Case Study Questions Class 11 Biology Chapter 22 Chemical Coordination and Integration
CBSE Class 11 Case Study Questions Biology Chemical Coordination and Integration. Important Case Study Questions for Class 11 Board Exam Students. Here we have arranged some Important Case Base Questions for students who are searching for Paragraph Based Questions Chemical Coordination and Integration.
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CBSE Case Study Questions Class 11 Biology Chemical Coordination and Integration
CASE 1
Our body has one pair of adrenal glands, one at the anterior part of each kidney. The gland is composed of two types of tissues. The centrally located tissue is called the adrenal medulla, and outside this lies the adrenal cortex.
The adrenal medulla secretes two hormones called adrenaline or epinephrine and noradrenaline or norepinephrine. These are commonly called as catecholamines. Adrenaline and noradrenaline are rapidly secreted in response to stress of any kind and during emergency situations and are called emergency hormones or hormones of Fight or Flight. These hormones increase alertness, pupilary dilation, piloerection (raising of hairs), sweating etc. Both the hormones increase the heartbeat, the strength of heart contraction and the rate of respiration. Catecholamines also stimulate the breakdown of glycogen resulting in an increased concentration of glucose in blood. In addition, they also stimulate the breakdown of lipids and proteins.
The adrenal cortex can be divided into three layers, called zonareticularis (inner layer), zonafasciculata (middle layer) and zonaglomerulosa (outer layer). The adrenal cortex secretes many hormones, commonly called as corticoids. The corticoids, which are involved in carbohydrate metabolism are called glucocorticoids. In our body, cortisol is the main glucocorticoid. Corticoids, which regulate the balance of water and electrolytes in our body are called mineralocorticoids. Aldosterone is the main mineralocorticoid in our body.Glucocorticoids, particularly cortisol, produces anti-inflammatory reactions and suppresses the immune response.
Pancreas is a composite gland which acts as both exocrine and endocrine gland. The endocrine pancreas consists of ‘Islets of Langerhans’. The two main types of cells in the Islet of Langerhans are called α-cells and β-cells. The α-cells secrete a hormone called glucagon, while the β-cells secrete insulin. Glucagon is a peptide hormone, and plays an important role in maintaining the normal blood glucose levels. Glucagon acts mainly on the liver cells (hepatocytes) and stimulates glycogenolysis resulting in an increased blood sugar (hyperglycemia). In addition, this hormone stimulates the process of gluconeogenesis which also contributes to hyperglycemia. Glucagon reduces the cellular glucose uptake and utilisation. Thus, glucagon is a hyperglycemic hormone. Insulin is a peptide hormone, which plays a major role in the regulation of glucose homeostasis. Insulin acts mainly on hepatocytes and adipocytes (cells of adipose tissue), and enhances cellular glucoseuptake and utilisation. As a result, there is a rapid movement of glucose from blood to hepatocytes and adipocytes resulting in decreased blood glucose levels (hypoglycemia). Insulin also stimulates conversion of glucose to glycogen (glycogenesis) in the target cells. The glucose homeostasis in blood is thus maintained jointly by the two – insulin and glucagons. Prolonged hyperglycemia leads to a complex disorder called diabetes mellitus which is associated with loss of glucose through urine and formation of harmful compounds known as ketone bodies. Diabetic patients are successfully treated with insulin therapy.
1.) ________________________ Hormone produces anti-inflammatory reactions and suppresses the immune response.
a) cortisol
b) Glucocorticoids
c) Insulin
d) both a & b
2.) ____________________________ Hormone secreted by the α-cells of Islet of Langerhans
a) Cortisol
b) Glucocorticoids
c) Glucagon
d) Insulin
3.) Enlist the name of hormones secreted by α-cells and β-cells.
4.) Name the hormone which involves in regulation of glucose homeostasis.
5.) What is main difference between hyperglycemia and hypoglycemia?
Answer key
1) b
2) c
3) The α-cells secrete a hormone called glucagon, while the β-cells secrete insulin.
4) The glucose homeostasis in blood is thus maintained jointly by the two – insulin and glucagons. Insulin is a peptide hormone, which plays a major role in the regulation of glucose homeostasis. Insulin acts mainly on hepatocytes and adipocytes (cells of adipose tissue), and enhances cellular glucose uptake and utilisation.
5) Hyperglycemia is the condition in which sugar level in blood is increased. While hypoglycemia is the condition in which sugar level in blood is decreased.
