Different glands and their hormones Questions in English

(D) The corpora allata are endocrine glands located in the head of insects,typically attached to the brain.
These glands are responsible for secreting the juvenile hormone.
The juvenile hormone plays a crucial role in regulating insect development by preventing metamorphosis into the adult stage during early larval stages,thereby prolonging the larval period.

(C) The metamorphosis of insects is primarily regulated by the hormone $Ecdysone$.
$Ecdysone$ is a steroid hormone secreted by the prothoracic glands in insects.
It triggers the molting process and the transition between different developmental stages (larva to pupa to adult).
Therefore,the correct option is $C$.

(A) Hormones are often referred to as "biological middlemen" or "chemical messengers" because they are secreted by endocrine glands and travel through the bloodstream to target organs, where they regulate various physiological processes and maintain homeostasis. They act as intermediaries between the site of production and the site of action.

(B) Vitamin $D$ is also known as calciferol.
The deficiency of calciferol leads to rickets in children and osteomalacia in adults.
Therefore,the correct option is $(b)$.

(B) Endocrine glands are ductless glands. Their secretions,known as hormones,are released directly into the blood or surrounding tissue fluid,from where they are transported to target organs via the circulatory system.

(C) $Ptyalin$ is an enzyme found in salivary juice,whereas $Thyroxin$,$Adrenocorticosteroid$,and $Estradiol$ are hormones. Therefore,$Ptyalin$ is the odd one out.

(A) Endocrine glands are ductless glands that secrete their chemical messengers directly into the bloodstream. These chemical messengers are known as hormones. Hormones act as signaling molecules that regulate various physiological processes in the body,such as metabolism,growth,and reproduction. Therefore,the action of endocrine glands is mediated through hormones.

(C) The term 'hormone' was first coined and used by $E. H. Starling$ in $1905$ to describe chemical messengers that are secreted by endocrine glands directly into the blood.

(D) $T. Addison$ is known as the "Father of Endocrinology".
He is credited with this title because he first described the condition known as $Addison's$ disease, which results from the destruction of the adrenal cortex, marking the beginning of the study of endocrine disorders.

(A) . Kupffer cells are specialized macrophages located in the lining of liver sinusoids. Their primary function is phagocytosis,which involves engulfing and destroying pathogens,debris,and old red blood cells. They do not secrete hormones.
$B$. Leydig cells (interstitial cells) in the testes secrete the hormone testosterone.
$C$. Lutein cells (luteal cells) in the corpus luteum of the ovary secrete progesterone and some estrogen.
$D$. Parafollicular cells ($C$-cells) of the thyroid gland secrete the hormone calcitonin.

(A) Endocrine glands are known as ductless glands.
They do not possess ducts to transport their secretions.
Instead,they release their secretions,known as hormones,directly into the surrounding blood stream to be transported to target organs.

(D) The correct answer is $D$.
$A$,$B$,and $C$ are endocrine or exocrine glands that secrete hormones or enzymes.
$D$ (Kidney) is primarily an excretory organ responsible for filtration and urine formation,not a gland.

(B) The correct set is $Pancreas$, $pituitary$ and $thyroid$.
$1$. $Pancreas$: Secretes $insulin$ and $glucagon$, which are primary regulators of blood glucose levels.
$2$. $Pituitary$: Regulates carbohydrate metabolism indirectly through hormones like $ACTH$ (Adrenocorticotropic hormone), which stimulates the adrenal cortex to release glucocorticoids.
$3$. $Thyroid$: Hormones like $thyroxine$ stimulate the absorption of monosaccharides from the intestine and promote $glycogenolysis$ (breakdown of glycogen to glucose).

(D) The hormone $Oxytocin$ acts on the smooth muscles of the uterus and stimulates their contraction during childbirth.
$Vasopressin$,also known as $Antidiuretic$ $Hormone$ $(ADH)$,acts on the kidney and stimulates the reabsorption of water and electrolytes by the distal tubules,thereby reducing urine output (diuresis). It also causes constriction of blood vessels,which leads to an increase in arterial blood pressure.

(A) Parathormone $(PTH)$ is secreted by the parathyroid gland and increases blood calcium levels by stimulating bone resorption.
Calcitonin is secreted by the thyroid gland and decreases blood calcium levels by inhibiting bone resorption.
Since these two hormones have opposite effects on blood calcium levels,they are considered antagonistic to each other.

