1. Lesson 1 The Nervous System Lesson 2 The Senses
Chapter Introduction
Lesson 1 The Nervous System
Lesson 2 The Senses
Lesson 3 The Endocrine System
Chapter Wrap-Up
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Chapter Menu

2. How do the nervous and endocrine systems help maintain the body’s homeostasis?
Chapter Introduction

3. What do you think?
Before you begin, decide if you agree or disagree with each of these statements. As you view this presentation, see if you change your mind about any of the statements.
Chapter Introduction

4. Do you agree or disagree?
1. The nervous system contains two parts—the central nervous system and the peripheral nervous system.
2. The autonomic nervous system controls voluntary functions.
3. A human has five senses that detect his or her environment.
Chapter Introduction

5. Do you agree or disagree?
4. The senses of smell and hearing work together.
5. Positive feedback systems in humans help maintain homeostasis.
6. Endocrine glands secrete hormones.
Chapter Introduction

6. The Nervous System What does the nervous system do?
How do the parts of the nervous system work together?
How does the nervous system interact with other body systems?
Lesson 1 Reading Guide

7. The Nervous System nervous system stimulus neuron synapse
central nervous system
cerebrum
cerebellum
brain stem
Lesson 1 Reading Guide

8. The Nervous System spinal cord peripheral nervous system reflex
Lesson 1 Reading Guide

9. Functions of the Nervous System
The part of an organism that gathers, processes, and responds to information is called the nervous system.
The nervous system receives information from the five senses: vision, hearing, smell, taste, and touch.
The nervous system can receive information, process it, and respond in less than one second.
Lesson 1

10. Functions of the Nervous System (cont.)
A stimulus is something in the environment that causes an organism to react.
stimulus
from Latin stimulare, means “goad, urge”
Lesson 1

11. Functions of the Nervous System (cont.)
Since the nervous system receives many stimuli at the same time, the type of response depends on how the information is processed.
The nervous system helps maintain homeostasis by responding to stimuli that affects a body’s internal environments.
Lesson 1

12. Functions of the Nervous System (cont.)
What are some of the tasks performed by the nervous system?
Lesson 1

13. Neurons
The basic functioning units of the nervous system are called nerve cells, or neurons.
Neurons help different parts of your body communicate with each other.
Neurons are made of three parts: dendrites, a cell body, and an axon.
A dendrite receives information from another nerve cell or body cell.
Lesson 1

14. Neurons (cont.) A cell body processes the information.
An axon sends the information to another cell.
There are three types of neurons.
Sensory neurons send information about your environment to your brain or spinal cord.
Lesson 1

15. Neurons (cont.)
Motor neurons send information from your brain or spinal cord to tissues and organs in your body.
Interneurons connect sensory and motor neurons.
The connection between two neurons is called a synapse.
Chemical signals carry information between neurons.
Lesson 1

16. Neurons and Synapses
Lesson 1

17. The Central Nervous System
The central nervous system (CNS) is made up of the brain and the spinal cord.
The CNS receives, processes, stores, and transfers information.
The brain is the control center of the body which receives information, processes it, and sends out a response.
The brain also stores some information as memories.
Lesson 1

18. The Central Nervous System (cont.)
The part of the brain that controls memory, language, and thought is the cerebrum.
The cerebrum is the largest, most complex part of the brain. It processes touch and visual information.
The cerebellum is the part of the brain that coordinates voluntary muscle movement, balance, and posture.
Lesson 1

19. The area of the brain that controls involuntary functions, sneezing, coughing, and swallowing is the brain stem.
Lesson 1

20. The Central Nervous System (cont.)
The spinal cord is a tube-like structure of neurons that extend to other areas of the body.
Neurons in the spinal cord send information back and forth between the brain and other body parts.
Bones called vertebrae protect the spinal cord.
Lesson 1

21. Doug Pensinger/Getty Images
Lesson 1

22. The Peripheral Nervous System
The peripheral nervous system (PNS), is made of sensory and motor neurons that transmit information between the CNS and the rest of the body.
The PNS is made of two parts: the somatic system and the autonomic system.
The somatic system controls skeletal muscles.
Lesson 1

23. The Peripheral Nervous System (cont.)
Neurons of the somatic system communicate between the CNS and skeletal muscle to cause voluntary movements.
The autonomic system controls smooth muscle and cardiac muscle and regulates involuntary actions.
Lesson 1

