The Nervous System Flashcards
axon hillock
between the soma and the axon, site of signal integration
oligodendrocytes
Produce myelin sheath in the central nervous system
Schwann Cells
produce myelin sheath in the peripheral nervous system
nodes of Ranvier
small breaks in the myelin sheath where axon membrane is exposed
nerve
A bundle of axons in the peripheral nervous system
Ganglia
Bundle of cell bodies in the peripheral nervous system
Tract
bundle of axons in the central nervous system
Nuclei
bundle of cell bodies in the central nervous system
Astrocytes
Form the blood brain barrier
Ependymal cells
Produce the cerebro-spinal fluid
Microglia
phagocytic cells that ingest and break down waste products and pathogens in the CNS
action potential
all or nothing electrical impulse
resting membrane potential
difference in charge between the inside of the neuron and extracellular space
Na/K ATPase
Pumps 3 Na ions out and 2 K ions in using ATP to maintain resting membrane potential
summation
The additive effects of multiple signals
temporal summation
multiple signals are integrated during a relatively short period of time
spatial summation
additive effects are based on the number and location of incoming signals
saltatory conduction
The jumping conduction pattern observed along axons due to ions only able to flow at nodes of ranvier
effector
a gland or muscle being signaled to by a neuron
Three ways to remove NT
- Broken down by enzymatic reactions
- Brought back into neuron using reuptake carries
- Diffuse out of the synapse
Sensory/afferent Neurons
transfer sensory information from receptors to the spinal cord and brain
Motor/efferent Neurons
transmit motor information from brain and spinal cord to the muscles and glands
Interneurons
Found between sensory and motor neurons, responsible for reflexes
supraspinal circuits
Neural circuits used when input from the brain or brainstem is required