Overview of Neurons, Brain Functions, and Sleep Theories

Neurons

A nerve cell; the basic building block of the nervous system and each neuron has a cell body and its branching fibers.

Motor Neuron (efferent)

Neurons that deal with movement.

Sensory Neuron (afferent)

Bring info from senses to the Central Nervous System (brain).

Interneurons

Neurons within the brain and spinal cord that let brain know what's going on and help brain carry out decisions.

Action Potential

A brief electrical charge that travels down the axon.

Dendrites

The neuron's bush, branching extensions that receive messages and conduct impulses towards the cell body.

Axon

The neuron's extension that passes messages through its branching terminal fibers that form junctions with other neurons, muscles, or glands.

Myelin Sheath

Covers and protects the axon. Helps speed up transmission of message.

Glial cells (gila)

Cells that support, nourish and protect neurons. Play a role in thinking, learning and memory.

Terminal Buttons (Terminal Branches of Axon)

End of axon that fits into dendrites.

Excitatory signal

Pushing accelerator (start actions).

Inhibitory signal

Pushing the break (stop actions).

Synapse

The space between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron.

Synaptic Gap

Tiny gap in between neurons (also called synaptic cleft) which when action potential reaches the synaptic gap, it releases neurotransmitters across the synaptic gap.

All or nothing response

Neurons fire or do not fire, greater sensations mean more neurons are firing.

Neurotransmitters

Chemical messengers that cross the synaptic gap, when released they travel across the gap and bind to the receptor site of the new neuron, completing the message.

Reuptake

Excess neurotransmitters are reabsorbed by neuron.

Dopamine

Acts on areas of the brain to give you feelings of pleasure, satisfaction and motivation. (reward feeling)

Serotonin

Acts on areas of the brain to give you feelings of pleasure, satisfaction and motivation.

Acetylcholine

Intervenes in numerous physiological functions, such as regulating cardiac contractions and blood pressure, intestinal peristalsis, glandular secretion, etc.

Endorphins

Hypothalamus and pituitary gland in response to pain or stress, this group of peptide hormones both relieves pain and creates a general feeling of well-being.

Glutamate

Plays a major role in shaping learning and memory.

GABA

Slows down your brain by blocking specific signals in your central nervous system, produces calming effect.

Substance P

Acts on bones and related tissues by binding to receptors, thereby regulating bone metabolism, cartilage metabolism, and fracture healing.

Agonist

Molecules that mimic a neurotransmitter and bind to its receptor and mimic its effect.

Antagonist

Bind to the receptor and block the absorption of neurotransmitter.

Central Nervous System (CNS)

Brain and Spinal Cord, Reflexes- automatic response to a sensory stimulus.

Peripheral Nervous System (PNS)

Brings information to and from the brain.

Autonomic Nervous System (ANS)

Controls our glands and muscles of internal organs and usually operates on autopilot.

Somatic Nervous System

Enablers control of skeletal muscles.

Sympathetic Nervous System

Arouses and expends energy.

Parasympathetic Nervous System

Calms your body and conserves energy.

Endocrine system

The body's 'slow' chemical communication system that secretes hormones into the blood.

Hormones

Chemicals that travel through the bloodstream and affect other tissues and our brain.

Adrenal gland

A pair of endocrine glands that secrete epinephrine and norepinephrine that help arouse the body in times of stress.

Pituitary gland

Pea size structure located in the core of the brain and it controls the release of hormones that promote growth in the human body.

Lesion

Brain tissue destruction (can be experimental or natural).

Brainstem

Oldest and innermost region of the brain and it begins where the spinal cord meets the skull.

Medulla

The base of brainstem, controls heartbeat and breathing.

Thalamus

Located at the top of the brain stem it takes all sense (besides smell) and routes them into the brain.

Pons

Links the medulla and thalamus and coordinates movement.

Reticular Formation

Nerve network in the brain that controls arousal which travels through the brain stem.

Cerebellum

'Little Brain', Rear of brainstem FUNCTIONS: Nonverbal learning, modulates emotions, processing sensory input, coordination movement output.

Limbic System

Maps up of 3 components that are associated with human emotions and drives.

Amygdala

Controls fear and aggression.

Hypothalamus

Control human drives and homeostasis.

Hippocampus

Converts short term memories into long term memories.

Cerebral Cortex

The outer layer of your brain's surface, carries out essential functions of your brain.

Motor Cortex

Region of the cerebral cortex involved in the planning, control, and execution of voluntary movements.

