s situations.
- Some actions may be delayed and our brain could not conduct reflex actions, which require immediate action to a stimulus.
- For example, when we touch a hot object, we require an immediate response to save our hand. If the brain controls this action, the time taken will be more and our hand will burn.
- So, it is controlled by spinal cord, the response will be quick, and we may escape the danger.
- Nerves can not reach the every corner of the body, whereas hormones of endocrine glands can do that.
- So it’s not good that all functions are controlled by brain.
If you visit a doctor, what doubts you would like to clarify about pancreas?
- What is pancreas?
- Where is pancreas located in our body?
- Why is it called mixed gland?
- What is the exocrine part of pancreas?
- What is the endocrine part of pancreas?
- What are the cells that secrete hormone insulin?
- What is the function of insulin?
- What happens if required amounts of insulin is not produced?
- What are the symptoms of diabetes?
- How can diabetes be controlled?
Take a small potted plant. Cover base portion of the plant tightly and hang the part upside down. Observe the plant for a week. Based on your observation how can you support phototropism?
Aim: To prove that phototropism is a character that is carried by stem.
Apparatus: Potted plant, a strong small rope.
Procedure : Take a small potted plant. Cover the base portion of the plant tightly so that the plant along with soil do not fell down. Now take a rope and hang the potted plant upside down to a support firmly.
Observe the plant after a week.
Observation: We observe that the end of the stem which is upside down takes ‘U’ turn and grows towards light.
Conclusion: Phototropism is a response of plants towards light. That the stem grows towards light that is negatively to gravitation. Auxins are responsible for phototropism.
Take a cock feather touch smoothly at different parts of your body. Findout which portion of the body has high sensation. Is this similar during sleeping ? Prepare a report on it.
Aim: To prove that our body shows high sensation in different parts.
Apparatus : Cock feather.
Procedure: Take a cock feather. Touch smoothly at different parts of our body with the cock feather.
Observation : It is observed that some of the body parts like palms of hands and soles of feet there is less sensation than the other body parts because the skin is thick. Some other parts where the skin is thin, the sensation is more.
Report: The nerve endings are situated in the skin. These nerve endings are responsible for the sensation of the body.
What procedure you follow to understand the effect of plant growth hormones (in agar medium) in the terminal portion of the tip of stem (coleoptile)?
Aim: To show the growth of Avena coleoptile involves a chemical substance.
Apparatus: Oat seedlings (Avena sativa), coleoptile, a slice of agar, a sharp blade. Procedure:
- Take some oat seedlings.
- Their coleoptile tips are cut off.
- Place the tips on a slice of agar and leave them for about an hour.
- Cut the agar into small blocks and place a block on one side each stump of the decapitated plants.
- The plants were kept in the dark during the entire experiment.
- Observe the plants after one hour.
- Within one hour a distinct bending away from the side on which the agar block was placed is observed.
- Agar block that had not been contact with coleoptile doesn’t show any bending.
Conclusion : The coleoptile tip exerted its effect by means of a chemical stimulus such as an electrical impulse. This chemical stimuls came to be known as auxin.
Collect information on the actions controlled by spinal cord by using reference books from your school library.
- Spinal cord is a long and cylindrical structure. It passes through vertibral column extending all along the dorsal surface of trunk.
- Vertebrae of the vertebral column protects the spinal cord.
- The spinal cord has two major functions, a) carrying information b) coordinating reflexes.
- It receives sensory information through the afferent nerves from the