Neuron: a nerve cell and the primary functional unit of the nervous system
Dendrites: structures extending from the left side of a neuron that look like tree branches; area where neurons receive most of their information
Receptor sites: areas on a dendrite designed to receive a specific neurotransmitter
Neurotransmitters: receptors on dendrites that are designed to pick up signals from other neurons that come in the form of chemicals
Soma: contains the nucleus, which contains the DNA or genetic material of the cell; those signals picked up by dendrites cause electrical changes in a neuron that are interpreted in the soma
Axon hillock: where the soma takes all the information from the dendrites and puts it together
Axon: the next part of the neuron that the signal is sent
Action potential: signal that travels down the axon, which is covered with myelin
Threshold: level of neurotransmitters required to ‘fire’ a neuron
Neural firing: electrochemical process; electricity travels within the cell and chemicals travel between cells in the synapse
Myelin: insulator material that helps to prevent the signal from degrading
Axon terminals: aka synaptic buttons; last stop of the action potential, then releases the neurotransmitter
Synapse: meeting point between neurons
All-or-none principle: the neuron either fires completely or it does not fire at all
Depolarization: a shift in a neuron’s electrical charge that makes it more likely to fire an action potential
Glial cells: brain cells that surround and support brain neurons
Afferent neurons: aka sensory neurons, take information from the senses to the brain, responsible for transmitting neural impulses from the rest of the body to the brain
Efferent neurons: aka motor neurons, take information from the brain to the rest of the body; carry information that exits the brain
Neurogenesis: the process of new neurons being formed in the brain

Neurotransmitters

Inhibitory neurotransmitters: chemicals released from the terminal buttons of a neuron that inhibit the next neuron from firing
Excitatory neurotransmitters: chemicals released from the terminal buttons of a neuron that excite the next neuron into firing
Acetylcholine: enables muscle action, learning, and memory; problems lead to Alzheimer’s
Dopamine: influences movement, learning, attention, and emotion; oversupply leads to schizophrenia, undersupply to Parkinson’s
Serotonin: affects mood, hunger, sleep, and arousal; undersupply leads to depression
Norepinephrine: helps control alertness and arousal; undersupply can depress mood
GABA (gamma-aminobutyric acid): major inhibitory neurotransmitter; undersupply linked to seizures, tremors, and insomnia
Glutamate: major excitatory neurotransmitter; involved in memory; oversupply leads to migraines or seizures
Endorphins: influence the perception of pain or pleasure; oversupply

with opiate drugs can suppress the body’s natural endorphin supply

Agonists: drugs that mimic neurotransmitters; fit in the receptor siteson a neuron that normally receive the neurotransmitter; function as that neurotransmitter normally would

Antagonists: drugs that block neurotransmitters; fit into receptor sites on a neuron, instead of acting like the neurotransmitter, they prevent natural neurotransmitters from using the receptor site

Psychoactive Drugs

Stimulants: increases neural activity

EX. caffeine, cocaine

Depressants: decreases neural activity

EX. alcohol, barbiturates

Hallucinogens: distortions in perception and/or cognition

EX. marijuana

Opiates: pain relievers

EX. heroin, oxycodone, fentanyl

Tolerance: the brain will produce less of a specific neurotransmitter if it is being artificially supplied by a psychoactive drug; this physiological change produces tolerance, a need for more of the same drug in order to achieve the same effect; will eventually causes withdrawal symptoms in users
Dependence/withdrawal: psychologically dependent individuals feel an intense desire for the drug, they are convinced they need it in order to perform or feel a certain way; physically dependent individuals have a tolerance for the drug, experience withdrawal symptoms without it, and need the drug to avoid the withdrawal symptoms

Nervous Systems

Central nervous system: part of the nervous system that consists of the brain and spinal cord; all the nerves are housed within bone (skull and vertebrae)
Peripheral nervous system: all the nerves in the body other than the brain and spinal cord nerves (that’s the central nervous system), all the nerves not encased in bone; divided into somatic and autonomic
Somatic nervous system: controls voluntary muscle movements; gets impulses from the motor cortex that controls the muscles that allow us to move
Autonomic nervous system: controls the automatic functions of the human body - heart lungs, internal organs, glands, etc.; controls responses to stress - the fight or flight response that prepares the body to respond to a perceived threat; divided into parasympathetic and sympathetic nervous systems
Sympathetic nervous system: mobilizes the body to respond to stress; part of the nervous system that carries messages to the control systems of the organs, glands, and muscles that direct the body’ response to stress; the alert system of the human body; accelerates some functions (heart rate, blood pressure, respiration) but conserves resources needed for a quick response by slowing down other functions (digestion)
Parasympathetic nervous system: responsible for slowing down the body after a stress response; carries messages to the stress response system that causes the body to slow down the autonomic nervous system
Reflex arc: neural chain involved in a reflex; in some reflexive reactions, a sensory neuron transmits an impulse to the spinal cord, and then the spinal cord sends an impulse directly to a motor neuron that moves the muscles
Parts of the Brain (and Body)
- Medulla: involved in the control of blood pressure, heart rate, and breathing; also known as the medulla oblongata and is located above the spinal cord
- Amygdala: vital to our experiences of basic emotions
- Cerebellum: located on the bottom rear of the brain; coordinates some habitual muscle movements
- Hippocampus: memories are not permanently stored in this area of the brain; memories are processed through this area and then sent to other locations in the cerebral cortex for permanent storage
- Thalamus: located on top of the brain stem; responsible for receiving the sensory signals coming up the spinal cord and sending them to the appropriate areas in the rest of the forebrain
- Hypothalamus: controls several metabolic functions; including body temperature, libido, hunger, thirst, and the endocrine system
- Pons: located just above the medulla and toward the front of the brainstem; connects the hindbrain with the midbrain and forebrain; involved in the control of facial expressions and sleep regulation
- Spinal cord: bundle of nerve that run through the center of the spine; transmits information from the rest of the body to the brain
- Limbic system: name for a group of brain structures - thalamus, hypothalamus, amygdala, and hippocampus
- Endocrine system: system of glands that secrete hormones - chemicals that travel through the bloodstream; affects many different biological processes in the body, such as reproduction
- Reticular formation/activating system: netlike collection of cells throughout the midbrain that controls general body arousal and the ability to focus attention; if the reticular formation does not function, we fall into a deep coma
- Broca’s area: located in the frontal lobe and responsible for controlling the muscles involved in producing speech; damage might leave us unable to make the muscle movements needed for speech
- Wernicke’s area: located in the left temporal lobe; interprets both written and spoken speech; damage would affect our ability to understand language
- Left hemisphere: gets sensory messages and controls the motor function for the right half of the body; may be more active during spoken language, logic, and sequential tasks
- Right hemisphere: gets sensory messages and controls the motor function of the left half of the body; may be more active during spatial and creative tasks
- Brain lateralization: aka hemispheric specialization; specialization of function in each brain hemisphere
- Corpus callosum: nerve bundle that connects the two brain hemispheres
- Cerebral cortex: wrinkled surface of the brain; a thin layer of densely packed neurons; covers the rest of the brain, including most of the structures
- Sensory cortex: aka somato-sensory cortex; thin vertical strip of the cerebral cortex that receives incoming touch sensations from the rest of the body; organized similarly to the motor cortex; top receives sensations from the bottom of the body, progressing down the cortex to the bottom, which processes signals from the face and head