Nervous System Flashcards
the __________ function is rapid communication by electrical and chemical signals
nervous system
it functions for coordination (integration) of many activities through the conduction of impulses from the receptors (sensory input - afferent) to the effectors (motor output - efferent)
nervous system
it helps maintain homeostasis and mental activity including consciousness, thinking, memory, and emotions
nervous system
what are the five functions of the nervous system
receiving sensory input
integrating information
controlling motor output
establishing and maintaining mental activity
maintaining homeostasis
sensory input
afferent
motor output
efferent
explain how the efferent and afferent work
sensory receptor —[sensory input]—> brain and spinal cord (CNS - Integration) —[motor output] PNS—> effector cells
what are the functional units of the nervous system
neurons or nerve cells
it is a cell that communicates either with one another or with muscles and glands
neurons or nerve cells
a neuron sends messages by conveying a __________
these signals result from the movement of charged ions across the cell membrane
neural impulse
part of the neuron that is the enlarged and rounded part that contains the nucleus, mitochondria that supply ATP, ribosomes that manufacture protein, and other organelles
cell body
parts of the neuron that are short, branched extensions that transmit information toward the cell body
dendrites
the number of dendrites may range from one to thousands, and each can __________ __________ from many other neurons
receive input
part of the neuron that is also called the nerve fiber, conducts nerve impulses away from the cell body
it is a long extension that is finely branched at its tip
axon
the __________, composed of fatty material, coats sections of the axon speeding up nerve impulse conduction
myelin sheath
these are gaps in the myelin sheath coating on the neural axon
nodes of ranvier
it is the propagation of neural impulse along myelinated axons from one node of ranvier to the next node, increasing the conduction velocity of the neural impulses
saltatory conduction
what are the major supporting cells in the nervous system
these cells help hold the nervous tissues together
neuroglia/neuroglial cells
neuroglial cells that are located at the brain and spinal cord, star shaped cells containing microfilaments giving them considerable strength to support neurons
astrocytes
processes of __________ wrapped around capillaries isolate the neurons from various potentially harmful substances in the blood maintaining selective permeability
astrocytes
neuroglial cells that are located at the brain and spinal cord, these cells function as phagocytes, removing microbes and damaged nervous tissues
microglia
neuroglial cells that line the brain ventricles and central canal of the spinal cord
produce and assist in the circulation of CSF
ependymal cells
the __________ protects and nourishes the brain and spinal cord
cerebrospinal fluid
neuroglial cells that are responsible for forming and maintaining the myelin sheath around the neural axons of the brain and spinal cord
a single __________ myelinate several axons
oligodendrocytes