24. The Peripheral Nervous System (cont.)
How does the PNS work with the CNS?
Lesson 1

25. Nervous System Health
Physical injuries are the most common way the nervous system can be damaged.
Injured nerves can no longer send and receive signals, which stops communication between the CNS and the PNS.
Paralysis is the loss of muscle function and sometimes loss of feeling that results from injured nerves.
Lesson 1

26. Nervous System Health (cont.)
An automatic movement in response to a stimulus is called a reflex.
Reflexes are fast because, in most cases, the information goes only to the spinal cord, not to the brain.
This fast response protects us from injuries because it takes less time to move away from harm.
Lesson 1

27. Lesson 1

28. Nervous System Health (cont.)
Drugs are chemicals that affect the body’s functions.
Many drugs affect the nervous system by either speeding up or slowing down the communication between neurons.
Lesson 1

29. The Nervous System and Homeostasis
The nervous system is vital to sensing changes in your environment.
The nervous system signals other systems, such as digestive, endocrine, and circulatory systems, to make adjustments when needed.
Lesson 1

30. The Nervous System and Homeostasis (cont.)
Give an example of how the nervous system works with another body system to maintain homeostasis.
Lesson 1

31. The nervous system gathers and interprets stimuli using a system of neurons that connect throughout the body.
Lesson 1

32. The central nervous system receives, processes, stores, and transfers information.
Lesson 1

33. The peripheral nervous system is made up of the neurons that transmit information between the CNS and the rest of the body.
Doug Pensinger/Getty Images
Lesson 1

34. Which of these refers to something in the environment that causes an organism to react?
A. neuron
B. synapse
C. stimulus
D. cerebellum
Lesson 1

35. Which part of the brain coordinates voluntary muscle movement?
A. cerebellum
B. cerebrum
C. brain stem
D. spinal cord
Lesson 1

36. Which term describes an automatic movement in response to a stimulus?
A. stimuli
B. synapse
C. neuron
D. reflex
Lesson 1

37. 2. The autonomic nervous system controls voluntary functions.
Do you agree or disagree?
1. The nervous system contains two parts—the central nervous system and the peripheral nervous system.
2. The autonomic nervous system controls voluntary functions.
Lesson 1

38. The Senses How do you learn about your environment?
What is the role of the senses in maintaining homeostasis?
Lesson 2 Reading Guide

39. The Senses sensory system receptor retina eardrum
Lesson 2 Reading Guide

40. You and Your Environment
The sensory system is the part of your nervous system that detects or senses the environment.
sensory
from Latin sentire, means “to perceive, feel”
Lesson 2

41. You and Your Environment (cont.)
A human uses five senses—vision, hearing, smell, taste, and touch—to detect his or her environment.
All parts of the sensory system have special structures called receptors that detect stimuli.
Each of the five senses uses different receptors.
Lesson 2

42. You and Your Environment (cont.)
Describe one way your senses help you to learn about the environment.
Lesson 2

43. Vision
The visual system uses photoreceptors in the eye and detects light and creates vision.
Light enters the eye through the cornea, a thin membrane that protects the eye and changes the direction of light rays.
Lesson 2

44. Vision (cont.)
The iris is the colored part of the eye that controls the amount of light that enters the eye by changing the size of the pupil, an opening in the iris.
Bright light constricts the iris, making it smaller. Dim light relaxes the iris, making is larger.
Lesson 2

45. Lesson 2

46. Vision (cont.)
The retina is an area at the back of the eye that includes two types of cells that contain photoreceptors: rod cells and cone cells.
Rod cells detect shapes and low levels of light.
Cone cells detect color and function best in bright light.
Lesson 2

47. Vision (cont.)
rod
Science Use one of the photoreceptors in the eye that distinguish the shapes of objects
Common Use any long, cylinder-shaped object
Lesson 2

48. Vision (cont.)
The retina sends information as electric signals through the optic nerve to the brain
The brain uses the information and creates a picture of what you are seeing.
If corneas or lenses are not curved exactly right, the eyes will have trouble focusing on images.
Lesson 2

49. Vision (cont.)
If a person’s eyes are longer than normal, the person is nearsighted and has trouble seeing.
If a person’s eyes are shorter than normal, the person is farsighted and has trouble seeing images that are close up.
Lesson 2

50. Lesson 2

51. Hearing Auditory receptors are needed to detect sounds.
The vibration of matter creates sound waves that travel through the air and other substances.
As waves travel within the ear, they are amplified, or increased, and move hair cells that send information about the sound waves to the brain.
Lesson 2

