Nervous System Flashcards
what does the abbreviation “CNS” stand for
central nervous system
what does the CNS consist of
billions of neurons in the brain and spinal cord
what are tracts
bundles of axons in the CNS
axons carry impulses in only one direction in the CNS.
what are those directions and the proper terms for them
ascending: sensory impulses traveling to the brain from the spinal cord
*to the brain
descending: motor impulses traveling from the brain to the spinal cord
*to the spinal cord
what does the abbreviation “PNS” stand for
peripheral nervous system
what does the PNS consist of
all the nerves and receptors outside of the brain and spinal cord
what are nerves
bundles of axons in the PNS
axons carry impulses in only one direction in the PNS.
what are those directions and the proper terms for them
afferent: sensory impulse traveling towards the CNS from PNS
*towards spine
efferent: motor impulses traveling from the CNS to the PNS
*towards receptors
what does autonomic efferent mean
involuntary impulses to smooth muscle, glands, and cardiac muscle
what does somatic efferent mean
voluntary major impulses to skeletal muscle
in the PNS there are sensory (________) and motor (________) neurons
afferent; efferent
in the CNS there are sensory (_____) and motor (_____) neurons
ascending; descending
what are the functions of neurons
sensory, motor, and integrative pathways
there are cranial nerves (enter/exit brain) and spinal nerves (enter/exit) spinal cord
are these nerve part of the CNS or PNS
PNS
what are the two types of cells in the nervous system
neurons and neuroglia (glial cells)
what is the general function of a neuron
to carry impulses across the body in response to stimuli
what is the general function of neuroglia
to support the neurons
what are the general functions of astrocytes
serve as a blood-brain barrier
potassium/sodium/carbon dioxide balance
metabolism of neurotransmitters
repair of damaged areas in CNS
neuronal connections during development
what is the general function of microglia
phagocytes that digest debris
what is the general function of ependymal cells
ciliated cells that line spaces in the brain and aid with movement of cerebrospinal fluid
what is the general function of oligodendrocytes
they make the myelin sheath in the CNS
what is a myelin sheath and what is its purpose
a phospholipid covering around axons of neurons in the CNS and PNS
they aid in conduction of electrical impulses and isolation of the neuron
what are satellite cells
cells in the PNS that support the neurons in ganglia
what are ganglia
nerve cell clusters in the PNS
what is a ganglion
group of neural cell bodies in the PNS
what are Schwann cells
cells that make the myelin sheath in the PNS
what is another name for Schwann cells
neurolemmocytes
satellite cells are analogous to which cells in the CNS
astrocytes
Schwann cells are analogous to which cells in the CNS
oligodendrocytes
why are neurtubules important in a neuron
they provide internal support to the neuron
what is the purpose of the myelin sheath
insulation
make impulses faster
save ATP
which cell makes the myelin sheath in the CNS
oligodendrocytes
which cell makes the myelin sheath in the PNS
Schwann cells
are all neurons in the PNS and CNS myelinated
no there are some unmyelinated neurons as well
does the CNS contain neurolemma
no
does the PNS contain neurolemma
yes
what is neurolemma
the nucleated cytoplasmic (outer) layer of the Schwann cells
unmyelinated axons conduct impulses ________ than myelinated ones
a. faster
b. slower
slower
how are neurons classified
by structure and function
what are the types of structures neurons can have in the nervous system
mulitpolar - many extensions
bipolar - 2 extensions
unipolar - single extension
what does it mean for a neuron to be classified structurally
it is based on the number of extensions on the soma of a neuron
what does it mean for a neuron to be classified functionally
based on the type of impulse that is carried by the neuron
what are the types of functional names a neuron can have
sensory
motor
association or integrative
define resting membrane potential
the difference in voltage between the inside and outside
what is the resting potential voltage in a neuron
-70 mV
why is the inside negatively charged relative to the outside of the membrane
there are many large proteins that are anions with a negative charge
what is the function of the Na+/K+ pump
to maintain resting potential
it pumps out potassium and takes in sodium
does the Na+/K+ pump require ATP
yes
what does the somatic nervous system do
carries sensory information from the PNS to the brain then to the skeletal muscles
does the somatic nervous system innervate with the skeletal system
yes
what does the autonomic nervous system do
involuntary movement of impulses
does the autonomic nervous system innervate with cardiac and smooth muscle
yes
what is the enteric nervous system
nervous system of the gastrointestinal tract that can work independently from the somatic and autonomic
can the enteric nervous system be influenced by the autonomic nervous system
yes
what is depolarization
reversing the charge
*negative to positive
what is repolarization
reversing the reverse charge and putting it back to normal
*positive back to negative
what happens to the membrane during depolarization
the membrane becomes more permeable to Na+ (sodium)
what happens to the membrane during repolarization
the membrane potential is reestablished