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Tamilnadu Samacheer Kalvi 11th Bio Zoology Solutions Chapter 11 Chemical Coordination and Integration

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Samacheer Kalvi 11th Bio Zoology Chemical Coordination and Integration Text Book Back Questions and Answers

Textbook Evaluation Solved
Choose The Correct Answer
Question 1.
The maintenance of constant internal environment is referred as .
(a) Regulation
(b) Homeostasis
(c) Co-ordination
(d) Hormonal control
Answer:
(b) Homeostasis

Question 2.
Which of the following are exclusive endocrine glands?
(a) Thymus and testis
(b) Adrenal and ovary
(c) Parathyroid and adrenal
(d) Pancreas and parathyroid
Answer:
(c) Parathyroid and adrenal

Question 3.
Which of the following hormone is not secreted under the influence of pituitary gland?
(a) Thyroxine
(b) Insulin
(c) Oestrogen
(d) Glucocorticoids
Answer:
(A) Insulin

Question 4.
Spermatogenesis in mammalian testes is controlled by?
(a) Luteinising hormone
(b) Follicle stimulating hormone
(c) FSH and prolactin
(d) GH and prolactin
Answer:
(A) Follicle stimulating hormone

Question 5.
Serum calcium level is regulated by?
(a) Thyroxine
(b) FSH
(c) Pancreas Assertion is true, but Reason is false
(d) Thyroid and parathyroid
Answer:
(d) Thyroid and parathyroid

Question 6.
Iodised salt is essential to prevent?
(a) Rickets
(b) Scurvy
(c) Goitre
(d) Acromegaly
Answer:
(c) Goitre

Question 7.
Which of the following gland is related with immunity?
(a) Pineal gland
(b) Adrenal gland
(c) Thymus
(d) Parathyroid gland
Answer:
(c) Thymus

Question 8.
Which of the following statement about sex hormones is correct?
(a) Testosterone is produced by Leydig cells under the influence of luteinizing hormone
(b) Progesterone is secreted by corpus luteum and softens pelvic ligaments during child birth
(c) Oestrogen is secreted by both sertoli cells and corpus luteum
(d) Progesterone produced by corpus luteum is biologically different from the one produced by placenta.
Answer:
(a) Testosterone is produced by Leydig cells under the influence of luteinizing hormone

Question 9.
Hypersecretion of GH in children leads to
(a) Cretinism
(b) Gigantism
(c) Graves disease
(d) Tetany
Answer:
(b) Gigantism

Question 10.
A pregnant female delivers a baby who suffers from stunted growth, mental retardation, low intelligence quotient and abnormal skin.This is the result of …………….
(a) Low secretion of growth hormone
(b) Cancer of the thyroid gland
(c) Over secretion of pars distalis
(d) Deficiency of iodine in diet.
Answer:
(b) Cancer of the thyroid gland

Question 11.
The structure which connects the hypothalamus with anterior lobe of pituitary gland is the
(a) Dendrites of neuro hypophysis
(b) Axons of neurohypophysis
(c) Bands of white fibers from cerebellar region
(d) Hypophysial portal system
Answer:
(b) Axons of neurohypophysis

Question 12.
Comment on homeostasis?
Answer:
Homeostasis: Maintenance of constant internal environment of the body by the different coordinating system. ‘

Question 13.
Which one of the following statement is correct
(a) Calcitonin and thymosin are thyroid hormones
(b) Pepsin and prolactin are selected in stomach
(c) Secretin and rhodopsin are polypeptide hormones
(d) Cortisol and aldosterone are steroid hormones
Answer:
(d) Cortisol and aldosterone are steroid hormones .

Question 14.
Which of the given option shows all wrong statement for thyroid gland Statements
(i) It inhibits process of RBC formation
(ii) It hepls in maintenance of water and electrolytes
(iii) Its more secretion can reduce blood pressure
(iv) It stimulates osteoblast
(a) (i) and (ii)
(b) (iii) and (iv)
(c) (i) and (iv)
(d) (i) and (iii)
Answer:
(c) (i) and (iv)

Question 15.
Hormones are known as chemical messenger? Justify?
Answer:
Hormones are released into the blood stream and circulated as chemical signals. These act specifically on certain organs or tissues called target organs or tissues. These speed up or slow down or alter the activity of target tissues or organs. Hence they are known as chemaical messengers.

Question 16.
Write the role of oestrogen in ovulation?
Answer:
Oestrogen is the ovarian hormone secreted during the proliferation phase of menstrual cycle from the 6th day to 14th day of the cycle. On 14th day of the cycle, under the influence of uteinizing hormone, ovum is released from the graffian follicles. This process is known as ovulation.

Question 17.
Comment on Acini of thyroid gland?
Answer:
Thyroid gland is a bilobed endocrine gland. Each lobe is made up of many lobules. The lobules consist of follicles called acini. Each acinus is lined with glandular, cuboidal or squamous epithelial cells. The lumen of acinus is filled with colloid, a thick glycoprotein mixture consisting of thyroglobulin molecules.

Question 18.
Write the causes for diabetes mellitus and diabetes insipids?
Answer:
Diabetes mellitus is caused due to reduced secretion of insulin. As a result, blood glucose level is elevated. Diabetes insipidus is caused due to under secretion of ADH or vasopression. As a result, reabsorption of water gets affected and hende large amount of urine is produced.

Question 19.
Specify the symptoms of acromegaly?
Answer:
Acromegaly is caused due to excessive secretion of growth hormone in adults. The symptoms of acromegaly are overgrowth of hand bones, feet bones, jaw bones malfunctioning of gonads. enlargement of viscera, tongue, lungs, heart, liver, splean and endocrine glands like thyroid, or adrenal glands.

