The Nervous System and Its Functions

These flashcards cover key vocabulary and concepts related to the nervous system, neurotransmitters, brain structures, and processes related to sensation and perception.

Nervous System

The body’s speedy, electrochemical communication network, consisting of all nerve cells.

Central Nervous System (CNS)

Comprises the brain and spinal cord, controlling most functions of the body and mind.

Peripheral Nervous System (PNS)

Connects the CNS to the rest of the body, consisting of sensory and motor neurons.

Autonomic Nervous System

Controls involuntary functions such as heartbeat, digestion, and breathing.

Sympathetic Nervous System

Prepares the body for 'fight or flight' responses; arousing.

Parasympathetic Nervous System

Calms the body down after a stressful event; promotes 'rest and digest' functions.

Somatic Nervous System

Controls voluntary movements of skeletal muscles.

Neurons

The basic building blocks of the nervous system, responsible for transmitting information.

Dendrites

Extensions of neurons that receive signals from other neurons.

Axon

The long projection of a neuron that transmits impulses away from the cell body.

Myelin Sheath

Insulates and protects the axon to increase the speed of neural transmission.

Action Potential

The electrical impulse that travels down the axon when a neuron fires.

Neurotransmitters

Chemical messengers that transmit signals across the synaptic gap between neurons.

Reuptake

The process where excess neurotransmitter molecules are reabsorbed by the axon terminals.

Reflex Arc

The neural pathway that mediates a reflex action.

Multiple Sclerosis (MS)

A chronic autoimmune disease that attacks the myelin sheath in the nervous system.

Myasthenia Gravis

A chronic autoimmune neuromuscular disorder causing weakness and fatigue in voluntary muscles.

Excitatory Neurotransmitters

Increase the likelihood of the postsynaptic neuron firing an action potential.

Inhibitory Neurotransmitters

Decrease the likelihood of the postsynaptic neuron firing an action potential.

Agonists

Drugs that mimic neurotransmitters by stimulating receptor sites.

Antagonists

Drugs that block neurotransmitter activity by occupying receptor sites.

Cerebral Cortex

Intricate fabric of interconnected neural cells covering the cerebral hemispheres that function as the body’s ultimate control and information-processing center. Plays a key role in memory, attention, perceptual awareness, thinking speaking, and consciousness, and is organized into loves based on function

Limbic System

Neural system located below the cerebral hemispheres that is associated with emotions and drives

Pituitary Gland

The 'master gland' that controls other endocrine glands and is responsible for the release of hormones throughout the body. 

Circadian Rhythm

The body’s natural 24-hour cycle of biological processes.

NREM Sleep

Non-rapid eye movement sleep; includes lighter stages of sleep leading to deep sleep.

Sensation

The process by which sensory receptors and the nervous system receive stimulus energies.

Perception

The process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events

Afferent Nerves

Nerves that carry sensory information to the central nervous system from the peripheral body.

Efferent Nerves

Nerves that transmit motor commands from the central nervous system to the peripheral body, controlling muscle movements.

Interneurons

Connect sensory and motor neurons within the central nervous system, facilitating communication between them.

Schwann Cells

Glial cells that form the myelin sheath around peripheral nerves, enhancing signal transmission.

Glial Cells

Supportive cells in the nervous system that provide protection, nourishment, and insulation for neurons.

Resting potential

The electrical charge difference across a neuron's membrane when it is not actively firing. This state is crucial for the neuron to be ready to respond to stimulation.

Threshold

The minimum level of stimulation required to trigger an action potential in a neuron, allowing it to transmit a signal.

Refractory Period

The time following an action potential during which a neuron is unable to fire another action potential due to the return to resting potential, ensuring one-way signal transmission.

Acetylcholine

Enables muscle action, learning, and memory. An undersupply is linked to Alzheimer’s disease and an oversupply is linked to paralysis

Dopamine

Influences voluntary movement, learning, attention, and emotion. Undersupply linked to Parkinson’s and an oversupply is linked to schizophrenia

Serotonin

Affects mood, hunger, sleep, and arousal. Undersupply linked to Depression

Norepinephrine

Helps control alertness and arousal. Undersupply linked to depression. Oversupply linked to anxiety

GABA

Inhibitory neurotransmitter: natural tranquilizer involved in calming you down. Undersupply linked to seizures, tremors, and insomnia

Glutamate

Excitatory neurotransmitter: involved in memory. Undersupply linked to concentration problems. Oversupply linked to seizures and migraines

Endorphins

Influence the perception of pain and pleasure. Undersupply linked to depression and an oversupply can make people anxious or create a feeling of euphoria.

Substance P

Pain transmission. Undersupply linked with pain insensitivity and oversupply linked to chronic pain, PTSD, IBD, and arthiritis

Endocrine System

Body’s slow chemical communication system that consists of a series of glands that secrete hormones into the bloodstream.

