Grade 11 : Biology - Chemical Coordination (Set 1)

Question 1

Endocrine glands are commonly referred to as ductless glands because:

Accepted Answer

A) They discharge their secretions directly into the bloodstream

Answer

B) They store secretions inside specialized epithelial ducts

Answer

C) They transport enzymes through the lymphatic channels

Answer

D) They secrete products exclusively onto epithelial surfaces

Question 2

Which structure serves as the primary link between the nervous system and the endocrine system?

Accepted Answer

B) Hypothalamus

Answer

A) Cerebellum

Answer

C) Medulla oblongata

Answer

D) Thalamus

Question 3

Which pituitary hormone is responsible for stimulating overall body growth and tissue elongation?

Accepted Answer

C) Growth Hormone (GH)

Answer

A) Oxytocin

Answer

B) Vasopressin

Answer

D) Insulin

Question 4

Deficiency of dietary iodine typically leads to enlargement of which endocrine gland?

Accepted Answer

C) Thyroid gland

Answer

A) Adrenal gland

Answer

B) Thymus gland

Answer

D) Pancreas

Question 5

Parathyroid hormone (PTH) increases blood concentrations of which ion?

Accepted Answer

B) Calcium ($Ca^{2+}$)

Answer

A) Sodium ($Na^+$)

Answer

C) Potassium ($K^+$)

Answer

D) Chloride ($Cl^-$)

Question 6

Adrenaline and noradrenaline, known as 'fight or flight' hormones, are secreted by the:

Accepted Answer

B) Adrenal medulla

Answer

A) Adrenal cortex

Answer

C) Anterior pituitary

Answer

D) Thyroid gland

Question 7

Which hormone is secreted by $\beta$-cells of the Islets of Langerhans to lower blood glucose levels?

Accepted Answer

B) Insulin

Answer

A) Glucagon

Answer

C) Somatostatin

Answer

D) Cortisol

Question 8

The pineal gland secretes melatonin, which primarily functions to regulate:

Accepted Answer

B) 24-hour diurnal (sleep-wake) rhythm

Answer

A) Blood pressure

Answer

C) Blood calcium homeostasis

Answer

D) Digestion of dietary proteins

Question 9

Which gland undergoes progressive degeneration in old age, leading to a weakened immune system?

Accepted Answer

B) Thymus gland

Answer

A) Thyroid gland

Answer

C) Adrenal gland

Answer

D) Parathyroid gland

Question 10

Which of the following is a steroid hormone produced by Leydig cells in the male testes?

Accepted Answer

A) Testosterone

Answer

B) Thyroxine

Answer

C) Insulin

Answer

D) Epinephrine

Question 11

Progesterone is primarily secreted after ovulation by which ovarian structure?

Accepted Answer

B) Corpus luteum

Answer

A) Primary follicle

Answer

C) Tunica albuginea

Answer

D) Ovarian stroma

Question 12

Which of the following hormones is derived from the amino acid tyrosine?

Accepted Answer

B) Epinephrine

Answer

A) Insulin

Answer

C) Cortisol

Answer

D) Progesterone

Question 13

Water-soluble peptide hormones bind to membrane receptors and commonly generate which second messenger?

Accepted Answer

A) Cyclic AMP (cAMP)

Answer

B) Hemoglobin

Answer

C) Cholesterol

Answer

D) Glycogen

Question 14

Lipid-soluble hormones (like steroids) bind intracellular receptors and directly regulate:

Accepted Answer

B) Gene expression and chromosome function

Answer

A) Cell wall breakdown

Answer

C) Direct secretion of digestive enzymes

Answer

D) Direct action potential propagation

Question 15

Atrial Natriuretic Factor (ANF) is secreted by heart atrial walls when blood pressure increases. ANF acts to:

Accepted Answer

B) Dilate blood vessels and decrease blood pressure

Answer

A) Constrict blood vessels and raise blood pressure

Answer

C) Increase glucose absorption in kidney tubules

Answer

D) Stimulate red blood cell formation

Question 16

Which hormone produced by kidney juxtaglomerular cells stimulates erythropoiesis (RBC production)?

Accepted Answer

B) Erythropoietin

Answer

A) Renin

Answer

C) Aldosterone

Answer

D) Calcitonin

Question 17

Secretin, a peptide hormone produced by the gastrointestinal mucosa, acts on the exocrine pancreas to stimulate secretion of:

Accepted Answer

A) Water and bicarbonate ions

Answer

B) Hydrochloric acid

Answer

C) Pepsinogen

Answer

D) Bile pigments

Question 18

Diabetes mellitus is characterized by hyperglycemia and glycosuria resulting from deficiency or hyposecretion of:

Accepted Answer

B) Insulin

Answer

A) Glucagon

Answer

C) Thyroxine

Answer

D) Parathormone

Question 19

Which posterior pituitary peptide hormone acts on uterine smooth muscles to induce contractions during childbirth?

Accepted Answer

B) Oxytocin

Answer

A) Prolactin

Answer

C) Vasopressin

Answer

D) ACTH

Question 20

Cortisol, produced by the adrenal cortex, belongs to which class of corticosteroid hormones?

Accepted Answer

A) Glucocorticoids

Answer

B) Mineralocorticoids

Answer

C) Gonadocorticoids

Answer

D) Catecholamines

Grade 11 : Biology - Chemical Coordination (Set 1)