CONTROL AND CO-ORDINATION: Short Answer Type Question for Class 10th Chapter 10 JKBOSE/NCERT
Question: Name the hormones secreted by the thyroid, parathyroid and pancreas.
Ans: The hormones secreted by the thyroid, parathyroid, and pancreas are:
Thyroid: Thyroxine (T4) and Triiodothyronine (T3)
Parathyroid: Parathyroid hormone (PTH)
Pancreas: Insulin and Glucagon
Question: List the functions of testosterone and oestrogen.
Ans: Functions of testosterone and estrogen:
Testosterone: Testosterone is the primary male sex hormone. Its functions include promoting the development of male reproductive organs, stimulating the production of sperm, regulating sex drive (libido), promoting muscle and bone growth, and influencing secondary sexual characteristics like facial hair and deepening of the voice.
Estrogen: Estrogen is a group of hormones primarily responsible for female sexual development and reproductive functions. Its functions include promoting the development of female reproductive organs, regulating the menstrual cycle, maintaining pregnancy, promoting the growth of breast tissue, and influencing secondary sexual characteristics like the distribution of body fat and the development of female curves.
Question: What are involuntary actions? Write three examples.
Ans: Involuntary actions are actions that occur without conscious control or voluntary effort. Three examples of involuntary actions are:
Heartbeat: The contraction and relaxation of the heart muscles to pump blood throughout the body occur involuntarily.
Breathing: The inhalation and exhalation of air by the lungs to provide oxygen to the body and remove carbon dioxide are involuntary actions.
Digestion: The movement of food through the digestive system, secretion of digestive juices, and absorption of nutrients occurs involuntarily.
Question: Write the name of three hormones secreted by the pituitary gland.
Ans: Three hormones secreted by the pituitary gland are:
Growth Hormone (GH): Promotes growth and development of bones, muscles, and other tissues.
Prolactin (PRL): Stimulates milk production in mammary glands after childbirth.
Adrenocorticotropic Hormone (ACTH): Stimulates the production and release of cortisol from the adrenal glands, which helps regulate the body’s response to stress.
Question: Give an account of any three diseases caused by the excess and deficit secretions of various endocrine glands.
Ans: Diseases caused by excess and deficit secretions of various endocrine glands:
Hyperthyroidism: Excess secretion of thyroid hormones (T3 and T4) by the thyroid gland, leading to symptoms such as weight loss, increased heart rate, anxiety, and heat intolerance.
Hypothyroidism: Insufficient secretion of thyroid hormones by the thyroid gland, resulting in symptoms like weight gain, fatigue, depression, and cold intolerance.
Diabetes mellitus: Insufficient secretion of insulin by the pancreas (Type 1 diabetes) or resistance to the effects of insulin (Type 2 diabetes), leading to high blood sugar levels and various complications if not managed properly.
Question: How does chemical coordination occur in plants?
Ans: Chemical coordination in plants occurs through the action of plant hormones or phytohormones. These hormones are chemical messengers that regulate various physiological processes and coordinate growth and development in plants.
Question: Which signals will get disrupted in case of a spinal cord injury?
Ans: In case of a spinal cord injury, several signals can get disrupted, including:
Motor signals: Signals that control voluntary movements from the brain to the muscles may be disrupted, leading to paralysis or weakness in certain body parts.
Sensory signals: Signals carrying sensory information from the body to the brain may be interrupted, resulting in a loss of sensation or altered perception of sensory stimuli.
Reflex signals: The spinal cord plays a crucial role in mediating reflex actions. A spinal cord injury can interfere with reflex responses, affecting involuntary muscle contractions and automatic responses to stimuli.
Question: Write one example of each of the following tropic movements:
(i) Positive phototropism (ii) Negative phototropism (iii) Positive geotropism (iv) Negative geotropism (v) Hydrotropism (vi) Chemotropism
Ans: Examples of tropic movements:
Positive phototropism: Growth of a plant towards a source of light. Example: The bending of a sunflower towards the direction of the sun.
Negative phototropism: Growth of a plant away from a source of light. Example: The growth of roots away from light in underground plants.
Positive geotropism: Growth of a plant towards gravity.
Example: The downward growth of roots.
Negative geotropism: Growth of a plant away from gravity.
Example: The upward growth of shoots or stems.
Hydrotropism: Growth of a plant towards or away from moisture. Example: The growth of plant roots towards a water source.
Chemotropism: Growth of a plant towards or away from specific chemicals.
Example: The growth of pollen tubes towards the ovules during pollination.
Question: Name the growth promoters and growth inhibitors present in plants. Write the function of any two.
Ans: Growth promoters and growth inhibitors in plants:
Growth promoters: Gibberellins and auxins are growth promoters in plants.
Gibberellins stimulate stem elongation, seed germination, and fruit development.
Auxins promote cell elongation, root initiation, and apical dominance.
Growth inhibitors: Abscisic acid (ABA) and ethylene are growth inhibitors in plants.
ABA regulates seed dormancy and stomatal closure during drought conditions.
Ethylene promotes fruit ripening, senescence, and abscission (shedding of leaves and fruits).
Question: Which animal or plant hormone is associated with the following:
(i) Increased sugar level in blood. (ii) Changes at puberty in boys (iii) Inhibits growth of plants. (iv) Rapid development of fruits (v) Dwarfism (vi) Goitre
Ans: Hormones associated with the following:
The increased sugar level in blood: The insulin hormone is associated with regulating blood sugar levels. Insufficient production or improper functioning of insulin leads to diabetes mellitus.
Changes at puberty in boys: The testosterone hormone is associated with the development of secondary sexual characteristics and reproductive functions in males during puberty.
Inhibits growth of plants: Abscisic acid (ABA) inhibits plant growth and induces seed dormancy and stomatal closure.
The rapid development of fruits: Gibberellins promote fruit development and play a role in regulating fruit size and quality.
Dwarfism: Growth hormone deficiency or malfunction can lead to dwarfism, a condition characterized by stunted growth and short stature.
Goitre: Goitre is primarily caused by insufficient or excessive production of thyroid hormones (T3 and T4) due to iodine deficiency or thyroid gland disorders.
Question: How is the movement of ‘Touch me not plant’ different from the movement of roots towards gravity?
Ans: The movement of the ‘Touch me not’ plant (Mimosa pudica) is a rapid plant movement known as thigmonasty. When the leaves of the plant are touched or disturbed, they rapidly fold up and droop. This response is a defence mechanism to protect the plant from potential harm or to reduce water loss by reducing the surface area exposed to the environment.
In contrast, the movement of roots towards gravity, known as gravitropism or geotropism, is a slow and growth-oriented response. The roots grow in the direction of gravity, allowing them to anchor the plant and facilitate nutrient and water absorption from the soil. Unlike the rapid movement of the ‘Touch me not’ plant, root gravitropism is a slower process that involves the growth and reorientation of root cells over time in response to gravity.
Question: Why is it advisable to use iodised salt in our diet?
Ans: It is advisable to use iodized salt in our diet because iodine is an essential micronutrient required for the synthesis of thyroid hormones. The thyroid gland uses iodine to produce hormones such as thyroxine (T4) and triiodothyronine (T3), which are crucial for regulating metabolism, growth, and development. Iodine deficiency can lead to various health problems, including goitre (enlargement of the thyroid gland), hypothyroidism, and impaired mental and physical development, especially in children. By using iodized salt, which contains a controlled amount of iodine, we can ensure an adequate intake of this essential nutrient and prevent iodine deficiency disorders.