Physiology of the central nervous system 2

Central Nervous system

1. Unit 10
Chapter 36
The Nervous System

2. The Nervous System
Neurons
Nerves cells, the basic unit of structure &
function of the nervous system

3. 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

4. The Nervous System
Categories of neurons:
Sensory neuronscarry impulses from the body
to the spinal cord & brain
Motor neuronscarry impulses from the spinal
cord & brain to the body
Interneurons are found within the spinal cord &
brain, pass response impulses between sensory
& motor

5. 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

6. Transmitting an impulse along the axon
Click on image to play video.

7. Transferring signals across the synapse
to an adjoining neuron
Click on image to play video.

8. 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

9. 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

10. Cerebrum
Cerebellum
Medulla

11. 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
& parasympatheticsystems,
relaying involuntary
responses, not under
conscious control

12. 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

13. The Senses
Sensing Chemicals:
Odor chemicals stimulate nerve endings in
the nasal passages, which transmit
through the olfactory nerveto the
cerebrum
Chemical dissolved in saliva
stimulate nerve endings in
the taste budsof your
tongue, detecting only
sweet, sour, bitter & salty

14. The Senses
Sensing light:
The eye’s retinacontains nerve enedings
called rods & cones, which transmit
impulses through the optic nerveto the
cerebellum
Rods and Cones

17. The eye

18. 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

20. The ear
Click on image to play video.

21. The Senses
Sense of Balance:
Within the inner ear are three
semicircular canals, which contain fluid &
nerve endings that transmit impulses to
the cerebellum

22. 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