Question 20.
Write the symptoms of cretinism?
Answer:
Cretinism is caused due to hypothyroidism in infants. A cretin child shows the following symptoms:-

  1. Retarded skeletal growth.
  2. Absence of sexual maturity
  3. Retarded mental ability
  4. Thick and short limbs
  5. Thick wrinkled skin
  6. Bloated face
  7. Protruded enlarged tongue
  8. Low BMR, slow pulse rate,subnormal body temperature and elevated blood cholesterol levels

 

Question 21.
Briefly explain the structure of thyroid gland?
Answer:
The thyroid gland is butterfly shaped, bilobed situated below the larynx on each side of the upper trachea. The two lobes are connected by a median tissue mass called isthmus. Each lobe is made up of many lobules. The lobules consist of follicles called acini. Each acinus is lined with glandular, cuboidal or squamous epithelial cells.

The lumen of acini is filled with colloid, a thick glycoprotein mixture consisting of thyroglobulin molecules. The thyroid gland secretes Tri-iodothyronine (T,) and tetra-iodothyronine (T4) or thyroxine hormones. These are concerned with metabolism.

Samacheer Kalvi 11th Bio Zoology Solutions Chapter 11 Chemical Coordination and Integration img 1

Question 22.
Name the layers of adrenal cortex and mention their secretions?
Answer:
A pair of adrenal glands are located at the anterior end of the kidneys. Elence, they are called suprarenal glands.The outer region is called cortex and the inner region is medulla. The adrenal cortex has three distinct zones,

  1. Zona Glomerulosa
  2. Zona fasciculata
  3. Zona reticularis

1. Zona Glomerulosa:

  • It is the outer thin layer. It constitutes about 15% of the cortex.
  • It secretes mineralocorticoids.

2. Zona fasciculata:

  • It is the middle wide layer constituting about 15% of adrenal cortex.
  • It secretes glucocorticoids such as cortisol, corticosterone and trace amounts of adrenal androgen and oestrogen.

3. Zona reticularis:

  • It is the inner zone of adrenal cortex.
  • It constitutes about 10% of adrenal cortex.
  • It constitutes about 10% of adrenal cortex.
  • It secretes the adrenal androgen, trace amount of oestrogen and glucocorticoids.

Question 23.
Differentiate hyperglycemia from hypoglycemia?
Answer:

Hyperglycemia

Hypoglycemia
1. Elevation in the blood sugar level is called hyperglycemia 1. Decrease in the blood sugar level is called hypoglycemia.
2. This happens due to reduced secretion of insulin. 2. This happens due to increased secretion of insulin.

 

Question 24.
Write the functions of CCK?
Answer:
CholecystokininCholecystokinin is secreted by duodenum in response to the presence of fat and acid in the diet. It acts on the gall bladder to release bile into duodenum and stimulates the secretion of pancreatic enzymes and its discharge.

Question 25.
Growth hormone is important for normal growth. Justify the statement?
Answer:
Growth hormone promotes growth of all the tissues and metabolic process of the body. It influences the metabolism of carbohydrate, proteins and lipids. It increases the rate of protein biosynthesis in the cells.

It stimulates chondrogenesis (cartilage formation), osteogenesis (bone formation) and helps in the retention of minerals like nitrogen, potassium, phosphorus, sodium etc in the body. It increases the release of fatty acid from adipose tissue and decreases the rate of glucose utilization for energy by the cells. The hyposecretion of growth hormones causes dwarfism in children.

Question 26.
Pineal gland is an endocrine gland, write its role?
Answer:
The pineal gland or epiphysis cerebri or conarium is located behind the third ventricle of brain. It is formed of paranchymal cells and interstitial cells. It secretes the hormone, melatonin.

It plays a central role in the regulation of circadian rhythm of our body and maintains normal sleep wake cycle. It also regulates the timing of sexual maturation of gonads. It also influences metabolism, pigmentation, menstrual cycle and defence mechanism of our body.

Question 27.
Comment on the functions of adrenalin?
Answer:
Adrenalin increases liver glycogen breakdown into glucose and increases the release of fatty acids from fat cells. During emergency, it increases heart beat rate and blood pressure.lt stimulates the smooth muscles of cutaneous and visceral arteries to decrease blood flow. It increases blood flow to the skeletal muscles and nervous tissue.

Question 28.
Predict the effects of removal of pancreas from the human body?
Answer:
Pancreas is both exocrine and endocrine gland. It is located just below the stomach as a leaf like structure. It secretes digestive enzymes and hormones like insulin and glucogon.

The digestive enzymes digest carbohydrates, proteins and fats. Insulin and glucose regulate blood sugar level. If pancreas is removed from the body, digestion and main’taince of blood sugar level gets afftected.

Question 29.
Enumerate the role of kidney as an endocrine gland?
Answer:
Kidney has endocrine tissues which act as partial endocrine gland. It secretes renin, erythropoietin and calcitripl. Renin is secreted by juxta glomerular cells. It increases blood pressure when angiotensin is formed in blood.

Erythropoietin is also secreted by the juxta glomerular cells of the kidney and stimulates erythropoieis in bone marrow. Calcitriol is secreted by proximal tubes of nephrons. It is an active form of vitamin D3 which promotes calcium and phosphorus absorption from intestine and accelerates bone formation.

Question 30.
Write a detailed account of gastro intestinal tract hormones?
Answer:
Group of specialized endocrine cells present in gastro-intestial tract secretes hormones such as gastrin, cholecystokinin (CCK), secretin and gastric inhibitory peptides (GIP). Gastrin acts on the gastric glands and stimulates the secretion of HC1 and pepsinogen.

Cholecystokinin (CCK) is secreted by duodenum in response to the presence of fat and acid in the diet. It acts on the gall bladder to release bile into duodenum and stimulates the secretion of pancreatic enzymes and its discharge. Secretin acts on acini cells of pancreas to secrete bicarbonate ions and water to neutralize the acidity. Gastric inhibitory peptide (GIP) inhibits gastric secretion and motility.

