Packet 1: Sensation, Perception, and Brain Structures

Epigenetics*

how genes and environment (diet, experiences, surroundings) interact to turn gene activity on or off

Heritability

how much variation in a group's trait is due to genes

Nervous system

network of specialized cells carrying information throughout the body

Neuroscience

study of the structure and function of neurons, nerves, and nervous tissue

Biological psychology / behavioral neuroscience

neuroscience focused on the biological basis of behavior, thinking, and learning

Neuron

specialized cell that sends and receives messages in the nervous system

Dendrites

branch-like structures that receive messages from other neurons

Soma

cell body that keeps the cell alive

Nucleus

control center inside the soma holding the genetic material

Axon

tube-like structure carrying the message from the soma to the axon terminals

Axon terminals

enlarged ends of the axon branches that communicate with other cells

Myelin

fatty coating on axons that insulates, protects, and speeds up the impulse

Nerves

bundles of myelin-coated axons that run through the body

Glial cells

support cells that feed neurons, make myelin, clean up waste, and help maintain homeostasis

Resting potential

neuron not firing, at about -70 mV (negative inside, positive outside)

Depolarization

the inside of the cell becomes less negative as sodium rushes in

Action potential

the neural impulse, a reversal of charge traveling down the axon

All-or-nothing principle

a neuron fires completely or not at all (threshold about -55 mV)

Refractory period

brief time (1-2 ms) after firing when the neuron can't fire again

Synaptic vesicles

sacs in the synaptic knob that hold neurotransmitters

Neurotransmitters

chemicals released into the synapse that affect the next cell

Synapse / synaptic gap

tiny fluid-filled space between the axon terminal and the next cell

Receptor sites

proteins on dendrites, muscles, or glands shaped to fit specific neurotransmitters

Excitatory neurotransmitter

makes the next neuron more likely to fire ("ON")

Inhibitory neurotransmitter

makes the next neuron less likely to fire ("OFF")

Antagonists

bind to a receptor and block it (e.g., Narcan)

Agonists

bind to a receptor and mimic the natural neurotransmitter (e.g., morphine)

Substance P

neuropeptide involved in pain perception and sending pain signals

Reuptake

neurotransmitters taken back into the sending neuron ("vacuum cleaner")

Enzymatic degradation

an enzyme breaks down a neurotransmitter (e.g., ACh)

Central nervous system (CNS)

brain and spinal cord

Spinal cord

bundle of neurons carrying messages between body and brain; handles fast reflexes

Sensory (afferent) neuron

carries info from the senses to the CNS

Motor (efferent) neuron

carries messages from the CNS to muscles and glands

Interneuron

connects sensory and motor neurons in the spinal cord; makes up most of the brain

Reflex arc

sensory neuron → interneuron → motor neuron, producing a reflex

Neuroplasticity

the brain's ability to change its structure and function in response to experience or injury

Neurogenesis

formation of new neurons

Stem cells

cells that can become other cell types

Peripheral nervous system (PNS)

all nerves outside the brain and spinal cord

Somatic nervous system

carries sensory info in and controls voluntary muscles

Autonomic nervous system

controls involuntary muscles, organs, and glands

Sympathetic division

"fight or flight"

Parasympathetic division

"rest and digest"