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Chapter 33 Nervous System

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2 Chapter 33 Nervous System
Section 1: Structure of the Nervous System Section 2: Organization of the Nervous System Section 3: The Senses Section 4: Effects of Drugs

3 Chapter 33 Nervous System 33.1 Structure of the Nervous System Neurons Neurons are specialized nerve cells that help you gather information about your environment, interpret the information, and react to it. Neurons consist of three main regions: the dendrites, a cell body, and an axon.

4 The axon passes those impulses on to the other neurons or muscles.
Chapter 33 Nervous System 33.1 Structure of the Nervous System Dendrites pass signals they receive on to the cell body in electrical impulses. The axon passes those impulses on to the other neurons or muscles.

5 Interneurons carry impulses to motor organs.
Chapter 33 Nervous System 33.1 Structure of the Nervous System There are three kinds of neurons: sensory neurons, interneurons, and motor neurons. Sensory neurons send impulses from receptors in the skin and sense organs to the brain and spinal cord. Interneurons carry impulses to motor organs.

6 resulting in a secretion or movement.
Chapter 33 Nervous System 33.1 Structure of the Nervous System Motor neurons carry impulses away from the brain and spinal cord to a gland or muscles, resulting in a secretion or movement. The nerve impulse completes a reflex arc, or a nerve pathway that consists of a sensory neuron, an interneuron, and a motor neuron.

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8 Neurons at rest do not conduct impulses.
Chapter 33 Nervous System 33.1 Structure of the Nervous System A Nerve Impulse Neurons at rest do not conduct impulses. Sodium ions (Na+) collect on the outside of the cell membrane.

9 Potassium ions (K+) collect on the inside of the cell membrane.
Chapter 33 Nervous System 33.1 Structure of the Nervous System Potassium ions (K+) collect on the inside of the cell membrane. Negatively charged proteins actively transport sodium ions out of the cell and potassium ions into the cell.

10 A nerve impulse is also known as an action potential.
Chapter 33 Nervous System 33.1 Structure of the Nervous System An Action Potential A nerve impulse is also known as an action potential. The minimum stimulus to cause an action potential to be produced is called a threshold.

11 33.1 Structure of the Nervous System
Chapter 33 Nervous System 33.1 Structure of the Nervous System When a stimulus reaches threshold, channels open in the plasma membrane. Sodium ions are rapidly pumped through these channels causing a temporary change in the electrical charges. More positive charges are now inside the membrane.

12 The potassium restores the positive charge outside the cell.
Chapter 33 Nervous System 33.1 Structure of the Nervous System The now positive charge inside the membrane causes other channels to open and the potassium is quickly pumped out of the cell. The potassium restores the positive charge outside the cell.

13 Chapter 33 Nervous System 33.1 Structure of the Nervous System This rapid positive to negative to positive charge reversal moves along the axon like a wave. The movement can be seen by finding the sodium-potassium reversal pattern in the three diagrams.

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15 Speed of an Action Potential
Chapter 33 Nervous System 33.1 Structure of the Nervous System Speed of an Action Potential Nodes along the axon allow ions to pass through the myelin layer to the plasma membrane. The ions jump from node to node and increase the speed of the impulse.

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17 An action potential is carried across these gaps by neurotransmitters.
Chapter 33 Nervous System 33.1 Structure of the Nervous System The Synapse The small gap between the axon of one neuron and the dendrite of another neuron is called a synapse. An action potential is carried across these gaps by neurotransmitters.

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19 Chapter 33 Nervous System 33.2 Organization of the Nervous System The nervous system consists of two major divisions: the central nervous system and the peripheral nervous system.

20 The Central Nervous System
Chapter 33 Nervous System 33.2 Organization of the Nervous System The Central Nervous System The central nervous system (CNS) is made up mostly of interneurons. Coordinates all of the body’s activities Relays messages, processes information, and analyzes responses

21 The brain is sometimes called the control center of the entire body.
Chapter 33 Nervous System 33.2 Organization of the Nervous System The Brain The brain is sometimes called the control center of the entire body. Divided into the cerebrum, the cerebellum, and the brain stem.

22 Chapter 33 Nervous System 33.2 Organization of the Nervous System The cerebrum is divided into two halves called the left and right hemispheres. The functions of the brain include thought processes (learning), memory, language, speech, voluntary body movements, and sensory perception.

23 The cerebellum controls balance, posture, and coordination.
Chapter 33 Nervous System 33.2 Organization of the Nervous System The cerebellum controls balance, posture, and coordination. The skeletal muscles are controlled to make your motor skills coordinated and smooth.

24 The pons also aids in breathing.
Chapter 33 Nervous System 33.2 Organization of the Nervous System The brain stem connects the brain and spinal cord and is composed of the medulla oblongata and the pons. The medulla oblongata helps control breathing rate, heart rate, and blood pressure. The pons also aids in breathing.