In Text Questions Solved

Question 1.
Pituitary gland is located in a depression in the sphenoid bone of skull below the brain, so is also called hypothalamus cerebri. Discuss the following:
(a) Pituitary gland is commonly called “master gland” of the body?
(b) Discuss the role of hypothalamus and pituitary as a coordinated unit in maintaining physiological processes?
(c) How does the posterior lobe of pituitary help in osmoregulation?
Answer:
(a) Pituitary gland is commonly called “master gland” of the body because it regulates the activity of other endocrine glands such as adrenal gland, thyroid gland, testis and ovary.

(b) The hypothalamus sends signals to the pituitary gland to release or inhibit pituitary hormone releasing factor production thus maintaining Homeostasis of the body.

(c) The posterior lobe of pituitary helps in osmoregulation by secreting the hormones namely vasopressin and oxytocin which increases tubular reabsorption of water in the nephrons.

Question 2.
Endocrine glands control and coordinate the body functions through secreting certain chemical messengers called hormones. Due to certain physiological reasons, the blood glucose level of an otherwise normal person?
(a) Give the possible cause for the increases in blood glucose level?
(b) What is the chemical nature of this hormone? Discuss its role in the body?
(c) How can this condition be reversed?
Answer:
(a) Stress and anxiety could have been the possible causes for the sudden increase in blood glucose level.

(b) Insulin is a polypeptide hormone. Insulin is secreted by the Islets of Langerhans of pancreas. It helps in converting glucose into glycogen or fat and allowing-oxidation of glucose inside the cells. Thus, insulin helps maintain the blood sugar level.

(c) This condition can be reversed by relaxing and taking a walk.

Question 3.
Identify the peaks of FSH, LH, Oestrogen and Progesterone hormones through out the menstrual cycle?
Answer:

Samacheer Kalvi 11th Bio Zoology Solutions Chapter 11 Chemical Coordination and Integration img 2

Oestrogen, FSH are in the peak during the follicular phase (6 -13 days) of menstruation. LH is at the peak during ovulation that is on the 14th day of menstrual cycle. Progesterone is at the peak in the luteal phase of menstruation (14 – 28 days).

Samacheer Kalvi 11th Bio Zoology Chemical Coordination and Integration Additional Questions & Answers

I. Choose The Correct Answer

Question 1.
Which of the following is not related to hormones?
(a) They are secreted by ductless glands
(b) They act on the target
(c) They act as chemical messengers
(d) They play an important role in disgestion
Answer:
(d) They play an important role in disgestion

Question 2.
Which of the following is a partial endocrine?
(a) Thymus gland
(b) Pineal gland
(c) Gonads
(d) Parathyroid gland
Answer:
(c) Gonads

Question 3.
Which of the following is the function of Growth Hormone?
(a) It increases blood pressure
(b) It influences the metabolism of carbohydrates, proteins and lipids
(c) It stimulates melanin synthesis in melanocytes
(d) It promotes reabsorption of water by nephrons
Answer:
(b) It influences the metabolism of carbohydrates, proteins and lipids

Question 4.
Which of the following stimulates milk secretion after the child birth in females?
(a) Luteotropic hormone
(b) Luteinizing hormone
(c) Follicle stimulating hormone
(d) Somatotropin
Answer:
(a) Luteotropic hormone

Question 5.
Which of the following is the reason for calling vasopressin as the anti Jiuretic hormone?
(a) It promotes dilution of urine
(b) It reduces dilution of urine
(c) It increases blood pressure
(d) It constricts blood vessels
Answer:
(b) It reduces dilution of urine

Question 6.
A person is unable to sleep normally. He may not get proper secretion of?
(a) Thyroxine
(b) Vasopression
(c) Melatonin
(d) Oxytocin
Answer:
(c) Melatonin

Question 7.
Why is parathormone called hypercalcemic hormone?
(a) It decreases blood calcium level
(b) It increases blood potassium level
(c) It increases blood calcium level
(d) It decreases blood potassium level
Answer:
(b) It increases blood potassium level

Question 8.
Which of the following is not the function of cortisol?
(a) It produces anti inflammatory reactions
(b) It stimulates RBC production
(c) It supresses the immune response
(d) It regulates water and electrolyte balance of the body
Answer:
(d) It regulates water and electrolyte balance of the body

Question 9.
Which adrenal hormone is concerned with maintaining electrolytes, osmotic pressure and blood pressure?
(a) Cortisol
(b) Glucocorticoids
(c) Aldosterone
(d) Adrenalin
Answer:
(c) Aldosterone

Question 10.
Which of the following hormones prepares the body for meeting emergency situations?
(a) Aderenalin and noradrenalin
(b) Glucocorticoids and mineralocorticoids
(c) Cortisol and Aldosterone
(d) Glucocorticoids and corticosterone
Answer:
(a) Aderenalin and noradrenalin

Question 11.
Which of the following is the function of insulin?
(a) It promotes Glycogenolysis
(b) It increases the uptake of glucose into the body cells
(c) It promotes gluconeogenesis
(d) It reduces the cellular uptake and utilization of glucose
Answer:
(b) It increases the uptake of glucose into the body cells

Question 12.
Which of the following is the functiion of Glucogon?
(a) It increases the cellular utilization of glycogen into glucose
(b) It promotes the breakdown of glycogen into glucose
(c) It inhibits the breakdown of glycogen into glucose
(d) It inhibits the production of glucose from non-carbohydrate sources
Answer:
(b) It promotes the breakdown of glycogen into glucose

Question 13.
Which of the following promotes the appearance of secondary sexual characters in male and female respectively?
(a) Testosterone and progesterone
(b) Progesterone and testosterone
(c) Testosterone and oestrogen
(d) Oestrogen and testosterone
Answer:
(c) Testosterone and oestrogen

