Chemical Coordination & Integration: Important Questions

Very Short Answer Questions [1 Mark]

Ques. Name the endocrine gland present in males but absent in females.

Ans. A pair of testes are present in males, which performs functions of the endocrine gland as well as acts as a sex organ. This is absent in females since they possess a pair of ovaries situated in the abdomen.

Ques. Explain erythropoiesis and name the hormone that triggers it.

Ans. The process of formation of RBC is known as erythropoietin. Ideally, the peptide hormone erythropoietin produced from the juxtaglomerular cells of the kidney triggers the erythropoiesis.
Also Read: Aerobic Anaerobic Respiration

Ques. Which is the only hormone that is secreted by the pars intermedia of the pituitary gland?

Ans. Melanocyte Stimulating Hormone (MSH).

Ques. Which is the endocrine gland that secretes calcitonin? What role does this hormone play?

Ans. The thyroid gland is responsible to secrete calcitonin. It restricts excess Ca²⁺ and phosphate in the plasma by lowering mobilization from bones. Its deficiency leads to osteoporosis or loss of bone density.

Ques. Which hormone aids in cell-mediated immunity?

Ans. Thymosins play a significant role in the differentiation and development of T-lymphocytes that provide cell-mediated immunity.

Ques. Which hormone is responsible for the metamorphosis of tadpoles into adult frogs?

Ans. The hormone thyroxine secreted by the thyroid gland is responsible for the metamorphosis of tadpoles into adult frogs.

Ques. What is castration?

Ans. The surgical removal of the testis is called castration.

Ques. What are hormones?

Ans, The endocrine glands secrete chemical substances which affect various body activities in target organs, by reaching there through blood.

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Short Answer Questions [2 Marks]

Ques. Explain the significance of luteinizing hormones in males and females.

Ans. The luteinizing hormone in males helps in the production and secretion of hormones known as androgens from testes with Follicle Stimulating Hormone (FSH), androgens control the spermatogenesis. The LH in females leads to ovulation of the Graafian follicles and maintains the corpus luteum, which is developed from the traces of the Graafian follicles after ovulation that produces progesterone.
Also Read: Aerobic Respiration

Ques. Tell the importance of the second messenger in hormone action.

Ans. The hormones which do not enter the target cells, and communicate with specific receptors situated on the surfaces of the target cell membranes and produce 2nd messengers on the plasma membrane. And in turn, this performs all the functions related to the hormones.

Ques. Which steroid controls inflammatory responses? Name its source and other functions.

Ans. Glucocorticoids. These are secreted by the adrenal cortex and they trigger gluconeogenesis, proteolysis, and hinder the cellular uptake and utilization of amino acids.

Ques. Highlight the reason why old people have a weak immunity system.

Ans. The reason is that thymus gland, which is situated on the dorsal side of the heart and the aorta and is a lobular structure. This is derived from the endoderm of the embryo; the thymus which produces the thymosin hormone. In older individuals, the thymus degenerates and hence leads to a decreased thymosin secretion. Thus, their immune system becomes weak.

Ques. How does hypothyroidism affect the maturation and development of a growing baby, which is generally seen during pregnancy?

Ans. During pregnancy, hypothyroidism leads to defective maturation and development of the fetus (unborn baby), that induces stunted growth, low Intelligence Quotient (IQ), mental retardation, abnormal skin, etc.

Ques. Tell the difference between hyperthyroidism and hypothyroidism.

Ans. Hyperthyroidism is basically the over secretion of thyroid hormone and which occurs due to the cancer of the thyroid gland whereas hypothyroidism is the low secretion of the thyroxine hormone.

Ques. Name and state briefly the functionality of the hormones secreted by the adrenal cortex.

Ans. The hormones secreted are,

1. Glucocorticoids: The glucocorticoids regulate the metabolism of carbohydrates, fats, and the proteins.
2. Mineralocorticoids: These are responsible to maintain the sodium, potassium level in the blood.
3. Sex corticoids: These are responsible to stimulate the development of external sex characters like male patterns of body hair distribution.

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Long Answer Questions [3 Marks]

Ques. Suppose, a milkman’s cow refuses to give milk. On being fondled by its calf, the cow produces milk it first refused to. Now, explain the significance of the endocrine gland and the pathway related to this response.

