?
1:20 —> widespread response from sympathetic division
Parasympathetic response is also known as what and why?
Craniosacral division because pre-ganglionic neurons are bundled with cranial nerves 3,7,9,10 and the other pre-ganglionic neurons comes off spinal cord segments S2,S3,S4.
Where do pre and post ganglionic neurons synapse in parasympathetic response?
Close to or on an Effector: pre-ganglions are long and post-ganglions are short
Ratio of pre to post ganglionic neurons in Parasympathetic response?
1:4 –> focused response
Dual innervation?
When an organ is innervated by both sympathetic and parasympathetic fibers, they antagonize each other. Most organs have dual innevervation.
Example of dual innervation?
Sympathetic increases HR, Parasympathetic decreases HR.
When does the sympathetic and parasympathetic response work together?
Male reproductive system: Para = Erection, Symp=Ejaculation
What is the net effect of both divisions?
To get the level of activity
Example of single innervations?
Adrenal medulla and blood vessels = sympathetic innervation
Lacrimal glands = parasympathetic innervation
Total activity of particular division Sympathetic?
Increase Symp = Constriction of BV’s
Decrease Symp = Dilation of BV’s
What are the kinds of neurotransmitters released by neurons?
- Acetylcholine (Ach)
- Biogenic Amines
- Amino Acids
- Peptides
- Misc. (NO - Nitric oxide, ATP)
Biogenic Amines examples?
Catecholamines and Indolamines
What do Catecholamines release?
Dopamine
Norepinephrine
Epinephrine
What do the Indolamines releases?
Histamine
Serotonin
Amino Acid examples?
Glycine
GABA
Glutamate
Kinds of Peptides?
Endorphins
Enkephalins
Dynorphins
Which neurotransmitters act in the PNS?
Ach, Epinephrine, Norepinephrine, Dopamine
Neurons that synthesize and release Ach are called?
Cholinergic neurons
Neurons that synthesize and release NE?
Adrenergic Neurons
What organ synthesizes and releases Epinephrine and NE?
Adrenal Medulla
Dopaminergic neurons synthesize and release?
Dopamine
Receptors that bing Ach are called?
Cholinergic receptors
Two kinds of Cholinergic receptors?
Muscarinic
Nicotinic
Subtype of Nicotinic receptors?
N1
N2
What kind of receptors are N1 & N2 and where are they found in relation to the synapse?
Excitatory, found Postsynaptic
Subtype of Muscarinic receptors?
M1, M2, M3, M4, M5
Excitatory/Postsynaptic Muscarinic Receptors?
M1,M3,M5
Inhibitory/Postsynaptic Muscarinic receptor?
M2
Inhibitory/Presynaptic Muscarinic receptor?
M4
Excitatory/Postsynaptic Nicotinic receptors?
N1,N2
Adrenergic receptors respond to?
Epinephrine, NE, Dopamine
Two kinds of Adrenergic receptors?
Alpha
Beta
Subtypes of Alpha/Beta?
A1,A2
B1,B2
Excitatory/Postsynaptic Alpha receptors?
A1
Inhibitory/Presynaptic Alpha receptor?
A2
Excitatory/Postsynaptic Beta receptor?
B1
Inhibitory/Postsynaptic Beta receptor?
B2
Dopaminergic receptor subtypes?
D1,D2
Inhibitory/Postsynaptic Dopamine receptor?
D1
Inhibitory/Presynaptic Dopamine receptor?
D2
Why are Inhibitory/Presynaptic receptors called auto receptors?
Regulate the release of neurotransmitters from M4,A2,D2
Where can you find an N2 receptor?
Skeletal muscle
Where can you find an M2 receptor?
SA node of heart (hyper polarizes = deceased HR)
List Excitatory/Postsynaptic receptors.
N1 N2 M1 M3 M5 A1 B1
List Inhibitory/Presynaptic receptors.
M4,A2,D2
List Inhibitory/Postsynaptic receptors.
M2
B1
B2
D1
Fate of neurotransmitters?
- Some diffuse away from synapse
- Some are broken down by catabolic enzymes
- some get taken back up by neuron that released them
Define Direct Mimicry
When the drug closely resembles in structure the endogenous molecule and it binds to the same receptor (having affinity and intrinsic activity).
Example of Direct mimicry drug?
Bethanechol (mimics Ach)
Define indirect mimicry?
When the drug increases the amount of neurotransmitters in the synapse, it can be done in 3 ways.
What are the three ways indirect mimicry occurs?
- Drug enhances the release of neurotransmitters from neuron. Ex. Amphetamines ^ release of NE
- Drug inhibits the catabolic enzymes that break down the neurotransmitter. Ex. Physostigmine (Myasthenia Gravis)
- Drug blocks the re-uptake of the neurotransmitter. Ex. Cocaine - more NE in synapse
Define direct blockade and give example
Antagonist- Inhibits the synthesis of the neurotransmitter. Ex. Hemicholinium inhibits the synthesis of Ach, Atropine blocks cholinergic drug
Define indirect blockade and give an example
When a drug inhibits the release of the neurotransmitter. Ex. Botox- inhibits the release of Ach, no muscle contraction
Direct Acting Cholinergic Drugs Bind to?
Cholinergic receptors and cause receptor activity