Text Book Back Questions and Answers - Chapter 11 Chemical Coordination and Integration 11th Biology Zoology Guide Samacheer Kalvi Solutions - SaraNextGen [2024-2025]

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On April 24, 2024, 11:35 AM

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) $\mathrm{GH}$ 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.
lodised 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 6 th 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 $A D H$ 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.

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:

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 $\mathrm{HC} 1$ 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:

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).