Ans. A neuroendocrine reflex occurs when its calf suckling occurs that causes an increase in the oxytocin from the neurohypophysis. On the other hand, in the hypothalamus, oxytocin is synthesized in specific nuclei, the paraventricular nucleus, and the supraoptic nucleus. Here, the neurons produce the oxytocin precursor and bundle it into vesicles. The level of oxytocin in the blood gets concentrated within a minute or 2 after the stimulation which leads to smooth muscle contraction of the udder causing milk to flow. Following is a summary. Suckling stimulus → to Hypothalamus →to Neurohypophysis → to Oxytocin → to Udder → Flow of milk.
 

Ques. A urine sample consists of increased content of glucose and ketone bodies. Now, answer the questions below based on this observation.

• Which hormone and the gland associated with this condition.

• On which cells do these hormones act?

• Name the condition. How can it be rectified?

Ans. The observations are,

1. Insulin hormone and Insulin gland.
2. It acts on the β-cells of islets of Langerhans, which is present in the pancreas
3. Prolonged hyperglycemia leads to diabetes mellitus that is linked to loss of glucose via urine and accumulation of harmful compounds called ketone bodies. Insulin therapy, which can be done with the help of injection, can be successfully used to treat Diabetic patients.

Ques. What are the causes and symptoms of hormonal disorders?

Ans. Hormonal disorders or imbalance occurs when there is an under secretion or an oversecretion of respective hormones by the respective endocrine glands. There are many other environmental factors and medical conditions behind this hormonal disorders in an individual and it varies with the age and sex. These factors include:

• Obesity and Cancer.
• Allergies and Poor diet.
• Infections.
• Benign tumors.
• Intake of oral steroids.

The symptoms of a hormonal imbalance usually change according to the type of hormones. The more common causes are:

1. Fatigue and Bloating.
2. Depression and Headaches.
3. Infertility.
4. Mood swings and Blurred vision.
5. Sleep Disorders and Increased thirst.
6. Reduced sex drive and Excessive sweating.
7. Changes in appetite and Tenderness of the breast.
8. Brittle or weak bones
9. Weight gain or weight loss.
10. Sensitivity to cold and heat.
11. Changes in the voice in females.
12. Dry skin, thinning and brittle hair.
13. Variations in blood pressure, blood sugar concentration and heartbeat.

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Very Long Answer Questions [5 Marks]

Ques. Write a brief note on Thyroid. Describe the disorders of thyroid hormones.

Ans. The thyroid gland is situated in the neck, which is close to the trachea in human beings. It consists of two elongated oval lobes, which are joined together by a narrow band called ISTHMUS. Cells of the follicle secrete jelly-like semi-fluid, which are called Colloid of Thyroid and these are stored in the lumen of the follicle. This contains iodinated forms of an amino acid, which is called THYRONINE. When required, two thyroid hormones, Thyroxine, and TRIIODOTHYRONINE are released to the blood.

Disorders:

1. Failure of the thyroid from childhood causes a disease called cretinism. In this, there is a slow body growth and mental development in patients.
2. The deficiency of thyroid gland hormones in adults produces Myxedema. The patient generally shows a kind of puffy appearance and lacks intelligence, lateness, and initiative.
3. The deficiency of iodine produces enlargement of thyroids which leads to Iodine Deficiency to Goiter.
4. Some thyroid enlargement is accompanied by a bulging of the eyeball and this disease is called Grave’s Disease or Exophthalmic Goiter.

Ques. Explain an account of the primary male sex organ in man and mention briefly the functions of the hormone testosterone.

Ans. The testes are the primary sex organ. They are usually coupled in two. Each testis is covered by a thick connective tissue sheath, which is called Tunica Albuginea. Both of the testes normally remain suspended in a pouch called Scrotum outside the abdominal cavity. Cells which are lining the tubules give rise to spermatozoa, which are released into the lumen of the tubule. These are the present groups of polyhedral cells.

Functions of Testosterone:

1. It stimulates the growth and development of male secondary sex organs (prostate, seminal vesicles, and penis).
2. It stimulates and maintains the normal function of secondary sex organs in reproduction.
3. It also stimulates and maintains the development of external male characters such as beards, mustaches, and low-pitch male voices in males.
4. It also stimulates the formation of sperms in the testes.
5. It promotes the growth of many body tissues including bones and muscles.
    

Ques. Distinguish between,

• Follicle-stimulating hormone and luteinizing hormone.

• Somatostatin and somatomedin

Ans. 

1. The difference between follicle-stimulating hormone and luteinizing hormone include,

1. The difference between Somatostatin and somatomedin include,

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