Divisions of the Nervous System. November 15, 2012 Mr. Alvarez

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1 Divisions of the Nervous System November 15, 2012 Mr. Alvarez

2 Divisions of the Nervous System Nerves- A bundle of Neurons The Nervous System is broken down into TWO parts Central Nervous System Peripheral Nervous System

3 Central Nervous System The central nervous system relays messages, processes information, and analyzes information. The central nervous system consists of TWO parts: Brain Spinal Cord

4 Central Nervous System

5 The Brain Brain- The major control center of the body There are THREE main parts of the brain

6 Cerebrum Cerebrum- The largest and most prominent region of the brain Responsible for voluntary or conscious activities of the body Site of intelligence, learning and judgment Divided into left and right hemisphere

7 Cerebrum

8 Cerebellum Cerebellum- Region of the brain that coordinates body movements Responsible for: Coordination of muscles The center of balance

9 Medulla Medulla (brain stem)- Connects the brain to the spinal cord Responsible for involuntary actions such as: Breathing Blood Pressure Heart Rate Peristalsis

10 Do Now: Describe the pathway of an impulse down a neuron Be sure to include: Cell Body Terminal Branches Axon Myelin Sheath Dendrites (2X)

11 Spinal Cord THE SPINAL CORD. The spinal cord is the tubular mass of nerve cells that extends from the brain stem downward through the center of the spinal column. It is surrounded and protected by the vertebrae of the spinal column (backbone). The spinal cord relays impulses to and from the brain and is the center of some reflex actions. Injury to the spinal cord can result in paralysis and even death. Paralysis is caused by severe damage to the spinal cord. It results in loss of feeling and muscle function in the lower parts of the body. Paralysis occurs because impulses to and from the lower body muscles cannot be transmitted to the brain.

12 Review Questions 1. Describe the spinal cord. The tubular mass of nerve cells that extends from the brain stem downward through the center of the spinal column 2. What is the function of the spinal cord? Relays impulses to and from the brain and is the center of some reflex actions 3. What causes paralysis? Severe damage to the spinal cord

13 The Peripheral Nervous System Made up of the nerves that lie outside the central nervous system Carries impulses to and from the Central nervous system Sensory Neurons- Carry impulses to Central Nervous System Motor Neurons- carry impulses from the central nervous system to various body parts such as muscles or glands

14 H. THE REFLEX ARC. The reflex is an example of involuntary behavior. It is inborn, involuntary response to a particular stimulus. In a reflex response, nerve impulses travel in a set pathway called a reflex arc. The path an impulse follows in a reflex arc is as follows: Receptor Sensory Neuron Interneuron Motor Neuron Effector

15 For example, the receptors in a knee jerk reflex are the nerve endings in the knee. The receptors receive the message. The sensory neuron passes along the message to the spinal cord. The interneuron connects the sensory neuron with the motor neuron. The motor neuron sends the message to the muscle in the leg called the effector. An effector does something. In this case it jerks the knee. A reflex arc is a short cut for nerve impulses. The message does not have to take the long route to the brain where thinking occurs. A reflex action does not require thought; it is an automatic action. Blinking is another example of a reflex

16 REVIEW QUESTION 1. Describe the path of a reflex arc.

17 J. NERVOUS SYSTEM DISORDERS. Some disorders of the nervous system are cerebral palsy, meningitis and polio. Nervous System Disorders *Meningitis. Meningitis is an inflammation of the membranes that surround the brain and spinal cord. The disease is caused by bacteria. The symptoms include severe headache and stiffness of the neck. Meningitis can be fatal. Antibiotics are used to treat meningitis. *Cerebral Palsy. Cerebral palsy is a group of birth disorders characterized by disturbances of the motor functions. It is a crippling disorder and treatment is still experimental. *Polio. Polio is a viral disease of the Central Nervous System that can cause paralysis. It can be prevented by immunization. Review Question 1. Complete the following chart concerning diseases of the nervous system. DISEASE SYMPTOMS TREATMENT

18 Review Question 1. Complete the following chart concerning diseases of the nervous system. DISEASE SYMPTOMS TREATMENT Meningitis severe headache and stiffness of the neck Antibiotics Cerebral Palsy disturbances of the motor functions Experimental treatments Polio paralysis Immunization

19 Receptor Pain Receptor Thermoreceptors Mechanoreceptors Chemoreceptors Photoreceptors Purpose Located everywhere except brain. Respond to pain in order to indicate danger, injury or disease Located in skin, body core, and hypothalamus. Detect variations in temperature Found in skin, skeletal muscles and inner ear. Sensitive to touch, pressure, stretching of muscles, sound and motion. Located in nose and taste buds. Sensitive to chemicals in external environment. Found in eyes. Sensitive to light

31.1 The Neuron. BUILD Vocabulary. Lesson Objectives

31.1 The Neuron. BUILD Vocabulary. Lesson Objectives Name Class Date 31.1 The Neuron Lesson Objectives Identify the functions of the nervous system. Describe the function of neurons. Describe how a nerve impulse is transmitted. BUILD Vocabulary A. The chart