intro to the nervous system Flashcards
what are some examples of neurobiology on a chemical level?
neurotransmitters, receptors, signaling pathways
what are some examples of neurobiology on a cellular level?
neurons, glia, astrocytes
what are some examples of neurobiology on a tissues level?
parenchyma, cerebral cortex
what are some examples of neurobiology on an organs level?
brain, spinal cord
what are some examples of neurobiology on an organ systems level?
nervous, endocrine
what are the two categories of the nervous system?
central nervous system
peripheral nervous system
what makes up the CNS?
brain and spinal cord
what two divisions make up the PNS?
sensory and motor division
what two divisions make up the sensory division of the peripheral nervous system?
visceral sensory division and somatic sensory division
what two divisions make up the motor division of the peripheral nervous system?
visceral motor division and somatic motor division
what two divisions make up the visceral motor division of the motor division of the peripheral nervous system?
sympathetic division and parasympathetic division
what do afferent signals do?
carries signals from receptors to CNS
what is the integration center of the nervous system?
brain
what do efferent signals do?
carries signals from the CNS to muscles and glands
are afferent signals sensory or motor?
sensory
are efferent signals sensory or motor?
motor
where do somatic efferent signals go?
to skeletal muscle
where do visceral efferent signals go?
to glands, or cardiac and smooth muscles
what do sympathetic visceral efferent signals do?
arousal (increase heart rate, respiration, digestion)
what do parasympathetic visceral efferent signals do?
calming (decrease heart rate, respiration, digestion)
what are ganglia?
concentration of cell bodies
what are dendrites?
the detectors. they receive messages from other cells and environment
what is the cell body?
the cell’s life support center
what is does an axon do?
passes messages away from the cell body to other neurons, muscles, or glands
what does the myelin sheath do?
covers the axon of some neurons and helps speed neural impulses (like insulation around a wire makes it more efficient and quicker)
what is a neuron?
a cell that is able to generate its own electricity
what are the three parts of cells?
conductive
secretion
excitability
what is the propagation of action potentials?
conductive
ex) sodium and potassium channels along the axon
what is the release of neurotransmitter?
secretion
ex) vesicle fusion to membrane at axon terminal
what is the binding of neurotransmitter?
excitability
ex) ligand gated channels and receptors at dendrites
what is a synapse?
communication space between axon terminal and the dendrite
T/F: the axon of one neuron touches the dendrite of the other?
False they rarely touch the space between is the synapse for neurotransmitters to be released
how many neurotransmitters are there?
over a 100 that all work in different ways and match with different receptors
what are the two types of receptors?
ion channels
g protein coupled receptors
what are ion channels?
transmembrane proteins that can form a pore in the cell membrane for fast chemical signaling
what are g protein coupled receptors?
receptors involved in a slower cascade of signaling to intracellular proteins
T/F: receptors will only bind a certain type of neurotransmitter
True- sometimes can bind other molecules that “modulate” the activity of the receptor
light, heat, pressure, chemicals
begin in organs and end in CNS
sensory neurons
send signals to muscles and glands
control contraction
motor neurons
exclusively in the CNS
comprise 90% of neurons
integrate signals from multiple neurons to “make decisions”
connect incoming sensory neurons and outgoing motor pathways
interneurons
what are bipolar neurons?
have two processes (dendritic process and axon)
where are bipolar neurons found?
in special sense organs between receptors and other neurons
what are unipolar neurons?
fused dendrite and axon
T/F: most motor neurons are unipolar
false- most sensory neurons are for general senses
what are multipolar neurons?
two or more dendrites and single axon
what is the most common neuron in CNS and all motor neurons controlling skeletal muscles?
multipolar neurons
where are proteins for neurons primarily made?
in the soma
where do proteins for neurons need to go?
axon/dendrite
where do proteins that need to be disposed go?
back to the soma from the axon/dendrites
what are the three types of axonal transport?
fast anterograde, fast retrograde, and slow anterograde
describe fast anterograde
20-400 mm/day
mitochondria
synaptic vesicles
enzymes
small ions and molecules
describe fast retrograde
20-400 mm/day
used synaptic vesicles
pathogens
sends back up
describe slow anterograde
.5-10 mm/day
“stop and go”
cytoskeletal components
replaces worn-out enzymes
repairs damaged nerves
what glia are located in the CNS?
oligodendrocytes
ependymal cells
microglia
astrocytes
what glia are located in the PNS?
schwann cells
satellite cells
describe oligodendrocytes
resembles octopus with up to 15 arms
each arm wraps around nearby axon which forms insulating myelin sheath
job= to make myelin
1 cell can myelinate up to 15 axons
describe ependymal cells
lines internal cavities of brain and spinal cord
they produce and circulate CSF
describe microglia
macrophages that phagocytize dead tissue, debris and pathogens
concentrated at sites of trauma and injury
describe astrocytes
cover brain surface, providing framework for tissue
contact capillaries to form blood-brain barrier
regulate blood flow and composition of tissue fluid
describe schwann cells
has a single arm that produces myelin sheath on axons
job: make myelin
1 cell can myelinate 1 axon
describe satellite cells
insulate somas in ganglia of the PNS
what does the speed of nerve signal transmission rely on?
diameter of the fiber and amount of myelin
how does diameter of fiber effect nerve signal transmission?
conduction occurs at surface, not in axoplasm. more surface area means faster conduction
how does the amount of myelin effect speeds of nerve signal transmission?
unmyelinated 0.5-2 m/s
small myelinated 3-15 m/s
large myelinated up to 120m/s
what are unmyelinated fibers for?
hormonal secretion and pupil dilation
what are myelinated fibers for?
skeletal muscle, sensory signals, balance