(D) Insulin is a peptide hormone that regulates blood glucose levels by facilitating the uptake of glucose into cells.
It primarily acts on insulin-sensitive tissues such as skeletal muscle,cardiac muscle,and adipose tissue by promoting the translocation of $GLUT4$ glucose transporters to the plasma membrane.
However,glucose uptake in the intestinal mucosa,brain,and red blood cells is insulin-independent,as these tissues utilize different glucose transporters (such as $GLUT2$ or $GLUT1$) that do not require insulin for their activity.
Therefore,the correct answer is intestinal mucosa.

(C) $Progesterone$,$Testosterone$,and $Estrogen$ are hormones secreted by the gonads (ovaries and testes). $Adrenaline$ (also known as $Epinephrine$) is a hormone secreted by the adrenal medulla,which is part of the adrenal gland,not the gonads.

(B) $Cushing's$ syndrome is caused by the hypersecretion of glucocorticoids (like cortisol) from the adrenal cortex of the adrenal gland.
Myxoedema is a condition caused by the hyposecretion of thyroid hormones (thyroxine) from the thyroid gland.
Therefore,$Cushing's$ syndrome is associated with the adrenal gland and myxoedema is associated with the thyroid gland.
Thus,the correct sequence is adrenal and thyroid.

(C) Sympathin was the historical term used to describe the chemical substance released by sympathetic nerve endings. It was later identified as $Nor-adrenaline$ (also known as $Nor-epinephrine$). Therefore,the correct option is $C$.

(B) Epinephrine is an amino acid derivative. Specifically,it is derived from the amino acid tyrosine. It belongs to the class of catecholamines,which are synthesized in the adrenal medulla. In contrast,Estrogen and Progesterone are steroid hormones,and Prostaglandins are fatty acid derivatives.

(A) The hormone prolactin,also known as luteotropic hormone $(LTH)$,was discovered by Oscar Riddle and his colleagues in $1932$. They identified its role in stimulating milk production in the mammary glands of pigeons and other mammals. Therefore,the correct answer is Riddle.

(B) The correct answer is $B$. Sex hormones (such as estrogen,progesterone,and testosterone) are steroid hormones derived from cholesterol,not proteins. Relaxin is a peptide hormone,but the general category of sex hormones is steroid-based. Vasopressin $(ADH)$ is indeed an antidiuretic hormone. $LH$ (Luteinizing Hormone) and $ICSH$ (Interstitial Cell-Stimulating Hormone) refer to the same hormone in different sexes. Glucagon is considered a catabolic hormone because it promotes the breakdown of glycogen into glucose (glycogenolysis).

(B) Progesterone is a steroid hormone.
It is derived from cholesterol,which is a lipid (fat) derivative.
Therefore,its chemical nature is steroid.

(C) The $Ovary$ secretes hormones like $Estrogen$ and $Progesterone$.
The $Testis$ secretes $Androgens$ (mainly $Testosterone$).
The $Pancreas$ acts as a heterocrine gland and secretes hormones like $Insulin$ and $Glucagon$.
The $Spleen$ is a lymphoid organ involved in the immune system and the destruction of old red blood cells; it does not function as an endocrine gland and does not secrete any hormones.

(C) Serotonin is a neurotransmitter and hormone primarily produced by the enterochromaffin cells in the gastrointestinal tract. However, in the context of the Islets of $Langerhans$ in the pancreas, it is known that $\delta$ cells (delta cells) are responsible for secreting somatostatin, while $\alpha$ cells secrete glucagon and $\beta$ cells secrete insulin. In some specific physiological contexts or literature, serotonin is also associated with the regulation of insulin secretion within the pancreas, often linked to the activity of $\delta$ cells or other specialized cells. Given the standard options provided in many competitive biology contexts, $\delta$ cells are frequently associated with the regulatory pathways involving serotonin in the pancreas.

(C) The appearance of facial hair in women,a condition known as hirsutism,is primarily caused by an imbalance in hormones. Specifically,it is often due to an excess of androgens (male sex hormones like testosterone) or an increased sensitivity of hair follicles to these hormones. These hormones are produced by the ovaries or the adrenal glands. Therefore,hormonal regulation is the key factor in this physiological change.

