Q3: Biology of the Brain Flashcards
Neurons
the building blocks of our nervous system
Santiago Ramon y Cajal
“father of neuroscience” said the nervous system is cells and calls them neurons.
dendrites
receive signals
cell body (soma)
maintains cell life
myelin
insulates axon
axon
sends signals electrically (action potential)
axon terminal
(synaptic button) sends signals chemically
neurons receive inputs:
from the environment via specialized receptors (sensory neuron in skin, ear, eye)
-from other neurons via dendrites
-to other neurons
-to muscles, organs, glands
neurons send signals:
-electrically via axons (1)
-chemically via synapses (2)
1-2-1-2-1-2-1-2-1-2-1-2-1-2-1-2-1-2-1-2-1-2
action potential
a brief change in electrical charge
resting potential
stored energy that results from the separation of positive and negative ions across the axon’s membrane (start straight of graph)
depolarization
Na+ rushes in: less -, more + (climbing hill on graph, after threshold)
repolarization
K+ rushes out, more -, less + (falling back down on graph)
neural threshold
the minimum amount of stimulation needed to fire an action potential
node of ranvier
spaces on a myelinated axon without myelin
saltatory conduction
Action potential jumps from node to node
myelin
insulation of an axon
oligodendrocytes (many)
myelinate the axons in the CNS
schwann (1)
myelinate axons in PNS
unmyelinated axons
can signal at speeds of 1 mph (pain)
myelinated axons
can signal at speeds of 355 mph
plasticity
ability of a brain to rewire/form new connections
neurotransmitter
chemical to be released
synaptic vesicle
carries neurotransmitters
receptors
receives synaptic vesicles via exocytosis
acetylcholine
activates muscles, involved in learning and memory
Alzheimer’s: low levels of it, inc. to treat
dopamine
vital for voluntary movements, attention, emotion, motivation
addiction
schizophrenia: too much of it, dec. to treat
parkinson’s disease: too little of it, inc. to treat (L-DOPA)
reuptake pump
recycles the neurotransmitters after they go into receptors.
serotonin (5 HT)
affects mood, hunger, sleep, and arousal
depression: treated with SSRI, too little serotonin
SSRI
selective serotonin reuptake inhibitor
treatment for depression
norepinephrine
helps control alertness and arousal
depression: low levels
anxiety: high levels
EPSP
positive ions. excitatory postsynaptic potential (allows AP to be fired)
(norepinephrine, serotonin, acetylcholine, dopamine, glutamate)
IPSP
negative ions. inhibitory postsynaptic potential. (GABA)
GABA
inhibitory neurotransmitter.
seizures: too little GABA
anxiety: too little GABA
comas: too much GABA (can be medically induced)
Glutamate
major excitatory neurotransmitter, involved in memory.
seizures: too much
migraines: too much
EEG
(sleep studies) electrodes attach to skull to record brain activity.
-function
CT
computer enhanced x-ray technique.
-structure
PET
computer generated image of the brain, formed by measuring a radioactive tracer, often glucose.
-function
MRI
computer generated image of the brain
-structure
fMRI
computer generated image of the brain, formed by measuring the flow of blood.
-function
Central Nervous System (CNS)
brain and spinal cord
Peripheral Nervous System (PNS)
all neurons not in brain/spinal cord.
have the ability to regrow, regenerate, or reattach if damaged.
Somatic Nervous System (SNS)
info from sensory organs, motor commands to muscles (voluntary functions)
Autonomic Nervous System (ANS)
involuntary bodily processes (ex heart rate, breathing, digestion)
Sympathetic Nervous System
stress response. (norepinephrine). mobilizes resources in response to threat, speeds heart and breathing.
Parasympathetic Nervous System
replenishes bodily resources by promoting digestion and slowing other bodily processes. (rest and digest)
Communication Function
passes messages from body to brain and from brain to body
Integrative Function
mediates spinal reflexes
spinal reflexes
simple, autonomic behaviors that occur without voluntary action.
