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 CellsForm 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