52. Hearing (cont.)
The brain processes information about the loudness and tone of the sound, and you hear.
Human ears are divided into three areas: the outer ear, the middle ear, and the inner ear.
The eardrum is a thin membrane between the outer ear and the inner ear which vibrates as it collects sound waves.
Lesson 2

53. Lesson 2

54. Hearing (cont.)
The vibrations pass from the eardrum to the small bones in the middle ear: the hammer, the anvil, and the stirrup.
The inner ear converts sound waves into messages that are sent to the brain.
The cochlea is filled with fluid that vibrates when sound waves reach it.
Lesson 2

55. Hearing (cont.)
Parts of the inner ear, called the semicircular canals, maintain balance.
The canals contain fluid that move hair cells whenever you move your head and send information about the movement to your brain.
The brain signals muscle to move your head and body in order to maintain your balance.
Lesson 2

56. The Ear and Balance
Fluid in your inner ear maintains balance by sensing changes in the position of your head.
Lesson 2

57. Smell Humans have hundreds of different receptors for detecting odors.
Odors are molecules that are detected by chemical receptors, called chemoreceptors, in your nose.
Chemoreceptors send messages to the brain, which processes the information about the odor.
Lesson 2

58. Taste Foods and drinks are detected by chemoreceptors on your tongue.
The receptors, called taste buds, then send messages to the brain for processing.
Taste buds can detect five different tastes: bitter, salty, sour, sweet, and a taste called umami.
Lesson 2

59. Lesson 2

60. Touch
Receptors in your skin can detect temperature, pain, and pressure.
These receptors are all over your body, but some areas, such as the palms of your hands and the soles of your feet, have lots of receptors.
Just like the other senses, touch receptors send messages to the brain for processing.
Lesson 2

61. The Senses and Homeostasis
The five senses are the means by which your nervous system receives information about the environment.
Your brain is able to respond and activate your body to maintain homeostasis.
Lesson 2

62. The Senses and Homeostasis (cont.)
Why are senses important in maintaining homeostasis?
Lesson 2

63. The sensory system is the part of the nervous system that uses receptors in five senses to collect information about the environment.
Lesson 2

64. Your eyes detect light as it passes through the cornea, the pupil, the lens, and the retina.
Lesson 2

65. The eardrum is a structure between the outer and middle ear that vibrates in the presence of sound waves.
Lesson 2

66. What is the name for the area at the back of the eye that includes rod cells and cone cells?
A. pupil
B. retina
C. iris
D. lens
Lesson 2

67. Sound vibrations pass from the eardrum to small bones in which of these?
A. middle ear
B. outer ear
C. inner ear
D. cochlea
Lesson 2

68. What is the name for the chemoreceptors found on the tongue?
A. flavors
B. umami
C. taste buds
D. cochlea
Lesson 2

69. 3. A human has five senses that detect his or her environment.
Do you agree or disagree?
3. A human has five senses that detect his or her environment.
4. The senses of smell and hearing work together.
Lesson 2

70. The Endocrine System What does the endocrine system do?
How does the endocrine system interact with other body systems?
Lesson 3 Reading Guide

71. The Endocrine System endocrine system hormone negative feedback
positive feedback
Lesson 3 Reading Guide

72. Functions of the Endocrine System
The endocrine system consists of groups of organs and tissues that release chemical messages into the bloodstream.
Endocrine tissues that secrete chemical molecules are called endocrine glands.
Lesson 3

73. Functions of the Endocrine System (cont.)
A hormone is a chemical that is produced by an endocrine gland in one part of an organism and is carried in the bloodstream to another part of the organism.
hormone
from Greek hormon, means “that which sets in motion”
Lesson 3

74. Functions of the Endocrine System (cont.)
The chemical messages are usually sent to more cells and last longer than the messages sent by the nervous system.
What does the endocrine system do?
Lesson 3

75. Endocrine Glands and Their Hormones
Hormones move from endocrine glands to other parts of the body in the bloodstream.
Hormones change the functions of organs and tissues by carrying messages to specific cells called target cells.
Lesson 3

76. Endocrine Glands and Their Hormones (cont.)
Hormones recognize their target cells because the target cells have certain receptor proteins on or inside them.
The hormone recognizes the receptor protein and attaches to it.
Once a hormone finds its target cell, it binds to a receptor protein and delivers its chemical message.
Lesson 3

77. Lesson 3

78. Endocrine Glands and Their Hormones (cont.)
The target cell responds by taking a specific action.
There are many different hormones with various purposes that are produced and distributed throughout your body.
Lesson 3

