The Nervous System 2 Flashcards
State the divisions of the nervous system:
The central nervous system, brain, spinal cord
Peripheral nervous system, somatic (voluntary) nerves, autonomic nerves, sympathetic and parasympathetic
What are the two types of nerve cells?
glial cells (support and metabolism) and neurons (functional unit of nervous sytem)
State the role of:
- dendrites
- axons
- myelin sheath
- neurilemma
dendrites receive information from the environment or from other neurons, conduct nerve impulses toward the cell body
axons are an extension of cytoplasm, conducts nerve impulses from cell body to neurons or other effectors
myelin sheath is a coat of fatty protein and acts as insulation, formed by special glial cells (Schwann cells in PNS)
unmyelinated sections called nodes of ranvier
speed up nerve impulses
in all PNS in some CNS
Multiple sclerosis caused by destruction of myelin sheath
neurilemma is a thin outer membrane that surrounds the axon
promotes regeneration formed by schwann cells
found in all nerve cells in pns, not in cns
Describe the three types of neurons.
Sensory Neurons
receive information from sensory receptors (sensors) and relay to CNS
Interneurons
link neurons to neurons in the CNS (brain and spinal cord)
connect sensory neurons to motor neurons
Motor neurons
relay information to effector
What is the reflex arc? Describe the five basic parts.
It is the simplest nerve pathway, involuntary
Sensory receptor
Sensory neuron
Interneuron
Motor neuron
Effector
