Unit 3: Biology & Behavior

central nervous system

the brain and the spinal cord; coordinates body functions, connects body with brain, and simple reflexes

peripheral nervous system

all nerve cells in the body that are not part of the central nervous system; includes the somatic and autonomic nervous systems

neurons

basic units of the nervous system; cells that receive, integrate, and transmit information; operate through electrical impulses, communicate with each other through chemical signals, and form neural networks

dendrites

branchlike extensions of the neuron that detect information from each other

cell body/soma

the site in the neuron where information from thousands of other neurons is collected and integrated; the contains the nucleus and other parts that keep the cell healthy

axon

a long, narrow outgrowth of a neuron by which information is conducted from the cell body to the terminal buttons; sends neural impulse

terminal buttons/terminals/axon terminals

at the ends of axons, small nodules that release chemical signals from the neuron into the synapse, hold neurotransmitters

synapse

the tiny, fluid-filled gap between the terminal buttons of a “sending” neuron and the dendrites of a “receiving” neuron; where chemical communication occurs between the neurons

action potential

the electrical signal that passes along the axon and subsequently causes the release of chemicals from the terminal buttons; “on” condition of the neuron; generated by the movement of positively charged atoms in and out of channels in the axon’s membrane

resting potential

the electrical charge of a neuron when it is not active; “off” state; positively charged ions waiting to flow into the axon and be stimulated by another neuron

refractory period/hyperpolarization

the brief period of time following action potential when a neuron’s membrane potential is more negative, or hyper-polarized, making it harder to fire again; reloading

all-or-none principle

the principle that when a neuron fires, it fires with the same potency each time; a neuron either fires or not, although the frequency of firing can vary (ex. gunshots)

split brain

a condition that occurs when the corpus callosum is surgically cut and the two hemispheres of the brain do not receive information directly from each other, two separate brains

myelin sheath

a fatty material; made up of glial cells; insulates some axons to allow for faster movement of electrical impulses along the axon; degeneration of this causes multiple sclerosis

nodes of ranvier

small gaps of exposed axon between the segments of myelin sheath, where action potentials take place; gaps in the myelin sheath where there is no myelin among an axon

neurotransmitters

chemical substances that transmit signals from one neuron to another; SNAGGED

receptors

in neurons, specialized protein molecules on the postsynaptic membrane; neurotransmitters bind to these molecules after passing across the synapse

reuptake

the process whereby a neurotransmitter is taken back into the presynaptic terminal buttons, thereby stopping its activity; reabsorption

amygdala

the part of the brain that controls emotional responses such as fear or anger

brainstem

the part of the brain that contains the pons, the medulla, and the reticular formation; responsible for automatic and survival functions like breathing

cerebellum

the part of the brain that helps coordinate voluntary movements, balance, and fine movement

cerebrum

the part of the brain that is the body’s ultimate control and information processing center

corpus callosum

the part of the brain that connects the two brain hemispheres and allows them to communicate with each other

hippocampus

the part of the brain that helps process new memories for permanent storage

hypothalamus

the part of the brain that regulates body maintenance, activities such as eating, drinking, body temperature; linked to emotion; feeding, fighting, fleeing, fOrNiCaTiNg

medulla

the part of the brain that controls life-supporting functions like heartbeat and breathing

pituitary gland

the part of the brain that controls the other endocrine glands

pons

the part of the brain that is involved with movement, sleep, and arousal

reticular formation

the part of the brain that that plays an important role in controlling alertness and arousal; nerve network

thalamus

the part of the brain that acts as the sensory switchboard relay system; directs messages to the sensory receiving areas for all senses except smell

left hemisphere

the hemisphere of the brain that controls verbal processing, logical ability, the right side of the body, language functions, computation, speech, reading, and writing

right hemisphere

the hemisphere of the brain that controls the left side of the body, non-verbal communication, visual spatial tasks, making connections between words, musical ability, and emotions

plasticity

the brain’s capacity for modification and reorganization following damage, especially in children

split brain

a condition in which the two hemispheres are separated by cutting the connecting fibers (mainly those of the corpus callosum) between them

frontal lobes

lobes of the brain that are involved in speaking, muscle movement, making plans and judgments, language, and higher-level thinking skills; contains Broca’s area

parietal lobes

lobes of the brain that register our sense of touch; include the somatosensory cortex; behind the frontal lobes

occipital lobes

lobes of the brain that include the visual areas and receive information from the opposite visual field

temporal lobes

lobes of the brain that process sound and smell information, and recognition of faces; contains Wernicke’s area

Wernicke’s area

the area in our brain in charge of our ability to understand anything said to us

limbic system

the brain’s emotional center; helps regulate memory, aggression, fear, hunger, and thirst; includes the hypothalamus, hippocampus, and amygdala

lesion

destruction of brain tissue that can be either naturally or experimentally caused

