CONTROL_AND_COORDINATION_notes _class 10
- 1. CONTROL AND COORDINATION NEURON- It is the structural and functional unit of nervous system. TYPES OF NEURONS • SENSORY NEURON The neuron which carries the nerve impulses from the receptors of the sense organs to the brain or spinal cord are called sensory neurons. • MOTOR NEURON The neuron which carries nerve impulses from the brain or spinal cord to the effectors (muscle or glands). • MIXED NEURON/RELAY NEURON: It is neuron which acts as a link between the sensory and motor neuron.
- 2. TERMS • SYNAPSE – A point of junction between two neurons. It is a contact between the dendrite of one neuron and the axon of the next neuron. • RECEPTORS It is a specialized nerve cell which receives stimulus from the environment. • EFFECTORS: Any muscle or gland which produces a suitable response to any stimulus. • STIMULUS : Any change in the environment to which an organism responds. NEUROMUSCULAR JUNCTION
- 3. HOW DOES A NERVE IMPULSE TRAVEL IN A NEURON All information is detected by the specialized tips of the nerve cells called the receptors which are usually located in the sense organs. This information which is acquired at the end of the dendrite sets off a chemical response that creates an electrical impulse . This impulse travels from the dendrite to the cell body and then along the Axon towards its end. At the end of the axon, the electrical impulse sets off the release of some chemicals which are neurotransmitters such as Acetylcholine. The chemical crosses the synapse and starts a similar electrical impulse in the dendrite of the next neuron. NAMES OF RECEPTORS NAME OF RECEPTOR SENSATION LOCATION Gustatory Receptors Taste Tongue Olfactory Receptors Smell Nose Thigmo Receptors Touch Skin Thermoreceptor Heat Skin Phono Receptors Audio Ear Photo Receptors Light Eye TYPES OF NERVOUS SYSTEM
- 4. 1) CENTRAL NERVOUS SYSTEM : (CNS) It consists of th.e brain and spinal cord 2) PERIPHRAL NERVOUS SYSTEM: It consists of the nerves arising from the brain called Cranial nerves (12 pairs ) and spinal cord called as Spinal nerves (31 pairs) 3) AUTONOMOUS NERVOUS SYSTEM: It is a system which operates automatically or involuntarily. It includes all those responses which are not under our control. This is divided into : A) SYMPATHETIC NERVOUS SYSTEM: B) PARASYMPATHETIC NERVOUS SYSTEM: The smooth muscles of various internal organs receive both sympathetic and parasympathetic nerve fibres. Both the systems have involuntary opposing effects. If one system exerts stimulatory effect on an organ the other system exerts inhibitory effect on that organ . REFLEX ACTION Reflex action is an automatic, quick, immediate involuntary response to a stimulus involving only the spinal cord.
- 5. REFLEX ARC The path taken by the nerve impulses in a Reflex action is called as Reflex Arc. Stimulus Receptors Sensory Neuron Relay Neuron ( Spinal Cord) Effectors ( Glands/ Muscles) Motor Neurons BRAIN • Brain is protected by the cranium which is the bony box in the skull. • The brain is covered with three membranes called meninges .
- 6. • The spaces between the membranes is filled with a CerebroSpinal fluid (CSF) that protects the brain and spinal cord from mechanical shocks.
- 7. PARTS OF THE BRAIN The different parts of the brain are a) FOREBRAIN b) MID BRAIN c) HIND BRAIN a) The forebrain consists of the Cerebrum, Hypothalamus , Pituitary Glands and Olfactory Lobes. CEREBRUM : The cerebrum is concerned with thinking, reasoning and intelligence. It consists of two cerebral hemispheres and has distinct sensory and motor areas for sensing and giving response to stimulus. It has distinct lobes. And they are:
- 8. OCCIPITAL LOBE: Visual Perception TEMPORAL LOBE: Auditory perception PARIETAL LOBE : Touch, Smell, Temp FRONTAL LOBE : muscular and facial expressions, speech OLFACTORY LOBE : Smell 2. MIDBRAIN :Reflex actions of neck and eye. 3. HIND BRAIN : It consists of the following parts: a. MEDULLA OBLONGATA- Controls all Involuntary actions in the body like coughing, salivation, vomitting, sneezing, swallowing, and maintaining the blood pressure. b. PONS- It regulates the respiration. c. CEREBELLUM- It is called the ‘Little Brain’ and is responsible for coordination and adjustment of movement and posture. It maintains the balance in the body.
