Download Unit 10 Chapter 36 The Nervous System

Unit 10
Chapter 36
The Nervous System
The Nervous System
Neurons
Nerves cells, the basic unit of structure &
function of the nervous system
The Nervous System
Neuron structure:
Dendrites
Branchlike extensions that receive impulses &
carry them toward the cell body
Cell body
Location of the nucleus & much of the
cytoplasm
Axons
Extensions carrying the impulse away from the
cell body
The Nervous System
 Categories of neurons:
 Sensory neurons carry impulses from the body
to the spinal cord & brain
 Motor neurons carry impulses from the spinal
cord & brain to the body
 Interneurons are found within the spinal cord &
brain, pass response impulses between sensory
& motor
The Nervous System
 Transmitting an Impulse:
 Each impulse consists of an electrical charge
that travels the length of a neuron’s cell
membrane to a gap, called a synapse
 The impulse is caused by the depolarization of
chemicals surrounding the cell membrane
 Chemicals called nuerotransmitters, are
released into the synapse, which stimulates a
charge in the next neuron
Transmitting an impulse along the axon
Click on image to play video.
Transferring signals across the synapse
to an adjoining neuron
Click on image to play video.
The Nervous System
Division of the Nervous System:
Central Nervous
System (CNS)
Consists of the
brain and spinal cord
Peripheral Nervous
System (PNS)
Consists of the nerves
that carry messages
to & from the CNS
The Central Nervous System
Anatomy of the Brain:
Cerebrum
Largest lobe, controlling voluntary movement,
intelligence, memory, & the senses
Cerebellum
Located at the back,
controlling balance, posture, and coordination
Medulla oblongata
Located within the brain stem,
controlling involuntary (vital) activities
Cerebrum
Cerebellum
Medulla
The Peripheral Nervous System
 Somatic Nervous System
(SNS)
Made up of cranial & spinal
nerves, relaying voluntary
information between the
CNS and the skin & muscles
 Autonomic Nervous
System (ANS)
Made up of the sympathetic
& parasympathetic systems,
relaying involuntary
responses, not under
conscious control
The Peripheral Nervous System
Reflexes
An automatic, unconscious response for
protecting the body
This response travels to the spinal cord
where it responds directly back to a muscle
The Senses
Sensing Chemicals:
Odor chemicals stimulate nerve endings in
the nasal passages, which transmit
through the olfactory nerve to the
cerebrum
Chemical dissolved in saliva
stimulate nerve endings in
the taste buds of your
tongue, detecting only
sweet, sour, bitter & salty
The Senses
Sensing light:
The eye’s retina contains nerve enedings
called rods & cones, which transmit
impulses through the optic nerve to the
cerebellum
Rods and Cones
The eye
The Senses
Sensing vibrations (sound)
Sounds waves vibrates
the eardrum, the three
small bones—hammer,
anvil, & stirrup—then the
nerve endings in the
cochlea, which transmit
impulses through the
auditory nerve to the
cerebrum
The ear
Click on image to play video.
The Senses
Sense of Balance:
Within the inner ear are three
semicircular canals, which contain fluid &
nerve endings that transmit impulses to
the cerebellum
The Senses
Sense of Touch:
Nerve endings in the dermis of your skin
respond to temperature, pressure and
pain, transmitting impulses through
sensory neurons to the CNS