Unit 2 Test Flashcards
Neurons
The building blocks of the nervous system. Consists of brain, spinal cord, and nerves
Three Tasks of Neurons:
Receive, Carry, Pass information
The main capability of a neuron is
Transmitting an impulse or “firing”
Dendrites
The branching extensions of a neuron that receive information and conduct impulses toward the cell body. Comes from the Greek word meaning tree
Soma
The cell body of a neuron, which contains the nucleus and other parts that keep the cell healthy. Comes from the Greek word meaning body
Axon
The extension of a neuron through which neural impulses are sent. Some Axons can be up to 3 feet long. Longer axons are covered in myelin sheath that protects it and speeds up transmission
Axon Terminals
The endpoint and point of departure for information
All or None Principle
The principle stating that if a neuron fires it always fires at the same intensity; all action potentials have the same strength. All action potentials are the same strength
Action Potential
A neural impulse; a brief electrical charge that travels down the axon of a neuron. Represents the “on condition” of a neuron
Refractory Period
The “recharging phase” during which a neuron, after firing, cannot generate another action potential
Resting Potential
The state of a neuron when it is at rest and capable of generating an action potential
Synapse
The tiny, fluid-filled gap between the axon terminal of one neuron and the dendrite of another
Neurotransmitters
A chemical messenger that travels across the synapse from one neuron to the next and influences whether a neuron will generate an action potential
Excitatory Effect
A neurotransmitter effect that makes it more likely that the receiving neuron will generate an action potential or “fire.”
Inhibitory Effect
A neurotransmitter effect that makes it less likely that a receiving neuron will generate an action potential or “fire.”
Receptor Cells
Specialized cells in every sensory system of the body that can turn other kinds of energy into action potentials (neural impulses) that the brain can process
Central Nervous System
Includes the brain and spinal cord, encased in bone to protect them. Brain: information processing happens. Spinal Cord: main pathway
Peripheral Nervous System
The sensory and motor nerves that connect the brain and the spinal cord to the rest of the body
Somatic Nervous System
The division of the peripheral nervous system that controls the body’s skeletal muscles
Autonomic Nervous System
The division of the peripheral nervous system that controls the glands and muscles of the internal organs. Its subdivisions are the sympathetic (arousing) division and the parasympathetic (calming) division. Breathing, Blood Pressure, Digestion
Sympathetic Nervous System
The part of the autonomic nervous system that arouses the body to deal with perceived threats. Flight or fight response
Parasympathetic Nervous System
The part of the autonomic nervous system that calms the body
The Endocrine System
One of the body’s two communication systems; a set of glands that produce hormones, chemical messengers that circulate in the blood
Hormones
A chemical messenger produced by the endocrine glands and circulated in the blood. Carry messages. Lock into receptor sites. Slower communication, longer lasting effects
