Drugs Acting on the CNS Flashcards
(43 cards)
What are 5 of the diverse and pharmacological effects of drugs acting on the CNS?
- pain relief
- induction of anesthesia
- prevention of epileptic seizures
- depression treatment
- reduce anxiety
What special importance do drugs working on the CNS have for humans?
recreational use —> addiction/abuse
- alcohol
- teas and coffee
- nicotine
- cannabis
- ecstasy
- opioids
- cocain
- amphetamines
How do drugs acting on the CNS affect the brain?
affects the use and output of neurotransmitters
- speed up production
- slow down production
- mimic neurotransmitters
What are the 6 major classifications of CNS drugs?
- analgesics - narcotics (pain relievers) and non-narcotics (acetaminophen, NSAIDs)
- anticonvulsants
- CNS stimulants
- tranquilizers
- muscle relaxants
- anesthetics
What makes up the CNS? PNS?
brain, spinal cord
nerves
What is the difference between afferent and efferent systems in the PNS?
AFFERENT: sensory system that conveys information from PNS receptors to the CNS
EFFERENT: motor system that conveys information from the CNS to muscles and glands
What is the somatic and autonomic nervous systems?
(PNS)
SOMATIC: conveys information from CNS to skeletal muscle
AUTONOMIC: converys information from CNS to smooth muscle, cardiac muscle, and glands
- enteric NS, sympathetic NS, parasympathetic NS
What are the sympathetic and parasympathetic nervous systems?
(part of the autonomic NS - counteracts each other)
SYMPATHETIC: fight or flight, allows body to function under stress
- increased HR, adrenalin rush
PARASYMPATHETIC: rest and digest, feed or breed
- decreased HR
How does a dog’s brain compare to a human’s?
very similar - smaller, less surface area (less folds)
What is a nerve? What are the 4 major types?
clusters of nervous tissue (neurons) and blood vessels
- EFFERENT: conduct signals from the CNS along motor neurons to their target muscles and glands
- AFFERENT: carries nerve impulses from sensory receptors or sense organs toward the CNS
- MIXED: contain both afferent and efferent axons and can conduct both incoming sensory information and outgoing muscle commands
- SPINAL: mixed nerve that carries motor, sensory, and autonomic signals between the spinal cord and the body
What 2 cells are found in the CNS?
- neurons - specialized nerve cells that can recieve and transmit chemical and electrical signals
- glial cells/neuroglia - supportive functions
- astrocytes, oligodendrocytes, microglial cells, ependymal cells
What do oligodendrocytes do?
provide myelin for many axons in the CNS
What are the major structures of a neuron?
Where do 2 neurons communicate?
synapse composing of presynaptic terminal and a postsynaptic neuron (+ receptors) acting as a junction that allow signals to pass
How do neurons communicate?
orchestrated chemical (neurotransmitter release) and electrical (altering neuronal membrane potential) actions
What are action potentials? Neurotransmitters? Receptors?
AP: electrical signals carried along neurons that pass an impulse along the neuron membrane (starts the process)
NT: chemical signaling molecule released from presynaptic neurons so they can “talk” to and affect another cell (neuron, gland, muscle)
R: present on postsynaptic neuron that allows it to “hear” the message
What are the 2 types of neural synapses?
- chemical: ionotropic receptors (ligand-gated ion channels), metabotropic receptors (G-protein coupled receptors)
- electrical: gap junction proteins
What are the 2 major characteristics of action potentials?
- all-or-nothing (on-off switches)
- one-directional (from the body to axon terminal)
What makes electrical signals happen? What is membrane potential?
polarity change across plasma membrane
difference in charge between inside and outside of the cell
How does the charge inside and outside the cell differ during resting potential? Action potential?
RESTING POTENTIAL: - inside, + outside; channels CLOSED
ACTION POTENTIAL: + inside, - outside; channels OPEN
What are the different configurations of voltage-gated ion channels?
When do changes in polarization of the neuron occur? What are the 2 possible potentials?
when ion channels in the membrane open or close, altering the ability of particular types of ions to enter or exit the neuron
- DEPOLARIZATION: positive potential; opening of channels that let Na+ rush into a neuron and allows it to send electrical signals
- HYPERPOLARIZATION: negative potential; opening of channels that let negative ions frow in to prevent the neuron from receiving another stimulus
Chemical vs electrical synapses:
What are the 5 steps of neuron communication?
- action potential arrives at axon terminal
- when the presynaptic membrane is depolarized, voltage-gated Ca++ channels allow Ca++ to enter
- Ca++ entry causes synaptic vesicle to fuse with the membrane and release NT molecules into the synaptic cleft
- NT diffuses across the synaptic cleft and binds to ligand-gated ion channels in the postsynaptic cleft, resulting in depolarization or hyperpolarization of the postsynaptic neuron
- reuptake by the presynaptic neuron, enzymatic digestion, and diffusion reduced NT levels, terminating the signal
