33 Brain & Behavior X Flashcards
Label this neuron
- Dendrites
- Cell body/Soma
- Nucleus
- Myelin sheaths
Function of DENDRITES
RECEIVE information from OTHER neurons
Function of axon
TRANSMIT nerve impulses
What is at the END of an axon?
Function?
Axon Terminals
= Release information to the DENDRITES of other neurons
Difference between MYELINATED and NON-myelinated neurons?
(What TISSUE TYPE do they give rise to?
Myelinated = WHITE matter
Unmyelinated = GREY matter
Name the TYPES of neurons
- MOTOR neurons
- SENSORY neurons
- INTERneurons
Describe the ROUTE of motorneurons
CNS
Spinal cord
Muscle fibres
ROUTE of sensory neurons
SENSE organ
Spinal cord
CNS (brain)
Function of INTERneurons
BETWEEN neurons, large COMPUTATIONAL burden
90% of the cells in the brain are whay type?
90% are GLIAL cells
FUNCTION of glial cells
- Scaffold for GROWING neurons
- Scaffold and REPAIR of MATURE neurons
What is the RESTING potential in neurons?
-70mV
(NEG on the INSIDE)
What allows exceeding of the excitation THRESHOLD?
What is the threshold?
A PULSE exceeds the threshold of -55mV
What happens when the threshold -55mV is exceeded?
ACTION POTENTIAL occurs
How is the RESTING potential maintained?
OUTward Na+ channels OPEN
INward Na+ channels CLOSED
= keep inside NEG
What happens when a PULSE exceeding the threshold is applied?
INward Na+ channels OPEN
= Na+ flows IN
= DEPOLARISATION
How is homeostasis restored once the AP leaves?
K+ OUT of cell = restore -70mV
The place where one neuron meets another is called
Synapse
(Axon terminals meet Dendrites)
2 types of APs and their effect on the receiving neuron?
INHIBITORY = inhibit firing
EXCITATORY = induce firing
What happens once the AP arrives at the axon terminal?
Release of neurotransmitters from vesicles into synaptic SPACE
= bind to POSTsynaptic receptors
= either inhibit/excite next neuron
Explain the Lock-and-Key model of NT binding
Specificity
NTs only bind to specific receptors
What happens to the NTs in the synaptic space AFTER an AP, to restore homeostasis?
- Enzyme degradation = inactivated
- Reused via synaptic reuptake
What are the 3 proccesses that DRUGS can act on at the SYNAPSE to affect activity?
- Stimulate/Inhibit NT release
- Stimulate/Inhibit POSTsynaptic RECEPTORS
- Inhibit reuptake
Name 2 substances that affect NT release
- Black widow VENOM = constitutive ACh release
- Botulinum toxin = inhibit ACh release
Effects of black spider VENOM
ACh AGONIST
= constitutive ACh release
= EXHAUST ACh stores
= Paralysis/Death in small animals, abdominal pain in humans
Botulinum toxin is present in…
Improperly CANNED food
Effect of botulinum toxin?
ACh ANTAGONIST
= inhibit ACh release
= paralysis + suffocation
Name drugs that stimulate/inhibit POSTsynaptic RECEPTORS
Nicotine stimulates ACh receptors
Curare inhibits ACh receptors
Effect of nicotine in low vs high doses?
LOW = Pleasure, addiction, excitatory
HIGH = convulsions + DEATH
Curare blocks ACh receptors in what tissue?
Curare blocks ACh receptors on MUSCLE fibres
Effect of inhibiting ACh reuptake?
Prolonged + Increased effect of ACh
Name drugs that inhibit reuptake
What NTs do they inhibit the reuptake of?
Amphetamines + Cocaine
= AGONISTS of dopamine, norepinephrine, epinephrine
= affects autonomic arousal
= restlessness, insomnia, euphoria
Name an antidepressant and its MoA
Prozac
= block reuptake of serotonin
= relieves depression
Name a benzodiazepine and its MoA
Valium
=GABA agonist
= reduces anxiety, helps sleep
MoA of heroin
AGONIST
= MIMICS endorphins at postsynaptic receptor
= feels good, euphoria, sedation