Question 14.
Which of the following is not the function of progesterone?
(a) Implantation of zygote in the uterus
(b) Decreasing the contraction of uterus
(c) Formation of placenta
(d) Maturation of reproductive organs
Answer:
(d) Maturation of reproductive organs

Question 15.
Which of the following hormone is secreted by proximal tubules of nephron?
(a) Renin
(b) Calcitriol
(c) Erythropoietin
(d) Cholecystokinin
Answer:
(b) Calcitriol

Question 16.
A person attains a maximum of 4 feet height. What could be the reason for this?
(a) Hypersecretion of somatotropic hormone
(b) Hypersecretion of ACTH
(c) Hyposecretion of TSH
(d) Hyposecretion of somatotropic hormone
Answer:
(d) Hyposecretion of somatotropic hormone

Question 17.
An excessive secretion of growth hormone in adults lead to ……………….
(a) Gigantism
(b) Dwarfism
(c) Acromegaly
(d) Cretinism
Answer:
(c) Acromegaly

Question 18.
Why does cretenism occur?
(a) Hypothyroidism in adults
(b) Hypothyroidism in infants
(c) Hyperthroidism in adults
(d) lower level of iodine in blood
Answer:
(b) Hypothyroidism in infants

Question 19.
Increased heartbeat, high BP and protrusion of eyeball are the characteristics of …………….
(a) Endemic goitre
(b) Tetany
(c) Myxodema
(d) Grave’s disease
Answer:
(d) Grave’s disease

Question 20.
Hypocalcemia occures due to?
(a) Hypersecretion of parathyroid hormone
(b) Hyposecretion of parathyroid hormone
(c) Hypersecretion of cortisol
(d) Hyposecretion of cortisol
Answer:
(b) Hyposecretion of parathyroid hormone

Question 21.
Demineralization occurs due to?
(a) Hypoparathyroidism
(b) Hypothyroidism
(c) Hyperthyroidism
(d) Hyperparathyroidism
Answer:
(d) Hyperparathyroidism

Question 22.
Hyper pigmentation of skin and low metabolic rate are the symptoms of …………………..
(a) Cushing’s syndrome
(b) Addison’s disease
(c) Grave’s disease
(d) Gull’s disease
Answer:
(b) Addison’s disease

Question 23.
Excess secretion of cortisol leads to
(a) Addison’s disease
(b) Grave’s disease
(c) Cushing’s syndrome
(d) Gull’s diesease
Answer:
(c) Cushing’s syndrome

Question 24.
In Type I diabetes ………………
(a) Insulin is produced in sufficient quantity
(b) Insulin resistance occurs
(c) Insulin is produced more
(d) Insulin is not produced
Answer:
(d) Insulin is not produced

Question 25.
Excessive intake of food in diabetes is called as …………………..
(a) Polydipsia
(b) Polyurea
(c) Polyphagia
(d) Ketosis
Answer:
(c) Polyphagia

Question 26.
The hyposecretion of vasopressin results in …………….. ?
(a) Diabetes mellitus
(b) Diabetes insipidus
(c) Ketosis
(d) Hyperglycemia
Answer:
(b) Diabetes insipidus

Question 27.
What does peptide hormone do as it cannot cross the phospholipid cell membrane?
(a) It combines with cAMP
(b) It binds to the receptors on the exterior cell surface
(c) It combines with steroids
(d) It combines with adenylate cyclases
Answer:
(a) It binds to the receptors on the exterior cell surface

Question 28.
In case of steroids hormones, dimer of receptor-hormone complex is formed. What does it do then?
(a) It binds with golgi complex
(b) It binds with tRNA
(c) It binds with mRNA
(d) It binds with DNA
Answer:
(d) It binds with DNA

II. Fill in the Blanks

Question 1.
The hormones are converted into inactive compounds by the …………………….. and excreted by the ……………………..
Answer:
(liver, kidneys )

Question 2.
Hormones act as …………………….. to perform specific functions in the target organs.
Answer:
( organic catalysts / coenzymes )

Question 3.
The pituitary gland is controlled by the ……………………..
Answer:
(hypothalamus)

Question 4.
Hypothalamus produces …………………….. which regulate the secretions of the pituitary gland.
Answer:
(neurotransmitters)

Question 5.
The pituitary gland is located in the bony cavity of the sphenoid bone called ……………………..
Answer:
( sella turcica)

Question 6.
The pituitary gland is connected to the hypothalamus by a stalk called ……………………..
Answer:
(infundibulum)

Question 7.
The anterior lobe of the pituitary gland originates from the embriyonic invagination of pharyngeal epithelium called ……………………..
Answer:
(Rathke’s pouch)

Question 8.
…………………….. decreases the rate of glucose
Answer:
(Growth Hormone)

Question 9.
ACT4 stimulates melanin synthesis in ……………………..
Answer:
(Melanocytes)

Question 10.
LH is also known as ……………………..
Answer:
(Interstitial cell stimulating Hormone)

Question 11.
FSH and LH are collectively referred as ……………………..
Answer:
(gonadotropins)

Question 12.
High prolactin secretion during lactation supresses LH secretion and ……………………..
Answer:
(ovulation)

Question 13.
…………………….. promotes reabsorption of water and electrolytes by distal tubules of nephron.
Answer:
(ADH / vasopressin )

Question 14.
…………………….. stimulates ejection of milk from the mammary glands.
Answer:
(oxytocin)

Question 15.
The pineal gland secretes …………………….. which plays a central role in the regulation of circadian rhythm of our body.
Answer:
(melatonin)

Question 16.
The two lateral lobes of thyroid gland are connectd by a median tissue mass called ……………………..
Answer:
(isthmus)

Question 17.
…………………….. gland produces ‘T’ lymphocytes which provides cell mediated immunity.
Answer:
(Thymus)

Question 18.
…………………….. produces anti inflammatory reactions and suppresses the immune response.
Answer:
(cortisol)

Question 19.
…………………….. increases the breakdown of liver glycogen into glucose
Answer:
(Adrenalin)