- 9. HOW DOES NERVOUS TISSUE CAUSE ACTION
- 10. COORDINATION IN PLANTS MOVEMENTS IN PLANTS TROPIC MOVEMENT NASTIC MOVEMENT The movement or orientation of any part of the plant body towards or away from the external stimulus. The movement which occurs in plants due to the variations in environmental conditions and difference in turgor pressure. It is directional It is non directional Growth is involved Growth is not involved. The rate at which the movement occurs is slow It is quick and immediate. Eg: Growth of stem towards light, growth of roots towards the soil. Eg Touch Me Not plant folds when you touch it.
- 11. TROPIC MOVEMENTS OR TROPISM The movement or orientation of any part of the plant body towards or away from the external stimulus. TYPES OF TROPIC MOVEMENTS a) PHOTOTROPISM : The movement of a part of plant body towards or away from the stimulus of LIGHT is called phototropism. Eg Growth of stem towards the sunlight. b) HYDROTROPISM The movement of a part of plant body towards or away from the stimulus of water is called hydrotropism Eg Growth of roots towards the water. EXPERIMENT TO DEMONSTRATE HYDROTROPISM c) GEOTROPISM The movement of a part of plant body towards or away from the stimulus of gravity is called geotropism Eg Growth of roots towards the ground .
- 12. d) THIGMOTROPISM The movement of a part of plant body towards or away from the stimulus of TOUCH is called THIGMOTROPISM Eg: The growth of tendrils against a support in climbers like cucumber, grapes. e) CHEMOTROPISM The movement of a part of plant body towards or away from the stimulus of CHEMICAL is called CHEMOTROPISM Eg; The growth of pollen tube towards the ovary in flowering plants after pollination.
- 14. The folding of leaves of mimosa plant ( Touch Me Not) is an example of thigmonastic movement . They change their shape by changing the amount of water in them thus resulting in swelling or shrinking. ROLE OF AUXINS IN PHOTOTROPISM
- 15. PHYTOHORMONES The chemicals synthesized by plants which are involved in the growth, metabolism and control and coordination in plants. They are also called as growth regulators. The different phytohormones are: a. AUXINS- Cell growth, differentiation and phototropism b. CYTOKININS: Cell division c. GIBBERELLINS: Stem elongation . Cell differentiation in presence of Auxins. d. ABA ( Abscisic Acid) : Growth Inhibitor, Wilting of leaves, Closing of stomata, Promotes seed dormancy. e. ETHYLENE (gaseous hormone. ) : Ripening of fruits. DIFFERENCE BETWEEN CHEMICAL AND NERVOUS CONTROL CHEMICAL COORDINATION IN ANIMALS
- 16. NERVOUS CONTROL CHEMICAL CONTROL It is sent as an electrical impulse along the neuron. It is sent via hormones in the blood. Information travels rapidly Information travels slowly Information is directed to specific receptors and responses are sent to effectors or muscles and glands. Information spreads throughout the body by blood from which it reaches to target cells or organs. Response is immediate Response is slow. Effects are short lived. Effects are prolonged. LIMITATIONS OF ELECTRICAL IMPULSES The electrical impulses will reach only those cells which are conected by nervous tissue not each and every cell of the body. Once an electrical impulse is generated in a cell and transmitted the cell will take some time to reset its mechanism. ENDOCRINE GLANDS: The glands which do not have ducts in them and pour their secretions directly into the blood. Therefore they are also called ductless glands.
