nervous system Flashcards
neuron
functioning unit of nervous system - those found in brain/spinal chord can’t divide
dendrite
receive messages (diagram term)
cell body
contains organelles (diagram term)
nissl bodies
clusters of rough er and free ribosomes (gray)
axon
continues messages to axon/synaptic terminals
myelin
insulating sheath around an axon consisting of multiple layers of glial plasma membrane; makes message send faster
Schwann cells
glial cell of the PNS that cover axons and make myelin
nodes of Ranvier
small gaps between adjacent cell bodies where message jumps along axon
oligondendrocytes
glial cell that myelinates axons in CNS
multiple sclerosis
progressive destruction of myelin sheaths
lots of inflammation
damage/scarring of nervous tissue
gradual loss of motor control and sensation
can affect brain/SC (produces plaques)
loss of coordination, problems with vision/speech
sensory/afferent neurons
can pick up information on the external or internal environments (diagram term)
motor/efferent neurons
cause of movement of smooth, skeletal, or cardiac muscle (diagram term)
inter neurons
only in brain/sc, link nerves in reflex arch, may playa role in memory (diagram term)
gray matter
neuron cell bodies, located in ganglia (diagram term)
white matter
neuron axons, bundled together as nerve (diagram term)
neuroglia
aka glial cells, support neurons by regulations environment and destroying pathogens. several types exist
action potential
actual message being sent through a neuron
resting potential
+ charge outside axon (Na+)
- charge inside axon (K+)
polarized
depolarization
stimulus triggers an action potential, Na+ channels open and Na+ rushes in: charges switch, hence depolarization
repolarization
K+ ion channels open and repolarization occurs restoring the original charges ( - on inside and + on outside) but the ions are switched
refractory period
reestablishing the correct ion position with the Na+/K+ pump (ATP needed)
no messages can be sent at this time
axon terminal
action potential may jump at the synapse or use a neurotransmitter to inhibit or activate the next neuron
Na+ excites next neuron
K+ inhibits next neuron
endorphins
mood elevators, natural pain killers
norepinephrine
excitatory, alert, energy
dopamine
pleasure, appetite control, focused
phenylethylamine
bliss
serotonin
anger, aggression, mood, metabolism
central nervous system
brain and spinal chords
peripheral nervous system
everything else
somatic nervous system
division of PNS - moves skeletal muscles
automatic nervous system
division of PNS - moves smooth/cardiac muscles and affects fat and glands
brain contains how much neural tissue?
98%
gyrus
brain bump
sulcus
brain depression
fissure
major brain depression
longitudinal fissure
divides cerebrum into left and right cerebral hemisphere
meninges
3 layers that surround brain and spinal chord
cerebrospinal fluid
supports brain / spinal cord; transports nutrients, chemical messengers, and waste products
meningitis
inflammation or infection of the meninges, usually caused by bacteria or virus; symptoms include fever, headache, stiff neck, photophobia or vomiting. bacterial has high mortality rate if not treated
