Nervous Regulation
Brain•Organ of the Central Nervous•It is the primary center for the regulation and control of bodily activities, receiving and interpreting sensory impulses, and transmitting information to the muscles and body organs.•composed of gray matter and white matter.
Neuron-a cell that is specialized to conduct nerve impulses
Cell Body-contains the nucleus and cell
organelles of a neuron, controls metabolic activity
Dendrites-short, highly branched fibers that
receive impulses.• Conduct impulses toward the cell body• Give the cell a “bushy” appearance
Axon- a long, thin fiber that extends
from the cell body.- Carry impulses away from the cell
body and send them either to other neurons or to effectors.
- Range in length: 1 centimeter to 1 meterAlso called a nerve fiber.
Schwann Cells
Form a covering around the axon and produce layers of a white, fatty substance called mylein.
Neuromuscular Junction
The neuromuscular junction (NMJ) is the site of
communication between motor nerve axons and
muscle fibers. The function of the NMJ is to transmit signals from the motor neuron to the skeletal muscle fiber quickly and reliably, to ensure precise control of skeletal muscle
contraction and therefore voluntary movement
Neurotransmitter-are the chemicals which
allow the transmission of signals from one neuron to the next across synapses
Sodium-Potassium Pump-the mechanism that uses ATP energy to reset the sodium and
potassium ions after transmission of a nerve impulse.
Refractory Period
-is when the Na+ and K+ are returned to their original sides: Na+ on the outside and K+ on the inside.
ThresholdThe minimum level of a stimulus required to activate a neuron
Nerve NetA diffuse network of cells that conducts impulses in all directions from the area stimulated, forming a primitive nervous system in coelenterates, and other simple organisms.
Irritability
is an excessive response to stimuli.
ability of a cell to respond to its environment
Ganglion
-a group of nerve cells forming a nerve
center, especially one located outside the brain or spinal cord
Central Nervous System-receives information from and sends
information to the peripheral nervous system.
- the two main organs of the CNS are the brain and spinal cord.
Peripheral Nervous System
--the section of the nervous system lying outside the brain and
spinal cord