25 Regulates body temperature, thirst, appetite, and water balance.
Chapter 33 Nervous System 33.2 Organization of the Nervous System The hypothalamus, located between the brain stem and the cerebrum, is essential for homeostasis. Regulates body temperature, thirst, appetite, and water balance.

26 Nerve column that extends from the brain to the lower back.
Chapter 33 Nervous System 33.2 Organization of the Nervous System The Spinal Cord Nerve column that extends from the brain to the lower back. Protected by the vertebrae Processes reflexes

27 The Peripheral Nervous System
Chapter 33 Nervous System 33.2 Organization of the Nervous System The Peripheral Nervous System A nerve is a bundle of axons and may contain sensory and motor neurons. The peripheral nervous system (PNS) contains all the neurons that are not part of the central nervous system.

28 The Somatic Nervous System
Chapter 33 Nervous System 33.2 Organization of the Nervous System The Somatic Nervous System Nerves in the somatic nervous system relay information from external sensory receptors to the central nervous system, and motor nerves relay information from the central nervous system to skeletal muscles. Voluntary movements and reflexes are a part of the somatic nervous system.

29 The Autonomic Nervous System
Chapter 33 Nervous System 33.2 Organization of the Nervous System The Autonomic Nervous System The autonomic nervous system carries impulses from the central nervous system to the heart and other internal organs. The body responds involuntarily, not under conscious control.

30 There are two branches of the autonomic nervous system.
Chapter 33 Nervous System 33.2 Organization of the Nervous System There are two branches of the autonomic nervous system. The sympathetic nervous system is most active in times of emergency or stress when the heart rate and breathing rate increase. The parasympathetic nervous system is most active when the body is relaxed.

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32 Chapter 33 Nervous System 33.3 The Senses Taste and Smell Specialized neurons in your body enable you to taste, smell, hear, see, and touch, and to detect motion and temperature. Taste buds detect combinations of chemicals that we identify as sweet, sour, salty, and bitter.

33 Signals from these receptors work together to create
Chapter 33 Nervous System 33.3 The Senses Receptors associated with taste and smell are located in the mouth and nasal cavity. Signals from these receptors work together to create a combined effect in the brain.

34 Light travels through the cornea and the pupil to the lens.
Chapter 33 Nervous System 33.3 The Senses Sight Light travels through the cornea and the pupil to the lens. The lens focuses the image on the retina. Rods and cones in the retina provide light-sensitivity and information about color.

35 Sound waves enter the auditory canal and cause a membrane,
Chapter 33 Nervous System 33.3 The Senses Hearing Sound waves enter the auditory canal and cause a membrane, called the tympanum, at the end of the ear canal to vibrate. These vibrations cause the cochlea to generate nerve impulses that are interpreted by the brain.

36 Chapter 33 Nervous System 33.3 The Senses Balance The semicircular canals, located in the inner ear, transmit information about body position and balance to the brain.

37 Chapter 33 Nervous System 33.3 The Senses Touch Many types of sensory receptors that respond to temperature, pressure, and pain are found in the epidermis and dermis layers of the skin.

38 Chapter 33 Nervous System 33.4 Effects of Drugs How Drugs Work A drug is a substance, natural or artificial, that alters the function of the body.

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40 Some drugs affect the nervous system in the following ways:
Chapter 33 Nervous System 33.4 Effects of Drugs Some drugs affect the nervous system in the following ways: can cause an increase in the amount of a neurotransmitter that is released into a synapse can block a receptor site on a dendrite, preventing a neurotransmitter from binding can prevent a neurotransmitter from leaving a synapse can imitate a neurotransmitter

41 Many drugs that affect the nervous system influence the level of
Chapter 33 Nervous System 33.4 Effects of Drugs Many drugs that affect the nervous system influence the level of a neurotransmitter called dopamine. Normally, dopamine is removed from a synapse by being reabsorbed by the neuron that released it.

42 Classes of Commonly Abused Drugs
Chapter 33 Nervous System 33.4 Effects of Drugs Classes of Commonly Abused Drugs Stimulants Drugs that increase alertness and physical activity Nicotine Caffeine

43 Drugs that tend to slow down the central nervous system
Chapter 33 Nervous System 33.4 Effects of Drugs Depressants Drugs that tend to slow down the central nervous system Alcohol Inhalants Illegal drugs

44 Tolerance and Addiction
Chapter 33 Nervous System 33.4 Effects of Drugs Tolerance and Addiction Tolerance occurs when a person needs more and more of the same drug to get the same effect. The psychological and/or physiological dependence on a drug is addiction.

