Overview Of The Nervous System Part 1

Front 1

Nervous System

Back 1

Consists of neurons and neuroglia; has two main parts, the CNS and the PNS

Front 2

Central Nervous System

Back 2

Consists of neurons and neuroglia; has two main parts, the CNS and the PNS

Front 3

Peripheral Nervous System

Back 3

Consists of nerves and ganglia; lies outside of CNS

Front 4

Nerve

Back 4

A bundle of axons and/or dendrites that lies outside of the brain and spinal cord

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Neuron

Back 5

Consists of a cell body, dendrites and an axon

Convert stimuli into a nerve impulse

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Neuroglia

Back 6

Perform various supporting functions

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Mechanical Signals

Back 7

Touch, temperature, etc.

Front 8

Action Potential

Back 8

Electrical signal that travels along the surface of a neuron's plasma membrane

Beings and propagates through the movement of ions across the plasma membrane

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Neurite

Back 9

any neuronal process - axon or dendrite

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Cell Body

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Soma

Contains nucleus surrounded by cytoplasm

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Perikaryon

Back 11

The cytoplasm surrounding a nucleus

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Nissl bodies

Back 12

Prominent clusters of rough ER

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Neurofibrils

Back 13

Bundles of intermediate filaments that give the cell shape and support

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Microtubules

Back 14

Move substances between the cell body and the axon (transports)

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Dendrites

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Short branching processes that receive signals from other neurons

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Axons

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Long, thin processes (extensions) of neurons. Typically conduct impulses away from the cell body

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Axoplasm

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The cytoplasm of an axon

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Axolemma

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The plasma membrane of an axon

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Axon Hillock

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Where axon attaches to the cell body

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Initial Segment

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Distal to the axon hillock

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Trigger Zone

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Lies in the junction between the axon hillock and initial segment

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Axon Terminals

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End of an axon and any axon collaterals that divide into fine processes

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Multipolar Neurons

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Several dendrites and on axon

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Bipolar Neurons

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One main dendrite and one axon

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Unipolar Neurons

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Have dendrites and one axon that are fused together during development

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Afferent Neurons

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Sensory Neurons

Carry information to the direction impulses are conducted relative to the CNS

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Efferent Neurons

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Motor Neurons

Carry information from the CNS to the effectors

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Interneurons

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Carry information within the CNS

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Astrocytes

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Star-shaped, have many processes

Provide structure for blood-brain barrier

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Protoplasmic Astrocytes

Back 30

Found in gray matter

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Fibrous Astrocytes

Back 31

Found in white matter

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Oligodendrocytes

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Resemble astrocytes, but are smaller

Responsible for forming the myeline sheath of CNS neurons

One myelinates several neurons

Front 33

Microglial Cells

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Small cells with slender processes

Removes debris

Function as phagocytes

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Ependymal Cells

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Cuboidal to columnar-shaped cells arranged in a single layer

Produce cerebrospinal fluid

Form the blood-cerebrospinal fluid barrier

Line ventricles of brain and central canal of spinal cord

Front 35

Glial Cells

Back 35

PNS

Completely surround axons and cell bodies. Two types.

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Schwann Cells

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Form myelin sheath around axons

Myelinates only one neurons

Envelope twenty or more unmyelinated axons

Participate in axon regeneration

Front 37

Satellite Cells

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Flat cells that surround cell bodies

Provide structural support of cell bodies

Regulate exchange of substances between neurons and extracellular fluid

Front 38

Myelin

Back 38

Many layers of plasma membrane wrapped around an axon

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Node of Ranvier

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The gap between each myelinating Schwann cell

Front 40

Neurolemma

Back 40

Provides a sheath or tube that aids in axonal regeneration after injury

Front 41

Rostral-caudal Axis

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Beak and Tail

Front 42

Dorsal-ventral Axis

Back 42

Back and Belly

Front 43

Spinal Cord

Back 43

Mass of nerve tissue located in the vertebral canal, which 31 pairs of spinal nerves origninate

Front 44

Ascending Pathways

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Relay sensory information from the PNS to the brainstem and brain

Front 45

Descending Pathways

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Carry commands from the brain to motor neurons located in the spinal cord

Front 46

Somatic Efferents

Back 46

Within PNS, carry motor neuron commands to skeletal muscle

Front 47

Visceral Efferents

Back 47

Within PNS, carry motor neuron commands to smooth muscle, cardiac muscle and glands

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Medulla

Back 48

Most caudal part of the brainstem and is continuous with the spinal cord

Front 49

Pons

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Lies rostral to the medulla

Front 50

Midbrain

Back 50

Lies rostral to the pons

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Diencephalon

Back 51

Lies rostral to the midbrain

Front 52

Thalamus

Back 52

Processes most sensory input to the brain from the spinal cord and brainstem (except sense of smell)

Front 53

Hypothalamus

Back 53

Integrates information within the autonomic nervous system

Regulates hormone secretion by the pituitary glad

Front 54

Cerebellum

Back 54

Attached to the pons

Important for coordination of muscle movement and learning

Front 55

Cerebral Hemispheres

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Comprised of the cerebral cortex and the basal ganglia

Front 56

Exteroceptors

Back 56

Sensory receptors located in superficial structures like skin

Front 57

Proprioceptors

Back 57

Sensory receptors located in muscles, tendons and joints

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Interoceptors

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Sensory receptors located in visceral organs

Front 59

Somatic Afferents

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Afferent neurons that relay sensory input from body structures

Front 60

Visceral Afferents

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Afferent neurons that relay sensory input from viscera

Front 61

Spinal Nerves

Back 61

Carry afferent input and efferent output to and from spinal cord

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Craininal Nerves

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Carry afferent input and efferent output to and from the brainstem, thalamus and brain

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Endoneurium

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Covers each individual nerve fiber (axon)

Front 64

Perineurium

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Encloses each of the bundles (fascicles)

Front 65

Epineurium

Back 65

Surrounds entire nerve

Front 66

Ganglia

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Swellings on a nerve that contain sensory cell bodies

"Knot"

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Somatic Nervous System

Back 67

Somatic afferent neurons

Somatic efferent neurons

Front 68

Autonomic Nervous System

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Visceral afferent neurons

Visceral efferent neurons

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Sympathetic Division

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Fight or flight division

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Parasympathetic Division

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Rest-and-digest division

Front 71

Enteric Nervous System

Back 71

Digestive system