79. Mark Andersen/Getty Images
Lesson 3

80. The Endocrine System and Homeostasis
Hormones change the function of tissues and organs in the body to regulate internal conditions.
Organisms can maintain homeostasis using negative feedback systems.
Negative feedback is a control system where the effect of a hormone inhibits further release of the hormone.
Lesson 3

81. Negative feedback controls the amount of hormone released.
Lesson 3

82. The Endocrine System and Homeostasis (cont.)
Positive feedback is a control system in which the effect of a hormone causes more of the hormone to be released.
Because positive feedback does not help maintain homeostasis, your body uses fewer positive feedback systems.
Lesson 3

83. Lesson 3

84. The Endocrine System and Homeostasis (cont.)
How do other body systems work with the endocrine system to maintain homeostasis?
Lesson 3

85. The endocrine system is made up of glands that secrete chemical hormones to send messages throughout the body and maintain homeostasis.
Lesson 3

86. Negative feedback systems maintain homeostasis by inhibiting the release of a hormone as a part of the effect of that hormone.
Lesson 3

87. Positive feedback systems increase the effects caused by a hormone by signaling more of that hormone to be released.
Lesson 3

88. Where do the hormone molecules carry their message to?
A. endocrine glands
B. the brain
C. target cells
D. the skin
Lesson 3

89. Which of these are able to change the functions of organs and tissues?
A. target cells
B. glands
C. receptors
D. hormones
Lesson 3

90. What is the term to describe a control system in which the effect of a hormone causes more of the hormone to be released?
A. positive feedback
B. negative feedback
C. homeostasis
D. an endocrine gland
Lesson 3

91. 5. Positive feedback systems in humans help maintain homeostasis.
Do you agree or disagree?
5. Positive feedback systems in humans help maintain homeostasis.
6. Endocrine glands secrete hormones.
Lesson 3

92. Interactive Concept Map Chapter Review Standardized Test Practice
Key Concept Summary
Interactive Concept Map
Chapter Review
Standardized Test Practice
Chapter Review Menu

93. The nervous and endocrine systems work to sense the environment and coordinate body functions.
The BIG Idea

94. Lesson 1: The Nervous System
The nervous system gathers information from the environment, processes it, and signals the body to respond.
The nervous system is made up of the central nervous system and peripheral nervous system. The peripheral nervous system gathers and transmits information to and from the central nervous system, which processes the information.
The nervous system helps other body systems maintain homeostasis by responding to the environment.
Doug Pensinger/Getty Images
Key Concepts 1

95. Lesson 2: The Senses
The sensory system provides information about the environment.
The senses help maintain homeostasis by gathering information about changes in the environment so the body can respond.
Key Concepts 2

96. Lesson 3: The Endocrine System
The endocrine system releases chemical messages that control or affect body functions.
Chemicals released by the endocrine system cause other body systems to react to changes in the environment to maintain homeostasis.
Key Concepts 3

97. What term refers to connections between two neurons?
A. stimulus
B. synapse
C. reflex
D. cerebellum
Chapter Review - MC

98. Which of these send information from your brain or spinal cord to tissues and organs in your body?
A. sensory neurons
B. interneurons
C. motor neurons
D. stimuli
Chapter Review - MC

99. What is the name for the part of the sensory system that detects stimuli?
A. receptor
B. lens
C. cornea
D. semicircular canal
Chapter Review - MC

100. Which of these is the thin membrane between the outer ear and the inner ear?
A. hammer
B. anvil
C. stirrup
D. eardrum
Chapter Review - MC

101. Which of these refers to the control system in which the effect of a hormone inhibits further release of the hormone?
A. positive feedback
B. endocrine system
C. homeostasis
D. negative feedback
Chapter Review - MC

102. Which system receives information from your five senses?
A. endocrine system
B. synapse system
C. nervous system
D. reflex system
Chapter Review - MC

103. What is the term for something in the environment that causes an organism to react?
A. neuron
B. stimulus
C. reflex
D. synapse
Chapter Review - MC

104. Which part of the ear detects sound?
A. outer ear
B. inner ear
C. eardrum
D. middle ear
Chapter Review - MC

105. Which of these refers to molecules detected by chemoreceptors in the nose?
A. positive feedback
B. sound waves
C. odors
D. hormones
Chapter Review - MC

106. Which system consists of groups of organs and tissues that release chemical messages into the bloodstream?
A. sensory
B. hormone
C. nervous
D. endocrine
Chapter Review - MC