45 Chapter Resource Menu Chapter Diagnostic Questions
Nervous System Chapter Resource Menu Chapter Diagnostic Questions Formative Test Questions Chapter Assessment Questions Standardized Test Practice biologygmh.com Glencoe Biology Transparencies Image Bank Vocabulary Animation Click on a hyperlink to view the corresponding feature.

46 Which is not one of the main parts of a neuron?
Chapter 33 Nervous System Chapter Diagnostic Questions Which is not one of the main parts of a neuron? axon cell body dendrites nucleus A B C D CDQ 1

47 Another name for a nerve impulse is _______.
Chapter 33 Nervous System Chapter Diagnostic Questions Another name for a nerve impulse is _______. synapse threshold reflex arc action potential A B C D CDQ 2

48 What occurs when a motor neuron synapses with a muscle cell?
Chapter 33 Nervous System Chapter Diagnostic Questions What occurs when a motor neuron synapses with a muscle cell? muscle contracts muscle relaxes pain numbness A B C D CDQ 3

49 What type of neuron begins a reflex arc?
Chapter 33 Nervous System 33.1 Formative Questions What type of neuron begins a reflex arc? interneuron motor neuron sensory neuron transmitter neuron A B C D FQ 1

50 What is another name for nerve impulse?
Chapter 33 Nervous System 33.1 Formative Questions What is another name for nerve impulse? synapses threshold action potential neurotransmitter A B C D FQ 2

51 A B A stronger stimulus will cause a stronger action potential. True
Chapter 33 Nervous System 33.1 Formative Questions A stronger stimulus will cause a stronger action potential. True False A B FQ 3

52 Chapter 33 Nervous System 33.1 Formative Questions When a neuron is at rest, what maintains the high concentration gradients of potassium ions inside the cell and sodium ions outside the cell? diffusion osmosis active transport ion channels A B C D FQ 4

53 Which is not part of the central nervous system?
Chapter 33 Nervous System 33.1 Formative Questions Which is not part of the central nervous system? brain spinal cord interneurons sensory neurons A B C D FQ 5

54 What does the cerebrum regulate?
Chapter 33 Nervous System 33.2 Formative Questions What does the cerebrum regulate? breathing and heart rates complex motor skills sleep, aggression, and fear voluntary body movements A B C D FQ 6

55 Chapter 33 Nervous System 33.2 Formative Questions Some reflexes are processed only in the spinal cord and do not need input from the brain. True False A B FQ 7

56 What is a nerve? a bundle of axons a chain of neurons
Chapter 33 Nervous System 33.2 Formative Questions What is a nerve? a bundle of axons a chain of neurons a sensory synapse a series of impulses A B C D FQ 8

57 What part of the nervous system is usually under voluntary control?
Chapter 33 Nervous System 33.2 Formative Questions What part of the nervous system is usually under voluntary control? autonomic nervous system somatic nervous system sympathetic nervous system parasympathetic nervous system A B C D FQ 9

58 What are sensory receptors?
Chapter 33 Nervous System 33.3 Formative Questions What are sensory receptors? cells that create action potentials and thresholds localized areas of the central nervous system chemicals that cross a synapse between two nerve cells specialized neurons for detecting the world around you A B C D FQ 10

59 Which part of the eye contains light-detecting receptors?
Chapter 33 Nervous System 33.3 Formative Questions Which part of the eye contains light-detecting receptors? A B C D FQ 11

60 What is the function of the optic nerve?
Chapter 33 Nervous System 33.3 Formative Questions What is the function of the optic nerve? It forms a visual image. It controls the muscles of the iris. It interprets light intensity and colors. It sends action potentials to the brain. A B C D FQ 12

61 Where are sound vibrations converted into nerve impulses?
Chapter 33 Nervous System 33.3 Formative Questions Where are sound vibrations converted into nerve impulses? A B C D FQ 13

62 Where are the sensory receptors that
Chapter 33 Nervous System 33.3 Formative Questions Where are the sensory receptors that detect your body’s position and motion? A B C D FQ 14

63 It is an artificial substance. It influences the nervous system.
Chapter 33 Nervous System 33.4 Formative Questions Why is caffeine a drug? It is a depressant. It is an artificial substance. It influences the nervous system. It builds tolerance to its effects. A B C D FQ 15

64 Which neurotransmitter is influenced by
Chapter 33 Nervous System 33.4 Formative Questions Which neurotransmitter is influenced by nicotine and amphetamines, and is involved with most types of addiction? adenosine dopamine epinephrine serotonin A B C D FQ 16

65 Which is not a stimulant?
Chapter 33 Nervous System 33.4 Formative Questions Which is not a stimulant? alcohol caffeine nicotine methamphetamine A B C D FQ 17

66 What is the term for the body’s decreased response to a drug?
Chapter 33 Nervous System 33.4 Formative Questions What is the term for the body’s decreased response to a drug? addiction dependence tolerance withdrawal A B C D FQ 18