(B) Epinephrine (also known as adrenaline) is a hormone and neurotransmitter that plays a key role in the body's 'fight-or-flight' response.
When released,it acts on the heart by increasing the heart rate and the force of contraction,thereby stimulating cardiac activity.
Mescaline,$LSD$,and Hashish are hallucinogenic or psychoactive substances that do not primarily function as cardiac stimulants in the same physiological manner as epinephrine.

(A) The correct answer is $A$ (Renin).
$Renin$ is a digestive enzyme secreted by the gastric glands of the stomach that helps in the digestion of milk proteins in infants.
$Secretin$,$Calcitonin$,and $Oxytocin$ are all hormones.
$Secretin$ is a gastrointestinal hormone,$Calcitonin$ is a thyroid hormone,and $Oxytocin$ is a neurohypophysial hormone.
Since $Renin$ is an enzyme and the others are hormones,it is the odd one out.

(B) Chromium is a trace element that plays a crucial role in carbohydrate and lipid metabolism. It enhances the action of insulin,which is the hormone responsible for glucose uptake by cells. By potentiating insulin signaling,chromium helps in maintaining normal blood glucose levels. Therefore,it is considered essential for the maximum effect of insulin in glucose uptake.

(B) Thomas Addison is recognized as the father of endocrinology. He described the condition now known as Addison's disease,which is caused by the failure of the adrenal glands to produce sufficient hormones. His work laid the foundation for the study of the endocrine system.

(D) $Thomas \, Addison$ is widely recognized as the father of endocrinology. He was a British physician who,in $1855$,described the disease now known as $Addison's \, disease$,which is caused by the failure of the adrenal glands. His pioneering work on the adrenal glands laid the foundation for the study of the endocrine system.

(A) The hormone $CCK-PZ$ (Cholecystokinin-Pancreozymin) is secreted by the mucosa of the duodenum.
It acts on the gallbladder to stimulate its contraction,which releases bile into the duodenum.
It also stimulates the pancreas to secrete digestive enzymes.
Therefore,the correct option is $A$.

(B) The $Liver$ is the largest internal organ and the largest gland in the human body. It performs various metabolic functions, including the production of bile, detoxification, and the synthesis of plasma proteins. While the $Thyroid$ is the largest endocrine gland, the $Liver$ is the largest gland overall.

(B) Pheromones are chemical substances secreted by an organism into the environment that affect the behavior or physiology of other individuals of the same species.
These substances are released outside the body and are typically secreted by exocrine glands,such as scent glands,which possess ducts to transport their secretions to the body surface.

(C) $1$. The pituitary gland secretes $FSH$ (Follicle Stimulating Hormone),which is a correct pair.
$2$. The thyroid gland secretes $T_4$ (Thyroxine),which is a correct pair.
$3$. The Islets of Langerhans in the pancreas secrete insulin,which is a correct pair.
$4$. Calcitonin is secreted by the thyroid gland (specifically the parafollicular or $C$-cells),not the ovary. Therefore,the pair 'Ovary - Calcitonin' is incorrect.

(D) The substances $Gastrin$,$Renin$,and $Oxytocin$ are all hormones or hormone-like substances involved in physiological regulation.
$Gastrin$ is a peptide hormone that stimulates secretion of gastric acid.
$Renin$ is an enzyme secreted by the kidneys that acts as a hormone in the $Renin-Angiotensin-Aldosterone$ system.
$Oxytocin$ is a peptide hormone produced by the hypothalamus and released by the posterior pituitary.
$Creatinine$ is a waste product of creatine phosphate metabolism in muscles and is excreted by the kidneys; it is not a hormone or a signaling molecule.

(D) Steroid hormones are derived from cholesterol. Examples include androgens,estrogens,progesterone,cortisol,and aldosterone. Relaxin is a peptide hormone,not a steroid hormone. Therefore,the correct answer is $D$.

(D) Gynecomastia is a medical condition characterized by the abnormal enlargement or development of breast tissue in males.
This condition is often caused by an imbalance between the hormones estrogen and testosterone.
It can occur due to hormonal changes,certain medications,or underlying health conditions.