Hormones

Chemical messengers of the endocrine system

Adrenaline

Released from Adrenal glands. Prepares body for emergencies

Ghrelin

Released from the stomach. Feelings of hunger

Leptin

Released from fat cells. Feelings of satiety

Melatonin

Released from the pineal gland. Regulates the sleep/wake cycle

Oxytocin

Released from the pituitary gland. Facilitates lactation and improve relationships → bonding hormone

Reuptake inhibitors

Block the reuptake process, leaving the neurotransmitter in the synapse longer

Psychoactive drugs

Chemical substances that alter perceptions and moods

Hallucinogens

Distort perception. Can cause false sensory hallucinations, impair memory, feelings of relaxation, and/or euphoria.

ex. marijuana, LSD, ecstasy

Depressants

Reduce neural activity. Increase relaxation, decrease mood and arousal. Slow down bodily processes

ex. alcohol, barbiturates

Opiates

Decrease feelings of pain.

ex. heroin, morphine

Stimulants

Excite neural activity. Increase energy, decrease appetite, brief feelings of euphoria. Speed up bodily process.

ex. caffeine, nicotine, cocaine, meth

Alcohol

Depressant. Initial high followed by relaxation and disinhibition. Eventually leads to depression, memory loss, organ damage, and impaired reactions

Caffeine

Stimulant. Increased alertness and wakefulness. Leads to anxiety, restlessness, and insomnia in high doses; uncomfortable withdrawal

Cocaine

Stimulant. Rush of euphoria, confidence, energy. Leads to cardiovascular stress, suspiciousness, depressive crash

Marijuana

Hallucinogen. Enhanced sensation, relief of pain, distortion of time, relaxation. Leads to impaired learning and memory, increased risk of psychological disorders

Heroin

Depressant. Rush of euphoria, relief from pain. Leads to depressed physiology, agonizing withdrawal.

Brain stem

Oldest part of the brain found at the base of the skull above the spinal cord that is responsible for automatic survival functions

ex. breathing, heartbeat

Reticular formation

Nerve network that travels through the brainstem into the thalamus and plays an important role in controlling arousal. Damage to the activating system could induce a state of permanent sleep or wakefulness

Medulla

Base of the brainstem that controls breathing and heartbeat. If damaged, death is highly likely

Pons

Connects hindbrain, midbrain, and the forebrain together; involved in respiration and REM sleep. Also serves as a communication and coordination center between the two brain hemispheres

Cerebellum

“Little brain” Section at the rear of the brain stem. Coordinates movement and balance, processes sensory input, judgement of time, and enables nonverbal learning and memory.

Thalamus

Sensory “switchboard” located at the stop of the brainstem. Directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla. Receives all sensory information besides smell

Amygdala

responsible for survival emotions of fear and aggression

Hippocampus

Responsible for processing and storing explicit memories of facts and events

Hypothalamus

Located below the thalamus. Directs several maintenance behaviors like eating, drinking, and maintaining optimal body temperature. Helps regulate the endocrine system via the pituitary gland and is linked to emotion and reward.

Pineal gland

Produces melatonin, regulating the body’s sleep cycle

Corpus Callosum

Network of fibers connecting the two hemispheres of the brain together, allowing for communication between them. Can be severed as a treatment for epilepsy but has some interesting effects as one hemisphere no longer can communicate with the other.

Frontal Lobe

Largest lobe. Contains prefrontal cortex Broca’s area, and motor cortex.

Prefrontal cortex

Critical region of the brain located at the front part of the frontal lobe. It is involved in a variety of complex behaviors and executive functions:

ex. Ability to recognizes future consequences, making judgements, planning and decision making, abstract thought, and personality

Broca’s Area

Responsible for controlling muscles that produce speech, Aphasia results in problems with fluency in speech production.

Motor cortex

Sends signals to our body controlling muscle movements

Parietal lobe

Top of the head. Receives sensory input for touch sensations and body position. Contains somatosensory cortex and angular gyrus

Angular gyrus

Written language and number processing, spatial recognition, and elements of memory.

Somatosensory cortex

Specified area of the parietal lobe that takes in sensory input from corresponding body parts

Temporal Lobes

Above the ears. Includes auditory areas, each receiving input from the OPPOSITE ear. Assists with memory. Contains the auditory cortex and Wernicke’s Area

Auditory Cortex

Organization and processing of auditory information

Wernicke’s Area

Responsible for language comprehension. Aphasia results in problems with meaning of speech.

Occipital Lobes

Back of the head and above the cerebellum. Receives input from the visual fields of opposite eyes for visual processing. Contains the visual cortex

Visual cortex

Cortex which is involved with organization and processing of visual information

Neurogenesis

Process of the brain producing new neurons

Neuoplasticity

Brain’s ability to change, build, and reorganize after damage or experience. Process is easier for children than adults

Lesions

Skulls are drilled into and brain tissue is destroyed for behavior modification.

EEG

Electrodes are placed on the scalp to measure electrical activity in neurons. Does not show where the activity originated from.

ex. Depression and anxiety have high activity on the right frontal lobe

CT Scan

X-rays of the head generate images that may locate brain damage. Does not show what part of the brain does what or measure activity. Uses x-rays that can be harmful.

ex. Children’s brain injuries predict impairments in their intelligence and memory processing

fMRI

Measures blood flow to brain region by comparing continuous MRI scans. Considered the best technique because it can show both activity and locate where it is from to tell what part of the brain does what.

ex. Years after surviving a near plane crash, passengers who viewed material related to their trauma showed greater activation in the brain’s fear memory, and visual centers than when they were showed the 9/11 attacks

Split Brain

The Corpus Callosum is severed which causes difficulty in basic tasks because the two hemispheres of the brain cannot communicate with each other

Brain Lateralization

Tendency for some neural functions of cognitive processes to be specialized to one side of the brain or the other.

What does the Left brain control?

Movements and receives sensory inputs from the right side of the body

What does the Right brain control?

Movements and receives sensory input from the left side of the body.

Consciousness

Subjective awareness of ourselves and our environment

Sleep

Periodic, natural loss of consciousness- as distinct from unconsciousness resulting in a coma or hibernation. We sleep for protection, recuperation, restoration of memory, and growth

Stages of sleep

NREM-1, NREM-2, NREM-3, and REM

NREM-1

Light sleep, easily awoken → alpha waves. Can experience hallucinations and hypnagogic sensations

NREM-2

Fully asleep → theta waves with sleep spindles and k-complexes