Project on Nervous System NEXT PROPOSED BY S

Project on Nervous System NEXT

PROPOSED BY S. P. SINGH & RAMA BACK NEXT

CLASS----TEN AGE GROUP ---13 -15[YEARS] BACK NEXT

GENRAL OBJECTIVES CO-ORDINATION IN ANIMALS SPECIFIC OBJECTIVES 1. To Know About Nervous System. a. Central Nervous System b. Peripheral Nervous System. c. Structure Of Neuron. d. Reflex Action e. Diseases Related To Nervous System. f. To Know About BACK NEXT

NERVOUS SYSTEM STRUCTURE OF NEURON REFLEX ACTION DISEASES BACK NEXT

DEFINITION OF NERVOUS SYSTEM Nervous System, those elements within the animal organism that are concerned with the reception of stimuli, the transmission of nerve impulses, or the activation of muscle mechanisms. BACK HOME NEXT

A Nerve Cell This photomicrograph shows a number of multipolar nerve cells. The central cell body is clearly visible in each of the cells, as are the dendrites, which are short extensions of the BACK nerve cell body that function in the reception of NEXT stimuli. Oxford Scientific Films. HOME

NERVEOUS SYSTEM OF DIFFERENT ANIMALS Although all many-celled animals have some kind of nervous system, the complexity of its organization varies considerably among different animal types. In simple animals such as jellyfish, the nerve cells form a network capable of mediating only a relatively stereotyped response. In more complex animals, such as shellfish, insects, and spiders, the nervous system is more complicated. The cell bodies of neurons are organized in clusters called ganglia. BACK NEXT

II ANATOMY AND FUNCTION The reception of stimuli is the function of special sensory cells. The conducting elements of the nervous system are cells called neurons; these may be capable of only slow and generalized activity, or they may be highly efficient and rapidly conducting units. The specific response of the neuron—the nerve impulse— and the capacity of the cell to be stimulated make this cell a receiving and transmitting unit capable of transferring information from one part of the body to another ` BACK HOME NEXT

Vertebrate Systems Vertebrate animals have a bony spine and skull in which the central part of the nervous system is housed; the peripheral part extends throughout the remainder of the body. The brain is the part of the nervous system located in the skull; the spinal cord is that found in the spine. The brain and spinal cord are continuous through an opening in the base of the skull; both are also in contact with other parts of the body through the nerves. The distinction made between the central nervous system and the peripheral nervous system is based on the different locations of the two intimately related parts of a single system. Some of the processes of the cell bodies conduct sense impressions and others conduct muscle responses, called reflexes, such as those caused by pain. NEXT BACK HOME

The Nerve Network BACK HOME

Cranial Nerves Whereas most major nerves emerge from the spinal cord, the 12 pairs of cranial nerves project directly from the brain. All but one pair relay motor or sensory information (or both); the tenth, or vagus nerve, affects visceral functions such as heart rate, vasoconstriction, and contraction of the smooth muscle found in the walls of the trachea, stomach, and intestine BACK HOME NEXT

REFLEX ACTION Reflex, in physiology, involuntary response to a stimulus by the animal organism. In its simplest form, it consists of the stimulation of a sensory (afferent) nerve through a sense organ, or receptor, followed by transmission of the stimulus, usually through a nerve centre, to a motor (efferent) nerve, resulting in action of a muscle or gland, called the effector BACK HOME NEXT

Autonomic Nervous System Among the motor fibres may be found groups that carry impulses to organs within the body cavities such as the stomach and intestines (viscera). These fibres are designated as the autonomic nervous system. BACK HOME NEXT

DISORDERS OF THE NERVOUS SYSTEM Tumour, broadly interpreted, any abnormal local increase in size of a tissue or organ. Medical research at the microscopic level, however, has made clear that swelling can be due either to the infiltration of cells from another part of the body (inflammation BACK HOME NEXT

CHEMICAL TRANSMISSION OF AN IMPULSE: THE SYNAPSE This electron micrograph shows a synapse in the human brain. The synapse is a specialized junction through which neurons communicate, usually via chemicals known as neurotransmitters BACK HOM NEXT

Poliomyelitis, infectious viral disease of the central nervous system, sometimes resulting in paralysis. The greatest incidence of the disease, also known as infantile paralysis, is in children between the ages of five and ten years. The disease was described in 1840 by the German orthopaedist Jacob von Heine. In its clinical form it is more prevalent in temperate zones. BACK HOME NEXT

Arthritis, inflammation of one or more joints. Over 100 different diseases can produce arthritis. In its most common and troubling forms arthritis may occur in several joints of the body and is usually a long-term condition that may cause progressive disability. Inflammation of the joints can be caused by gout, rheumatic fever, or ankylosing spondylitis, a disease that affects the spine. BACK HOME NEXT

EVALUATION 1. Write a note on central nervous system. 2 Explain the perepheral nervous system. 3 Draw a well labelled diagram of a nerve cell (neuron) 4 Explain Reflex action by showing its path. BACK HOME NEXT

REFERENCE 1. N. C. E. R. T. A TEXT BOOK OF CLASS ___TEN. 2. ENCARTA ENCYCLOPEDIA___2000. 3. INTERNET. BACK HOME