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

Neurons  Neurons - 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: 1.dendrites 2.cell body 3.axon. video clip Chapter 33

 Dendrites - receive signals and pass them to the cell body. Nervous System  axon - passes those impulses on to the other neurons or muscles Structure of the Nervous System Chapter 33

 three kinds of neurons: 1.sensory neurons, 2. interneurons, and 3. motor neurons. Nervous System  1. Sensory neurons send impulses from receptors in the skin and sense organs to the brain and spinal cord.  2. Interneurons carry impulses to motor organs Structure of the Nervous System Chapter 33

Nervous System 33.1 Structure of the Nervous System  3. Motor neurons carry impulses away from the brain and spinal cord to a gland or muscles, resulting in a secretion or movement. Order of signals: Sensory to interneuron to motor neuron Chapter 33

Nervous System Chapter 33

A Nerve Impulse Nervous System  Neurons at rest: inside is negatively charged, outside is positively charged  Sodium ions (Na + ) are outside of axon and K+ is inside 33.1 Structure of the Nervous System Chapter 33

An Action Potential Nervous System  During an action potential (AP): Na+ moves into the axon, K+ rushes out.  Charges switch: Becomes negative outside, positive inside  After the AP, the Na/K pump restores the membrane (3 Na+ move out for every 2 K+ moving inside). Inside becomes negative and outside becomes positively charged Structure of the Nervous System Chapter 33

Nervous System Chapter 33

Nervous System Chapter 33

 Synapse - The small gap between the axon of one neuron and the dendrite of another neuron Nervous System  Neurotransmitters – carries action potentials across the gaps The Synapse 33.1 Structure of the Nervous System Chapter 33

Nervous System Chapter 33

 two major divisions: the central nervous system (CNS) and the peripheral nervous system (PNS).  video clip (8 min) video clip (8 min) 33.2 Organization of the Nervous System Nervous System Chapter 33

The Central Nervous System Nervous System  made up mostly of interneurons.  Coordinates all of the body’s activities  Relays messages, processes information, and analyzes responses  video clip video clip 33.2 Organization of the Nervous System Chapter 33

The Brain Nervous System  the control center of the entire body Organization of the Nervous System Chapter 33

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

The Peripheral Nervous System Nervous System  The PNS contains sensory and motor neurons  The PNS is divided into somatic and autonomic systems Organization of the Nervous System Chapter 33

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

The Autonomic Nervous System Nervous System  carries impulses from the CNS to the heart and other internal organs.  The body responds involuntarily  Example: Digestion 33.2 Organization of the Nervous System Chapter 33

 Two branches of the autonomic nervous system: Nervous System  The sympathetic nervous system: most active in times of emergency or stress (fight or flight).  The parasympathetic nervous system is most active when the body is relaxed.  mirror neuron video clip - 13 min mirror neuron video clip - 13 min 33.2 Organization of the Nervous System Chapter 33

Nervous System Chapter 33

Taste and Smell (DON’T COPY!)  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

 Receptors associated with taste and smell are located in the mouth and nasal cavity. Nervous System 33.3 The Senses (DON’T COPY!)  Signals from these receptors work together to create a combined effect in the brain. Chapter 33

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

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 (DON’T COPY!) Chapter 33

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

Nervous System Chapter 33

 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

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

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

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

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

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. Chapter 33

1.A 2.B 3.C 4.D CDQ 1 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

1.A 2.B 3.C 4.D CDQ 2 Nervous System Chapter Diagnostic Questions Chapter 33 Another name for a nerve impulse is _______. A. synapse B. threshold C. reflex arc D. action potential

1.A 2.B 3.C 4.D CDQ 3 Nervous System Chapter Diagnostic Questions Chapter 33 What occurs when a motor neuron synapses with a muscle cell? A. muscle contracts B. muscle relaxes C. pain D. numbness

1.A 2.B 3.C 4.D FQ 1 Nervous System Chapter 33 What type of neuron begins a reflex arc? A. interneuron B. motor neuron C. sensory neuron D. transmitter neuron 33.1 Formative Questions

1.A 2.B 3.C 4.D FQ 2 Nervous System Chapter Formative Questions What is another name for nerve impulse? A. synapses B. threshold C. action potential D. neurotransmitter

1.A 2.B FQ 3 Nervous System Chapter Formative Questions A stronger stimulus will cause a stronger action potential. A. True B. False

1.A 2.B 3.C 4.D FQ 4 Nervous System Chapter 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? A. diffusion B. osmosis C. active transport D. ion channels

1.A 2.B 3.C 4.D FQ 5 Nervous System Chapter Formative Questions Which is not part of the central nervous system? A. brain B. spinal cord C. interneurons D. sensory neurons

1.A 2.B 3.C 4.D FQ 6 Nervous System Chapter Formative Questions What does the cerebrum regulate? A. breathing and heart rates B. complex motor skills C. sleep, aggression, and fear D. voluntary body movements

1.A 2.B FQ 7 Nervous System Chapter Formative Questions Some reflexes are processed only in the spinal cord and do not need input from the brain. A. True B. False

1.A 2.B 3.C 4.D FQ 8 Nervous System Chapter Formative Questions What is a nerve? A. a bundle of axons B. a chain of neurons C. a sensory synapse D. a series of impulses

1.A 2.B 3.C 4.D FQ 9 Nervous System Chapter Formative Questions 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

1.A 2.B 3.C 4.D FQ 10 Nervous System Chapter 33 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

1.A 2.B 3.C 4.D FQ 11 Nervous System Chapter Formative Questions Which part of the eye contains light-detecting receptors?

