Neurons
cells that carry information through your nervous system
Dendrite
a branchlike structure that picks up the impulses
Axon
the long structure leading away from the cell body
Synapse
gap between neurons
transfers a nerve impulse from one neuron to another
Salutatory conduction
process in which electrical signal from sensory neuron moves down axon
Axon tips
where electrical signals change to a chemical form, allowing the message to cross the gap in the synapse
Myelin sheath
insulating layer or sheath that forms around nerves; allows electrical impulses to transmit quickly along the nerve cells
like the outside of a wire
Nerve impulses
messages neurons can carry
Stimulus
any change or signal in the environment that an organism can recognize and react to
Response
a reaction to a stimulus
Sensory neuron
picks up a stimulus and converts it into a nerve impulse
Motor neuron
sends an impulse to a muscle or gland, enabling it to respond
Interneuron
carries a nerve impulse to another interneuron or a motor neuron
Neurotransmitters
chemical messengers
Serotonin
regulates sleep, appetite, mood etc.
Melatonin
sleep/tiredness
Dopamine
happiness/reward
Epinephrine (adrenaline)
excitement/fear at work in flight/fight/freeze
Cortisol
stress hormone
Central Nervous System
directs body activities and interprets stimuli
brain and spinal cord are part of CNS
Peripheral Nervous System
gathers information & carries out activities
Somatic Nervous System
controls voluntary actions
Autonomic Nervous System
controls involuntary actions
Sympathetic NS
active when in fight/flight/freeze reaction
Parasympathetic NS
at work when your body is at rest/relaxed
Brain
86 billion neurons, central control of nervous system
Cerebrum
“thinking,” problem solving, learning: voluntary actions
Cerebellum
coordinates muscle movement/balance
Spinal Cord
thick bundle of nerves through vertebrae, connects brain to PNS
Brain Stem
controls involuntary body functions; connects brain to spinal cord
Corpus callosum
connects left and right hemispheres of the brain
Frontal Lobe
thinking, reasoning, behavior, judgment, emotions
Parietal Lobe
perception of stimuli
Temporal Lobe
language, hearing
Occipital Lobe
vision & spatial reasoning
Limbic system
is a set of brain structures located at the top of the brain stem involved in emotions, motivation, memory, especially those related to survival
Amygdala
almond shaped structure responsible for autonomic responses associated w/ fears + hormones, determines memory storage
Hippocampus
directs long term memories to appropriate storage areas and retrieves memories
Hypothalamus
connects brain to endocrine system (hormones),what releases/controls hormones
Thalamus
controls sleep/consciousness by relaying sensory perceptions between brain stem + cerebrum
Cornea
clear tissue that covers the front of the eye
Pupil
opening through which light enters the eye
Iris
a circular structure that surrounds the pupil/regulates how much light enters the eye
Lens
is a flexible structure that focuses light
Aqueous Humor
the clear fluid filling the space in the front of the eyeball between the lens and the cornea
Retina
lines the back of the eye and contains light-sensitive cells
Rods (receptor cell)
work best in dim light and enable you to see black, white, and shades of gray
Cones (receptor cell)
work best in bright light and enable you to see colors
Eardrum
a membrane that vibrates when sound waves strike it
these vibrations pass to the hammer, anvil, and stirrup
Hammer/Anvil/Stirrup
small bones named for their shapes
hammer → anvil → stirrup
Semicircular canal (above cochlea)
helps your Central NS maintain your balance
Ear canal
sound waves travel down (part of outer ear)
Cochlea
a snail-shaped tube lined with sound receptor cells
Auditory nerve
used by sensory neurons to send nerve impulses to the cerebrum
Taste buds
sensory receptors on your tongue
respond to chemicals from anything that have dissolved in your saliva
Touch receptor
enable us to detect the location of the stimulus when an outer force (i.e., touch, pressure) applied and deformed our skin
Myelination
Adding myelin (fat) to the axon of a neuron to speed up signal transfer → learning
Pruning
Getting rid of neural/synapse connection