CASE 2
The pituitary gland is located in a bony cavity called sellatursica and is attached to hypothalamus by a stalk. It is divided anatomically into an adenohypophysis and a neurohypophysis. Adenohypophysis consists of two portions, pars distalis and pars intermedia. The pars distalis region of pituitary, commonly called anterior pituitary, produces growth hormone (GH), prolactin (PRL), thyroid stimulating hormone (TSH), adrenocorticotrophic hormone (ACTH), luteinizing hormone (LH) and follicle stimulating hormone (FSH). Pars intermedia secretes only one hormone called melanocyte stimulating hormone (MSH). However, in humans, the pars intermedia is almost merged with pars distalis. Neurohypophysis (pars nervosa) also known as posterior pituitary, stores and releases two hormones called oxytocin and vasopressin, which are actually synthesised by the hypothalamus and are transported axonally to neurohypophysis.
Over-secretion of GH stimulates abnormal growth of the body leading to gigantism and low secretion of GH results in stunted growth resulting in pituitary dwarfism. Excess secretion of growth hormone in adults especially in middle age can result in severe disfigurement (especially of the face) called Acromegaly. Prolactin regulates the growth of the mammary glands and formation of milk in them. TSH stimulates the synthesis and secretion of thyroid hormones from the thyroid gland. ACTH stimulates the synthesis and secretion of steroid hormones called glucocorticoids from the adrenal cortex. LH and FSH stimulate gonadal activity and hence are called gonadotrophins.
After ovulation. FSH stimulates growth and development of the ovarian follicles in females. MSH acts on the melanocytes (melanin containing cells) and regulates pigmentation of the skin. Oxytocin acts on the smooth muscles of our body and stimulates their contraction. In females, it stimulates a vigorous contraction of uterus at the time of child birth, and milk ejection from the mammary gland. Vasopressin acts mainly at the kidney and stimulates resorption of water and electrolytes by the distal tubules and thereby reduces loss of water through urine (diuresis). Hence, it is also called as anti-diuretic hormone (ADH). An impairment affecting synthesis or release of ADH results in a diminished ability of the kidney to conserve water leading to water loss and dehydration. This condition is known as Diabetes Insipidus.
`1.) ________________ are the hormones secreted by Pars intermedia.
a) Adrenocorticotrophic hormone
b) Melanocyte stimulating hormone
c) Luteinizing hormone
d) Follicle stimulating hormone
2.) Growth and functioning of the mammary glands is regulated and controlled by the
a) Glucocorticoids Hormone
b) Stimulating hormone
c) Prolactin hormones
d) Luteinizing hormone
3.) Name the hormones which acts on the smooth muscles of our body and stimulates their contraction.
4.) Write short note on the hormone which stimulates resorption of water and reduces loss of water.
5.) What are the adverse effect of over secretion of GH on human body?
Answer key
1) b
2) c
3) Oxytocin acts on the smooth muscles of our body and stimulates their contraction.
4) Vasopressin is hormone stimulates resorption of water and reduces loss of water. It acts mainly at the kidney and stimulates resorption of water and electrolytes by the distal tubules and thereby reduces loss of water through urine (diuresis). Hence, it is also called as anti-diuretic hormone (ADH).
5) Over-secretion of GH stimulates abnormal growth of the body leading to gigantism. Excess secretion of growth hormone in adults especially in middle age can result in severe disfigurement especially of the face.
CASE 3
The thyroid gland is composed of two lobes which are located on either side of the trachea. Both the lobes are interconnected with a thin flap of connective tissue called isthmus. The thyroid gland is composed of follicles and stromal tissues. Each thyroid follicle is composed of follicular cells, enclosing a cavity. These follicular cells synthesise two hormones, tetraiodothyronine or thyroxine (T4) and triiodothyronine (T3). Iodine is essential for the normal rate of hormone synthesis in the thyroid. Deficiency of iodine in our diet results in hypothyroidism and enlargement of the thyroid gland, commonly called goitre. Hypothyroidism during pregnancy causes defective development and maturation of the growing baby leading to stunted growth (cretinism), mental retardation, low intelligence quotient, abnormal skin, deaf-mutism, etc. In adult women, hypothyroidism may cause menstrual cycle to become irregular. Due to cancer of the thyroid gland or due to development of nodules of the thyroid glands, the rate of synthesis and secretion of the thyroid hormones is increased to abnormal high levels leading to a condition called hyperthyroidism which adversely affects the body physiology.
