Brain and spinal cord
Nerves and ganglia
Motor nerves of PNS
Somatic or autonomic
Somatic system nerves
Stimulate skeletal muscle
Autonomic system nerves
Stimulate smooth/cardiac muscles and glands
Subdivisions of PNS
Sensory(afferent) and motor (efferent)
Sensory nerve fibers carry impulses...
toward the CNS.
Motor division carries impulses...
from the CNS to effector organs.
Subdivisions of motor division
Voluntary and autonomic (involuntary)
Two types of nervous tissue cells
Supporting cells and neurons
CNS supporting cells (glia)
Astrocytes, microglia, ependymal, ogliodendrocytes
Function of glia
Support,insulate, and protect neurons
PNS supporting cells
Schwann cells and satellite cells
These form the myelin sheaths around nerve fibers
Most abundant glial cells
Parts of a neuron
Cell body and processes (dendrites and axons)
A neuron may have himdreds of dendrites but...
only one axon.
Role of myelin
Increases rate of nerve impulse transmission
Nodes of Ranvier
Gaps between Schwann cells in myelin sheath
3 functional classifications of neurons
Sensory(afferent), motor (efferent), and association (interneurons)
3structural classifications of neurons
Multipolar, bipolar, unipolar (based on number of processes)
Properties of neurons
Irritability and conductivity
Nerve impulse, all-or-none response
Dense collections of myelinated fibers (tracts) in the CNS
Unmyelinated fibers and cell bodies in CNS
In PNS, bundles of nerve fibers are called...
Reflexes that stimulate the skeletal muscles
Regulate the activity of smooth muscles, heart, glands, body functions
Elements of a reflex arc
Sensory receptor, effector organ, sensory and motor neurons