EX1; Cell Communication Flashcards by Courtney Kast

Neurons make up what percentage of CNS cells

10%

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What are the 3 main parts of a neuron

soma; containing the nucleus; protein synthesis
dendrites; major input processes (respond with graded potentials)
axon; output processes for signaling (action potentials)

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This is the initial segment of a neuron; the trigger zone for action potentials

axon hillock

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This part of the axon is used for vesicle storage

axon terminals

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This type of neuron is a sensory/input neuron; transmit information to CNS; the bodies lie outside the CND in ganglia

afferent neuron

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This type of neuron is motor/output; transmits commands to effector cells; bodies lie within CNS but axons project outside

efferent neurons

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This type of neuron is located within the CNS; functions as integrators and switches

interneurons

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What percentage of the CNS do glial cells make up

90%

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Which undergoes cell division, neurons or glial cells

glial cells

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What are the two types of myelinating glia

PNS; Schwann cells (one axon)

CNS; oligodendrocytes (many axons)

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These are macrophage-like glial cells and can be in either unreactive or reactive

microglia

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These glial cells regulate ECF, provide neurons metabolically, and surround brain capillaries forming the blood brain barrier

astrocytes

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This provides movement of proteins and other material from one part of neuron to another

microtubules

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What are the two types of microtubule transport

anterograde

retrograde

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This type of transport is from cell body toward terminal

anterograde

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What type of motor protein is required for anterograde transport, and what are the speeds of it

kinesins
fast transport for organelles such as neurotransmitter vesicles
slow transpire for structural proteins

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This type of transport is from axon terminal towards cell body

retrograde

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What type of motor protein is required for retrograde transport and it moves what

dyneins

fast transport of things like growth factors and also viruses

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This virus is easily transmitted through oral contact and is transmitted retrogradely where it remains latent in the trigeminal ganglion

herpes simplex virus type 1

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True or False

Damaged CNS neurons regenerate

False; they do not

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CNS axons do this, but do not reach targets

sprout

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This prevents surviving CNS axons from reaching targets

scar formation

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Astrocytes make this that inhibits neuron growth

chondroitin sulfate proteoglycans

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This is clinically signifiant; dental procedures (extractions) can cause nerve damage

PNS

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True or False | functional recovery of the PNC can take place depending on the severity

True

This is associate with protein synthesis; cell body swells, eccentric nucleus

chromatolysis

What becomes of a neuron in response to a severe nerve injury

terminal degeneration transganglionic degeneration transynaptic degeneration

What becomes of a neuron in response to a less severe injury

anterograde degeneration | injured cell nucleus (chromatolysis)

These cells produce laminin for substrate for regenerating axons and nerve growth factor (NGF)

Schwann cells

This regulates gene expression and promotes sprouting

NGF

What are the specific components NGF is involved with

microtubules and microfilaments neurotransmitter production ion channels neurotransmitter receptors

Collateral sprouting explains what when there is ipsilateral removal of trigeminal nerve leaving once side anesthetic

crossed-midline sensitivity

This is an anatomically specialized junction between a neuron and another cell at which the electrical activity of the presynaptic neuron influences the electrical activity in the post synaptic cell

synapse

What are the four types of synapses

chemical vs electrical | excitatory vs inhibitory

What are the three types of chemical synpases

axo-somatic axo-dendritic axo-axonis

Where are the three location of receptors

postsynaptic presynaptic autoreceptors

What are the 6 steps of synaptic transmission

1. action potential reaches terminal 2. voltage-gated Ca channels open 3. calcium enters axon terminal 4. neurotransmitter is released and diffused into the cleft 5. neurotransmitter binds to post synaptic receptors 6. neurotransmitter removed from synaptic cleft

A post-synaptic potential is only how many mVs

0.5mV

What determines if a threshold is reached of a PSP

the combined effect to excitatory or inhibitory synaptic input

This is the adding together of PSPs from one synaptic contract (over time)

temporal summation

This is adding together of PSPs produced by different synapses

spatial summation

At which type of sites can drugs interact with the synaptic junction

a whole bunch of different places

This functions in rapid communication and acts on postsynaptic cell to produce EPSP or IPSP (excitatory or inhibitory)

classical neurotransmitter

This may act postsynaptically to amplify or dampen on-going synaptic activity or may act on pre-synaptic cell to alter synthesis, release, uptake, or metabolism of neurotransmitters

neuromodulators

Actions of neuromodulators includes what

changes in DNA/protein synthesis or enzyme activity; can thus be much slower in action (min-days)

This is synthesized from choline and acetyl in the synaptic terminal; action stopped by diffusion and degration

acetylcholine

What is choline re-uptakes by

presynaptic neuron

What are four examples of neurons that release ACh

motor neurons neurons in nuclus basalis and pons all preganglionic neurons all postganglionic parasympathetic neurons

