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Click on a lesson name to select. Chapter 33 Nervous System Section 1: Structure of the Nervous System Section 2: Organization of the Nervous System.

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Presentation on theme: "Click on a lesson name to select. Chapter 33 Nervous System Section 1: Structure of the Nervous System Section 2: Organization of the Nervous System."— Presentation transcript:

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3 Click on a lesson name to select. 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

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

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

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

7 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. Chapter 33

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

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

10 An Action Potential Nervous System 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 Structure of the Nervous System Chapter 33

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

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

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

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

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

16 Nervous System Chapter 33

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

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

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

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

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

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

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

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

25 The Peripheral Nervous System 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 Organization of the Nervous System Chapter 33

26 The Somatic Nervous System 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 Organization of the Nervous System Chapter 33

27 The Autonomic Nervous System 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 Organization of the Nervous System Chapter 33

28 There are two branches of the autonomic nervous system. 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 Organization of the Nervous System Chapter 33

29 Nervous System Chapter 33

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

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

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

33 Hearing Nervous System 33.3 The Senses 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. Chapter 33

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

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

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

37 Nervous System Chapter 33

38 Some drugs affect the nervous system in the following ways: Nervous System 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 33.4 Effects of Drugs Chapter 33

39 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. Chapter 33

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

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

42 Nervous System 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 Effects of Drugs Chapter 33

43 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 lesson. Chapter 33

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

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

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

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

48 What is another name for nerve impulse? A. synapsis B. threshold C. action potential D. neurotransmitter Nervous System 33.1 Formative Questions Chapter 33

49 Nervous System True or False A stronger stimulus will cause a stronger action potential Formative Questions Chapter 33

50 Nervous System When a neuron is at rest, what maintains the high concentration gradients of potassium ions inside the cell and sodium ions outside the cell? 33.1 Formative Questions Chapter 33

51 Nervous System A. diffusion B. osmosis C. active transport D. ion channels 33.1 Formative Questions Chapter 33

52 Nervous System Which is not part of the central nervous system? A. brain B. spinal cord C. interneurons D. sensory neurons 33.2 Formative Questions Chapter 33

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

54 Nervous System True or False Some reflexes are processed only in the spinal cord and do not need input from the brain Formative Questions Chapter 33

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

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

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

58 Nervous System Which part of the eye contains light- detecting receptors? 33.3 Formative Questions Chapter 33

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

60 Nervous System Where are sound vibrations converted into nerve impulses? 33.3 Formative Questions Chapter 33

61 Nervous System Where are the sensory receptors that detect your bodys position and motion? 33.3 Formative Questions Chapter 33

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

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

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

65 Nervous System What is the term for the bodys decreased response to a drug? A. addiction B. dependence C. tolerance D. withdrawal 33.4 Formative Questions Chapter 33

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

67 Nervous System True or False Physiological dependence on a drug is stronger than psychological dependence Formative Questions Chapter 33

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

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

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

71 How do nerve impulses travel in a neuron? Nervous System A. dendrite cell body axon B. dendrite cell body axon C. dendrite cell body axon Standardized Test Practice Chapter 33

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

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

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

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

76 Why is this receptor located closest to the surface of the skin? Nervous System Standardized Test Practice Chapter 33

77 Nervous System A. It detects cold. B. It detects heat. C. It detects heavy pressure. D. It detects light touch. Standardized Test Practice Chapter 33

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

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

80 Which step is blocked by cocaine? Nervous System Standardized Test Practice Chapter 33

81 Glencoe Biology Transparencies Nervous System Chapter 33

82 Image Bank Nervous System Chapter 33

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

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

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

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

87 Nervous System Animation Visualizing Action Potential Impulse Movement


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