1. Chapter 12: Section 1 How the Nervous System Works. By Ashley Hannah

2. Functions  Receives Information  Responds to Information  Maintains Homeostasis (The balance in a system)

3. Receiving  Without your nervous system, you would be unaware of your surrounding environments. Examples- your receive information about the wind, a funny joke, a fly buzzing. Also receives info from inside your body such as glucose level.

4. Responding What your body does as a reaction to a stimulus (any change that can make an organism react). What your body does as a reaction to a stimulus (any change that can make an organism react). Examples- (voluntary)- swatting a buzzing fly. (Involuntary)- blinking, heart rate, etc. Examples- (voluntary)- swatting a buzzing fly. (Involuntary)- blinking, heart rate, etc.

5. Maintaining Homeostasis Helps the body respond appropriately. Examples- If you are hungry, your nervous system tells you to eat. This maintains Homeostasis by supplying nutrients and energy.

6. Section 1 Continued Neurons

7. Structure  Enables to carry impulses. Has a large body.  Dendrites carry impulses up to the neuron’s body  Axon carries impulses away from the neurons body  Can have many dendrites but only one axon.

8. Breaking down the neuron.  Large Body. The axon is like a long tail and the dendrites are like hairs attached to the head.

9. Kinds of Neurons Sensory-Picks up stimuli from environment and converts it into an impulse. Sensory-Picks up stimuli from environment and converts it into an impulse. Interneurons-Comes from the sensory neuron. Carries impulses from one neuron to another. Interneurons-Comes from the sensory neuron. Carries impulses from one neuron to another. Motor-Carried from the Interneurons. Sends an impulse to a muscle or a gland. Motor-Carried from the Interneurons. Sends an impulse to a muscle or a gland.

10. Motor Neuron

11. Interneuron

12. Sensory Neuron

13. How Impulses Travel ► Receives a chemical signal at the dendrite. ► Moves rapidly to the body, where an electrical impulse is sent down to the axon. ► Can travel as fast as 120 meters per second. ► When the impulse reaches the axon tip, it creates a Synapse where the impulse is converted again into a chemical signal and sent to another dendrite.

14. Path of Impulses  How impulses travel. Synapse 

15. Division of the Nervous System. Chapter 12; Section 2

16. Central Nervous System  Control center of the body.  Includes brain and spinal cord.  All information about surroundings brought through central nervous system.  Brain, located in skull, is the control of most functions.  Spinal cord is a link from brain to nerves in the peripheral nervous system.

17. Picture of Central Nervous System

18. Peripheral Nervous System All nerves outside of the central nervous system. All nerves outside of the central nervous system. Most impulses from peripheral system travel through spinal cord. Most impulses from peripheral system travel through spinal cord. Example- If you lose a quarter under the couch. When your fingers touch the quarter stimulus triggers

19. Peripheral Nervous System

20. Brain and Spinal Cord Contains 100 billion neurons in the brain. Each of which can receive from 10,000 other neurons.Contains 100 billion neurons in the brain. Each of which can receive from 10,000 other neurons. Three layers of tissue cover the brain.Three layers of tissue cover the brain. In between the middle and innermost layer is filled with fluids.In between the middle and innermost layer is filled with fluids.

21. Pictures

22. Cerebrum ► The largest part of the brain. ► Interprets input from senses, controls movement, and carries out complex mental processes. ► Divided into right and left sides. ► The right side sends impulses to the skeletal muscles on the left side and the left side controls the right side of your body.

23. Cerebrum Picture

24. Cerebellum and Brain Stem  The second largest part of your brain; the cerebellum.  Coordinates the actions of your muscles.  The brain stem, located between the cerebellum and the spinal cord, controls involuntary actions.

25. Cerebellum

26. Reflexes  A response that occurs automatically such as blinking or flinching.  Sensory neurons send impulses to the brain.  The brain sends an impulse to the motor neurons which causes a reaction in the muscle.

27. Chapter 12; Section 3 Senses

28. Senses Vision Vision Hearing and Balance Hearing and Balance Smell Smell Taste Taste Touch Touch

29. Vision Light strikes the cornea, then goes through the pupil (a small opening in which light enters). Your pupil size depends on how dim or bright the lights is. The iris regulates how much light enters the eye. A lens focuses the light After passing through the lens, it strikes the retina, They have rod and cone cells. Rod cells work best in dim light and cone cells work best in bright light.

30. Eyes

31. Near and Farsightedness Nearsightedness is when the eye can see nearby objects clearly but not far away objects as a result of the eyeball being too long.Nearsightedness is when the eye can see nearby objects clearly but not far away objects as a result of the eyeball being too long. Farsightedness is when the eye can see far away objects clearly but not close up as a result from the eyeball being too small.Farsightedness is when the eye can see far away objects clearly but not close up as a result from the eyeball being too small. To correct nearsightedness lenses with thicker edges are used.To correct nearsightedness lenses with thicker edges are used. To correct farsightedness lenses with thicker centers are used.To correct farsightedness lenses with thicker centers are used.

32. Hearing and Balance. Sound is produced by vibrations.Sound is produced by vibrations. The outer ear is structured to receive vibrations.The outer ear is structured to receive vibrations. The middle ear, containing the eardrum, carries vibrations from the outer ear.The middle ear, containing the eardrum, carries vibrations from the outer ear. The inner ear vibrates against a think membrane that produces fluid in the Cochlea which in turn responds to sound.The inner ear vibrates against a think membrane that produces fluid in the Cochlea which in turn responds to sound. Your inner ear controls balance. Semicircular canals are responsible for balance.Your inner ear controls balance. Semicircular canals are responsible for balance.

33. Ear Diagram

34. Smell  Cribiform Plate has chemical receptors linked to the brain that can detect the chemicals in the air and register the scent.

35. Cribiform Plate

36. Taste  Taste buds respond to chemicals in foods.  Your saliva dissolves the chemicals when it comes in contact with the food.  Five main tastes- sweet, sour, salty, bitter, and umami (a meat like taste).

37. Taste Buds

38. Touch  Skin is the largest sensory organ.  Touch receptors all over your body.  The fingertips contain approximately 16,000 nerve receptors.  The upper part of the dermis is sensitive to light touches.  The Dermis also contains receptors that respond to pain, pressure, and temperature.