NEET Biology Chemical Coordination and Integration MCQs Set 02

Answer: (d) 2 and 3 both

Explanation:
1. A hormone is a chemical messenger made in an endocrine gland; it is the first (primary) messenger that reaches the target cell through blood.
2. Options 2 and 3 describe the same idea, so both are right.

Teacher's Note:
1. Hormone = chemical messenger = primary or first messenger.
2. The second messenger (cAMP, Ca2+) works inside the target cell.

Answer: (d) Both endocrine and nervous system

Explanation:
1. Both systems coordinate and integrate body functions.
2. The nervous system gives fast, short-lived control; the endocrine system gives slower, longer-lasting chemical control.

Teacher's Note:
1. Nervous and endocrine systems work together.
2. Blood vascular system only transports; it does not integrate.

Answer: (a) Internal secretion mostly discharged in the blood by endocrine glands

Explanation:
1. Hormones are internal secretions poured directly into blood by ductless endocrine glands.
2. Exocrine secretions use ducts, and enzymes are biological catalysts, so the other options are wrong.

Teacher's Note:
1. Endocrine means ductless.
2. Hormones travel by blood to distant target organs.

Answer: (c) E.H. Starling

Explanation:
1. The term hormone was introduced by Starling (with Bayliss) after the discovery of secretin in 1902.
2. Schally is known for hypothalamic hormones and Harris for the neurovascular theory.

Teacher's Note:
1. Bayliss and Starling discovered secretin, the first hormone.
2. Starling coined the word hormone.

Answer: (c) Secretin

Explanation:
1. Secretin from the duodenal mucosa was the first hormone discovered (Bayliss and Starling, 1902).
2. Thyroxine, adrenaline and insulin were identified later.

Teacher's Note:
1. Secretin stimulates pancreatic juice secretion.
2. It is a gastrointestinal hormone.

Answer: (d) Relaxin

Explanation:
1. Androgens, aldosterone and estrogens are steroid hormones made from cholesterol.
2. Relaxin is a peptide hormone from the ovary and placenta.

Teacher's Note:
1. Steroid hormones: cortisol, aldosterone, sex hormones.
2. Peptide hormones: insulin, glucagon, relaxin, pituitary hormones.

Answer: (b) Aldosterone

Explanation:
1. TSH, LH and FSH are glycoproteins (protein nature).
2. Aldosterone is a mineralocorticoid, a steroid made in the adrenal cortex.

Teacher's Note:
1. All adrenal cortex hormones are steroids.
2. Pituitary and pancreatic hormones are protein or peptide.

Answer: (c) Entering into the cell and modifying nuclear organisation.

Explanation:
1. Steroid hormones enter the cell, bind an intracellular receptor and the complex enters the nucleus.
2. There it changes gene expression, so protein synthesis is altered.

Teacher's Note:
1. Steroid action is slow but long lasting.
2. Peptide hormone action is quick but short lived.

Answer: (d) Thomas Addison

Explanation:
1. Thomas Addison described Addison's disease and is called the father of endocrinology.
2. Whittaker proposed the five kingdoms, Pasteur worked on microbes and Einthoven on ECG.

Teacher's Note:
1. Addison's disease is due to adrenal cortex hyposecretion.
2. Remember the name with the disease.

Answer: (c) Fatty acid

Explanation:
1. Prostaglandins are modified fatty acids (20-carbon unsaturated) made by many tissues.
2. They act as local hormones.

Teacher's Note:
1. Prostaglandins are lipid derived local messengers.
2. They are not made by a single endocrine gland.

Answer: (c) Adrenal medulla

Explanation:
1. The anterior pituitary controls thyroid (TSH), adrenal cortex (ACTH) and gonads (FSH, LH).
2. The adrenal medulla is controlled by the sympathetic nervous system, not by the pituitary.

Teacher's Note:
1. ACTH acts only on the adrenal cortex.
2. Medulla is neural in control.

Answer: (b) Pituitary

Explanation:
1. The pituitary controls most other endocrine glands through its tropic hormones, so it is called the master gland.
2. Thyroid, thymus and adrenal are controlled by it, not controlling it.

Teacher's Note:
1. Pituitary is itself controlled by the hypothalamus.
2. The hypothalamus is the neuro-endocrine link.

Answer: (c) ADH, pitressin, and vasopressin

Explanation:
1. ADH, pitressin and vasopressin are three names of the same posterior pituitary hormone.
2. The other sets contain different hormones.

Teacher's Note:
1. Vasopressin = ADH = pitressin.
2. Oxytocin is a separate hormone.

Answer: (c) Gonadotrophic hormone

Explanation:
1. FSH and LH act on the gonads and are together called gonadotrophins.
2. They are glycoproteins from the anterior pituitary.

Teacher's Note:
1. FSH: gametogenesis.
2. LH: ovulation and androgen or progesterone secretion.

Answer: (d) Anterior lobe of pituitary gland

Explanation:
1. FSH is secreted by gonadotrophs of the anterior lobe of the pituitary.
2. The gonads secrete sex steroids, not FSH.

Teacher's Note:
1. Anterior pituitary = adenohypophysis.
2. FSH acts on ovarian follicles and Sertoli cells.

Answer: (a) Hypothalamus

Explanation:
1. The hypothalamus controls the pituitary through releasing and inhibiting hormones and by nerve fibres to the posterior lobe.
2. The other glands do not control the pituitary directly.

Teacher's Note:
1. Hypothalamus is above the pituitary and joined by the infundibulum.
2. It links nervous and endocrine systems.

Answer: (a) Depression in skull enclosing pituitary

Explanation:
1. Sella turcica (hypophyseal fossa) is a depression in the sphenoid bone of the skull that holds the pituitary.
2. It is not related to the ear or testis.

Teacher's Note:
1. Pituitary is protected in the sella turcica.
2. A tumour here presses on the optic chiasma.

Answer: (c) Initiate and maintain secretion of milk by mammary gland

Explanation:
1. Prolactin initiates and maintains milk secretion from mammary glands after childbirth.
2. Milk ejection is caused by oxytocin.

Teacher's Note:
1. Prolactin: milk production.
2. Oxytocin: milk ejection.

Answer: (c) ADH

Explanation:
1. ADH controls facultative water reabsorption in the distal convoluted tubule and collecting duct.
2. The other hormones listed do not act on nephrons for water reabsorption.

Teacher's Note:
1. Obligatory reabsorption occurs in the proximal tubule.
2. Facultative reabsorption depends on ADH.

Answer: (a) Neurohypophysis

Explanation:
1. Herring bodies are swollen nerve endings in the neurohypophysis that store neurohormones.
2. The adenohypophysis has glandular cells, not Herring bodies.

Teacher's Note:
1. Herring bodies are in the posterior pituitary.
2. They store oxytocin and vasopressin.

Answer: (a) Darkening of skin

Explanation:
1. MSH from the pars intermedia disperses melanin in melanophores, so lower vertebrates show darkening of the skin.
2. Melatonin has the opposite effect.

Teacher's Note:
1. MSH darkens skin.
2. Melatonin lightens it.

Answer: (d) All

Explanation:
1. LTH (luteotropic hormone) is another name for prolactin, which is also lactogenic and mammotropic hormone.
2. So all the names in options 1 to 3 refer to it.

Teacher's Note:
1. Prolactin has many names.
2. It is secreted by the anterior pituitary.