The chapter discusses the structure and function of the nervous system. It covers nerve structure, the central nervous system which includes the brain and spinal cord, the peripheral nervous system including somatic and autonomic nerves, and the five human senses. The chapter also addresses aging in the nervous system and how functions generally decline with loss of neurons and myelinization over time.

2. Chapter 9

3. Applied Learning Outcomes
Use the terminology associated with the
nervous system
Learn about the following:
• Nerve structure
• Types of nerve pathways
• Nervous system components
• Central nervous system structure and
function
• Peripheral nervous system structure and
function
Understand the aging and pathology of the
nervous system
Chapter 9 – Structure of the Nervous System

4. Overview
Chapter 9 – Structure of the Nervous System

5. Nerve Structure
A typical nerve is
covered by a
continuous protective
sheet of connective
tissue called the
epineurium. Within
that are
neurofascicles
surrounded by a
covering called the
perineurium.
Chapter 9 – Structure of the Nervous System

6. The Central Nervous System
The central nervous system is composed of the brain and
the spinal cord. Afferent peripheral nerves act as trunks that
feed sensory information to the brain through their entry into
the spinal cord.
Chapter 9 – Structure of the Nervous System

7. The Peripheral Nervous System
The peripheral nervous
system is composed of
somatic nerves,
autonomic nerves, and
ganglia. It is divided into
the sympathetic and
parasympathetic nervous
systems.
Chapter 9 – Structure of the Nervous System

8. Human Senses
• Gustation—Chemoreceptors on the tongue sense
taste
• Olfaction—Chemoreceptors in the nose sense smell
• Vision—Photoreceptors in the retina of the eye
sense light
• Hearing—Neurons in the cochlea sense sound
vibrations
• Equilibrium—Neurons in the semicircular canals and
vestibule of the ear sense position
• Taction or Tactility—Sensory receptors in the skin
perceive touch
Chapter 9 – Structure of the Nervous System

9. Wellness and Illness over
the Life Span
• Most brain aging is due to loss of myelinization
and decreased blood flow.
• Most people show a decrease in complex brain
functions as they age.
• Aging is accompanied by some neuron loss in
the brain. Plasticity and redundancy
compensate for neuron loss in the CNS.
Chapter 9 – Structure of the Nervous System

10. Summary
• The human nervous system is formed of two
components that work together to coordinate
body functions: the central and peripheral
nervous systems.
• Information from the environment is transmitted
to the CNS by nerves of the PNS.
• Sensory information is used by the brain to
formulate a response. Responses of the brain are
channeled to the body via the somatic or
autonomic nervous system.
• Nervous system structure is subject to damage
resulting from a variety of diseases.
Chapter 9 – Structure of the Nervous System