4f Flashcards
neuron structure
dendrites
cell body
axon
synaptic terminals
define resting potential
Inactive neuron maintains a constant electrical voltage (-40 -90 mV)
threshold value
minimum reqired energy for the action potential to be triggered
myelin sheath
way to speed up conduction is to cover the axon with a fatty insulation called myelin.
ganglion
woven through the Cnidarians tissues, with a cluster of neurons
cnidarin system
Are composed of a network of neurons, often called a nerve net, woven through the animal’s tissues, with a cluster of neurons, called a ganglion
CNS
Central Nervous system (brain and spinal cord)
PNS
The Peripheral Nervous System (neurons and axons outside the CNS)
somatic
Controls voluntary movements by activating skeletal muscles
parasympathetic
Dominates during times of
“rest and digest”;
directs maintenance activities
brain proctection
Skull
3 layers of connective tiisue (meninges)
Cerebrospinal fluid
Blood brain barrier
brain segments
hindbrain
midbrain
forebrain
symapthetic system
Prepares the body for
stressful or energetic
activity; “fight or flight”
reflex arc
stimulus -> spinal cord -> interneuron -> motor neuron stimulus -> effector muscle -> brain
The motor neurons activate the effector muscle faster than the brain
blood brain barrier
a capillary system that is far less permeable than capillaries in the rest of the body and selectively transports needed materials into the brain while keeping many dangerous substances out
