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Quizzes > Health & Medicine > Human Anatomy & Medicine

Think You Know the Endocrine System? Take the Quiz

Ready to ace this endocrine quiz? Dive into our endocrine system practice questions now!

Difficulty: Moderate
2-5mins
Learning OutcomesCheat Sheet
Paper art illustration for endocrine system quiz showing glands hormones and pathways on golden yellow background.

This endocrine system quiz helps you practice core facts on glands, hormones, and feedback loops across the thyroid, pituitary, adrenals, and pancreas. Use it to spot gaps before an exam and build recall speed. For extra practice, try another quiz and the hormone review .

Which of the following is NOT classified as an endocrine gland?
Pancreas
Salivary gland
Adrenal gland
Thyroid gland
Endocrine glands secrete hormones directly into the bloodstream, while exocrine glands release their products through ducts. The salivary glands are exocrine, producing saliva that travels via ducts into the mouth. The pancreas, adrenal gland, and thyroid gland all have endocrine functions.
What is the primary role of hormones in the body?
Provide cellular energy
Catalyze digestive reactions
Act as signaling molecules
Form structural proteins
Hormones are chemical messengers produced by endocrine cells that travel through the bloodstream to target organs. They regulate physiological processes like growth, metabolism, and reproduction. This signaling function distinguishes them from nutrients or structural components.
Which hormone is secreted by the beta cells of the pancreatic islets?
Insulin
Triiodothyronine (T3)
Antidiuretic hormone (ADH)
Cortisol
Beta cells in the pancreatic islets of Langerhans produce insulin, a peptide hormone that lowers blood glucose. Cortisol is produced by the adrenal cortex, T3 by the thyroid, and ADH by the posterior pituitary. Insulin promotes glucose uptake into cells for energy.
Steroid hormones are synthesized from which precursor molecule?
Fatty acids
Glucose
Amino acids
Cholesterol
All steroid hormones, including cortisol, aldosterone, and sex steroids, are derived from cholesterol. The steroidogenesis pathway in glands like the adrenal cortex uses cholesterol as the starting point. Peptide hormones and amines derive from amino acids, not cholesterol.
Which of the following hormones lowers blood glucose levels?
Glucagon
Insulin
Growth hormone
Cortisol
Insulin facilitates glucose uptake by cells and stimulates glycogenesis in the liver, reducing blood glucose. Glucagon raises glucose by promoting glycogenolysis. Cortisol and growth hormone can increase blood glucose via gluconeogenesis.
Negative feedback in endocrine systems primarily serves to do what?
Amplify the original stimulus
Prevent any change in hormone concentration
Reverse changes in hormone levels
Maintain elevated hormone secretion indefinitely
Negative feedback reduces or negates deviations from a set point, maintaining homeostasis. When hormone levels rise too high, signals inhibit further secretion until levels drop. This mechanism is common in the hypothalamic-pituitary axes.
Which gland is often referred to as the "master gland" of the endocrine system?
Adrenal gland
Thyroid gland
Pineal gland
Pituitary gland
The pituitary gland secretes multiple tropic hormones that regulate other endocrine glands like the thyroid and adrenals. It is controlled by the hypothalamus and thus exerts broad regulatory influence. This central role earns it the nickname "master gland."
Calcitonin, a hormone involved in calcium homeostasis, is secreted by which cells?
Parafollicular (C) cells of the thyroid
Alpha cells of the pancreas
Chief cells of the parathyroid
Zona glomerulosa of the adrenal cortex
Calcitonin is produced by parafollicular cells (C cells) in the thyroid gland and lowers blood calcium by inhibiting osteoclasts. Parathyroid hormone from parathyroid chief cells has the opposite effect. The other listed cells produce unrelated hormones.
Which hypothalamic hormone directly stimulates the anterior pituitary to secrete thyroid-stimulating hormone (TSH)?
Growth hormone - releasing hormone (GHRH)
Thyrotropin-releasing hormone (TRH)
Gonadotropin-releasing hormone (GnRH)
Corticotropin-releasing hormone (CRH)
TRH from the hypothalamus binds to thyrotrophs in the anterior pituitary, prompting the release of TSH. TSH then acts on the thyroid gland to produce T3 and T4. CRH, GnRH, and GHRH regulate other pituitary hormones.
Activation of Gs protein - coupled receptors typically increases which second messenger?
cAMP
IP3
DAG
cGMP
Gs-coupled receptors activate adenylate cyclase, converting ATP to cyclic AMP (cAMP). cAMP then activates protein kinase A and downstream signaling. IP3 and DAG are associated with Gq-coupled receptors, while cGMP is linked to nitric oxide pathways.
Which hormone circulates bound to carrier proteins for transport in the blood?
Cortisol
Epinephrine
Insulin
Glucagon
Cortisol is lipophilic and circulates largely bound to corticosteroid-binding globulin (CBG). Peptide hormones like insulin and glucagon are water-soluble and circulate freely. Epinephrine also travels unbound or weakly protein-bound.
Which enzyme converts thyroxine (T4) to the more active tri-iodothyronine (T3) in peripheral tissues?
5?-deiodinase
Thyroid peroxidase
Deiodinase type II
Tyrosine hydroxylase
Type I and II 5?-deiodinases remove an iodine atom from T4 to produce active T3 in liver and other tissues. Thyroid peroxidase catalyzes oxidation and iodination of thyroglobulin in the thyroid gland. Tyrosine hydroxylase is involved in catecholamine synthesis.
Parathyroid hormone increases blood calcium levels primarily by:
Stimulating osteoclast activity
Decreasing intestinal calcium absorption
Increasing renal calcium excretion
Inhibiting vitamin D activation