- 17. EXOCRINE GLANDS: The glands which have ducts in them and pour their secretions through the ducts.EG : Salivary glands, Sweat glands, Liver. HETEROCRINE GLAND or MIXED GLAND /DUAL GLAND: The glands which are both exocrine and endocrine gland. EX: Pancreas, Ovary, Testis . ENDOCRINE SYSTEM IN HUMANS
- 18. ENDOCRINE GLANDS IN HUMANS NAME OF GLAND LOCATION HORMONE FUNCTION
- 19. HYPOTHALAMUS GLAND BRAIN RELEASOR HORMONE Stimulates the anterior and intermediate lobe of pituitary gland to secrete hormones. INHIBITING HORMONES Inhibits anterior and intermediate lobe of pituitary gland to secrete hormones. PITUITARY GLAND (MASTER GLAND) BRAIN a. STIMULATING HORMONES i FSH (Follicle Stimulating Hormone) Stimulates spermatogenesis and oogenesis in males and females respectively. ii.TSH (Thyroid Stimulating Hormone) Stimulates Thyroid gland to produce Thyroxine. b. GROWTH HORMONE Deficiency- DWARFISM Oversecretion- GIGANTISM It regulates protein metabolism and growth of bones in the body. PINEAL GLAND BRAIN MELATONIN Sleep and wake up cycle. Working of gonads
- 20. THYROID GLAND NECK THYROXINE Maintains the BMR as it regulates the protein and carbohydrate metabolism Less secretion- Hypothroidism More secretion – hyperthyroidism GOITRE- Iodine deficiency disorder THYMUS GLAND (Shrinks with age) THYMOSINE Stimulates development of lymphocytes that increases the resistance to infections. PANCREAS Between stomach and small intestine INSULIN Deficiency leads to Diabetes Mellitus Decreases the blood glucose level GLUCAGON Increases Blood Glucose level ADRENAL GLANDS ABOVE THE KIDNEYS ADRENALINE (Emergency Hormone) Helps to cope with stress, anxiety .Increases the metabolism in emergency situations. The effects of adrenaline secretion are increase in heart beat, blood pressure, breathing rate and blood sugar level. NORADRENALINE Decreases the metabolism.
- 21. GONADS a) OVARY IN FEMALES ABDOMEN OESTROGEN It develops the genital organs and is responsible for secondary sexual characteristic features in females. It also stimulates the formation of eggs or ova in females. ABDOMEN PROGESTERONE It stops egg production during pregnancy by from the ovaries. It also helps in attaching the foetus to the uterus. It takes care of all development in the females body during pregnancy. b) TESTIS In males ABDOMEN TESTOSTERONE It promotes Spermatogenesis. It is also responsible for all secondary sexual characteristic features in males.
- 22. HORMONAL DISORDERS GOITRE - CAUSE :It is caused by iodine deficiency. The thyroxine hormone cannot be synthesised by the thyroid gland in the absence of Iodine. Usually prevalent in people living in hilly and mountainous area as diet is deficient in Iodine. SYMPTOMS – Inflammation of Thyroid gland , Swollen neck, Lethargy, and Weight gain. CURE: Having food rich in Iodine like Seafood, Iodized Salt. Hormonal Disorder of Growth Hormones. GIGANTISM – Excess secretion of growth hormone by Pituitary gland . DWARFISM – Less Secretion of Growth Hormone by Pituitary gland. DIABETES MELLITUS- Less secretion of Insulin from pancreas.
- 23. FEEDBACK MECHANISM or HOMEOSTASIS The timing and amount of hormones released or regulated by the endocrine glands by the feedback mechanism. EXAMPLE 1 : When we eat a carbohydrate rich meal , the blood sugar level increases. It stimulates the pancreas to secrete Insulin. The insulin stimulates the target cells to take up the extra glucose which is either utilized in respiration or stored as Glycogen. In this way blood sugar level is brought back to normal. CARBOHYDRATE RICH MEAL GLUCOSE LEVEL INCREASES IN BLOOD
- 24. BETA CELLS OF PANCREAS SECRETE INSULIN INSULIN STIMULATES CELLS TO TAKE UP GLUCOSE GLUCOSE LEVEL FALLS IN BLOOD EXAMPLE 2 EXTERNAL STIMULUS HYPOTHALAMUS RELEASES THYROTROPHIN RELEASING HORMONE (TRH) STIMUALTES THE PITUITARY GLAND TO SECRETE TSH TSH STIMULATES THE THYROID GLAND TO PRODUCE THYROXINE IF thyroxine level is excess in the blood, it exerts a negative feedback effect on Hypothalamus and Pituitary Gland to secrete less amount of TRH and TSH respectively and as a result Thyroxine level decreases.