Chapter 3 Flashcards
central nervous system
brain & spinal cord
peripheral nervous system
- all the other nerves in the body
- divided into somatic and autonomic (inside)
3 types of neurons
sensory, motor, & interneurons
sensory neurons
- detect info from world
- somatosensory provide info from skin and muscles
motor neurons
direct muscles to contract/relax
interneurons
communicate within short circuits
parts of a neuron
dendrites, cell body, axon, and terminal buttons
dendrites
short, branchlike appendages that detect chemical signals
cell body
- aka soma
- collect & integrate info
axon
- transmit signals
- can be really long
- covered in a myelin sheath
terminal buttons
at the end of the axon
synapse
gap where chemical communication occurs between neurons
what is a neuron covered with
a semipermeable membrane that allows ions to travel through ion channels
resting membrane potential
inside a neuron is slightly more negative than outside, so it’s polarized
sodium potassium pump
increases potassium & decreases sodium within cell to maintain resting potential
action potential
aka neural firing
electrical signal that passes along the axon
types of chemical signals
excitatory (depolarize cell membrane by making inside more +) or inhibitory (increase polarization by making inside more -)
what happens when a neuron fires
- sodium gates open–> sodium ions rush in and inside becomes +
- potassium gates open–> K rushes out and inside becomes even more +
- Na then K gates close, cell is even more - than normal
- K-Na pump restores resting state
myelin sheath
insulates axons and allows signals to travel faster
made of glial cells
nodes of Ranvier
small gaps of exposed axon between the sheath
all or none principle
a neuron fires with the same potency each time or not at all
what are the neurons that send/receive signals called
presynaptic sends and postsynaptic receives
neurotransmitters
- made in axon, stored in vesicles in terminal buttons
- convey signals across synapses
receptors
specialized protein molecules located on receiving membrane that respond to a specific neurotransmitter and can open or close ion channels
three major events that terminate a neurotransmitter’s influence
reuptake, enzyme deactivation, or autoreception
reuptake
a neurotransmitter is taken back into the presynaptic terminal buttons
enzyme deactivation
an enzyme destroys a neurotransmitter
autoreceptors
monitor how much neurotransmitter has been released and detect excesses
agonist vs. antagonist
agonists are drugs that enhance actions of neurotransmitters by blocking reuptake or mimicking a neurotransmitter, antagonists inhibit them
epinephrine
- aka adrenaline
- fuels fight or flight response
serotonin
- emotional states, impulse control, dreaming
- lack of it causes depression
dopamine
- associated with motivation and reward
- fuels eating, drinking, and sex
- lack of it causes Parkinson’s
GABA (gamma-aminobutyric acid)
- primary inhibitory neurotransmitter
- lack of it causes anxiety and seizures
glutamate
- primary excitatory transmitter
- excess causes seizures and destruction of neurons
endorphins
-defense against pain
Broca’s area
left frontal region crucial for producing language
electroencephalograph (EEG)
- device that measures brain activity using electrodes
- reflects all brain activity, so too noisy isolate specific responses
positron emission tomography (PET)
- inject a radioactive substance into the blood and see which brain areas receive increased blood flow
- can be dangerous
magnetic resonance imaging (MRI)
-powerful magnetic field disrupts brain’s magnetism–> we can measure energy released from different brain tissues
fMRI
measures blood flow indirectly by assessing changes in oxygen level
transcranial magnetic stimulation (TMS)
uses fast and powerful magnetic field to disrupt brain activity momentarily in a specific region
gray vs. white matter
in the spinal cord: gray is neurons’ cell bodies where white is axons and myelin sheaths
in the brain: gray is neuron bodies with nonmyelinated axons that only communicate locally, where white is the opposite
brain stem
- portion of spinal cord at the base of the skull
- consists of medulla oblongata, pons, and midbrain
- control basic survival functions
- contains reticular formation=network of neurons affecting alertness and sleep
cerebellum
- large protuberance connected to back of brain stem
- important for proper motor function and balance, muscle memory, etc.
forebrain
above brain stem and cerebellum, has a left and right hemisphere, contains cerebral cortex and subcortical regions
limbic system
- subcortical, links older and newer parts of the brain
- includes hypothalamus, thalamus, hippocampus, amygdala, and basal ganglia
thalamus
receives incoming sensory information, organizes it, and relays it to the cortex
hypothalamus
- master regulatory structure, regulates body temperature, blood pressure, and glucose levels
- also involved in motivation like thirst, aggression, and lust
hippocampus
- creates new memories by creating interconnections within cerebral cortex
- involved in how we remember spatially
amygdala
- emotional processing of stimuli, especially fear
- evaluates others’ emotions
- strengthens memory of frightful events
basal ganglia
- system of subcortical structures used for planning, producing, and remembering movement
- contains nucleus accumbens which motivates behavior and experiences rewards
cerebral cortex
- outer, wrinkly layer of cerebral hemispheres
- site of all thoughts, detailed perceptions, and complex behaviors
what are the 4 lobes
occipital, pareital, temporal, and frontal
corpus callosum
bridge between hemispheres
occipital lobes
- located at back of the head
- responsible for vision
- contains primary visual cortex
parietal lobes
- each one receives touch info from opposite side of the body
- contains a primary somatosensory cortex that groups nearby sensations
- this cortex is covered by a somatosensory homunculus, a distorted representation of the body
- also involved in attention
- hemineglect=one side is damaged so patients can’t notice anything on the other side
temporal lobes
- hold primary auditory cortex
- specialized visual areas for recognizing faces (fusiform face area)
- hipppocampus and amygdala
frontal lobes
- planning and movement
- contains primary motor cortex that move muscles
- prefrontal cortex that is responsible for attention to ideas, social life, cultural norms, and a sense of self
lobotomy
damages prefrontal cortex and leaves patients emotionally flat and disconnected from social surroundings
split brain
- when hemispheres are cut, the right and left hemispheres can no longer communicate
- right brain can react but not talk about objects it sees
somatic nervous system
- part of PNS
- transmits signals to the CNS via nerves about sensory details
automatic nervous system
- other part of PNS
- regulates internal environment by stimulating glands & maintaining organs
- sends signals to CNS via nerves about internal conditions like fullness
- contains sympathetic and parasympathetic divisions
sympathetic division
- part of ANS
- prepares body for action when aroused
parasympathetic division
- part of ANS
- returns body back to resting state
endocrine system
- communication network that influences thoughts and behaviors
- slower than nervous system and uses hormones
- primarily controlled by hypothalamus
hormones
- chemical substances released into bloodstream by endocrine glands like pancreas, thyroid, and testes/ovaries
- can be long-lasting
gonads
- endocrine glands influencing sexual behavior (testes or ovaries)
- androgens are more prevalent in males vs. estrogens in females
pituitary gland
- located at the base of the hypothalamus, controls endocrine system
- influences all other glands by producing hormones
plasticity
- ability of the brain to change itself continually
- connections are strengthened by experience during critical periods
- includes neurogenesis, especially in the hippocampus as memory is overwritten
- when done early, certain aspects of the brain compensate for those that have been injured
fire together, wire together
connections are strengthened when neurons fire at the same time
gene expression
whether a particular gene is turned on or off based on environmental factors
heritability
- whether a trait is inherited– found by comparing e.g. a mother and daughter to two strangers and seeing if they have less than the avg variation
- expressed as a decimal or percent
epigenetics
study of how environment can create genetic tags that can be passed on
