75 practice questions on Chemical Coordination and Integration , sorted Easy → Hard. Try each one first, then open its answer page for the worked explanation. Want the full theory first? Read the Chemical Coordination and Integration notes .
Hypothalamus-Pituitary Axis (Negative Feedback) Hypothalamus releasing hormone Pituitary ("relay", not the boss) trophic hormone Target gland (e.g. thyroid, adrenal) hormone output negative feedback The hypothalamus releases hormones that direct the pituitary, which releases its own trophic hormone to a target gland; that gland's hormone output then feeds back (dashed lines) to suppress both the pituitary and hypothalamus once levels are sufficient - a self-correcting loop running the entire endocrine system.
Easy - 25 questions Q1.
The hormone that prepares and maintains the uterus for pregnancy is:
A ProgesteroneB AdrenalineC ThyroxineD InsulinShow answer & explanation →
Q3.
The hormone secreted by the thymus gland, important for immunity, is:
A InsulinB MelatoninC ThymosinD GlucagonShow answer & explanation →
Q4.
Chemically, hormones may be proteins, steroids or ___ derivatives:
A CarbohydrateB Nucleic acidC Fatty acidD Amino acidShow answer & explanation →
Q5.
The pituitary hormone that stimulates the thyroid gland is:
A Thyroid-stimulating hormoneB General growth hormoneC Milk-releasing prolactinD Water-saving vasopressinShow answer & explanation →
Q10.
The adrenal medulla secretes the hormone:
A Cortisol, from the adrenal cortexB Adrenaline, also called epinephrineC Aldosterone, from the outer cortex regionD Thyroxine, from the thyroid glandShow answer & explanation →
Q11.
Growth hormone is secreted by the:
A Thyroid gland in the neckB Pancreas behind the stomachC Pituitary gland at the brain baseD Adrenal gland above the kidneyShow answer & explanation →
Q12.
Thyroxine, the principal hormone of the thyroid gland, requires which element for its synthesis?
A IronB ZincC CalciumD IodineShow answer & explanation →
Q13.
The testes mainly secrete the hormone:
A Testosterone, from the Leydig cellsB Progesterone, from interstitial cellsC Relaxin, from interstitial cellsD Estrogen, from interstitial cellsShow answer & explanation →
Q14.
A gland that secretes hormones directly into the bloodstream, without ducts, is called an:
A Endocrine glandB Salivary glandC Exocrine glandD Sebaceous glandShow answer & explanation →
Q15.
Which hormone is mainly responsible for maintaining the basal metabolic rate of the body?
A Insulin, from the pancreasB Thyroxine, from the thyroidC Glucagon, from the pancreasD Oxytocin, from the pituitaryShow answer & explanation →
Q16.
The chemical messengers secreted by endocrine glands are called:
A hormonesB enzymesC vitaminsD antibodiesShow answer & explanation →
Q17.
The gland regarded as the "master gland" of the body is the:
A pituitary glandB thyroid glandC adrenal glandD the pancreasShow answer & explanation →
Q22.
The hormone responsible for the "fight or flight" response is:
A adrenalineB insulinC thyroxineD oxytocinShow answer & explanation →
Q24.
The endocrine gland located just above each kidney is the:
A adrenal glandB thyroid glandC pituitary glandD pancreasShow answer & explanation →
Medium - 25 questions Q26.
The four small glands embedded on the back of the thyroid are the:
A Adrenal glandsB Parathyroid glandsC Pineal glandsD Thymus lobesShow answer & explanation →
Q27.
The adrenal cortex hormones that regulate salt and sugar balance are the:
A CatecholaminesB Sex steroids onlyC CorticoidsD Thyroid hormonesShow answer & explanation →
Q28.
The hormone that stimulates strong contraction of the uterus during childbirth is:
A InsulinB ThyroxineC GlucagonD OxytocinShow answer & explanation →
Q29.
An overactive thyroid secreting excess thyroxine causes the condition:
A HyperthyroidismB HypothyroidismC Infant cretinismD Simple goitreShow answer & explanation →
Q30.
A deficiency of thyroxine in an infant, causing stunted growth and mental retardation, is:
A Simple goitreB CretinismC AcromegalyD Muscle tetanyShow answer & explanation →
Q32.
Type 1 diabetes is caused by:
A Down-regulation of GLUT4 receptors on target cells reducing glucose uptakeB Autoimmune destruction of beta cells (no insulin produced)C Chronic excess caloric intake leading to adipose tissue expansionD Glomerular damage impairing glucose reabsorption in the nephronShow answer & explanation →
Q33.
Negative feedback in the endocrine system means:
A Rising hormone levels sometimes trigger the hypothalamus to release more releasing factorsB Increased hormone levels signal the gland to reduce further production (maintaining balance)C Target tissues sometimes amplify the hormonal signal through second messenger cascadesD Antagonistic glands typically secrete in roughly equal proportions most of the timeShow answer & explanation →
Q34.
