Psychology U1- the nervous system, hormones, neurotransmitters and brain scans

Neurons, neurotransmitters, hormones

Nervous system

The body’s speedy, electrochemical communication network, consisting of all the nerve cells of the central and peripheral nervous systems.

Central nervous system

the brain and spinal cord

Peripheral nervous system

sensory and motor neurons that connect the CNS to the rest of the body.

Nerves

bundled axons that form neutral cables connecting the CNS with muscles, glands and sensory organs

Sensory neuron

Afferent neurons that carry messages from tissues and sensory receptors to the brain and spinal cord

Motor neurons

Efferent neurons that carry messages from the brain and spinal cord to muscles and glands

Interneurons

Neurons within the brain and spinal cord that communicate internally and process information between sensory inputs and motor outputs.

Somatic nervous system

Within the peripheral; voluntary control of skeletal muscles.

Autonomic nervous system

Within the peripheral; involuntary, controls glands and muscles

Sympathetic nervous system

Within the autonomic; arouses body and expends energy.

Parasympathetic

Within the autonomic; calms body and conserves energy.

Homeostasis

For the body to maintain a steady internal state.

Reflex (arc)

A simple, autonomic response to a sensory stimulus.

Neuron

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

Cell body

Part of the neuron that contains the nucleus; the life support center; gives the neuron energy.

Dendrites

Finger-like projections that receive and integrate messages to conduct impulses toward the cell body.

Neural transmission

the electrochemical process in which neurons communicate with eachother.

Myelin Sheath

Fatty tissue layer that segmentally encases axon, enables greater transmission speeds.

Glial cells

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

Action potential

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

threshold

the level of stimulation required to trigger a neural impulse.

Refractory period

A brief resting pause after a neuron has fired. Action potential cannot occur until it has returned to a resting state.

All-or-none response

A neuron’s reaction. Either fires or does not.

Synapse

Small gap between the dendrites of one neuron and the axon terminals of the next which neurotransmitter’s pass through.

Neurotransmitters

Chemical messengers that pass through the synapse.

Reuptake

When leftover neurotransmitters are taken back into the presynaptic neuron, stopping the signal and refusing new ones.

Agonist

a molecule that increases a neurotransmitter’s action

Antagonist

a molecule that inhibits/blocks a neurotransmitter’s action

Endocrine system

the body’s “slow” chemical communication system. A set of glands and fat tissue that secrete hormones into the bloodstream.

Hormone

Chemical messengers created by endocrine glands, travel through the bloodstream and affect other tissues.

Presynaptic terminal

at the end of the axon of a presynaptic neuron, where neurotransmitters are stored in the synaptic vesicles.

Post synaptic membrane

Membrane of the dendrites/cell body of a post synaptic neuron, containing receptors for neurotransmitters.

Receptors

Protein molecules embedded in post synaptic neuron’s membrane that bind to neurotransmitters. When this happens, ion channels will open or close, changing it’s electrical activity

Ion channels

Protein channels in postsynaptic membrane that allow ions to flow in/out in response to neurotransmitters binding. This flow of ions generates electrical signals called postsynaptic potentials.

(neuro)plasticity

the brain’s ability to change, especially during childhood, by reorganizing after damage or by rebuilding new neuro-pathways from new experiences

Lesion

Tissue destruction; may occur naturally during surgery, or experimentally (using electrodes to destroy cells)

EEG (electroencephalogram)

amplified recording of the waves of electrical activity sweeping across the brain’s surface. Measured by electrodes placed on the scalp.

MEG (magnetoencephalography)

brain-imaging technique that measures magnetic fields from the brain’s natural electrical activity

CT (computer tomography)

x-rays of the head generate images that may locate brain damages.

PET (Positron emission tomorgraphy)

Tracks where in the brain a temporarily radioactive form of glucose goes while the person performs a task.

MRI (magnetic resonance imaging)

People sit or lie in a chamber that uses magnetic fields or radio waves to provide a map of brain structure

fMRI (functional magnetic resonance imaging)

Measures blood flow to brain regions by comparing continuous MRI’s

What is the number for the threshold of a neuron

-55 mv

depolarization

the inside of a neuron becomes less negative than the outside as the action potential begins to pass

Repolarization

the inside of the neuron becomes more negative as the action potential has passed

resting potential

the point at which a neuron is recharged and ready for the next action potential

What is the number for the resting potential of a neuron

-70 mv

excitatory neurotransmitters

increases the likelihood that the receiving neuron will fire by allowing positive ions in

Inhibitory neurotransmitter

decreases the likelihood of a neuron firing by allowing negative ions in

Glutamate

Primary excitatory neurotransmitter in the brain. Plays a key role in synaptic transmission and neuron communication

GABA (gamma-aminobutyric acid)

neurotransmitter that promotes relaxation and reduces anxiety, supports sleep

acetylcholine

neurotransmitter with a role in the CNS and PNS; muscle contraction, learning, and memory

Dopamine

neurotransmitter that regulates mood, reward, motivation and movement. Comes in “a rush”

Serotonin

neurotransmitter that regulates mood, sleep, appetite and stress; long term pleasantry

Endorphins

Natural opioids; pain reliever and mood enhancer. “runner’s high”

Substance P

neurotransmitter that transmits pain signals in the nervous system

Ghrelin

Hormone that stimulates appetite and promotes hunger

Leptin

Hormone that regulates energy balance and hunger; feeling of fullnes

Melatonin

Hormone that regulates sleep cycle

Oxytocin

Hormone of social bonding; “love hormone”

adrenaline

hormone of stress response; “fight or flight”

Norepinephrine

hormone and neurotransmitter; In the brain, it regulates arousal, alertness, mood, learning. In the body, it increases heart rate, blood pressure/sugar, prepares body for fight or flight.

Multiple sclerosis

An autoimmune disease that affects the CNS; attacks the myelin sheath causing it to break down overtime

Myasthena Gravis

autoimmune disease that affects the neuromuscular junction, where nerve impulses are transmitted to muscles.

Contralateral Hemispheric organization

phenomenon where each hemisphere of the brain controls opposite sides of the body.

Hemespheric specialization

each hemisphere specializes in it’s functions

Linguistic processing

complex cognitive processing; understanding and producing language

Broca’s area

region in the frontal lobe and left hemisphere; language processing and speech production

Broca’s aphasia

Speech becomes less fluent and broken after a stroke

wernicke’s area

region in the temporal lobe and left hemisphere; language comprehension, understanding of speech/writing

Wernicke’s aphasia

comprehension of language is poor after a stroke