EEG (electroencephalogram)

records electrical activity in brain; electrodes placed on scalp; can show brain wave patterns of electrical activity during sleep stages and seizures; shows function of brain; noninvasive but difficult to determine which specific brain structures are producing electric activity

CT scan (computed tomography)

a series of x-ray photographs taken from different angles; composite representation of a slice through the brain; looks at brain structure; views large brain abnormalities

PET scan (positron emission tomography)

displays brain activity; detects where a radioactive form of glucose goes; looks at brain function; allows investigation of mental illness, neurological problems, and drugs

MRI (magnetic resonance imaging)

uses magnetic fields and radio waves to produce computer generated images distinguishing different types of soft tissue; provides an in detail look at brain structure; cannot be used by patients with metal structures

nervous system

the electrochemical communication system of the body

glial cells

provide structural support and insulation for neurons

synaptic vesicles

small sacs within the terminal buttons that contain neurotransmitters

serotonin, norepinephrine/noradrenaline, acetylcholine, glutamate, GABA (gamma aminobutyric acid), endorphins, dopamine

what does SNAGGED stand for? (neurotransmitter acronym)

serotonin

neurotransmitter involved in mood control, appetite, and sleep; linked to depression, increased anxiety, OCD, impulsive behavior, aggression

norepinephrine/noradrenaline

neurotransmitter involved in arousal, reward, fight/flight response; linked to anxiety and mood conditions like depression and bipolar disorder

acetylcholine

neurotransmitter involved in motor movement, short term memory, anger, and agression; lack → Alzheimer’s disease, paralysis; excess → muscle spasms

glutamate

neurotransmitter involved in memory and learning; an excitatory neurotransmitter that encourages neurons to fire

GABA (gamma aminobutyric acid)

neurotransmitter involved in inhibition of the central nervous system; an inhibitory neurotransmitter that reduces neurons’ likelihood of firing an action potential; involved in floods of brain signals epileptic seizures

endorphins

neurotransmitter involved in pain control and positive emotions; natural opiate; released during aerobic exercise

dopamine

neurotransmitter involved in feelings of pleasure, motor movement, reward and motivation, alertness, and mood; lack → Parkinson’s disease; excess → schizophrenia

inhibitory PSP (postsynaptic potential) effect

makes it less likely for the 2nd neuron to fire

excitatory PSP (postsynaptic potential) effect

makes it more likely for the 2nd neuron to fire

agonist

mimics/strengthens the effects of neurotransmitters; ex. heroin, oxycodone, methadone, morphine (mimics endorphins)

interneurons

neurons that act as the middleman between other neurons

somatic nervous system

part of the peripheral nervous system that controls the body’s skeletal muscles; contains motor nerves (afferent and efferent) needed for the voluntary muscles

afferent nerves

sensory nerves; connects the sense organs to the brain and spinal cord

efferent nerves

motor nerves; carry messages from the brain and spinal cord to move other parts of your body

autonomic nervous system

part of the peripheral nervous system that controls glands and muscles that work on their own; controls processes like breathing, blood pressure, digestive processes; contains sympathetic and parasympathetic nervous system

sympathetic nervous system

part of the autonomic nervous system that arouses the body to deal with perceived threats; freeze/fight/flight response, stimulates the body

parasympathetic nervous system

part of the autonomic nervous system that calms the body and brings it back to its relaxed state; in control most of the time; rest and digest

hormones

slower chemical messenger than neurotransmitters; released from the endocrine glands that travel through the bloodstream to targeted tissues which become influenced; lower communication system with longer lasting effects than neurotransmitters

pineal gland

gland that secretes melatonin and regulates the sleep cycle

adrenal gland

gland that releases norepinephrine; arouses the body in times of stress; located above kidneys

thyroid gland

gland that regulates energy level and metabolism; located in neck

gonads

the organs that secrete either testosterone or estrogen; also glands that influence emotion and physical development

behavior genetics

studies effects of genes vs environmental influence on behavior

depolarization

the process in neural communication in which positively charged ions flood through the axon’s membrane; toilet flushing

direction of impulse

the neural impulse travels in a direction toward the axon terminals

threshold

the level of stimulation required inside the axon to trigger a neural impulse

heritability

a statistical estimate of the extent to which variation in a trait within a population is due to genetics

endocrine system

a communication system that uses hormones to influence thoughts, behaviors, and actions

Broca’s area

part of the brain involved in the physical production of speach

ion channels

these gates are closed when the neuron is at rest and allows ions to flow in and out when the neuron receives a signal

postsynaptic neurons

the type of neuron that receives neurotransmitters and their message

presynaptic neurons

the type of neuron that sends its neurotransmitters across the synapse

fMRI

uses magnetic fields to produce images of the brain and tracks real-time brain activity by measuring blood flow carrying oxygen to active brain tissue; provides a look at both brain function and structure