Answer: The source gland of glucagon is pancreas and the source gland of parathormone is parathyroids.
Q.2. Name the hormone that regulates calcium level in blood.
Answer: The hormone that regulates calcium level in blood is parathormone.
Q.3. Deficiency of which hormone causes goitre?
Answer: Deficiency of thyroxine hormone causes goitre.
Q.4. Name the hormones secreted by adrenal gland.
Answer: The hormones secreted by adrenal gland are-
- Glucocorticoids (cortisol and corticosterone)
- Mineralocorticoids (aldosterone)
- Sex corticoids (androgens)
- Adrenaline
- Noradrenaline.
Q.5. Which hormone helps in lowering the level of blood glucose in human beings?
Answer: Insulin helps in lowering the level of blood glucose in human beings.
Q.6. Write the function of hormone 'thyroxine' in our bodies.
Answer: Thyroxine promotes tissue metabolism, growth and differentiation.
Q.7. Which hormone is responsible for the development of moustache and beard in men?
Answer: Testosterone is responsible for the development of moustache and beard in men.
Q.8. Which type of glands in human body secrete hormones? State any one location for them.
Answer: Type of glands which secrete hormones and their location in human body are:
- Andrenal gland: located at the top of each kidney.
- Thyroid gland: situated in front of the neck, below the larynx.
- Pituitary gland: located at the base of the brain.
- Pancreas: situated behind the stomach.
- Parathyroids gland: located near the thyroid gland.
- Thymus: located just behind the chest bone.
- Gonads: located at testis in male and in female at the ovary.
Q.9. List two functions performed by ovaries in a human female.
Answer: The two functions performed by ovaries in a human female are:
- Egg production
- Development of secondary characters such as mammary glands, hair, voice, etc.
Q.10. What is the function of the hormone secreted by the pituitary gland?
Answer: The functions of the hormones secreted by the pituitary gland are as follows:
- Growth hormone: It regulates protein metabolism and body growth.
- Adrenocorticotropic hormone(ACTH): It stimulates secretion from adrenal cortex.
- Thyroid stimulating hormone (TSH): It stimulates thyroid secretion.
- Luteinising hormone (LH): In male - secretion of testosterone; in female - ovulation, development of corpus luteum and secretion of progesterone.
- Follicle stimulating hormone (FSH): In male - spermatogenesis; in female - growth of Graafian follicles and estrogen secretion.
- Prolactin: It stimulates milk production and secretion.
- Melanocyte stimulating hormone (MSH): It controls skin colour.
- Oxytocin: It causes contraction of uterine muscles during childbirth and release of milk.
- Vasopressin (ADH): It increases re-absorption of water from kidneys, contraction of blood vessels causing rise in blood pressure.
Q.11. Which endocrine gland secretes the growth hormone?
Answer: Pituitary gland secretes the growth hormone.
Q.12. Name the endocrine gland that secretes insulin in our bodies.
Answer: The endocrine gland that secretes insulin in our bodies is Pancreas.
Q.13. Name the main hormone secreted by thyroid gland and state its one function.
Answer:The main hormones secreted by thyroid gland and their function are-
- Thyroxine: Promotes tissue metabolism, growth and differentiation.
- Calcitonin: Prevents movement of calcium ions from blood to bones.
Q.14. Name the hormone, secretion of which is responsible for dramatic changes in appearance in girls when they approach 10-12 years of age.
Answer: Oestrogen.
Q.15. Why is iodised salt necessary for our body?
Answer: Iodised salt is necessary for our body for the synthesis of thyroxine hormone.
Q.16. Give a negative feedback control of blood glucose level in humans.
Answer: In a negative feedback control, synthesis of a hormone slows or halts when its level in the blood rises above normal. The regulation of secretion of thyroxine from the thyroid gland and insulin from pancreas are examples of negative feedback mechanism.
Q.17. Answer the following:
(a) Name the endocrine gland associated with brain?
Answer: Pituitary gland.
(b) Name the endocrine gland associated with kidneys?
Answer: Adrenal gland.
(c) Which endocrine gland is present in males but not in females?
Answer: Testis.
Q.18. Name the hormone responsible for regulation of:
(a) metabolism of carbohydrates, fats and proteins.
Answer: Thyroxine.
(b) balance of calcium and phosphate.
Answer: Parathormones.
(c) blood pressure.
Answer: Vasopressin (ADH).
Q.19. Name the hormones secreted by testis and ovary. Write one function each of these hormones.
Answer: The hormones secreted by testis and ovary and their functions are-
- Testosterone: Sperm production.
- Oestrogen and progesterone: Egg production.
Q.20. Name the source gland and give one main action of the following hormones:
(i) prolactin
Answer: The source gland of prolactin hormone is pituitary gland and one main action of prolactin is to stimulate milk production and secretion.
(ii) calcitonin
Answer: Source gland: Thyroid gland.
Main action: Prevents movement of calcium ions from blood to bones.
(iii) insulin
Answer: Source gland: Pancreas.
Main action: Lowers blood sugar level.
Q.21. Name the hormones secreted by thyroid, parathyroid and pancreas.
Answer: The hormones secreted by thyroid, parathyroid and pancreas are-
- Thyroid - thyroxine and calcitonin.
- Parathyroid - parathormone.
- Pancreas - insulin, glucagon and somatostatin.
Q.22. What are the male and female gonads in human beings? State any two functions of each of them.
Answer: The male and female gonads in human beings are testis and ovary.
Two functions of testis are-
- Sperm production
- Development of masculine features like beard and moustache.
- Egg production
- Development of secondary characters such as mammary glands, hair, voice, etc.
Q.23. Define hormones. Name the hormone secreted by thyroid. Write its function. Why is the use of iodised salt advised to us?
Answer: Hormones are information molecules or chemical regulators secreted in response to environmental changes in or outside the body.
The hormone secreted by thyroid gland are thyroxine and calcitonin.
The functions are-
- Thyroxine- Promotes tissue metabolism, growth and differentiation.
- Calcitonin - Prevents movement of calcium ions from blood to bones.
Q.24. Which animal hormone is associated with the following:
(i) increased sugar level in blood
Answer: Glucagon.
(ii) dwarfism
Answer: Growth hormone.
(iii) changes at puberty in boys
Answer: Testosterone.
(iv) goitre
Answer: Thyroxine.
Q.25. Mention one function for each of these hormones:
(a) Thyroxine
Answer: Thyroxine promotes tissue metabolism, growth and differentiation.
(b) Insulin
Answer: Lowers blood sugar level.
(c) Adrenaline
Answer: It whip up metabolism in emergency by increasing heart beat, blood pressure, etc.
(d) Growth hormone
Answer: It regulates protein metabolism and body growth.
(e) Testosterone.
Answer: Sperm production.
Q.26. (a) What are hormones?
Answer: Hormones are information molecules or chemical regulators secreted in response to environmental changes in or outside the body.
(b) List four characteristics of hormones.
Answer: The four characteristics of hormones are-
- They are produced in very small quantities.
- They are effective in extremely low concentrations.
- They regulate, physiological processes by chemical means.
- Hormones also adjust and restore homeostasis.
(c) Name the hormones required for the following:
(i) Functioning of mammary glands.
Answer: Oestrogen.
(ii) Regulation of calcium and phosphate in blood.
Answer: Parathormone.
(iii) Lowering of blood glucose.
Answer: Insulin.
(iv) Development of moustache and beard in human male.
Answer: Testosterone.
Q.27. What is homeostasis?
Answer: Homeostasis means keeping the internal chemical environment of the body constant.
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