Nervous System COPY Flashcards
what are the 2 anatomical subdivisions of the nervous system?
central nervous system and perioheral nervous system
the CNS includes?
the brain and the spinal cord
the PNS includes?
all the neural tissue outside the central nervous system
what are the two divisions of the PNS?
the afferent division and the efferent division
what does the afferent division do?
brings sensory information to the central nervous system
what does the efferent division do?
carries motor commands to muscles and glands
what are somatic sensory receptors?
monitor skeletal muscles, joints and the skin
what are the visceral sensory receptors?
monitor other internal tissues such as smooth muscles, cardiac muscle, and glands
?what are special sense organs?
eye and ear (examples)
what is the somatic nervous system?
part of efferent division that controls skeletal muscle contractions
what is the autonomic nervous system?
part of efferent division that regulates smooth muscle, cardiac muscle, and glandular activity
two distinct neural tissue cell types would be?
nerve cells/neurons and supporting cells/neuroglia
what are neurons?
responsible for the transfer and processing of information in the nervous system
what are neuroglia?
supporting cells that isolate the neurons
three functions of neuroglia are?
provide a supporting framework for the neural tissues, help maintain the intercellular environment, act as phagocytes
glial cells are
another name for neuroglia
what are four types of glial cells?
astrocytes, oligodendrocytes, microglia and ependymal cells
what are the five main functions of astrocytes?
maintain the blood-brain barrier, create a 3D frameworl for the CNS, perform repairs in damaged neural tissue, guide neuron development, control the interstitial environment
oligodendrocytes have ___ cell bodies and ____ processes than the astrocytes
smaller and fewer
oligodendrocytes processes
tie clusters of axons together, help regulate extracellular ion concentrations, improve functional performance or neurons
what is myelin?
multilayered mambranous coating with insulating properties
regions dominated by myelinated axons constitute the
white matter
regions dominated by neuron cell bodies, dendrites and unmyelinated axons are called
gray matter
the microglia are the
smallest of the glial cells. they engulf cullular debris, waste products, and pathogens
the ependymal cells are the
cellular lining of the ventricles in the brain and central canal of the spinal cord
two involved glial cell types are
Schwann cells and Satellite cells
satellite cells
regulate the exchange of nutrients and waste products between the neuron cell body and the extracellular fluid
schwann cells
are the covering of every peripheral axon
what is a synapse?
a specialized site where the neuron communicates with another cell
anaxonic neurons are
small, and found only in CNS. not very well understood
bipolar neurons are
rare. they have fine dendrites that fuse to form a single dendrite. important in relaying sensory information concerning sight, smell and hearing. NOT MYELINATED
pseudounipolar neurons are
sensory neurons of the PNS and axons MAY be myelinated
multipolar neurons are
most common type of neuron found in CNS. have several dendrites with one axon.
what are the three classifications of receptors?
exteroceptors, proprioceptors, and interoceptors
exteroceptors do what?
provide information about the external environment in the form of touch, temp, and pressure. and sight, smell and hearing
proprioceptors monitor
the position and movement of skeletal muscles and joints
interoceptors monitor
the digestive, respiratory, cardiovascular, urinary and reproductive systems and provide sensations of deep pressure and pain as well as taste
axons traveling away from the CNS are called
efferent fibers
motor neurons are
multipolar neurons that form efferent division of the nervous system
interneurons are
sutuated between sensory and motor neurons
interneurons are located where?
entirely with in the brain and spinal cord
wallerian degeneration
the axon distal to the injury site deteriorates and macrophages migrate in to phagocytize the debris
the Schwann cells are involved how?
release growth factors to promote axonal regrowth
what is excitability?
the ability of a cell membrane to conduct electrical impulses
what are nerve impulses?
action potentials traveling along axons
the rate of impulse conduction depends on what 2 properties?
the presence or absence of the myelin sheath and the diameter of the axon
electrical synapses
found between neurons in both the CNS and PNS
what is a neuronal pool?
group of interconnected neurons with specific functions
five functions of neuronal pools
divergence, convergence, serial processing, parallel processing, reverberation
what is divergence?
spread of information from one neuron to several neurons
what happens in convergence?
several neurons synapse on the same postsynaptic nueron
what happens in serial processing?
information may be relayed in a stepwise sequence, from one neuron to anotheer
parallel processing occurs when
several neurons or neuronal pools are processing the same information at one time
reverberation is
a positive feedback
in the CNS a collection of neuron cell bodies is called what?
a center
