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Introduction |
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As the complexity of the individuals, plants or animals increases the different cells and organs become separated from each other by greater distance. |
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Nervous Control in Human Beings - Nervous System |
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It stores the previous experiences as memory that helps us to think and analyse our reactions.It conducts messages between different parts of the body. |
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Units of Nervous System |
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The units of nervous system are specialised cells called the neurons. |
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Transmission of Messages |
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The messages are transmitted in the form of electrical impulses along the fibres of the neurons. |
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Types of Nerves |
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Nerves are of three types based on the types of neurons they carry. |
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Receptors and Effectors |
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Receptors are structures at the ends of the nerve fibres that collect the information to be conducted by the nerves. |
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Parts of the Nervous System - Central Nervous System |
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The human nervous system can be divided into three main parts:Central nervous system, Peripheral nervous system, Autonomic nervous system. |
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Parts of the Nervous System - Peripheral Nervous System |
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The peripheral nervous system is made up of nerves that connect the different parts of the body (peripheral tissues) to the central nervous system. |
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Reflex Action |
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When the stimulation of a receptor results in a spontaneous, involuntary reaction, it is called reflex action or simply reflex. |
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Coordination in Plants |
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In case of plants, growth and development is in a coordinated manner. The higher plants do not show locomotion. |
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Growth Regulators |
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Growth substances are also called the phytohormones. The phytohormones have been put in five different categories based on their actions. |
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Endocrine System - Hormonal Control |
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Exocrine glands are those which pour their secretions into a duct. For example, sweat glands, tear glands, etc. |
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Pituitary Gland |
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It is made up of three lobes - anterior, middle and posterior. They secrete hormones in response to the secretion of neurohormones by the hypothalamus. |
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Pineal, Thyroid and Parathyroid Glands |
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It is a butterfly-shaped, bilobed gland that is situated at the base of the larynx. The two lobes are joined by an isthmus. The hormone secreted is thyroxine. |
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Thymus and Pancreas |
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It is a gland that is prominent behind the breastbone in children.It gradually decreases in size in adults. |
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Adrenal and Gonads |
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The adrenal glands are present on top of the kidneys and appear cap-like on top of each kidney. Each adrenal gland has two layers - outer cortex and inner medulla. |
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Feedback Mechanism |
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It is a method of controlling the hormone production. In some cases the production of hormones is controlled by the nervous system. |
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Summary |
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With increasing complexity, the organisms have had to develop means of control and coordination between the different parts of the body. |
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Question and Answers |
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Multiple Choice Questions |
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