Unit 1: Module 1.2 - 1.3b Flashcards
Nervous system
The body’s speedy, electrochemical, communication network
CNS
The brain and spinal cord
PNS
The sensory and motor neurons that connect the central nervous system to the rest of the body
Nerves
Neural cables connecting the CNS with muscles, glands, and sensory organs
Sensory (afferent) neurons
Neurons that carry incoming information from the body’s tissues to the brain/spinal cord
Motor (efferent) neurons
Neurons that carry outgoing information from the brain to the muscles and glands
Inter neurons
Neurons in the brain and spinal cord that process information (motor or sensory)
Somatic nervous system
The division of the peripheral nervous system that controls the body’s skeletal muscles
ANS
Part of the peripheral nervous system that controls the glands and muscles of internal organs
Sympathetic nervous system
The division of the autonomic nervous system that arouses the body
Parasympathetic nervous system
The division of the autonomic nervous system that calms the body
Reflex
A simple, automatic response to a sensory stimulus
Neuron
A nerve cell (building block of nerves)
Cell body
The part of a neuron that contains the nucleus
Dendrites
A neuron’s extension that receives and integrates messages (bushy/branching)
Axon
The segmented neuron extension that passes messages through its branches
Myelin sheath
A fatty tissue layer segmentally encasing the axons of some neurons (faster transmission speed)
Glial cells
Cells in the nervous system that support, nourish, and protect neurons
Action potential
A neural impulse (brief electrical charge that goes down an axon
Threshold
The level of stimulation required to trigger a neural impulse
refractory period
A brief resting pause that occurs after a neuron has fired (happens after a guy you know…)
All-or-none response
A neuron’s reaction of either firing or not firing
Synapse
The junction between the axon tip of the sending neuron and the dendrite
Neurotransmitters
Chemical messengers that cross the synaptic gap between neurons.
Reuptake
A neurotransmitter’s reabsorption by the sending neuron
Endorphins
“Morphine within”; natural, opioid-like neurotransmitters linked to pain or pleasure
Agonist
A molecule that increases a neurotransmitter’s action
Antagonist
A molecule that inhibits or blocks a neurotransmitter’s action
Endocrine system
The body’s “slow” chemical communication system
Hormones
Chemical messengers that are manufactured by the endocrine gland and travel through the bloodstream
Psychoactive drug
A chemical substance that alters the brain (causes changes in perceptions and mood)
Substance use disorder
Continued substance use despite resulting life disruption
Depressants
Drugs that reduce neural activity and slow body functions
Tolerance
The diminishing effect with regular use of the same dose of a drug, requiring the user to take a larger size of a dose
Addiction
An everyday term for compulsive substance use that continues despite harmful consequences
Withdrawal
The discomfort and distress that follow discontinuing an addictive drug or behavior
Barbiturates
Drugs that depress CNS activity (reduces anxiety but impairs memory/judgement
Opioids
Opium and its derivatives; they depress neural activity
Stimulants
Drugs that excite neural activity and speed up body functions
Hallucinogens
Psychedelic drugs that distort perceptions and evoke sensory images in the absence of sensory input
Near-death experience
An altered state of consciousness reported after a close brush with death
