class 10 science ch 7 important questionclass 10 science ch 7 important question download PDF Downloadclass 10 science ch 7 important questionclass 10 science ch 7 important question
Chapter 7 Summary for revision
- Any change in environment to which an organism responds and reacts is called stimulus. Plants not only respond to light but show tropisms in response to other stimuli as well.
- Plants not only respond to light but show tropisms in response to other stimuli as well.
- Phytohormones are of different types e.g. Auxins, gibberellins, adscisic acid and ethylene.
- flowering and seed germination in plants are regulated by the duration of light. This is known as photoperiodism.
- Body functions of animals are controlled and coordinated by two systems : nervous and endocrine system.Structural and functional units of nervous system are neurons. Each neuron is formed of three parts : nucleated cyton and cell body. small sized branched dendrons and a long axon.
- Nervous control and coordination of body functions involves three systems : Receptors organs, Nervous system and effectors (e.g. muscles and glands).
- Nervous system is differentiated into three systems : CNS, PNS and ANS.
- Central nervous system is formed of brain and spinal cord.
- Human brain lies in the cavity of cranium of skull and is formed of three parts: Fore brain , mid brain and hind brain.
- Fore brain is composed of olfactory lobes (for smell). cerebrum (controls voluntary movements and locomotion) and diencephalamus (formed of thalami and hypothalamus).
- Each cerebral hemisphere is divided into four lobes: Frontal, parietal, temporal and occipital lobe, each of which is concerned with specific function.
- Hind brain is formed of three lobes : Cerebellum (control posture and equilibrium of body); Pons (coordinated the muscles of two sides) and medulla oblongata (controls involuntary functions of body).
- Spinal cord lies in the neural canal of vertebral column and controls reflex actions.
- Peripheral nervous system is formed of two types of nerves: 12 pairs of cranial nerves and 31 pairs of spinal nerves.
- Autonomic nervous system controls the involuntary actions of visceral organs.
- Reflex actions are spontaneous, automatic, and involuntary mechanical responses. These are controlled by spinal cord, while path followed in reflex action is called reflex arc.
- Plants are generally rooted in the soil so are mostly non-motile.
- Geotropism involves the orientation of body parts of plants in relation to gravitational pull of earth.
- Phototropism is the movement of body parts of plants in relation to direction of light stimuli.
- In seismonastic movements, mechanical stimuli like touch, etc., lead to folding of leaflets in plants like touch-me-not and they are sensitive plant
- In hydrotropism, movements of root occurs in the direction of (towards) water.
- Endocrine system is formed of endocrine and ductless glands whose secretions are called hormones and are generally released in the blood.
- Hormones and secretions of endocrine glands. They are produced in small amounts and have specific function on the specific target organs.
- Thyroid gland secretes thyroxine hormone which controls BMR. Its deficiency causes cretinism.
- Hypothalamus secretes releasing hormones which regulate hormonal secretions from anterior lobe of pituitary.
- Pituitary is commonly called Master gland of the body as its tropic hormones control the hormonal secretions from a number of other endocrine glands.
- Pancreas secretes two hormones: Insulin and glucagon which collectively regulate glucose level in the blood.
- Endocrine part of testes secretes testosterone which regulates growth and functioning of secondary sexual characters related to male.
- Ovaries secrete estrogens and progesterone. Estrogens regulate growth and functioning of secondary sexual characters of female type, while progesterone maintains pregnancy.
- Endocrine glands and nervous system together form the integrating system.
- class 10 science ch 7 important question
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Important Questions chosen from Previous Years Board Exam Papers
Very Short Answer Questions:
1. What will happen to a plant shoot if sunlight falls on it from one direction only? What do you call this movement? (2012-13)Solution:Stem shoot will move towards light direction side. This type of movement is called Phototropism.