Contol and coordination

• Hormones are secreted by endocrine glands such as the pituitary gland, thyroid gland, adrenal gland, pancreas etc.
• Major endocrine glands in humans are Pituitary, Hypothalamus, Pineal, Thyroid, Parathyroid, Thymus, Pancreas, Adrenal, Testis in men /ovary in women.
• A feedback mechanism (positive and negative) regulates the action of the hormones.
• Hormones are chemical secretions that bring about various changes in the body.
• Hormones are produced by endocrine glands and are released into blood to reach specific target site.
• Production of hormones is under the control of hormones produced from pituitary gland.
• Cytokinin is a plant hormone that promotes cell division.
• Gibberellin is a plant hormone that promotes stem elongation.
• Geotropism is the response of a plant to gravity.
• Growth and development in plants is possible because of plants hormones or phytohormones.
• Tropic movement is the directional movement of a specific part of the plant in response to an external stimulus.
• Chemotropism is the response of a plant to chemicals.
• Hormones act as chemical messengers, are secreted by living cells/tissues or organs called glands, are secreted in very small quantities by glands, act upon specific cells, tissues, or organs called the target sites, are generally slow in action, but have long lasting effects, either accelerate or inhibit a reaction.
• Phototropism is the response of a plant to light.
• Abscisic acid is a plant hormone that promotes seed dormancy.
• Hydrotropism is the response of a plant to water.
• Thigmotropism is the response of a plant to touch.
• Ethylene is a plant hormone that regulates fruit ripening.
• Auxin is a plant hormone that promotes the growth of stem.
• Pituitary gland is a pea sized gland situated at the base of the brain, secretes a growth hormone (GH), required for proper body growth, hyposecretion of growth hormone causes a condition called dwarfism, hypersecretion causes gigantism in children and acromegaly in adults.
• Thyroid gland is located close to trachea in the neck, produces a hormone called thyroxine, required for regulating metabolism in the body, hyposecretion of thyroxine causes hypothyroidism, excess secretion of thyroxine causes hyperthyroidism, results in high metabolism, protrusion of the eye balls, high BP, nervous tension, etc.
• Parathyroid Gland consists of four parathyroid glands present on back side of thyroid glands that secrete parathyroid hormone or parathormone (PTH), regulates the level of calcium ions in the bloodstream, excess of parathyroid hormone removes calcium from bones and makes them soft.
• Plants respond to stimuli by showing movement, examples of movements in plants include folding of leaves when touched and directional movement of a seedling caused by growth.
• The inner portion of the nervous system contains the cell bodies of neurons and is known as the grey matter.
• A feedback mechanism (positive and negative) regulates the action of the hormones.
• Major endocrine glands in humans are pituitary, hypothalamus, pineal, thyroid, thymus, pancreas, adrenal, testis in men/ovary in women.
• Nastic movements may be classified as thigmonastic, thermonastic and photonastic.
• Reflex action is a sudden movement or response to a stimulus, occurs in very short duration of time, does not involve will or any thinking of brain, and examples include pulling back our hand when we touch a hot plate.
• Hormones act as chemical messengers, are secreted by living cells/tissues or organs called glands, are secreted in very small quantities by glands, act upon specific cells, tissues, or organs called the target sites, are generally slow in action, but have long lasting effects, and either accelerate or inhibit a reaction.
• Hormones are secreted by endocrine glands such as the pituitary gland, thyroid gland, adrenal gland, pancreas etc.
• Reflex action is an automatic action or response provoked by a stimulus, with a reflex pathway comprising of the following: receptor, sensory or afferent neuron, association neuron, motor or efferent neuron, and effector.
• Plants show tropic movement and nastic movement, in tropic movement plant either moves towards or away from the stimulus, and nastic movements occur in response to environment stimulus but the direction of response is not dependent on the direction of stimulus.
• Three types of responses of the nervous system are reflex action, voluntary action and involuntary action.
• Voluntary action are actions such as writing, talking etc. that can be controlled consciously.
• Involuntary action are actions such as breathing, digestion etc. that cannot be controlled consciously.
• Pancreas produces two hormones - Insulin and Glucagon, maintain blood sugar level, deficiency of insulin results in diabetes.
• Adrenal Gland consists of two parts - cortex and medulla, cortex secretes the hormones like cortisol that regulates the rate of metabolism, the medulla secretes a hormone like adrenaline that prepares the body to face various stressful situations.
• Gonads include testes in males and ovaries in females, male sex hormone is testosterone, produced by the testes on the onset of puberty, female sex hormones produced by ovaries are estrogen and progesterone, deficiency of estrogen causes infertility.
• Control and coordination in animals is provided by the nervous system and endocrine system.
• The brain is enclosed in a bony box called the cranium and spinal cord is protected by vertebral column.