Transcript Nervous System

Project
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Nervous System
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PROPOSED BY
S.P.SINGH & RAMA
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CLASS----TEN
AGE GROUP ---13-15[YEARS]
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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
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NERVOUS SYSTEM
STRUCTURE OF NEURON
REFLEX ACTION
DISEASES
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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.
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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.
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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
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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.
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The Nerve Network
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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
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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
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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.
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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
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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
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Poliomyelitis,
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.
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Arthritis
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.
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EVALUATION
1.Write a note on central nervous system.
2Explain the perepheral nervous system.
3Draw a well labelled diagram of a nerve cell
(neuron)
4Explain Reflex action by showing its path.
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REFERENCE
1. N.C.E.R.T. A TEXT BOOK OF CLASS ___TEN.
2. ENCARTA ENCYCLOPEDIA___2000.
3. INTERNET.
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