Question 20.
Both adrenalin and nor adrenalin are ……………………..
Answer:
(catecholamines)

Question 21.
…………………….. stimulates the reabsorption of sodium and water.
Answer:
(Aldosterone)

Question 22.
The beta cells of islets of langerhans secrete ……………………..
Answer:
(Insulin)

Question 23.
The alpha cells of islets of langerhans secrete ……………………..
Answer:
(glucagon)

Question 24.
The delta cells of islets of langerhans secrete ……………………..
Answer:
(somatostatin)

Question 25.
Insulin inhibits the breakdown of …………………….. into glucose.
Answer:
(glycogen)

Question 26.
…………………….. is called a hypoglycemic hormone.
Answer:
(Insulin)

Question 27.
…………………….. promotes the breakdown of glycogen into glucose.
Answer:
(Glucogon)

Question 28.
The breakdown of glucose is called ……………………..
Answer:
(glycogenolysis)

Question 29.
The synthesis of glucose from non – carbohydrate molecules is called ……………………..
Answer:
(gluconeolysis)

Question 30.
…………………….. reduces the cellular update and utilization of glucose.
Answer:
(Glugocon)

Question 31.
…………………….. is called a hyperglycemic hormone.
Answer:
(Glucogon)

Question 32.
The …………………….. cells of testes secrete male sex hormone.
Answer:
(Leydig)

Question 33.
…………………….. is reposible for development of secondary sexual charactes of female.
Answer:
(Oestrogen)

Question 34.
…………………….. prepares the uterus for implantation of the fertilized ovum.
Answer:
(Progesterone)

Question 35.
…………………….. on the atrial wall secretes atrial natriuretic factor to reduce the blood pressure .
Answer:
(cardiocytes)

Question 36.
…………………….. increases blood pressure when angiotension is formed in blood.
Answer:
(Renin)

Question 37.
stimulates the erythyropoiesis in bone marrow.
Answer:
(Erythropoietin)

Question 38.
…………………….. is the hormone secreted by proximal tubules of nephron which promotes calcium and phosphorus absorption from intestine.
Answer:
(Calcitriol)

Question 39.
…………………….. stimulates the secretion of HCl and pepsinogen.
Answer:
(Gastrin)

Question 40.
…………………….. stimulates the release of bile into duodenum and secretion of panereatic enzymes.
Answer:
(Cholecystokinin)

Question 41.
…………………….. acts on acini cells of pancreas to secrete bicarbonate ions and water to neutralise the acidity.
Answer:
(secretin)

Question 42.
…………………….. is caused due to hyposecretion of growth hormone in children.
Answer:
(dwarfism)

Question 43.
…………………….. is caused due to hypersecretion of growth hormone in childre.
Answer:
(Gigantism)

Question 44.
…………………….. is caused due to excessive secretion of growth hormone in adults.
Answer:
(Acromegaly)

Question 45.
The hypothyroidism in children causes ……………………..
Answer:
(cretinism)

Question 46.
The hyposecretion of thyriod in adults causes ……………………..
Answer:
(Myxodema)

Question 47.
Myxodema is otherwise called ……………………..
Answer:
(Gull’s disease)

Question 48.
The hypersecretion of thyriod gland causes as ……………………..
Answer:
(exopthalmic goitre)

Question 49.
The hyposecretion of parathyroid hormone causes ……………………..
Answer:
(Tetany)

Question 50.
The exophthalmic goitre is called as ……………………..
Answer:
(Grave’s disease / thyrotoxicosis)

Question 51.
Due to hyposecretion of parathyroid hormone serum …………………….. level decreases.
Answer:
(calcium)

Question 52.
Demineralisation is caused due to ……………………..
Answer:
(hyperparathyroidism)

Question 53.
…………………….. is caused due to hyposecretion of glucocorticoids and mineralocorticoids from the adrenal cortex.
Answer:
(Addison’s disease)

Question 54.
The hypersecretion of cortisol causes ……………………..
Answer:
(Cushing’s syndrome)

Question 55.
Type II diabetes is caused due to ……………………..
Answer:
(insulin resistance)

Question 56.
Type I diabetes is ……………………..
Answer:
(insulin dependent)

III. Answer The Following Questions

Question 1.
Distinguish between Exocrine glands and Endocrine glands?
Answer:

Exocrine

Endocrine glands
1. Exocrine glands have ducts to carry their secretions. 1. Endocrine gland do not have ducts to carry their secretions. They are directly released into the blood. Hence these are called ductless glands.
2. These are concerned with digestion and other functions. 2. These are concerned with growth, puberty, metabalosim and maintenance of homeostasis.
3. eg. liver, teargland, mammary gland. 3. eg. pituitary gland, thyroid gland.

 

Question 2.
Why is hypothalamus considered as neuro endocrine gland?
Answer:
The hypothalamus alone with its neural function produces hormones. Hence it is considered as neuro-endocrine gland.

Question 3.
What are the functions of hypothalamus?
Answer:
Hypothalamus maintains homeostasis, blood pressure, body temperature, cardio and fluid electrolyte balance of the body. It influences various emotional responses.

Question 4.
Write on the origin of pituitary gland?
Answer:
The anterior lobe of pituitary gland originates from the embryonic invagination of pharyngeal epithelium called Rathke’s pouch. The posterior lobe originates from the base of the brain as an outgrowth of hypothalamus.

Question 5.
What are the lobes of adenohypophysis?
Answer:
Pars distalis, Pars intermedia and Pars tuberalis.

Question 6.
What is Pars nervosa?
Answer:
The neurohypophysis of the pituitary gland is known as pars nervosa.

