Transcript NERVOUS SYSTEM & SPECIAL SENSES

NERVOUS SYSTEM
& SPECIAL SENSES
By: Alyce Baughman and Jessica Woodruff
Period 3
FUNCTION OF THE
SYSTEM
-Main function is to control the operation and
movements of the body based on the sensory
information it gathers, both internally and externally
FUNCTIONS INCLUDE:
-To maintain your consciousness
-To help you respond to your senses
-To help coordinate what you sense and feel
-To allow learning and memory
-To control other body systems
NEURON
-Includes a cell
body, dendrites,
and an axon
-Dendrites and the
cell body provide
receptive surfaces
-Axon arises from
the cell body and
can be enclosed in
a myelin sheath
and a neurilemma
-Either multipolar,
bipolar, or unipolar
SYNAPSE
-Junction between 2 neurons
-Presynaptic neuron carries an
impulse into a synapse; postsynaptic neuron responds
-Axons have synaptic knobs at
distal ends, which secrete
neurotransmitters
-Neurotransmitter released
when nerve impulse reaches
end of axon-Neurotransmitter
reaching the postsynaptic
neuron membrane may trigger
nerve impulse
STRUCTURES OF THE
-Composed of100 BRAIN
billion multi-polar
neurons
-Multi-polar neurons
communicate with
one another and with
neurons in other parts
of nervous system
-Subdivided into the
cerebrum,
diencephalon,
brainstem, and
cerebellum
FUNCTIONS OF THE BRAIN
CENTRAL NERVOUS
SYSTEM(CNS)
-Nerves of the brain
and spinal cord
-Central core of the
body
PERIPHERAL NERVOUS
SYSTEM
-Cranial nerves
arising from the
brain
-Spinal nerves
arising from the
spinal cord
-Sensory neurons running from stimulus
receptors that inform the CNS of the stimuli Motor neurons running from the CNS to the
muscles and glands, called effectors, that take
action.
CNS AND PNS
CENTRAL VERSES
PERIPHERAL
AUTONOMIC NERVOUS SYSTEM
-Functions independently(autonomously) and without
conscious effort
-Regulates the visceral activities that maintain homeostasis
-Reflexes controlled from the nerve centers in the brain and
spinal cord
SUB-LEVELS
Sympathetic
-Responds to stressful
and emergency
conditions
-Leave the spinal cord
and synapse in
paravertebral ganglia
Parasympathetic
-Most active under
ordinary conditions
-Begin in the brainstem
and sacral region of
the spinal cord and
synapse in ganglia
near viscera
SOMATIC SENSES
-Senses we feel with our bodies
-Include sensations of touch and pressure, pain
and temperature, and our muscle senses
(proprioception)
Example: If you feel someone touch your arm or
face
SENSE
OF
TASTE
&
SMELL
-The perception of chemicals in the air or in our
food
-Tastants, chemicals in foods, are
detected by taste buds
-Taste buds consist of special
sensory cells
-When stimulated, these cells send
signals to specific areas of the brain,
which make us conscious of the
perception of taste.
-Specialized cells in the nose pick up
odorants, airborne odor molecules
-Odorants stimulate receptor proteins
found on hairlike cilia at the tips of the
sensory cells
-Initiates a neural response.
*Ultimately, messages
about taste and smell
converge, allowing us to
detect the flavors of food*