unit 2 biological bases of behavior Flashcards
neuroanatomy
study of parts & functions of neurons
neurons
individual nerve cells
- make up entire nervous system
dendrites
stretch out from cell body, grow to make synaptic connections w/ other neurons
cell body (soma)
contains nucleus & other parts of cell neded to sustain its life
axon
wirelike structure ending in terminal buttons that extends from cell body
myelin shealth
fatty covering around axon that spreads neural impulses
terminal buttons
branched end of axon that contains neurotransmitters
neurotransmitters
chemicals contained in terminal buttons that enable neurons to communicate
- fit into receptor sites on dendrites of neurons
synapse
space btwn terminal buttons of one neuron & dendrites of next neuron
process of neuron firing
neuron in resting state: slightly negative charge (negative ions inside), selectively permeable membrane
1) terminal buttons of neuron A stimulated -> releases neurotransmitters into synapse
2) neurotransmitters fit into receptor site on dendrites of neuron B
3) when enough neurotransmitters are received (Reaches threshold) -> cell membrane of neuron B becomes permeable & positive ions rush into cell, positive charge
4) action potential: change in charge spreads down length of neuron B & electric message fires
5) charge reaches terminal buttons of neuron B -> buttons release their neurotransmitters into synapse
all-or-none principle
neuron either fires completely or doesn’t fire
- if dendrite receives enough neurotransmitters to push neurons past its threshold, neuron will fire completely every time
neuron firing is electrochemical process
- electricity travels within the cell (dendrite->terminal button, doesn’t jump between neurons!!)
- chemicals (neurotransmitters) travel between cells in synapse
excitatory neurotransmitter
excites next neuron into firing
inhibitory neurotransmitter
inhibits next cell from firing
acetylcholine
function: motor movement
problem when lack: Alzheimer’s disease
dopamine
function: motor movement & alertness
problem when lack: Parkinson’s disease
when excess: schizophrenia
endorphins
function: pain control
problems: involved in addiction
serotonin
function: mood control
problems when lack: clinical depression
GABA
important inhibitory neurotransmitter
problem: seizures, sleep problems
glutamate
excitatory neurotransmitter involved in memory
problem: migraines, seizures
norepinephrine
alertness, arousal
- problem: depression
sensory neurons (afferent neurons)
take information from senses to brain
- part of nervous system
interneurons
when information reaches brain/spinal cord -> take messages & send them elsewhere in brain or on to efferent neurons
motor neurons (efferent neurons)
take information from brain to rest of body
central nervous system (CNS)
brain & spinal cord
spinal cord
bundle of nerves that run through center of spine
- transmits information from rest of body to brain
peripheral nervous system (PNS)
all the neurons not covered in bone
- somatic nervous system & autonomic nervous system
somatic nervous system
controls voluntary muscle movements
- motor cortex of brain sends impulses -> somatic nervous system controls muscles that allow us to move
autonomic nervous system
- controls automatic functions (e.g. heart, lungs)
- controls response to stress: fight or flight response
- sympathetic nervous system & parasympathetic nervous system
sympathetic nervous system
mobilizes body to respond to stress
- carries messages to control systems of organs, glands & muscles that direct body’s response to stress
- alert system: accelerates some functions (heart rate, blood pressure, respiration) BUT conserves energy needed for quick response by slowing down other functions (e.g. digestion)
parasympathetic nervous system
carries messages to stress response system that causes body to slow down “after” stress response
overall structure of nervous system
reflex
certain reactions that occur the moment sensory impulses reach the spinal cord
- in response to intense heat/cold
- adaptive value: passed on to offspring
accidents - study method for brain
phineas gage - front part of brain damaged
- limbic system separated from frontal lobes
- doctor documented how his personality & behavior changed after accident
-> he became more emotional & impulsive, showing that damaged brain was involved in emotional control
lesions - study method of brain
removal/destruction of parts of brain (never done purely for experimental purposes)
- when doctor decides that best treatment is surgery that destroys/disables part of brain
- doctor monitor patient’s change in behavior -> try to infer function of damaged brain part
frontal lobotomy (lesion)
surgery used to control mentally ill patients
- lesioning part of frontal lobe makes patients calm & relieve serious symptoms
electroencephalogram (EEG) - brain study method
detects brain waves -> examines different wave types that brain produces during different stages of consciousness & uses this info to generalize about brain function
computerized axial tomography (CAT/CT) - brain study method
uses serval x-ray cameras that rotate around brain & combine all pictures into detailed 3-dimensional pic of brain structure
- only shows structure of brain, NOT functions/activity of diff brain parts
magnetic resonance imaging (MRI) - brain study method
give pictures of brain, NOT function (similar to CAT scan but w/ greater details)
- uses magnetic fields to measure density & location of brain material (doesnt use x-ray!!)
-> patient not exposed to carcinogenic radiation
functional MRI (fMRI) - brain study method
shows details of brain structure w/ info about blood flow in brain (MRI + PET combined)
- ties brain structure to brain activity during cognitive tasks
overall brain structure
hindbrain
top of spinal cord
- controls basic biological functions that keep us alive
- medulla, pons & cerebellum
medulla - hindbrain
located above spinal cord
- controls blood pressure, heart rate & breathing
pons - hindbrain
located above medulla & toward the front
- involved in control of facial expressions
- connects hindbrain w/ midbrain & forebrain
cerebellum - hindbrain
located on bottom rear of brain
- coordinates some habitual muscle movements (e.g. tracking object w/ eyes)
midbrain
located between hindbrain & forebrain
- coordinates simple movements w/ sensory info
- integrates sensory info & muscle movements
- reticular formation: netlike connection of cells throughout midbrain that controls general body arousal & ability to focus our attention (doesnt work -> deep coma)