Nervous system Flashcards
Bootcamp + booster
neuron
is the most basic unit of the nervous system.
-contains three parts: the soma, Dendrites, and the axon
Soma
Cell body
Dendrites
receive information and
transfer it to the cell body
Axon
sends signals out
Axon hillock
where the soma connects
to the axon; action potentials are generated here
Glial cells
nervous tissue support cells
that are capable of cell division
Oligodendrocytes
produce myelin sheath in the central nervous system (CNS)
Schwann cell
produce myelin sheath in the peripheral nervous system (PNS)
Mnemonic: COPS
CO: central nervous system (CNS)/Oligodendrocytes
PS: peripheral nervous system (PNS)/Schwann cell
Myelin sheath
fatty sheaths that act as insulators and are separated by Nodes of Ranvier that allow the action potential to travel continuously down the axon, jumping from node to node, a process known as saltatory conduction, that speeds up the impulse
saltatory conduction
are separated by Nodes of Ranvier that allow the action potential to travel continuously down the axon, jumping from node to node
Nodes of Ranvier
gaps between myelin sheaths where ion exchange occurs.
Microglial
- phagocytes of the CNS
- are macrophages that protect the central nervous system (CNS).
Ependymal cells
use cilia to circulate cerebrospinal fluid, which cushions the CNS
Satellite cell
groups of cell bodies in the PNS that serve as support cells
Sensory (afferent) neurons
receive stimulus from the environment and send the stimulus to the brain for processing (e.g., neurons in the retina of the eye)
- send signals to the spinal cord and subsequently the brain through dorsal roots.
Astrocytes
provide physical support to neurons of the CNS and maintain the mineral and
nutrient balance
- form the blood-brain barrier
Association (interneuron) neurons
located in the spinal cord and brain; receive impulses from sensory neurons and send impulses to motor neurons.
- 99% of nerves are interneurons
- Are found in reflex arcs but some do not require an interneuron
Motor (efferent) neurons
send signals back out to the muscles through ventral roots.
- May stimulate muscles, sweat glands, or cells in the stomach to secrete gastrin
Electrical transmission
a bidirectional action potential that travels along membranes of gap junctions; is less common in the body, fast, and found in cardiac and visceral smooth muscle
Steps of Nerve Impulse Transmission
- Resting potential
- Action potential
- Repolarization
- Hyperpolarization
- Refractory period: Absolute refractory period, and Relative refractory period
Chemical transmission
a unidirectional action potential that is most typical in animal cells
synapse
is the space between two neurons.
presynaptic
neuron sends the signal and releases neurotransmitters into the synapse