Insulin lowers blood glucose mainly by promoting:
A Breakdown of liver glycogen into glucose, releasing it into the blood in general clinical practiceB Conversion of fats into glucose within adipose tissue as frequently documented in most reference accountsC Excretion of excess glucose by the kidneys under normal conditions as generally observedD Uptake and utilization of glucose by cells, and its conversion to glycogen in the liverShow answer & explanation →
Q35.
Parathyroid hormone (PTH) helps regulate blood calcium levels mainly by:
A Increasing calcium reabsorption from bone, kidney, and intestine, raising blood calciumB Reducing vitamin D activation in the kidney in the majority of documented cases as widely reportedC Promoting calcium deposition into bone, lowering blood calcium in typical laboratory settingsD Stimulating the thyroid to release more calcitonin under usual circumstances according to most studiesShow answer & explanation →
Q36.
Which gland is correctly described as both an endocrine and exocrine gland?
A Pituitary gland, since it produces both mucus and growth hormone in most observed casesB Adrenal gland, since it produces both bile and adrenaline under most conditions studiedC Thyroid, since it secretes both T<sub>3</sub>/T<sub>4</sub> and digestive enzymes in standard reference materialD Pancreas, since it secretes digestive enzymes as well as hormones like insulinShow answer & explanation →
Q37.
The anterior pituitary is regulated by hormones released from the hypothalamus that travel to it via:
A Diffusion through cerebrospinal fluid in the third ventricle according to standard textsB Direct axonal connections from hypothalamic neurons under typical physiological conditionsC A specialized portal blood vessel system connecting the two structuresD General systemic circulation, like any other hormone in general clinical practiceShow answer & explanation →
Q38.
Excess secretion of growth hormone in adults, after the bones have stopped growing in length, results in:
A Cretinism, with stunted physical and mental growth in most reference accountsB Acromegaly, with enlargement of hands, feet, and facial bonesC Gigantism, with an overall increase in body height as frequently documentedD Dwarfism, with reduced overall body size under normal conditionsShow answer & explanation →
Q39.
The adrenal medulla, under sympathetic stimulation, mainly secretes:
A Adrenaline and noradrenaline, preparing the body for a fight-or-flight responseB Androgens, contributing to secondary sexual characteristics according to most studiesC Aldosterone, regulating sodium and water balance as generally observed in typical laboratory settingsD Cortisol, helping the body cope with prolonged stress under usual circumstancesShow answer & explanation →
Q40.
Melatonin, secreted by the pineal gland, is primarily involved in regulating:
A The body's circadian rhythm and sleep-wake cycleB Basal metabolic rate of body tissues in standard reference materialC Water reabsorption in the kidney tubules as widely reportedD Blood glucose levels following meals in the majority of documented casesShow answer & explanation →
Q46.
The hormone that promotes overall body growth is:
A growth hormoneB plain insulinC plain adrenalineD plain thyroxineShow answer & explanation →
Q49.
The endocrine (hormone-secreting) part of the pancreas is the:
A islets of LangerhansB the lung alveoliC the kidney nephronsD the gut villiShow answer & explanation →
Q50.
The hormone that controls water balance by acting on the kidneys is:
A ADHB insulinC thyroxineD adrenalineShow answer & explanation →
Hard - 25 questions Q51.
A fall in blood calcium can cause sustained, painful muscle cramps, a condition called:
A Simple goitreB Infant cretinismC TetanyD Diabetes mellitusShow answer & explanation →
Q52.
The hormones adrenaline and noradrenaline are chemically classified as:
A Steroid hormonesB Peptide hormonesC Simple fatty acidsD CatecholaminesShow answer & explanation →
Q53.
Insulin lowers, while glucagon raises, blood sugar; this pair of opposite effects is called:
A Antagonistic controlB Synergistic controlC Permissive actionD A feedback failureShow answer & explanation →
Q54.
The hormone that makes the kidney reabsorb Na<sup>+</sup> and excrete K<sup>+</sup> is:
A CortisolB AldosteroneC AdrenalineD InsulinShow answer & explanation →
Q55.
Human chorionic gonadotropin (hCG), which maintains the corpus luteum early in pregnancy, is secreted by the:
A The ovaryB The pituitaryC The placentaD The adrenal glandShow answer & explanation →
Q56.
Brown adipose tissue (BAT) generates heat through:
A Coupled oxidative phosphorylation that maximizes ATP yield from fatty acid oxidation within mitochondria themselves as frequently describedB Uncoupled mitochondrial respiration via UCP1 (uncoupling protein), dissipating proton gradient as heat instead of making ATPC Rhythmic skeletal muscle contraction driven by repeated motor neuron stimulation, as occurs in shivering in most textbook accountsD Conversion of stored triglycerides into glycogen, releasing heat during rapid glycolysis breakdown during normal conditionsShow answer & explanation →
Q57.
