#controlandcoordination full chapter | cbse Class 10th Biology | NCERT class 10 science chapter 7

Summary

This educational script delves into the intricate mechanisms of response and coordination in living organisms. It explains how organisms, including plants and animals, react to stimuli through their nervous and endocrine systems. The script covers the roles of neurons, receptors, and synapses in nerve conduction, as well as the function of sensory and motor neurons. It also explores the reflex arc and the division between the central and peripheral nervous systems. The script further discusses the importance of hormones in animals, detailing their impact on growth, metabolism, and response to stimuli, and highlights the significance of iodine in the diet for thyroid hormone production. Finally, it touches on plant responses to stimuli, such as tropisms, and the role of phytohormones in these processes.

Takeaways

• 🧠 The nervous system and hormonal systems are crucial for organisms to produce responses to stimuli for self-protection.
• 🌱 Neurons, including specialized receptors in sensory organs, are key in detecting stimuli and converting them into electrical impulses.
• 👃 Olfactory receptors in the nose detect smells, while gustatory receptors on the tongue help in detecting taste.
• 🚀 Nerve conduction is the process by which neurons carry information to different parts of the nervous system.
• 🔄 The synapse is a junction where electrical impulses are converted to chemical signals and back to electrical signals between neurons.
• 🔍 Sensory neurons transmit information from sense organs to the brain or spinal cord, while motor neurons carry information to muscles or glands.
• 🔁 There are two pathways for stimulus response: a long pathway involving the brain and a short reflex pathway involving the spinal cord.
• 🏃‍♂️ Reflex actions are quick responses to stimuli, executed through a reflex arc involving receptors, sensory neurons, relay neurons, motor neurons, and effectors.
• 🦴 The central nervous system consists of the brain and spinal cord, while the peripheral nervous system includes the nerves.
• 🧠 The brain is the main coordinating center of the body, responsible for thinking, decision-making, storing information, producing emotions, and controlling body functions.
• 🌿 Plants also respond to stimuli like sunlight, water, soil, and touch, often through growth or changes in cell shape, without a nervous or muscular system.
• 🌳 Tropic movements in plants, such as phototropism, gravitropism, hydrotropism, and thigmotropism, are directional responses to environmental stimuli and are caused by phytohormones.
• 💊 Hormones in animals, secreted by endocrine glands, control functions like growth, repair, and reproduction, and are distributed through the blood circulatory system to target tissues or organs.
• 🏥 Conditions like dwarfism and gigantism are related to the production levels of growth hormone, which is secreted by the pituitary gland and is essential for body growth.
• 🚨 Adrenaline, secreted by adrenal glands, helps in the 'fight or flight' response by increasing oxygen and glucose supply to skeletal muscles.
• 🍽️ Iodine is important for the production of thyroxine, a hormone that regulates metabolism, and its deficiency can lead to goiter.
• 🚫 Diabetes is a condition where insufficient insulin production leads to high blood sugar levels, which can be managed by controlling sugar and starchy food intake.

Q & A

What are neurons and what role do they play in the nervous system?

Neurons, also known as nerve cells, are the fundamental units of the nervous system that detect stimuli and conduct nerve impulses. They consist of parts like the cell body, nucleus, dendrites, axon, and nerve endings. Neurons play a crucial role in transmitting information between different parts of the nervous system.

What are receptors and where are they located?

Receptors are specialized tips present in neurons located in sense organs. They detect stimuli and convert them into electrical impulses. For example, olfactory receptors in the nose detect smell, and gustatory receptors in the tongue detect taste.

What is the function of sensory neurons and motor neurons?

Sensory neurons carry information from sense organs to the brain or spinal cord, while motor neurons carry information from the brain or spinal cord to muscles or glands, facilitating responses to stimuli.

What is a synapse and how does it function?

A synapse is the gap or junction between the nerve endings of one neuron and the dendrites of another neuron. At the synapse, the electrical impulse is converted into a chemical signal, which crosses the gap and is then converted back into an electrical signal in the receiving neuron.

What are reflex actions and what is the reflex arc?

Reflex actions are quick, involuntary responses to stimuli that help protect the body from danger. The pathway by which a reflex action is executed is called the reflex arc, which involves receptors, sensory neurons, relay neurons, motor neurons, and effectors.

What are the main parts of the brain and their primary functions?

The brain has three main parts: the forebrain, midbrain, and hindbrain. The forebrain is responsible for thought processes, sensory information analysis, and voluntary muscle control. The midbrain controls visual and auditory reflexes and eye movements. The hindbrain, which includes the pons, medulla oblongata, and cerebellum, controls involuntary functions such as sleep, wake cycles, breathing, heart rate, and maintaining posture and balance.

How do plants respond to stimuli and what are phytohormones?

Plants respond to stimuli like sunlight, water, soil, and touch through movements. These movements are often caused by growth or changes in cell shape and are directed by phytohormones. Phytohormones are special chemical compounds that regulate these movements and growth in plants.

What are the major phytohormones and their functions?

The five major phytohormones are auxins (stimulate cell growth and tropic movements), gibberellins (help in stem and root elongation), cytokinins (promote cell division), abscisic acid (acts as a growth inhibitor and helps in wilting of leaves), and ethylene (stimulates fruit ripening).

What is the endocrine system and what are its primary functions?

The endocrine system is comprised of various glands like the pituitary, thyroid, adrenal glands, pancreas, testis, and ovaries, which secrete hormones. Hormones help control many body functions such as growth, repair, and reproduction. They are released into the bloodstream and act on specific target tissues or organs.

How does adrenaline help in 'fight or flight' situations?

Adrenaline, secreted by the adrenal glands during dangerous situations, helps prepare the body for 'fight or flight.' It increases the supply of oxygen and glucose to the skeletal muscles, increases heart rate, diverts blood to muscles by reducing flow to the digestive system and skin, and increases breathing rate.

Why is iodine important in our diet and what condition can result from iodine deficiency?

Iodine is essential for the production of thyroxine, a hormone produced by the thyroid gland that controls metabolism. Iodine deficiency can lead to low production of thyroxine, resulting in a condition called goiter, characterized by a swollen neck.