Question 7.
Name the hormones secreted by the pituitary gland?
Answer:
The anterior lobe of pituitary secretes six tropic hormones such as growth hormone (GH), thyroid stimulating hormone (TSH), adreno corticotropic hormone (ACTH), follicle stimulaiton hormone (FSH), luteinizing hormone (LH), luteotropic hormone (LTH) and melanocyte stimulating hormone (MSH) (in lower animals only). The posterior lobe of pituitary secretes the hormones namely vasopressin and oxytocin.

Question 8.
Write a paragraph on the Growth Hormone?
Answer:
Growth hormone (GH):
It is also known as somatotropic hormone (STH) or Somatotropin. It is a peptide hormone Growth hormone promotes growth of all the tissues and metabolic process of the body. It influences the metabolism of carbohydrates, proteins and lipids and increases the rate of protein biosynthesis in the cells.

It stimulates chondrogenesis (cartilage formation), osteogensis (bone formation) and helps in the retention of minerals like nitrogen, potassium, phosphorus, sodium etc., in the body. GH increases the release of fatty acid from adipose tissue and decreases the rate of glucose utilization for energy by the cells. Thus it conserves glucose for glucose dependent tissues, such as the brain.

Question 9.
Write on the role of Thyroid stimulating hormone and Adreno cortico tropic hormone? Thyroid stimulating hormone (TSH) or thyrotropin?
Answer:
TSH is a glycoprotein hormone, which stimulates the thyroid gland to secrete Triiodothyronine (T3) and thyroxine (T4). TSH secretion is regulated by negative feedback machanism. It’s release from the anterior pitutary is induced by the thyrotropin releasing hormone (TRH). When thyroxine level in the blood increases, TRH acts on both the pituitary and hypothalamus to inhibit TSH secretion.

Adreno cortico tropic hormone (ACTH):
ACTH is a peptide hormone that stimulates the adrenal cortex to secrete glucocorticoids and mineralocorticoids. It stimulates melanin synthesis in melanocytes, induces the release of fatty acids from adipose tissues and stimulates insulin secretion. ACTH secretion is regulated by negative feedback mechanism.

Question 10.
What are the functions of follicle stimulation hormone?
Answer:
Follicle stimulating hormone (FSH):
FSH is a glycoprotein hormone which regulates the functions of the gonads (ovary and testis). In males, FSH along with androgens acts on the germinal epithelium of seminiferous tubules and stimulates the production and release of sperms (spermatogenesis). In females, FSH acts on the ovaries and brings about the development and maturation of gratfran follicles.

Question 11.
What is the role of Luteinizing hormone (LH)?
Answer:
Luteinizing Hormone is a glycoprotein hormone which is also known as interstitial cell stimulating hormone (ICSH). In males, ICSH acts on the interstitial cells of testis to produce the male sex hormone, testosterone. In females, LH along with FSH matures the ovarian follicles.

LH independently induces ovulation, maintains the corpus luteum and promotes synthesis and release of ovarian hormones. FSH and LH are collectively referred as gonadotropins. FSH and LH are not produced during childhood. The secretion of FSH and LH starts only during prepubertal period.

Question 12.
What is the significance of Luteotropic hormone (LTH)?
Answer:
Luteo Tropic Hormone is also called luteotropin or lactogenic hormone or prolactin or mammotropin. It is a protein hormone which stimulates milk secretion after the child birth in females. High prolactin secretion during lactation suppresses LH secretion and ovulation since it induces the corpus luteum hence named as luteo tropic hormone.

Question 13.
What are the hormones of neurohypophysis?
Answer:
(i) Vasopressin or antidiuretic hormone (ADH):
ADH is a peptide hormone which promotes reabsorption of water and electrolytes by distal tubules of nephron and thereby reduces loss of water through urine. Hence it is called as anti diuretic hormone. It also causes constriction of blood vessels when released in large amount and increases blood pressure. ADH deficiency causes Diabetes insipidus which induces the production of large amount of urine.

(ii) Oxytocin (means quick birth):
It is a peptide hormone which stimulates vigorous contraction of the smooth muscles of uterus during child birth and ejection of milk from the mammary glands.

Question 14.
What are the functions of pineal gland?
Answer:
In human, the pineal gland or epiphysis cerebri or conarium is located behind the third ventricle of brain and is formed of parenchymal cells and interstitial cells.

It secretes the hormone, melatonin, which plays a central role in the regulation of circadian rhythm of our body and maintains the normal sleep wake cycle. It also regulates the timing of sexual maturation of gonads. In addition melatonin also influences metabolism, pigmentation, menstrual cycle and defence mechanism of our body.

Question 15.
Write on the role of parathyroid gland?
Answer:
In human, four tiny parathyroid glands are found in the posterior wall of the thyroid glands. This galnd is composed of two types of cells, the chief cells and oxyphil cells. The chief cells secrete parathyroid hormone (PTH) and the functions of oxyphil cells are not known. Parathyroid hormone or parathormone (PTH).

PTH is a hypercalcemic hormone. It is a peptide hormone involved in controlling the calcium and phosphate homeostasis. The secretion of PTH is controlled by calcium level in the blood. It increases the blood calcium level by stimulating osteoclasts to dissolve the bone matrix.

As a result calcium and phosphate are released into the blood. PTH enhances the reabsorption of calcium and excretion of phosphates by the renal tubules and promotes activation by vitamin D to increase calcium absorption by intestinal muscosal cells.

Question 16.
Write a paragraph on Thymus gland?
Answer:
Thymus gland is partially an endocrine and partially a lymphoid organ. It is a bilobed structure located just above the heart and aorta, behind the sternum. It is covered by fibrous capsule and anatomically it is divisble into an outer cortex and an inner medulla.

It secretes four hormones such as thymulin, thymosin, thymopoietin and thymic humoral factor (THF). The primary function of thymus is the production of immuno competent ‘T’ lymphocytes which provides cell mediated immunity.

Question 17.
Explain the hormones secreted by Adrenal gland?
Answer:
A pair of adrenal glands are located at the anterior end of the kidneys, hence also called suprarenal glands. Anatomically the outer region is the cortex and the inner region is the medulla.