67 When people who are addicted try to quit, why
Chapter 33 Nervous System 33.4 Formative Questions When people who are addicted try to quit, why is it difficult to resist going back to the drug? Adenosine levels increase. Dopamine levels decrease. The central nervous system slows down. Action potentials in neurons become stronger. A B C D FQ 19

68 Chapter 33 Nervous System 33.4 Formative Questions Physiological dependence on a drug is stronger than psychological dependence. True False A B FQ 20

69 Name the part of the brain that is responsible for memory.
Chapter 33 Nervous System Chapter Assessment Questions Name the part of the brain that is responsible for memory. hypothalamus medulla oblongata cerebrum cerebellum A B C D CAQ 1

70 Contrast the functions of the cerebellum and the cerebrum.
Chapter 33 Nervous System Chapter Assessment Questions Contrast the functions of the cerebellum and the cerebrum. Answer: The cerebellum controls balance, coordination, and motor skills. The cerebrum controls learning, memory, speech, voluntary body movements, and sensory perception. CAQ 2

71 What part of the brain is identified in the image?
Chapter 33 Nervous System Chapter Assessment Questions What part of the brain is identified in the image? pons cerebrum hypothalamus medulla oblongata A B C D CAQ 3

72 How do nerve impulses travel in a neuron?
Chapter 33 Nervous System Standardized Test Practice How do nerve impulses travel in a neuron? dendrite  cell body  axon dendrite  cell body  axon dendrite  cell body  axon A B C STP 1

73 What carries signals from the axon of one
Chapter 33 Nervous System Standardized Test Practice What carries signals from the axon of one neuron to the dendrite of another neuron? interneurons ion channels neural nodes neurotransmitters A B C D STP 2

74 Which word best describes the hypothalamus?
Chapter 33 Nervous System Standardized Test Practice Which word best describes the hypothalamus? processor reflexor regulator transmitter A B C D STP 3

75 What part of the brain is highly developed
Chapter 33 Nervous System Standardized Test Practice What part of the brain is highly developed in animals that have finely tuned balance and complex coordination? cerebellum medulla thalamus temporal lobe A B C D STP 4

76 How do the sympathetic and parasympathetic
Chapter 33 Nervous System Standardized Test Practice How do the sympathetic and parasympathetic nervous systems act together? They send and receive neurotransmitters. They send opposing signals to the same organs. They balance voluntary and involuntary responses. They receive the same impulses from different receptors. A B C D STP 5

77 It detects heavy pressure. It detects light touch.
Chapter 33 Nervous System Standardized Test Practice Why is this receptor located closest to the surface of the skin? It detects cold. It detects heat. It detects heavy pressure. It detects light touch. A B C D STP 6

78 What substances in the body are most
Chapter 33 Nervous System Standardized Test Practice What substances in the body are most closely associated with a drug’s influence on the nervous system? endorphins Na+ and K+ ions neurotransmitters proteins A B C D STP 7

79 Where in the nerve pathway do drugs have their primary effect?
Chapter 33 Nervous System Standardized Test Practice Where in the nerve pathway do drugs have their primary effect? axons dendrites synapses myelin sheaths A B C D STP 8

80 Which step is blocked by cocaine?
Chapter 33 Nervous System Standardized Test Practice Which step is blocked by cocaine? A B C STP 9

81 Glencoe Biology Transparencies
Chapter 33 Nervous System Glencoe Biology Transparencies

82 Chapter 33 Nervous System Image Bank

83 Section 1 Vocabulary neuron dendrite cell body axon reflex arc
Chapter 33 Nervous System Vocabulary Section 1 neuron dendrite cell body axon reflex arc action potential threshold node synapse neurotransmitter

84 Section 2 Vocabulary central nervous system peripheral nervous system
Chapter 33 Nervous System Vocabulary Section 2 central nervous system peripheral nervous system cerebrum medulla oblongata pons hypothalamus somatic nervous system autonomic nervous system sympathetic nervous system parasympathetic nervous system

85 Section 3 Vocabulary taste bud lens retina rods cochlea
Chapter 33 Nervous System Vocabulary Section 3 taste bud lens retina rods cochlea semicircular canal

86 Section 4 Vocabulary drug dopamine stimulant depressant tolerance
Chapter 33 Nervous System Vocabulary Section 4 drug dopamine stimulant depressant tolerance addiction

87 Visualizing Action Potential Impulse Movement
Chapter 33 Nervous System Animation Rapid Reflex Arc Action Potential Visualizing Action Potential Impulse Movement

88 Chapter 33 Nervous System

89 Chapter 33 Nervous System

90 Chapter 33 Nervous System

91 Chapter 33 Nervous System


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