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1. Unit 10Chapter 36The 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 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
5. The Nervous System Transmitting an Impulse:
Each impulse consists of an electrical charge that travels the length of a neurons 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
7. Transferring signals across the synapse to an adjoining neuron
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
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 & parasympathetic systems, 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 nerve to the cerebrum
Chemical dissolved in saliva stimulate nerve endings in the taste buds of your tongue, detecting only sweet, sour, bitter & salty
14. The Senses Sensing light:
The eyes retina contains nerve enedings called rods & cones, which transmit impulses through the optic nerve to the cerebellum
17. The eye
18. The Senses Sensing vibrations (sound)
Sounds waves vibrates the eardrum, the three small boneshammer, anvil, & stirrupthen the nerve endings in the cochlea, which transmit impulses through the auditory nerve to the cerebrum
20. The ear
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