Histologically the adrenal cortex has three distinct zones, zona glomerulosa, zona fasciculata and zona reticularis. Zona glomerulosa an outer thin layer constitutes about 15% of adrenal cortex, and secretes mineralocorticoids.

Zona fasciculata, the middle widest layer constitutes about 75% of adrenal cortex and secretes glucocorticoids such as cortisol, corticosterone and trace amounts of adrenal androgen and oestrogen. Zona reticularis, an inner zone of adrenal cortex constitute about 10% of adrenal cortex and secretes the adrenal androgen, trace amount of oestrogen and glucocorticoids.

Adrenal medulla:
It is the central part of adrenal gland and is composed of ovoid and columnar cells, which are found around the network of blood capillaries. Adrenalin (epinephrine) and nor adrenalin (nor epinephrine) are the two hormones secreted by the adrenal medulla. Both adrenalin and nor adrenalin are catecholamines.

Function of adrenal hormones:
Glucocorticoids stimulate gluconeogenesis, lipolysis and proteolysis (the life saving avtivity). Cortisol is a glucocorticoid invloved in maintaining cardio vascular and kidney functions.

It produces anti-inflammatory reactions and suppresses the immune response. It stimulates the RBC production. It is also known as stress combat hormone. Mineralocorticoids regulates water and electrolyte balance of our body.

Aldosterone stimulates the reabsorption of sodium and water and eliminates potassium and phosphate ions through excretion,, thus it helps in maintainting electrolytes, osmotic pressure and blood pressure. Adrenal androgen plays a role in hair growth in the axial region, pubis and face during puberty.

The adrenal medulla secretes the hormones adrenalin and noradrenalin and are referred as “3F hormone” (fight, flight and fright hormone). Adrenalin increases liver glycogen breakdown into glucose and increases the release of fatty acids from fat cells.

During emergency it increases heart beat rate and blood pressure. It stimulates the smooth muscles of cutaneous and visceral arteries to decrease blood flow. It increases blood flow to the skeletal muscles therby increases the metabolic rate of skeletal muscles, cardiac muscles and nervous tissue.

Question 18.
What are the hormones responsible for maintaining blood glucose level?
Answer:
Insulin and glucogon are the hormones secreted by Islets of langerhans of pancreas:-
Insulin:
Insulin is a peptide hormone and plays an important role in glucose homeostasis. It’s main effect is to lower blood glucose levels by increasing the uptake of glucose into the body cells, especially muscle and fat cells. Insulin also inhibits the breakdown of glycogen to glucose, the conversion of amino acids or fats to glucose, so insulin is rightly called a hypoglycemic hormone.

Glucagon:
Glucagon is a polypeptide hormone. It is a potent hyperglycaemic hormone that acts on the liver and promotes the breakdown of glycogen to glucose (Glycogenolysis), synthesis of glucose from lactic acid and from non-carbohydrate molecules (gluconeogenesis).

Releases glucose from the liver cells, increasing the blood glucose levels. Since glucagon reduces the cellular uptake and utilisation of glucose it is called a hyperglycemic hormone. Prolonged hyperglycemia leads to the disorder called diabetes mellitus.

Question 19.
Explain the endorenal function of gonads?
Answer:
Testis:
A pair of testis is present in the scrotal sac of males. The testis functions as a sex organ and also as an endocrine gland. The testis is composed of seminiferous tubules and interstitial cells or Leyding cells. The Leyding cells secrete several male sex hormones, collectively called androgens, mainly testosterone.

Functions of testosterone:
Under the influence of FSH and LH testosterone initiates maturation of male reproductive organs, and the appearance of secondary sexual characters, muscular growth, growth of facial and axillary hair, masculine voice and male sexual behaviour. It enhances the total bone matrix and plays a stimulating role in the process of spermatogenesis.

Ovary:
Females have a pair of ovaries located in the pelvic region of the abdomen. The ovary is composed of ovarian follicles and stromal tissues. Besides producing the eggs or ova, the ovaries secrete the steroid hormones oestrogen and progesterone. Oestrogen is responsible for the maturation of reproductive organs and the development of secondary sexual characters at puberty. Along with progesterone, oestrogens promotes breast development and initiate the cyclic changes during menstrual cycle.

Progesterone prepares the uterus for implantaion of the fertilized ovum. It decreases the uterine contraction during pregnancy and stimulates mammary glands and milk secretion. It is responsible for premenstrual changes in the uterus and is essential for the formation of placenta.

Question 20.
Write the disorders associated with growth hormone?
Answer:
Dwarfism is due to hyposecretion of growth hormone (GH) in children, skeletal growth and sexual maturity is arrested. They attain a maximum height of 4 feet only. Gigantism is due to hypersecreion of growth hormone (GH) in children. Overgrowth of skeletal structure occurs (up to 8 feet) and the visceral growth is not appropriate with that of limbs.

Acromegaly is due to excessive secretion of growth hormone in adults. Over growth of hand bones, feet bones, jaw bones, malfunctioning of gonads, enlargement of viscera, tongue, lungs, heart, liver, spleen and endocrine gland like thyroid, adrenal etc., are the symptoms of acromegaly.

Question 21.
Write on Hyperthyroidism and Hypothyroidism?
Answer:
In infants, hypothyroidiam causes cretinism. A cretins shows retarded skeletal growth, absence of sexual maturity, retarded mental ability, thick wrinkled skin, protruded enlarged tongue, bloated face, thick and short limbs occurs. The other symptoms are low BMR, slow pulse rate, subnormal body temperature and elevated blood cholesterol level.

Hyposecretion of thyroid in adults causes myxodema. It is otherwise called Gull’s disease. This disease is characterised by decreased mental activity, memory loss, slowness of movement, speech, and general weakness of body, dry coarse skin, scarce hair, puffy appearence, disturbed sexual function, low BMR, poor appetite, and subnormal body temperature.

