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Cell Body
Life support center of the neuron.
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Dendrites
- Branching extensions at the cell body.
- Receives messages from other neurons.
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Axon
- Long single extension of a neuron, covered with myelin sheath.
- Messages pass to other neurons, muscles, or glands.
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myelin sheath
speeds up messages through neurons
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Terminal Branches of axon
Branched endings of an axon that transmit messages to other neurons.
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Threshold
the level of stimulation required to trigger a neural impulse.
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All-or-None Response
A strong stimulus can trigger more neurons to fire, and to fire more often, but it does not affect the action potentials strength or speed.
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Intensity
of an action potential remains the same throughout the length of the axon.
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Synapse
a junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron.
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Neurotransmitters
Chemincal messengers that cross the synaptic gaps sending neurons.
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Reuptake
a neurotransmitter's reabsorption by the sending neuron.
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How Neurotransmitters Influence Us
Serotonin pathways are involved with mood regulation.
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Acetylcholine
- (Neurotransmitter)
- enables muscle action, learning, and memory
- Ex. Alzheimers disease.
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Dopamine
- (Neurotransmitter)
- Influences movement, learning, attention, and emotion.
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Serotonin
- (Neurotransmitter)
- Affects mood, hunger, slee, and arousal.
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Norepinephrine
- (Neurotransmitter)
- Helps control alertness and arousal.
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GABA
- (Neurotransmitter)
- A major inhibitory neurotransmitter.
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Glutamate
- (Neurotransmitter)
- A major excitatory nurotransmitter.
- Involved in memory
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Agonist
Mimics neurotransmitters
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Antagonists
Blocks neurotransmitters.
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Nervous System
- It is the body’s speedy, electrochemical communication system.
- Consists of all the nerve cells of peripheral and central nervous system.
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Central Nervous System
(CNS)
the brain and spinal cord.
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Peripheral Nervous System
(PNS)
the sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body.
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Somatic Nervous System
The division of the peripheral nervous system that controls the body’s skeletal muscles.
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Autonomic Nervous System
Part of the PNS that controls the glands and other muscles.
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Sympathetic Nervous System
Division of the ANS that arouses the body, mobilizing its energy in stressful situations.
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Parasympathetic Nervous System
Division of the ANS that calms the body, conserving its energy.
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Sensory Neurons
Carry incoming info from the sense receptors to the brain and spinal cord(CNS).
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Motor Neurons
Carry outgoing info from the brain & spinal cord (CNS) to muscles and glands.
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Interneuron
- connect the two neurons (sensory & motor)
- Neurons within the brain & spinal cord that communicate internally & intervene between the sensory inputs & motor inputs.
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nerves
Bundled axons that form neural "cables" connecting the central nervous system with muscles glands and sense organs.
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Endocrine System
- The body's "slow" chemical communication system
- A set of glands that secrete hormones into the bloodstream.
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Hormones
Chemical messengers that are manufactured by the encocrine glands, travel throught the bloodstream & affect other tissues.
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Pituitary Gland
- Is called the “master gland.”
- The endocrine system's most influential gland
- Releases hormones that influence growth.
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Thyroid gland
affects metabolism
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Parathyroid gland
Helps regulate the level of calcium in the blood.
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Adrenal Glands
A pair of endocrine glands that sit jst above the kidneys and secrete hormones (epinephrine & norepinephrine) that help aourse the body in times of stress.
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Gonads
- They regulate bodily development and maintain reproductive organs in adults.
- Sex glands are located in different places in men and women.
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Brainstem
- the oldest part of the brain, beginning where the spinal cord swells and enters the skull.
- It is responsible for automatic survival functions.
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Medulla
is the base of the brainstem that controls heartbeat and breathing.
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Reticular Formation
Formation is a nerve network in the brainstem that plays an important role in controlling arousal.
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Thalamus
- is the brain’s sensory switchboard, located on top of the brainstem.
- It directs messages to the sensory areas in the cortex and transmits replies to the cerebellum and medulla.
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Cerebellum
The “little brain” attached to the rear of the brainstem. It helps coordinate voluntary movements and balance.
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lesion
tissue destruction
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Electroencephalogram (EEG)
An amplified recording of the electrical waves sweeping across the brain’s surface, measured by electrodes placed on the scalp.
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PET Scan
a visual display of brain activity that detects a radioactive form of glucose while the brain performs a given task.
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MRI Scan
a technique that uses magnetic fields & radio waves to produce computer-generated images of sort tissue.
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Limbic System
a doughnut-shaped system of neural structures at the border of the brainstem and cerebrum, associated with emotions such as fear, aggression and drives for food and sex
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Amygdala
consists of two lima bean-sized neural clusters in the limbic system, linked to the emotions of fear and anger.
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Hypothalamus
- It directs several maintenance activities like eating, drinking, body temperature, and control of emotions.
- It helps govern the endocrine system via the pituitary gland.
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cerebral cortex
The intricate fabric of interconnected neural cells that covers the cerebral hemispheres. It is the body’s ultimate control and information processing center.
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Frontal lobes
- (forhead)
- Receives sensory input for touch & body position
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Pariental lobe
(top to rear head)
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occipital lobe
- (back head)
- Includes areas that recive info from the visual fields.
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temporal lobe
- (side of head)
- Includes the auditory areas, each receiving info primarily from the opposite ear.
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Motor Cortex
area at the rear of the frontal lobes that control voluntary movements.
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Sensory Cortex
- (parietal cortex)
- receives information from skin surface and sense organs.
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Aphasia
impairment of language
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Broca’s area
impaired speaking
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Wernicke’s area
impaired understanding
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Plasticity
refers to the brain’s ability to modify itself after some types of injury or illness.
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Split brain
a condition resulting from surgery that isolates the brains two hemispheres by cutting the fibers connecting them.
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Corpus callosum
the large band of neural fibers connecting the two brain hemisphere & carrying msgs between them.
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