1. Chapter 31 The Nervous System
By: Aubrey Fischer
Jenny Czech

2. 31.1 The Function of the Nervous System:
Send and receive messages within the body
Respond to stimuli
Neuron- basic unit of structure and function of the nervous system

3. 31.1
peripheral nervous system: network of nerves and supporting cells that carries signals into and out of the central nervous system
central nervous system: includes the brain and spinal cord; processes information and creates a response that is delivered to the body
cell body: largest part of a typical neuron, contains the nucleus and much of the cytoplasm
Dendrite: extension of the cell body of a neuron that carries impulses from the environment or from other neurons toward the cell body
Axon: long fiber that carries impulses away from the cell body of a neuron
myelin sheath: insulating membrane surrounding the axon in some neurons
resting potential: electrical charge across the cell membrane of a resting neuron

4. 31.1
action potential: reversal of charges across the cell membrane of a neuron; also called a nerve impulse
Threshold: minimum level of a stimulus that is required to cause an impulse
Synapse: point at which a neuron can transfer an impulse to another cell
Neurotransmitter: chemical used by a neuron to transmit an impulse across a synapse to another cell

5. 31.1
Types of Neurons:
Sensory Neurons: Impulse from sense organ to spinal cord/brain
Motor Neurons: Impulse from brain/spinal cord to muscles and glands
Interneurons: Connect sensory and motor neurons

6. 31.1 Messages are electrical and chemical signals
Nerve Transmission:
Messages are electrical and chemical signals
An electric charge is conducted down a neuron (Dendrite to axon)
Axon is covered in an insulating layer called a myelin sheath to speed up impulses
As it reaches the end of the axon, chemicals (neurotransmitters) are released across the synapse (gap between neurons) to the next neuron
The message continues neuron to neuron

7. 31.2 Vocab Reflex: quick, automatic response to a stimulus
Cerebrum: part of the brain responsible for voluntary activities of the body; the “thinking” region of the brain
cerebral cortex: outer layer of the cerebrum of a mammal’s brain; center of thinking and other complex behaviors

8. 31.2 Vocab
Thalamus: brain structure that receives messages from the sense organs and relays the information to the proper region of the cerebrum for further processing
Hypothalamus: structure of the brain that acts as a control center for recognition and analysis of hunger, thirst, fatigue, anger, and body temperature
Cerebellum: part of the brain that coordinates movement and controls balance
brain stem: structure that connects the brain and spinal cord; includes the medulla oblongata and the pons
Dopamine: neurotransmitter that is associated with the brain’s pleasure and reward centers

9. 31.2 Central Nervous System
Brain- control center; transmits and receives messages
Cerebrum
Cerebellum
Brain Stem (midbrain, pons, medulla oblongata.)
Spinal Cord- connects brain with rest of the nervous system

10. 31.2 Dopamine – neurotransmitter released with pleasurable activities
Addiction and the Brain:
Dopamine – neurotransmitter released with pleasurable activities
Addictive drugs cause large release of dopamine (resulting in “high”)
Brain reacts by reducing number of receptors for dopamine  normal activities no longer produce the pleasure they once did

11. 31.3 Vocab
somatic nervous system: part of the peripheral nervous system that carries signals to and from skeletal muscles
reflex arc: the sensory receptor, sensory neuron, motor neuron, and affecter that are involved in a quick response to a stimulus
autonomic nervous system: part of the peripheral nervous system that regulates activities that are involuntary, or not under conscious control; made up of the sympathetic and parasympathetic subdivisions

12. 31.3 Link between the central nervous system and the rest of the body
Peripheral Nervous System:
Link between the central nervous system and the rest of the body
Network of nerves throughout the body
*Made of many neurons

13. 31.3
Sensory Division:
Transmits impulses from sense organs to central nervous system
Uses sensory receptors
Chemoreceptors
Photoreceptors
Mechanoreceptors
Thermoreceptors
Pain receptors

14. 31.3
Motor Division:
Transmits impulses from central nervous system to muscles or glands
Somatic nervous system: regulates activities under conscious controlAutonomic nervous system: regulates activities that are automatic or involuntary
Autonomic nervous system: regulates activities that are automatic or involuntary

15. 31.4 Vocab taste bud: sense organs that detect taste
Cochlea: fluid-filled part of inner ear; contains nerve cells that detect sound
semicircular canal: one of three structures in the inner ear that monitor the position of the body in relation to gravity
Cornea: tough transparent layer of the eye through which light enters
Iris: colored part of the eye

16. 31.4 Vocab
Pupil: small opening in the iris that admits light into the eye
Lens: structure in the eye that focuses light rays on the retina
Retina: innermost layer of the eye; contains photoreceptors
Rod: photoreceptor in the eyes that is sensitive to light but can’t distinguish color
Cone: in the eye, a photoreceptor that responds to light of different colors producing color vision

17. 31.4 Senses: Vision- eyes Hearing and Balance- ears
Smell and taste- nose and mouth
Touch- skin

18. 31.4 Hearing/balance Mechanoreceptor Smell Chemoreceptor Taste
Touch Mechanoreceptor Pain receptor
Thermoreceptor
Vision Photoreceptor