These comprehensive RBSE Class 10 Science Notes Chapter 7 Control and Coordination will give a brief overview of all the concepts.
RBSE Class 10 Science Chapter 7 Notes Control and Coordination
→ In our body, the functions of control and coordination are done by the nervous system and hormones.
→ In multicellular organisms, specialised tissues are used to provide the control and coordination activities.
→ The nervous system gets information from our sense organs and acts through our muscles.
→ The nerve cells conduct information via electrical impulses from one part of the body to another.
→ Neurons-Nerve cells or neurons form the nervous system. It is a functional and structural unit of nervous system.
→ Parts of neuron –
- Dendrites-They acquired the information.
- Axon-Through this information travels like electrical impulse.
- Synapse-From this impulse is converted into chemical indication and transmitted forward.
→ Reflex action-Touching a hot material or pricking of a needle or a spine, we suddenly move our hand and leg. A reflex action is a fast automatic response to a stimulus.
→ During a reflex action, the input nerve, the output nerve and spinal cord together forms reflex arch.
→ The following are the examples of reflex action lex action
- Sudden hearing of loud sound, mouth remains open.
- Sneezing and coughing.
- Crumpling in cold.
- Secretion of saliva on looking good food.
- Contraction of eyes on sudden bright light.
→ There are three types of nervous system in human –
(i) Central nervous system-This system constitute by two organs brain and spinal cord. They collects information from all parts of the body and integrate them.
(ii) Peripheral nervous system-This system consists of two types of nerves-spinal nerves arising from spinal cord and cranial nerves arising from the brain.
(iii) Autonomous nervous system From the point of view the body activity or structure or physiologically it is divided into two parts-(i) Sympathetic nervous system (ii) Parasympathetic system.
→ Human brain is differentiated into three parts-
- Fore-Brain-The fore-brain is the main thinking part of brain. It has regions which receive sensory impulses from various receptors. Separate areas of the fore-brain are specialised for hearing, smell, sight and so on.
- Mid-Brain – It controls many involuntary actions.
- Hind-Brain-It is responsible for precision of voluntary actions and maintaining the posture and balance of the body.
→ Nerves-On the basis of function they are of three types
- Sensory nerves-Such nerves which carry the nerves impulses to sensory organs and then to brain, called sensory nerves.
- Motor nerves-Such nerves which carry the nerves impulses to brain or spinal cord to effector organs, called motor nerves.
- Mixed nerves-Such nerves which function like sensory and motor both, called mixed nerves.
→ Nerve impulse-Due to stimulus the exciting of nerve cells are called nerve impulse.
→ Brain is located in bony box. Inside the box, the brain is present in fluid filled balloon which absorbs the shocks. Vertebral column protect the spinal cord.
→ Plants show two different types of movement – one dependent on growth and the other independent of growth.
→ Plant cells change shape by changing the amount of water in them, resulting in swelling or shrinking, and therefore, in changing shapes.
→ Seismonasty movement-This movement takes place by mechanical shock irritability. The petiole of Mimosa pudica (Chui-mui) is swollen, called pulvinus. In this as pressure put on the motor cells, the water come out and the turgor of cell decreases, flaccidity causes the droping down the leaves. On removal of pressure after some time it returns to original position.
→ Phototropic movement Plant organs move by the effect of light. Stem moves towards the light so they are positively phototrophic. Root moves away from light, so they are negatively phototropic.
→ Geotropic movement-Stem always move away from gravitional force, so they are negative geotropic while root always grow towards gravitional force, so they are positive geotropic.
→ Hydrotropic movement-Root always grow towards water, so they are positively hydrostropic but stem grow away from water, so they are negatively hydrotropic.
→ Thigmotropism-This movement induces by touch or contact. That part of the plant which is not in touch or contact condition, grow more, example-Tendrils of pea. In tendrils due to growth coiling develop.
→ Chemotropic movement-If the movement is due to chemical stimulus, then it is called chemotropic movement. Ex. Growth of pollen tube towards ovule.
→ Chemical coordination is seen in both plants and animals.
→ Plant hormones-Some chemical materials which control and conduct the growth, which synthesize by plants, called plant hormones. They are of following types (i) Auxin (ii) Gibberellin (iii) Cytokinin.
→ Auxins-These are synthesised at the shoot tips and helps the cell to grow longer.
→ Gibberellin-Help in the growth of stem.
→ Cytokinin-It promote the cell-division so it is found in such areas of plants where cell-division is going very fast, specially found in fruits and seeds in more concentration.
→ Growth, inhibitor substance-Plant growth hormones induces the growth of the plants but there are some substances or chemicals which inhibt the growth. Such substances are called growth inhibtor substances, example-abscissic acid.
→ Endocrine glands-Endocrine glands are ductless glands, they synthesises the hormones and secretes them directly into the blood. Hormones-These are the chemical substances secreted by endocrine glands and directly secreted into blood. They reach to different organs of body and affects the functions.
→ A feedback mechanism regulates the action of hormones.
→ Human endocrine glands-(i) Pituitary gland (ii) Thyroid gland (iii) Parathyroid gland (iv) Aderenal gland (v) Thymus gland (vi) Pineal body (vii) Islets of Langerhans (Pancreas) (viii) Testis and ovary.
→ Pituitary gland-The secretory hormone is called growth hormone. It control the growth and development of body. Due to deficiency of this hormone in childhood makes the individual dwarf.
→ Testis and Ovary-The secretory hormone is male hormone (Testosterone) and female hormone (estrogen). Testosterone develop the secondary sexual characters in male while estrogen regulate the secondary sexual characters in female.
→ Thyroid glands-The secretory hormone is called thyroxin. Thyroid gland need iodine for secretion of thyroxine hormone. Deficiency of iodine in food caused goitre diseases. It controls the metabolism of thyroxine, carbohydrates, protein and fats.
→ Insulin hormone-It synthesise by islets of langerhans (pancreas). Deficiency of this hormone cause diabetes disease.