1.A 2.B 3.C 4.D FQ 12 Nervous System Chapter Formative Questions 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.

1.A 2.B 3.C 4.D FQ 13 Nervous System Chapter Formative Questions Where are sound vibrations converted into nerve impulses?

1.A 2.B 3.C 4.D FQ 14 Nervous System Chapter Formative Questions Where are the sensory receptors that detect your body’s position and motion?

1.A 2.B 3.C 4.D FQ 15 Nervous System Chapter 33 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

1.A 2.B 3.C 4.D FQ 16 Nervous System Chapter Formative Questions Which neurotransmitter is influenced by nicotine and amphetamines, and is involved with most types of addiction? A. adenosine B. dopamine C. epinephrine D. serotonin

1.A 2.B 3.C 4.D FQ 17 Nervous System Chapter Formative Questions Which is not a stimulant? A. alcohol B. caffeine C. nicotine D. methamphetamine

1.A 2.B 3.C 4.D FQ 18 Nervous System Chapter Formative Questions What is the term for the body’s decreased response to a drug? A. addiction B. dependence C. tolerance D. withdrawal

1.A 2.B 3.C 4.D FQ 19 Nervous System Chapter Formative Questions 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. D. Action potentials in neurons become stronger.

1.A 2.B FQ 20 Nervous System Chapter Formative Questions Physiological dependence on a drug is stronger than psychological dependence. A. True B. False

1.A 2.B 3.C 4.D CAQ 1 Nervous System Chapter 33 Name the part of the brain that is responsible for memory. A. hypothalamus B. medulla oblongata C. cerebrum D. cerebellum Chapter Assessment Questions

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 CAQ 2

1.A 2.B 3.C 4.D CAQ 3 Nervous System Chapter 33 Chapter Assessment Questions What part of the brain is identified in the image? A. pons B. cerebrum C. hypothalamus D. medulla oblongata

1.A 2.B 3.C STP 1 Nervous System Chapter 33 How do nerve impulses travel in a neuron? A. dendrite  cell body  axon B. dendrite  cell body  axon C. dendrite  cell body  axon Standardized Test Practice

1.A 2.B 3.C 4.D STP 2 Nervous System Chapter 33 Standardized Test Practice What carries signals from the axon of one neuron to the dendrite of another neuron? A. interneurons B. ion channels C. neural nodes D. neurotransmitters

1.A 2.B 3.C 4.D STP 3 Nervous System Chapter 33 Standardized Test Practice Which word best describes the hypothalamus? A. processor B. reflexor C. regulator D. transmitter

1.A 2.B 3.C 4.D STP 4 Nervous System Chapter 33 Standardized Test Practice What part of the brain is highly developed in animals that have finely tuned balance and complex coordination? A. cerebellum B. medulla C. thalamus D. temporal lobe

1.A 2.B 3.C 4.D STP 5 Nervous System Chapter 33 Standardized Test Practice How do the sympathetic and parasympathetic nervous systems act together? A. They send and receive neurotransmitters. 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.

1.A 2.B 3.C 4.D STP 6 Nervous System Chapter 33 Standardized Test Practice Why is this receptor located closest to the surface of the skin? A. It detects cold. B. It detects heat. C. It detects heavy pressure. D. It detects light touch.

1.A 2.B 3.C 4.D STP 7 Nervous System Chapter 33 Standardized Test Practice What substances in the body are most closely associated with a drug’s influence on the nervous system? A. endorphins B. Na + and K + ions C. neurotransmitters D. proteins

1.A 2.B 3.C 4.D STP 8 Nervous System Chapter 33 Standardized Test Practice Where in the nerve pathway do drugs have their primary effect? A. axons B. dendrites C. synapses D. myelin sheaths

1.A 2.B 3.C STP 9 Nervous System Chapter 33 Standardized Test Practice Which step is blocked by cocaine?

Glencoe Biology Transparencies Nervous System Chapter 33

Image Bank Nervous System Chapter 33

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

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

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

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

Nervous System Animation  Rapid Reflex Arc Rapid Reflex Arc  Action Potential Action Potential  Visualizing Action Potential Visualizing Action Potential  Impulse Movement Impulse Movement

Chapter 33 Nervous System

Chapter 33 Nervous System

Chapter 33 Nervous System

Chapter 33 Nervous System