Biological Bases of Behavior : Vocab

Neuron

a nerve cell; the basic building block of the nervous system

Dendrite

a neuron's bushy, branching extensions that receive messages and conduct impulses toward the cell body

Axon

the neuron extension that passes messages through its branches to other neurons or to muscles or glands

Myelin sheath

a fatty tissue layer segmentally encasing the axons of some neurons; enables vastly greater transmission speed as neural impulses hop from one sausage-like node to the next

Nodes of Ranvier

gaps in the myelin sheath

Action potential

a neural impulse; a brief electrical charge that travels down an axon

Refractory period

a period of inactivity after a neuron has fired

Threshold

the level of stimulation required to trigger a neural impulse

Depolarization

The process during the action potential when sodium is rushing into the cell causing the interior to become more positive.

Synapse

the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron

Neurotransmitter

chemical messengers that cross the synaptic gaps between neurons

Dopamine

feel good hormone, gives pleasure feeling (nostalgia)
Excess: ADHD
Shortage: parkinsons

Serotonin

mood & sleep, produces melatonin; carries messages from nerve cells to brain; influence digestion, nausea, etc
Excess: severe serotonin syndrome
Shortage: depression, anxiety

GABA

primary inhibitory, blocks impulses for nerve cells
Excess: hypersomnia
Shortage: epilepsy, autism, schizophrenia

Glutamate

learning and memory, energy source for brain cells
Excess: death, parkinsons, alzheimer's

Acetylcholine (ACh)

involved in all body's movements, slows heart rate, contracts smooth muscles
Shortage: dementia, alzheimer's

Norepinephrine

increases alertness, constricts blood vessels, affects sleep-wake cycle
Excess: pheochromocytoma
Shortage: ADHD

Agonist

a molecule that, by binding to a receptor site, stimulates a response

Antagonist

a molecule that, by binding to a receptor site, inhibits or blocks a response

Central nervous system

brain and spinal cord

Peripheral nervous system

connects the CNS to the rest of the body

Sensory (afferent) neurons

carry signals from the body's sensory receptors to the brain

Motor (efferent) neurons

carry signals from brain to the body

Interneurons

within the brain they process info

Somatic nervous system

enables control of skeletal muscles

Autonomic nervous system

controls functions like gland activity, digestion, heartbeat, etc

Sympathetic nervous system

amps you up in response to a stressor

Parasympathetic nervous system

calms you down when stressor is over

Endocrine system

set of glands that secrete hormones into the bloodstream

Pituitary gland

releases hormones related to growth but tells other glands to release sex and stress hormones

Adrenal glands

near the kidneys, releases (nor)epinephrine that gives us fight or flight response

Brainstem

the oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull; responsible for automatic survival functions

Medulla

the base of the brainstem; controls heartbeat and breathing

Pons

helps coordinate movement

Reticular formation

Location: stretches from spinal cord through brainstem and thalamus
a relay network where neurons cross and is responsible for arousal (attention)

Amygdala

Location: in the core
associated with emotion and aggression

Hippocampus

Location: near thalamus
processes conscious memories, translates immediate experiences and transfers them to long term memory

Thalamus

Location: atop the brainstem in the core
"relay center" every sensory input except smell is routed through it

Hypothalamus

Location: below thalamus
contains pleasure centers (releases dopamine), responsible for 4 F's: fighting, fleeing, feeding, and mating

Cerebellum

Location: rear of the skull behind brainstem, below occipital lobe
processes sensory inputs, enables motor coordination and associated with non-verbal learning, sense of balance

Limbic system

neural system (including hippocampus, amygdala, and hypothalamus) located below the cerebral hemispheres; associated with emotions and drives

Cerebral cortex

the intricate fabric of interconnected neural cells covering the cerebral hemispheres; the body's ultimate control and information processing center

Glial cells

cells in the nervous system that support, nourish, and protect neurons

Frontal lobes

location: behind the forehead
involved in speaking, muscle movement, thinking, planning, making judgements, and inhibiting behavior

Parietal lobes

location: top rear of skull
involved in processing of physical touch, helps give us our sense of body positions, helps facilitate language

Occipital lobes

location: far back of skull
involved in visual processing

Temporal lobes

location: right inside and above the ears
responsible for processing hearing, involved in facial recognition

Corpus callosum

connects the hemispheres and transfers messages between them

Motor cortex

location: rear of frontal lobes
controls voluntary "big" movements

Somatosensory cortex

location: front of parietal lobes
processes sensory inputs (especially touch)

Broca's Area

Location: near the rear of the left frontal lobe
responsible for language production (written, spoken, signed)

Wernicke's Area

Location: in left temporal lobe
responsible for language comprehension

Association areas

Location: all over cerebral cortex
involved in cognitive tasks, learning, memory, reasoning, speaking, etc

Split brain

a condition resulting from surgery that isolates the brain's two hemispheres by cutting the fibers (mainly those of the corpus callosum) connecting them