Exopthalmic goitre is a form of hyperthyroidism, characterised by enlargement of the thyroid gland, protrusion of the eyeballs, increased basal metabolic rate, and weight loss, also called Graves’ disease. Thyroid hormones play an important role in the regulation of the basal metabolic rate. These hormones also support the process of red blood cell formation. Thyroid hormones control the metabolism of carbohydrates, proteins and fats. Maintenance of water and electrolyte balance is also influenced by thyroid hormones. Thyroid gland also secretes a protein hormone called thyrocalcitonin (TCT) which regulates the blood calcium levels.
1.) _______________ Protein hormone secreted by thyroid gland regulates the blood calcium levels along with PTH.
a) thyromelatonin
b) thyrocalcitonin
c) thyrocalciumtonin
d) thyrocarbotonin
2.) cretinism is referred as,
a) stunted growth due to deficiency of iodine
b) stunted growth due to deficiency of thyroid hormones
c) mental retardation due to deficiency of iodine
d) deaf-mutism due to deficiency of iodine
3.) Explain how the both lobes of thyroid gland are interconnected?
4.) Give the composition of thyroid follicle and their function?
5.) What are adverse effect of iodine deficiency on human body?
Answer key
1) b
2) a
3) Thyroid gland is composed of two lobes these lobes are interconnected with a thin flap of connective tissue called isthmus.
4) Thyroid follicle is made up of follicular cells.
5) Function – Follicular cells synthesise two hormones named as Tetraiodothyronine/Thyroxine (T4) and Triiodothyronine (T3).
6) Iodine is essential for the optimum level of thyroid hormones secretion. Deficiency of iodine in our diet results in hypothyroidism and enlargement of the thyroid gland, commonly known as goitre. Deficiency of iodine during pregnancy causes defective development and maturation of the growing baby leading to stunted growth (cretinism), mental retardation, low intelligence quotient, abnormal skin, deaf-mutism, etc. In adult women, deficiency of iodine may cause menstrual cycle to become irregular.
CASE 4
The pineal gland is located on the dorsal side of forebrain. Pineal secretes a hormone named melatonin. Melatonin plays a very important role in the regulation of a 24-hour (diurnal) rhythm of our body. For example, it helps in maintaining the normal rhythms of sleep-wake cycle, body temperature. In addition, melatonin also influences metabolism, anti-aging, pigmentation, the menstrual cycle as well as our defense capability.
In humans, four parathyroid glands are present on the back side of the thyroid gland, one pair each in the two lobes of the thyroid gland. The parathyroid glands secrete a peptide hormone called parathyroid hormone (PTH). The secretion of PTH is regulated by the circulating levels of calcium ions. Parathyroid hormone (PTH) increases the Ca2+ levels in the blood. PTH acts on bones and stimulates the process of bone resorption i.e. dissolution or demineralisation . PTH also stimulates reabsorption of Ca2+ by the renal tubules and increases Ca2+ absorption from the digested food. It is, thus, clear that PTH is a hypercalcemic hormone, i.e., it increases the blood Ca2+ levels. Along with TCT, it plays a significant role in calcium balance in the body.
The thymus gland is a lobular structure located between lungs behind sternum on the ventral side of aorta. The thymus plays a major role in the development of the immune system. This gland secretes the peptide hormones called thymosins. Thymosins play a major role in the differentiation of T-lymphocytes, which provide cell-mediated immunity. In addition, thymosins also promote production of antibodies to provide humoral immunity. Thymus is degenerated in old individuals resulting in a decreased production of thymosins. As a result, the immune responses of old persons become weak.
1.) _______________ is a lobular structure located between lungs behind sternum on the ventral side of aorta.
a) Pineal gland
b) Thymus gland
c) Thyroid glands
d) Parathyroid glands
2.) Reabsorption of calcium in body is stimulated by
a) Tymosins
b) Melatonin
c) Parathyroid
d) All of the above
3.) Name the hormone which helps in maintaining the normal rhythms of sleep-wake cycle.
4.) What is bone resorption?
5.) Explain why Parathyroid hormone are named as hypercalcemic hormone?
Answer key
1) d
2.) c
3) Melatonin is the hormone which helps in maintaining the normal rhythms of sleep-wake cycle.
Bone resorption is the process of dissolution or demineralisation of bones, which is stimulated by Parathyroid hormone secretion.
Parathyroid hormone are named as hypercalcemic hormone. PTH stimulates reabsorption of Ca2+ by the renal tubules and increases Ca2+ absorption from the digested food. it increases the blood Ca2+ levels. It plays a significant role in calcium balance in the body