Where are two locations of ACh neurons in the CNS

basal forebrain | pontine nuclei

These ACh receptors are mostly found in the CNS but also in parasympathetic postganglionic synapse (salivary glands)

muscarinic receptors

The binding of ACh in muscarinic receptors triggers what

G protein that either open or closes ion channels | depolarizing or hyperpolarizing

Muscarinic receptors are blocked by what

atropine

These ACh receptors are few in the CNS

nicotinic receptor

ACh binding in nicotinic receptors triggers what

opening ion channels with the receptor | depolarizing

Nicotinic receptors are blocked by what

curare (e.g. neuromuscular junction)

This ACh disease is an autoimmune disease in which individuals make autoantibodies to nicotinic receptors; muscle weakness; treated with acetylcholinisterase inhibitors

myasthenia gravis

This ACh is a common form of dementia, loss of neurons in the nucleus basal is leading to decrease in cholinergic activity in cortex

alzheimers disease

This is synthesized from amino acids, specifically tyrosine

catecholamines

What is the life cycle (3 steps) of catecholamines

1. synthesis in presynaptic terminal; stored in vesicles 2. release is Ca dependent 3. termination of action; presynaptic neuron re-uptake and degradation (MAO)

True or False | Neurons that synthesize catecholamines are found through the CNS

False; the neurons are only found in very limited locations

True or False | receptors for catecholamines are found extensively throughout the CNS

True

What are the type of catecholamines receptors

G-protein coupled receptors

True or False | Catecholamine is involved with only a few functions and dysfunctions

False; it is involved with many

This is synthesized in the pre-synaptic terminal and is found in specific areas of the midbrain and brainstem

dopamine

The two main groups of dopamine G-protien receptors are D1 and D2; what are their functions

D1 - activate adenylate cyclase | D2 - inhibit adenylate cyclase (leading to hyperpolarization)

This disorder involves the D2 receptors being impaired, commonly presented with rhythmic oral movements

tardive dyskinesia

This is found in locus ceruleus (attention/sleep) and other brainstem groups with autonomic and homeostatic functions and is often referred to as noradrenaline and adrenaline

norepinephrine and epinephrine

norepinephrine neurons include what

sympathetic postganglionic neurons and some CNS

epinephrine neurons include what

adrenal gland as circulating hormone (not much in CNS)

These are G protein coupled receptors involving NE

noradrenergic receptors

What are the functions of α receptors (α1 and α2) involving NE

α1; intracellular release of Ca; excitatory | α2; inhibitory via opening of K channels or blocking Ca

What is the function of β receptors ( β1, β2, β3) involving NE

open Ca channels

This is synthesized from tryptophan and is found in the rostral raphe nucleus (sleep, mood, homeostatic function) and the caudal raphe nuclei (sensori-motor function) and uses G protein coupled receptors

serotonin

What is the function of serotonin

may different functions ranging from sensrimotor systems to cognitive function (mood)

This is found only in a small population of hypothalamic neurons involved in sleep-wakefulness; G-protein coupled receptors

histamine (derived from histidine)

This is the most common excitatory amino acid (the other is aspartate)

glutamate

The excitatory amino acids bind several classes of what

ionotropic receptors; have channels permeable to Na, K, and Ca aslo binds to metabotropic receptors (G-protein)

This is involved with functions that last (memory, chronic pain, etc.); excitotoxcitiy; excessive excitation causes neuron death from Ca reading toxic levels

NMDA (n-methyl-D-asparate) receptor

NMDA receptors are involved in the synaptic mechanism of what

long term potentiation

What are two factors promoting long ted potentiation

phosphorylation of NMDA receptor | calcium entry into cell via NMDA; phosphorylation of AMPA and an increased number, synthesis of retrograde nitric oxide

This is a major inhibitory neurotransmitter in the CNS, modified form of glutamate of which can form Huntington chorea, form of motor spasticity

GABA (gamma-amminobutyric acid)

GABA (A) is an ionotropic receptor that opens what

Cl channels

GABA (B) is a metabotropic receptor that opens what

K channels

glycine is an inhibitory neurotransmitter in the spinal cord that does what

receptor opens Cl channels | blocked by strychnine

There are over 80 of these identified and are often co-released with neurotransmitters (synthesized in stroma and must be transported to be released) can function as a neuromodulator, and its action can last a long time terminated by proteolysis and diffusions

peptides

This is a gas transmitter that can modulate neurotransmitter release, plays a role in numerous brain functions and has an excitotoxicity role in injuries

nitric oxide

This is usually an excitatory (taste) transmitter usually co-release with classical neurotransmitters

ATP