Transcript Reflex and autonomic nervous system

Reflex and autonomic
nervous system
The peripheral nervous system
Remember
 The nervous system is
divided into 2 portions
 The central nervous system
 The peripheral nervous system
 The 2 systems are connected
 12 pairs of cranial nerves
connect with the brain
 31 spinal nerves connect CNS
to the rest of the body.
Nerves
 Bundles of axons & dendrites of
neurons.
 Spinal nerves have:
 A dorsal root: caries messages TO
CNS from sensory receptors
 A ventral root: Carries messages
FROM CNS to motor neurons.
 Carry massage to muscles and glands
 Interneurons: relay information
between neurons.
Sensory division
 Has sensory receptors that collect
information form internal and external
environments.
 The information is passed on to the
central nervous system.
Pair share: name 2
things that the sensory
receptors might collect
from the internal and
external environment.
Motor division
 The body’s way of
reacting to the sensory
information.
 Has independent
systems:
 Somatic
 Autonomic
Somatic nervous system
 Controls the movement of
skeletal muscles.
 Has both voluntary and
involuntary components.
 Voluntary is under conscious
control
 Involuntary maintains balance
 Includes reflexes: signals that go to the
spinal column but not the brain.
Pair share: Give a reason why it is important for the body to have
both voluntary and involuntary functions of the nervous system .
Autonomic Nervous
System
 Controls internal
organs and glands,
everything that is
involved in
maintaining
homeostasis.
 Ex: heart beat, pupils
of the eye, blood
vessels, and adrenal
glands.
Subdivisions of the
Autonomic system
 Sympathetic: stimulates the body (stress
response).
 Example: redirects blood from digestive
system to muscles and heart
 Parasympathetic: maintains body under
normal conditions.
 Example: signals body to return to normal
activity
White board Review
1. What are the 2
sections of the
peripheral nervous
system
2. What does the
somatic nervous
system regulate?
3. What is the difference
between the
sympathetic and
parasympathetic
divisions of the
autonomic system?