Unit 1 Quiz 2

Neurons

Specialized nerve cells that form the basic units of the nervous system

Cell Body (soma)

the main part of the neuron that contains the nucleus, keeps the cell functioning, and processes incoming information

Dendrites

Branching extensions that receive signals from other neurons or sensory receptors and carry them toward the cell body

Axon Hillock

the area where incoming signals are combined; if stimulation reaches the threshold, an action potential begins

Axon

A long extension that carries electrical signals away from the cell body

Myelin Sheath

A fatty covering around the axon that protects it and speeds up neural signals. Damage to myelin is associated with multiple sclerosis

Nodes of Ranvier

small gaps between sections of myelin where the neural impulse is regenerated, allowing the signal to travel faster

Terminal Buttons

structures at the ends of axons that release neurotransmitters into the synapse

Gilal Cells

Cells that support, feed, and protect neurons and also contribute to learning and memory

Neuron Firing

a nerve cell generates an electrical impulse, known as an action potential, to send a message through the body

Resting Potential

the neuron’s normal negative electrical charge when it is not sending a signal

Threshold

the minimum amount of stimulation needed for a neuron to fire

Action Potential

a brief electrical signal that travels down the axon after the neuron reaches threshold

All or None Response

Once threshold is reached, the neuron fires completely; if threshold is not reached, it does not fire

Refractory Period

A short recovery period after firing when the neuron cannot immediately fire another action potential

Synapse

The tiny space between neurons where chemical messages are passed from one neuron to another

Reuptake

The process in which the sending neuron transmitters back up after they have been released

Neurotransmitters

Chemical messengers released by neurons that travel across the synaptic gap and communicate with other neurons, muscles, or glands. There are dozens of different neurotransmitters

Acetylcholine

A neurotransmitter involved in muscle movement, learning, and memory. Too much ACh activity can cause uncontrolled muscle contractions or conclusion, while loss of ACh-producing neurons is associated with Alzheimer’s disease

Dopamine

Function: Affects movement, learning, attention, motivation, and reward

Too Little: Associated with Parkinson’s disease —> tremors and decreased movement

Too Much: Associated with schizophrenia and psychotic symptoms

Serotonin

Function: Affects mood, hunger, sleep, and arousal

Too Little: Associated with depression

Too Much: Can cause agitation, confusion, and excessive nervous-system activity

Norepinephrine

Function: Helps regulate alertness, arousal, and mood

Too Little: Associated with depressed mood and low energy

Too Much: Can cause anxiety and excessive arousal

GABA

Function: Major inhibitory neurotransmitters → slows/calms brain activity

Too Little: Anxiety, seizures, tremors, insomnia

Too Much: sleepiness/sedation and slowed brain activity

Glutomate

Function: Excitatory neurotransmitter that is involved in memory

Too Little: Problems with learning and memory, lose focus and mental energy

Too Much: Can overstimulate the brain, causing migraines or seizures (MSG)

Endorphins

Function: Natural painkillers produced by the body; help reduce pain and increase feelings of pleasure/well-being

Too Little: Increased sensitivity to pain and possibly lower mood and more stress

Too Much: Can reduce pain awareness and produce euphoria

Substance P

Function: Neurotransmitter involved in transmitting pain signals to the brain; also involved in inflammation

Too Little: Reduced ability to feel or respond to pain

Too Much: Increased pain and sensitivity and inflammation

Agonists

drugs or chemicals that activate a receptor and mimic or increase the effect of a neurotransmitter

Antagonists

drugs or chemicals that block a receptor, preventing or reducing the effect of a neurotransmitter

Endocrine System

a network of glands and organs that make and release hormones to control many important body functions

Hormones

Chemical messengers carried through the bloodstream that influence mood, growth, etc.

Pituitary Gland

Controls critical body functions by releasing central hormones. Known as the “master gland.” Regulates growth by releasing growth hormones. When the pituitary gland malfunctions, you get gigantism

Adrenal Gland

releases epinephrine or norepinephrine (adrenaline), preparing us for fight or flight, if adrenal gland over works, it can cause anxiety disorders

Thyroid Glands

Deals with the body’s metabolism (how fast your body burns energy), releases thyroxine (regulates how fast your body burns glucose), hypothyroid…hyperthyroid

Sex Glands

they are made up of ovaries (estrogen) and testes (testosterone) and release sex hormones