Hyposecretion of growth hormone in children, unlike in adults, leads to:
A Acromegaly, due to continued action on already-fused bone endsB Goitre, from compensatory enlargement of the thyroid glandC Pituitary dwarfism, since long bone growth plates have not yet fusedD Tetany, caused by a fall in blood calcium levelsShow answer & explanation →
Q58.
The renin-angiotensin-aldosterone system (RAAS) is activated when juxtaglomerular cells detect:
A A drop in blood calcium detected by the parathyroid-linked pathwayB A rise in blood glucose that is sensed directly by the kidneyC Excess ADH circulating in the blood reaching the kidneyD A fall in blood pressure or renal blood flow, triggering renin releaseShow answer & explanation →
Q59.
Iodine is essential for thyroid hormone synthesis because it is incorporated into:
A Calcitonin produced by parafollicular cells of the thyroidB Tyrosine residues of thyroglobulin to form T<sub>3</sub> and T<sub>4</sub>C TSH released by the anterior pituitary glandD The receptor protein that binds thyroid hormone in target cellsShow answer & explanation →
Q60.
Steroid hormones such as cortisol typically act on target cells by:
A Diffusing across the plasma membrane and binding intracellular or nuclear receptors that alter gene transcriptionB Being actively transported into the cell by receptor-mediated endocytosis in general clinical practice as frequently documentedC Binding a cell-surface receptor that activates a second messenger cascade without entering the cell in most observed casesD Opening ligand-gated ion channels directly on the plasma membrane under typical physiological conditions according to standard textsShow answer & explanation →
Q61.
In Addison's disease, hyposecretion of adrenal cortex hormones leads to all of the following except:
A Increased skin pigmentation linked to elevated ACTHB Weakness and fatigue from impaired glucose mobilizationC Low blood sodium from reduced aldosterone activityD Increased blood pressure due to sodium retentionShow answer & explanation →
Q62.
Oxytocin and ADH (vasopressin) are both synthesized in the hypothalamus but are:
A Released into the blood from the posterior pituitary, which mainly stores and releases them rather than producing themB Converted into TSH and ACTH respectively before reaching their target organs as generally observed in typical laboratory settingsC Synthesized in the posterior pituitary itself and transported to the hypothalamus for storage in most reference accountsD Released directly from hypothalamic neurons into cerebrospinal fluid without entering the bloodstream under normal conditionsShow answer & explanation →
Q63.
Down-regulation of hormone receptors occurs when target cells are exposed to:
A Hormone analogues that cannot bind the receptor at allB Persistently high hormone concentrations, reducing receptor number to limit further responseC Persistently low hormone concentrations, increasing receptor number to enhance sensitivityD A single brief pulse of hormone that has no lasting effect on receptor densityShow answer & explanation →
Q64.
Atrial natriuretic factor (ANF) is released by the heart's atrial wall in response to increased blood volume and acts to:
A Increase renin secretion from the juxtaglomerular apparatusB Dilate blood vessels and promote sodium/water loss, thereby lowering blood pressureC Stimulate the adrenal medulla to release more adrenalineD Constrict blood vessels and promote sodium/water retention, raising blood pressure furtherShow answer & explanation →
Q65.
Why does the thyroid gland enlarge in simple (endemic) goitre caused by iodine deficiency?
A Excess calcitonin from parafollicular cells causes the gland to hypertrophy according to most studies in the majority of documented casesB Autoimmune destruction of the gland triggers compensatory follicular cell division as widely reported in standard reference materialC High T<sub>3</sub>/T<sub>4</sub> directly stimulates follicular cells to enlarge, independent of any pituitary signal under usual circumstancesD Low T<sub>3</sub>/T<sub>4</sub> reduces negative feedback on the pituitary, so rising TSH chronically stimulates the thyroid to growShow answer & explanation →
Q66.
The hormone secreted during sudden stress by the adrenal medulla is:
A adrenalineB insulinC thyroxineD estrogenShow answer & explanation →
Q67.
Cortisol, released during prolonged stress, is secreted by the adrenal:
A cortexB medullaC gland ductD kidney tubuleShow answer & explanation →
Q68.
The hormone melatonin, which regulates the sleep–wake cycle, is secreted by the:
A pineal glandB thyroid glandC adrenal glandD pancreasShow answer & explanation →
Q70.
An excess of growth hormone in an adult leads to the condition called:
A acromegalyB dwarfismC goitreD diabetesShow answer & explanation →
Q71.
The part of the brain that links the nervous and endocrine systems by controlling the pituitary is the:
A hypothalamusB cerebellumC medullaD spinal cordShow answer & explanation →
Q74.
The hormone that stimulates milk production in the mammary glands after childbirth is:
A prolactinB insulinC adrenalineD thyroxineShow answer & explanation →
Q75.
The hormone oxytocin plays a key role during:
A childbirth (labour)B food digestionC gas exchangeD urine formationShow answer & explanation →