CH 2: the biological perspective

nervous system

network of cells that carries info to all parts of body

nervous system 2 divisions

central and peripheral

central nervous system 2 divisions

brain & spinal cord

peripheral nervous system 2 divisions

somatic and autonomic

neuroscience

structure and function of parts of nervous system

neuron

basic cell that receives and sends messages

dendrites

receives messages from other neurons

soma

cell body that maintains a neuron’s life

axon

carries neural message to other cells

axon terminals

communicate w other nerve cells

action potential

electrical signal traveling down axon

myelin sheath

helps speed neural impulses by insulating axons

synapse

site at which chemical communication occurs between neurons

terminal buttons

release chemical signs from neuron into synapse

ions

charged particles

inside neuron=?

negatively charged

outside neuron=?

positively charged

diffusion

ions move from high concentrated areas to low

resting potential

state of neuron when not firing neural impulse

action potential

release of neural impulse, reversal of electrical charge within axon, allows positive sodium ions to enter cell

all-or-none

a neuron either fires completely or non at all, they must be turned ON and OFF

synaptic vesicles

sac-like structures found inside axon terminal containing chemicals

neurotransmitter

messenger chemical in synaptic vesicles, has effect on the next cell when released

how the synapse works

nerve impulse reaches axon terminal. neurotransmitters are released from synaptic vesicles. molecules of neurotransmitter cross synaptic gap to fit into receptor sites. this opens the ion channel allowing sodium ions to rush in.

synaptic gap

space between rounded areas on ends of axon terminals of 1 cell and dendrites of the next cell

receptor sites

3D proteins found on dendrites or certain cells, shaped to fit only certain neurotransmitters

excitatory synapse

neurotransmitter that causes receiving cell to fire

inhibitory synapse

neurotransmitter that causes receiving cell to stop firing

agonists

mimic/enhance effects of neurotransmitter on receptor sites, increasing or decreasing cell’s activity

antagonists

block/reduce a cell’s response to action of other neurotransmitters

reuptake

neurotransmitters are taken back into the synaptic vesicles

enzyme

complex protein that is manufactured by cells

enzymatic degradation

structure of a neurotransmitter is altered so it can’t act on a receptor

lesioning studies

insertion of a thin insulated wire into brain through which an electrical current is sent

brain stimulation

mild electrical current causes neurons to react as if they received a message

deep brain stimulation

invasive; generator sends impulses to brain

transcranial magnetic stimulation

noninvasive; magnetic pulses are applied to the cortex using copper wire coils

computed tomography

computer x-rays of brain

magnetic resonance imaging

brain-imaging using radio waves and magnetic fields to produce detailed images of brain

electroencephalogram

device that records electrical activity of cortical neurons

magnetoencephalography

detects small magnetic fields generated by electrical activity of neurons

positron emission tomography (pet scan)

makes a color-coded image of brain activity

medulla

first large swelling at the top of the spinal cord & lowest part of the brain; breathing, swallowing, heart-rate

pons

larger swelling above medulla that connects top of brain to bottom; sleep, dreaming, left-right body coordination, and arousal

reticular formation

area of neurons running through middle of medulla and pons and slightly beyond; selective attention

cerebellum

parts of lower brain behind the pons; involuntary, rapid, fine motor movement

limbic system

group of several brain structures under cortex; learning, emotion, memory, motivation

thalamus

part of limbic system located in center of brain; processes and relays sensory info from lower parts of brain

hypothalamus

small structure below thalamus and right above pituitary gland; motivational behavior such a sleep, hunger, thirst, and sex

hippocampus

curved structure within each temporal lobe; formation of long-term declarative memories

amygdala

located near hippocampus; fear responses and memory of fear

cingulate cortex

limbic structure found in cortex; cognitive and emotional processing

cortex

outermost covering of brain consisting of densely packed neurons; higher thought processes & interpretation of sensory

corticalization

wrinkling of the cortex; allows larger area of cortical cells to exist in small space in skull

cerebral hemispheres

the 2 sections of the cortex on left and right sides of the brain

corpus callosum

thick band of neurons that connects left and right cerebral hemispheres

occipital lobe

at rear/bottom of each cerebral hemisphere; visual

primary visual cortex

processes visual info from eyes

visual association cortex

identifies and makes sense of visual info

parietal lobes

sections of brain at top & back of each cerebral hemisphere; touch, taste, temperature

somatosensory cortex

area of neurons running down front of parietal lobes; processes info from skin & internal body receptors for touch, temp, and body position

temporal lobes

areas of cortex along sides of brain; hearing & meaningful speech

primary auditory cortex

processes auditory info from ears

auditory association cortex

identifies and makes sense of auditory info

frontal lobes

areas of cortex in front & top of bran; higher mental processes, decision making, and fluent speech production

motor cortex

rear section of frontal lobe; sends motor commands to muscles of somatic nervous system

association areas

areas within cortex responsible for coordination & interpretation of info & higher mental processing

broca’s aphasia

condition resulting from damage to Broca’s area (left frontal lobe); causes loss of speech & mispronounciation

cerebrum

upper brain w 2 hemispheres & structures that connect them

central nervous system

consisting of brain & spinal cord

spinal cord

long bundle of neurons that carries msgs to & from body to brain, responsible for lifesaving reflexes

sensory neuron

carries info from senses to central nervous system (also called afferent neuron)

motor neuron

carries msgs from central nervous system to muscles of body (also called efferent neuron)

neuroplasticity

ability to constantly change both structure and function of cells in response to experience/trauma

neurogenesis

formation of new neurons

somatic nervous system

nerves that control voluntary muscles of body

sensory pathway

nerves carrying msgs from senses to CNS

motor pathway

nerves coming from CNS to voluntary muscles, consists of motor neurons

autonomic nervous system

nerves that control the involuntary muscles, organs, and glands

sympathetic division

fight or flight mode

parasympathetic division

eat, drink, and rest system; restores body to normal functioning after arousal