Download 02. Peripheral Nervous System

Peripheral Nervous
System
► All
nervous system outside of CNS.
► Nerves carry information between the organs and
CNS (sensory and motor neurons).
► Includes afferent neurons and efferent neurons.
► Afferent – neurons that collect information and
transmit it toward the CNS.
► Efferent – neurons that transmit information away
from the CNS.
It is made up of :
1. Somatic – voluntary
2. Autonomic – involuntary
Somatic
► Sends
impulses to those muscles that you
control voluntarily
► E.g. – when you use your hands to write
► Also controls many of your reflexes
Autonomic
► The
autonomic system regulates the organs
of the body without conscious control.
► Involves circulatory, respiratory and
digestive systems
► The autonomic system is made up of two
systems:
► 1. Sympathetic
► 2. Parasympathetic
Sympathetic
► Speeds
up certain activities in the body
► Emergency situations, “fight or flight”
response
► Releases adrenaline
► Nerves come from the thoracic and lumbar
sections of the spinal cord
Parasympathetic
► “house
keeper” system
► Promotes digestion, controls size of pupil
► Nerves come from brain, cervical and sacral
sections of spinal cord
Homeostasis and the Autonomic
Nervous System
► The
autonomic nervous system works with
the endocrine system to adjust the body to
the internal/external environment.
► All autonomic nerves are motor nerves that
regulate organs without us knowing it.
Motor somatic nerves are lead to muscles
that are regulated by conscious control.
► Example:
►
1. Blood carbon dioxide and oxygen levels
are monitored throughout the body. When
carbon dioxide or oxygen levels get higher
or lower than normal range, the autonomic
nerves act to restore homeostasis.
► Assigned
Readings:
► P. 435, 436, 437