(B) The hormones are identified as follows:
$1$. Milk secretion (lactation) is stimulated by Prolactin $(PRL)$.
$2$. Milk ejection (let-down reflex) is stimulated by Oxytocin $(OT)$.
$3$. Follicular growth in the ovary is stimulated by Follicle Stimulating Hormone $(FSH)$.
Therefore,the correct sequence is $PRL, OT$,and $FSH$.

(B) The $Testis$ secretes androgens (e.g.,$Testosterone$).
The $Stomach$ secretes hormones like $Gastrin$,$Secretin$,and $Cholecystokinin$ $(CCK)$.
The $Pancreas$ secretes $Insulin$ and $Glucagon$.
The $Spleen$ is a lymphoid organ involved in the filtration of blood and the immune response; it does not function as an endocrine gland and does not secrete any hormones.

(C) The hormone $ADH$ (Anti-Diuretic Hormone),also known as Vasopressin,is secreted by the posterior pituitary gland. It is also historically referred to as Pitressin. Therefore,$ADH$,Pitressin,and Vasopressin are different names for the same hormone.

(A) hormone is a non-nutrient chemical messenger that is produced in trace amounts by endocrine glands. These glands are ductless,meaning they release their secretions directly into the bloodstream to reach target organs. Therefore,the correct definition is that a hormone is the secretion of an endocrine gland.

(A) Endocrine glands are ductless glands. They release their secretions,known as hormones,directly into the surrounding blood capillaries or the bloodstream to be transported to target organs. Therefore,the correct answer is $A$.

(D) An endocrine gland is a ductless gland that secretes hormones directly into the bloodstream.
$A$,$B$,and $C$ (Pancreas,Adrenal gland,and Thyroid gland) are endocrine glands.
$D$ (Salivary gland) is an exocrine gland because it secretes saliva through ducts into the oral cavity.
Therefore,the salivary gland is not an endocrine gland.

(C) Insulin preparations are classified based on their duration of action.
$IZS$ stands for Insulin Zinc Suspension, which is a type of modified insulin preparation.
$PZI$ stands for Protamine Zinc Insulin, which is another type of modified insulin preparation.
Both $IZS$ and $PZI$ are synthetic or artificial forms of insulin used in the management of diabetes mellitus.
Therefore, the correct answer is $C$.

(A) hormone is a chemical substance produced by endocrine glands that acts as a chemical messenger.
Thyroxine is a hormone produced by the thyroid gland.
Adrenaline is a hormone produced by the adrenal medulla.
Vitamin $D$ is a fat-soluble vitamin that acts as a prohormone (it is converted into a hormone in the body),but it is classified as a vitamin,not a hormone in the strict sense of endocrine secretion.
Therefore,Vitamin $D$ is the correct answer.

(D) The $Testis$ (in males) secretes androgens like $Testosterone$. The $Placenta$ (in pregnant females) acts as an endocrine tissue and secretes hormones like $Human \text{ } Chorionic \text{ } Gonadotropin \text{ } (hCG)$, $Human \text{ } Placental \text{ } Lactogen \text{ } (hPL)$, $Estrogens$, and $Progesterone$. Therefore, both organs are involved in hormone secretion.

(C) The correct answer is $C$.
Parathyroid and adrenal glands are purely endocrine glands because they synthesize hormones and secrete them directly into the bloodstream to act on target organs at distant sites.
Thymus,testes,ovaries,and pancreas are heterocrine or mixed glands (having both endocrine and exocrine functions) or have additional non-endocrine roles.
Therefore,the pair consisting only of endocrine glands is parathyroid and adrenal.

(D) The hormones $Gastrin$,$Secretin$,and $Cholecystokinin$ are gastrointestinal hormones secreted by the gastrointestinal tract.
$Androgens$ are steroid hormones primarily secreted by the testes (Leydig cells) and are part of the reproductive endocrine system,not the gastrointestinal tract.
Therefore,$Androgens$ is the odd one out.

(C) Hormones are classified based on their chemical nature into peptide, steroid, iodothyronines, and amino-acid derivatives.
$1$. $Epinephrine$ is an amino-acid derivative.
$2$. $Glucagon$ and $Insulin$ are peptide hormones.
$3$. $Estradiol$ is a steroid hormone derived from cholesterol.
Therefore, the correct option is $C$.