Somatosensory Cortex

The part of the brain within the cerebral cortex that receives all sensory information from various parts of the body.

Frontal Lobe

Part of the brain that controls high-level cognitive skills and primary motor functions.

Parietal Lobe

Vital for sensory perception and integration.

Occipital Lobe

The visual processing area of the brain.

Temporal Lobe

Pair of areas on your brain's left and right sides.

Association Areas

An area of the cerebral cortex that functions in linking and coordinating the sensory and motor areas.

Aphasia

Impairment of language, usually caused by left-hemisphere damage either to Broca's area (impairing speaking) or to Wernicke's area (impairing understanding).

Broca's Area

Controls language expression and is located in the frontal lobe of the left hemisphere and directs muscle movements that make us speak.

Wernicke's Area

Controls language reception in the brain which is located in the left temporal lobe and is involved in language comprehension.

Plasticity

The brain's ability to adapt and change, works best in childhood and can reorganize the brain to make up for damage.

Neurogenesis

The formation of new neurons.

Corpus Callosum

The large band of neural fibers that connect the two brain hemispheres and shares information across the brain.

Split Brain Experiments

Surgery when the corpus callosum is severed in an attempt to help ease seizures.

Brain Imaging Machines

A method used to visualize and study the structure, function, and activity of the brain.

Roger Sperry and Michael Gazzaniga

Studied the split brain.

Paul Broca

French physician, anatomist and anthropologist known for his research on Broca's area.

Carl Wernicke

Studied nerve disease and parts of the brain; discovered Wernicke's area.

Drugs

Chemicals that change perceptions and moods through their actions at the neural synapses.

Tolerance

The diminishing effect with regular use of the same dose of a drug.

Withdrawal

Discomfort and distress when your body does not receive an addictive drug.

Physical Dependence

Body's reaction, body will demand drug and will feel bad.

Psychological Dependence

Not physically addictive, but needed mentally to relieve negative emotions.

Addiction

Compulsive craving for substance despite adverse consequences.

Depressants

Drugs that reduce or slow our neural activity and body functions.

Stimulants

Chemicals known to stimulate the nervous system.

Hallucinogens

Classification of drugs that are known to distort perception and evoke sensory images.

Alcohol

Depressant with pleasurable effects including initial high followed by relaxation and disinhibition.

Marijuana

Mild hallucinogen with pleasurable effects including enhanced sensation and relief of pain.

Cocaine

Stimulant with pleasurable effects including rush of euphoria, confidence and energy.

Methamphetamine

Stimulant with pleasurable effects including euphoria, alertness and energy.

Ecstasy

Can be classified as a stimulant or mild hallucinogen with pleasurable effects including emotional elevation.

Nicotine

Stimulant with pleasurable effects including arousal and relaxation.

Near-Death Experience

Personal experiences associated with impending death encompassing multiple possible sensations.

Alpha Waves

Produced when we are in a relaxed but awake state.

Delta Waves

Cause deep sleep.

Spindles

Bursts of rapid brain activity during NREM 2.

REM (Rapid Eye Movement)

10 minutes of rapid brain activity and our bodies cannot be awakened easily.

REM Rebound

When you don't get enough REM sleep your body will jump to your REM cycle sleep quicker.

Repair and Restoration Theory of Sleep

States that sleep allows for the body to repair and replete cellular components.

Evolutionary Theory of Sleep

Sleep is essential for restoration of resources expended during daily life.

Information Consolidation Theory of Sleep

Information is transferred between the hippocampus and neocortex during sleep.

Clean Up Theory of Sleep

Sleep allows the brain to clean itself, releasing toxins and other waste.

Sleep Apnea

Failure to breathe when asleep, affecting 1 in 20 people.

Insomnia

Difficulty and inability to fall asleep, affecting 10-15% of adults.

Narcolepsy

Strong urge to fall asleep, affecting 1 in 2000 people.

Cataplexy

Loss of muscle control.

Sleepwalking and Sleep Talking

Non-conscious activity such as sleep walking and talking which happens in NREM 3.

Night Terrors

Sudden arousal from sleep with intense fear, affecting 1 in 20, mostly children.

Psychoanalytic Theory of Dreams

Wish fulfillment occurs when unconscious desires are repressed by the ego and superego.

Activation Synthesis Theory of Dreams

A neurobiological approach to explain why humans have dreams.

Information Processing Theory

Theory suggests dreams may be important in helping the brain sort, process, and store information.