Grave’s disease also called as thyrotoxicosis or exophthalmic goitre. This disease is caused due to hyper secretion of thyriod. It is characterised by enlargement of thyroid gland, increases BMR (50% -100%), elevated respiratory and excretory rates, increased heart beat, high BP, increases body temperature, protrusion of eyeball and weakness of eye muscles and weight loss.

Simple goitre is also known as Endemic goitre. It is caused due to hyposecretion of thyroxine. The symptoms includes enlargement of thyroid gland, fall in serum thyroxine level, increases TSH secretion.

Question 22.
Write on the disorders associated with parathryroid gland?
Answer:
Tetany is caused due to the hyposecretion of parathyroid hormone (PTH). Due to hyposecretion of PTH serum calcium level decreases (Hypocalcemia), as a result serum phosphate level increases. Calcium and phosphate excretion level decreses. Generalized convulsion, locking of jaws increased heart beat rate, increases body temperature, muscular spasm are the major symptoms of tetany. Hyperparathyroidism is caused due to excess PTH in blood. Demineralisation of bone, loss of muscle tone, general weakness, renal disorders are the symptoms of hyperparathyroidism.

Question 23.
Write a paragraph on Addison’s disease?
Answer:
Addison’s disease is caused due to hyposecretion of glucocorticoids and mineralocorticoids from the adrenal cortex. Muscular weakness, low BP, loss of appetite, vomiting, hyper pigmentation of skin, low metabolic rate, subnormal temperature, reduced blood volume – weight loss are the symptoms that occur in Addison’s disease. Reduces aldosterone secretion increases urinary excretion of Na Cl. and decreases potassium excretion leading to dehydration.

Question 24.
Write a paragraph on Cushing’s syndrome?
Answer:
Cushing’s syndrome is caused due to excess secretion of cortisol. Obesity of the face and trunk, redness of face, hand, feet, thin skin, excessive hair growth, loss of minerals from bone (osteoporoses) systolic hypertension are features of Cushing’s syndrome. Suppression of sexual function like atrophy of gonads are the other symptoms of Cushing’s syndrome.

Question 25.
Write on Hypoglycaemia?
Answer:
Hypoglycaemia is due to increased secretion of insulin thereby blood glucose level decreases. In this disorder blood glucose level lowers than normal fasting index. Increased heartbeat, weakness, nervousness, headache, confusion, lack of co-ordination, slurred speech, serious brain defects like epilepsy and coma occurs.

Question 26.
Write a paragraph on different types of diabetes mellitus?
Answer:
Hyperglycaemia is otherwise known as Diabetes mellitus. Is is caused due to reduced secretion of insulin. As the result, blood glucose level is elevated. Diabetes mellitus is of two types, Type! Diabetes and Type II Diabetes. Type I diabetes is also known Insulin dependent diabetes, caused by the lack of insulin secretion due to illness or viral infections. Type II diabetes is also known as Non-Insulin dependent diabetes, caused due to reduced sensitivity to insulin, often called as insulin resistance.

Symptoms of diabetes includes, polyurea (excessive urination), polyphagia (excessive intake of food), polydipsia (excessive consumption of liquids due to thirst), ketosis (breakdown of fat into glucose results in accumulation of ketone bodies) in blood. Gluconeogenesis (Conversion of non- carbohydrate) also occur in diabetes.

Question 27.
Explain the mechanism of hormone action?
Answer:
Peptide hormones cannot cross the phospolipid cell membrane and bind to the receptors on the exterior cell surface. They are transported to the golgi, which is the site of modification. It acts as a first messenger in the cell. Hormones on binding to their receptors do not enter target cell but generate the production of second messengers such as cyclic AMP (cAMP), which in turn regulates cellular metabolism.

This is catalyzed by the enzyme adenylate cyclase. The interaction between the hormone at the surface and the effect brought out by cAMP within the cell is known as signaling cascade. At each step there is a possibility of amplification.

  1. One hormone molecule may bind to multiple receptor molecule before it is degraded.
  2. Each receptor may activate several adenylate cyclases each of which make much CAMP.
  3. Thus there is more signal after each step.

The actions of CAMP are terminated by phosphodiesterases. The effect of peptide hormones like insulin, glucagon, somatotropin are uauslly short lived because they work through second messenger system.

Steroid hormones can easily cross the cell membrane, and bind to their receptors, which are intracellular or intranuclear. Upon binding to the receptors, they pair up with another receptor – hormone complex (dimerize). This dimer can then bind to DNA and alter its transcription.

The effect of steroid hormones such as aldosterone, FSH are long lived, as they alter the amount of mRNA and protein in a cell.

Amino acid derived hormones are derived from one or two aminoacid with a few additonal modifications. Thyroid hormone is synthesised from thyrosine and includes the addtion of several iodine atoms. Epinephrine an amino acid derivative may function through second messenger system like peptide hormone or they may actually enter the cell and function like steroid hormones.

Question 28.
Tabulate the major hypothalamic hormones and their functions?
Answer:

S.No

Hormones

Functions
1. Thyrotropin releasing hormone (TRH) Stimulate the secretion of TSH
2. Gonadotropin releasing hormone (GnRH) Stimulates the secretion of FSH
3. Corticotropin releasing hormone (CRH) Stimulates the secretion of ACTH
4. Growth hormone releasing hormone (GHRH) Stimulates the secretion of GH
5. Prolactin releasing hormone (PRH) Stimulates the secretion of Prolactin
6. Luteinizing hormone releasing hormone (LHRH) Stimulates the secretion of LH
7. MSH releasing hormone Stimulates the secretion of MSH
8. Growth hormone-inhibiting hormone (GHIH) Inhibits the secretion of GH
9. Prolactin inhibiting hormone (PIH) Inhibits the secretion of Prolactin
10. MSH inhibiting hormone Inhibits the secretion of MSH

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