Nervous Flashcards
Neurons examples:
*Cell body
* Dendrites
* Axon
*Myelin sheath
* Nodes of Ranvier
—gaps between
myelin sheath on the axon fiber
*Cell body
contains nucleus and other
organelles
Dendrites
fan out to receive signals
from sensory receptors or other
neurons
Axon
fibers longer than dendrites,
conducts impulses away from cell body
Myelin sheath
formed from
membranes of tightly spiraled cells,
helps impulses travel faster on long
axons, makes nerves look white
Nodes of Ranvier
gaps between
myelin sheath on the axon fiber
The nerve impulse is dependent on ____ _____
concentration gradients
concentration gradients are maintained by ___-____ _____
sodium-potassium pump
sodium-potassium pump
Actively transports sodium ions (Na+) outside axon and
actively transports potassium ions (K+) inside
* This creates: the charge difference!
- Charge difference
inside of axon negative compared to
outside
* Due to unequal distribution of sodium and potassium
cause the inside to have an overall – charge where the
outside has an overall positive charge.
Action potential
or a nerve impulse uses this charge
difference to trigger quick responses throughout the body
Communication between cells
Dendrites receive the signal –> Signal travels to cell body
and is integrated –> Axons carry the signal out of cell body
–> Signal travels down axon to axon terminal where
neurotransmitters are released across synapse to
dendrites of another neural cell
Synapse
region where axon meets its target cell
Neurotransmitters
chemical messages allowing neurons
to communicate
Presynaptic cell
transmits the signal carrying the
message
Postsynaptic cell
– receives signal from presynaptic cell
Synaptic cleft
space between pre and postsynaptic cell
Nervous system is divided into two parts:
central nervous system (CNS) and
peripheral nervous system (PNS)
central nervous system (CNS)
brain and spinal cord
* White and gray matter organization
* Cerebrum and spinal cord structure
peripheral nervous system (PNS)
autonomic and somatic divisions