Unit 2 Flashcards
What is the overall function of the nervous system?
It is a major controlling, regulating, and communicating system in the body, and it uses neurons (nerve cells) to send electrical and chemical messages from cell to cell.
What are the 3 universal properties found in all neurons?
Excitability
Conductivity
Secretion
What are the nervous system’s anatomical subdivisions?
Central nervous system (CNS)—brain and spinal cord
Peripheral nervous system (PNS)—
nerves and ganglia
Define the three most basic functional categories of neurons.
Sensory (afferent) Neurons
Interneurons
Motor (efferent) Neurons
Identify the parts of the neuron
Name the six types of cells that aid neurons, and state their respective
functions.
Describe four structural classes of neurons.
Describe the myelin sheath that is found around certain axons, and explain its importance.
Describe the relationship of unmyelinated axons to their supportive cells.
Describe how conduction spreads in unmyelinated and myelinated axons.
Central Nervous System (CNS)
Brain and spinal cord
Peripheral Nervous System (PNS)
Nerves and ganglia
Nerve
a bundle of nerve fibers
(axons) wrapped in fibrous
connective tissue
Ganglion
a knot-like swelling in a nerve where neuron cell bodies of PNS are concentrated
Sensory (afferent) division of PNS
carries signals from receptors (sense organs)
Visceral sensory division
carries signals from the viscera (heart, lungs, stomach, and urinary bladder)
Somatic sensory division
carries signals from receptors in the
skin, muscles, bones, and joints
Motor (efferent) division
carries signals from the nervous system to effectors (glands and muscles that carry out the body’s response)
Somatic motor division
carries signals to skeletal muscles;
causes voluntary muscle contraction and automatic reflexes
Sympathetic division
stimulates and prepares the body for action
Visceral motor division (autonomic nervous system, ANS)
carries signals to glands, cardiac and smooth muscle; no voluntary
control; responses called visceral reflexes
Parasympathetic division
calming effect on the body
excitability
ability to respond to stimuli
Conductivity
produce electrical signals that are conducted to other
cells
Secretion
when the signal reaches the end of an axon, the neuron can secrete a neurotransmitter that stimulates the next cell