PTH binds to receptors on osteoblasts, leading to increased RANKL expression and activation of osteoclasts, releasing calcium from bone. It also enhances renal reabsorption of calcium and promotes vitamin D activation for gut absorption.
In the hypothalamic - pituitary - adrenal (HPA) axis, corticotropin-releasing hormone (CRH) directly stimulates the release of:
Adrenocorticotropic hormone (ACTH)
Thyroid-stimulating hormone (TSH)
Prolactin
Follicle-stimulating hormone (FSH)
CRH from the hypothalamus acts on corticotrophs in the anterior pituitary, triggering the secretion of ACTH. ACTH then stimulates cortisol production in the adrenal cortex. TSH, prolactin, and FSH are regulated by other hypothalamic releasing factors.
Which of the following is classified as a peptide hormone?
Cortisol
Insulin
Thyroxine (T4)
Aldosterone
Insulin is a peptide hormone consisting of amino acids. Cortisol and aldosterone are steroid hormones derived from cholesterol. Thyroxine (T4) is an amino acid - derived (amine) hormone but not a peptide.
Which hormone exhibits a diurnal secretion pattern peaking in the early morning hours?
Gastrin
Cortisol
Melatonin
Prolactin
Cortisol levels rise in the early morning as part of the circadian rhythm controlled by the suprachiasmatic nucleus. Melatonin peaks at night to promote sleep. Prolactin and gastrin have different regulatory patterns.
Which nuclear receptor forms a heterodimer with the thyroid hormone receptor to regulate gene transcription?
Estrogen receptor (ER)
Retinoid X receptor (RXR)
Peroxisome proliferator-activated receptor (PPAR)
Glucocorticoid receptor (GR)
The thyroid hormone receptor heterodimerizes with RXR to bind thyroid response elements on DNA. This partnership is essential for efficient transcriptional regulation by T3. Other nuclear receptors pair differently for their respective ligands.
Receptor downregulation in endocrine systems refers to:
A decrease in receptor number due to prolonged high hormone levels
An increase in receptor affinity for hormone
Translocation of receptors to the nucleus
Reversible phosphorylation of the receptor
Chronic exposure to high hormone concentrations often triggers endocytosis and degradation of cell-surface receptors, reducing sensitivity. This downregulation diminishes cellular responses despite continued hormone presence. It differs from affinity changes or receptor trafficking to the nucleus.
In primary hyperthyroidism, laboratory results typically show:
Low T3 and T4 with elevated TSH
Elevated T3 with normal T4 and normal TSH
Elevated T3 and T4 with suppressed TSH
Suppressed T3 and T4 with suppressed TSH
Primary hyperthyroidism arises from the thyroid gland itself, producing excess T3 and T4. High thyroid hormone levels exert negative feedback on the pituitary, suppressing TSH secretion. Central causes would elevate TSH.
Which enzyme catalyzes the rate-limiting step in catecholamine synthesis?
Phenylethanolamine N-methyltransferase
Monoamine oxidase
DOPA decarboxylase
Tyrosine hydroxylase
Tyrosine hydroxylase converts tyrosine to L-DOPA and is the rate-limiting enzyme in catecholamine biosynthesis. DOPA decarboxylase, PNMT, and MAO act downstream or in degradation. Regulation of tyrosine hydroxylase controls overall catecholamine production.
Which class of hormones acts primarily via intracellular receptors affecting gene transcription over hours?
Steroid hormones
Catecholamines
Peptide hormones
Amino acid - derived amines
Steroid hormones like aldosterone diffuse through the cell membrane and bind cytosolic or nuclear receptors, modulating transcription. Peptides and catecholamines use surface receptors and second messengers for rapid effects. Amine hormones can use both pathways but mostly not direct gene regulation.
In Addison's disease (primary adrenal insufficiency), expected lab values show:
High ACTH and low cortisol
High ACTH and high cortisol
Low ACTH and high cortisol
Low ACTH and low cortisol
Primary adrenal failure reduces cortisol, removing negative feedback on the pituitary and leading to elevated ACTH. Secondary causes (pituitary failure) would lower both. High ACTH with low cortisol is characteristic of Addison's.
Non-genomic actions of steroid hormones are mediated through which type of receptor?
Nuclear hormone receptors
Ionotropic receptors
Tyrosine kinase receptors
Membrane-bound G protein - coupled receptors
Non-genomic steroid effects occur rapidly via membrane-associated receptors such as GPER (G protein - coupled estrogen receptor). These signaling events do not involve direct gene transcription. Nuclear receptors mediate slower genomic responses.
Why is pulsatile secretion of GnRH essential for normal gonadotropin release?
Pulses increase GnRH degradation
Continuous GnRH enhances only FSH secretion
Pulsatile GnRH suppresses prolactin
Continuous GnRH causes receptor desensitization and decreased LH/FSH
GnRH pulse frequency and amplitude determine LH and FSH secretion patterns. Continuous GnRH downregulates GnRH receptors on pituitary gonadotrophs, reducing gonadotropin release. Pulsatile stimulation maintains receptor sensitivity.
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Study Outcomes

  1. Understand Nonsteroid Hormone Classes -

    Describe the structural differences and biological roles of peptides, proteins, glycoproteins, and amines in hormone signaling.

  2. Identify Endocrine Gland Functions -

    Recognize the primary secretory roles of major glands like the pituitary, thyroid, and adrenal, and how they maintain bodily homeostasis.

  3. Analyze Hormonal Feedback Mechanisms -

    Trace key endocrine pathways and feedback loops tested in our endocrine system quiz to understand hormone level regulation.

  4. Differentiate Hormone-Receptor Interactions -

    Compare nonsteroid versus steroid hormone mechanisms to master concepts covered in a quiz for endocrine system studies.

  5. Apply Knowledge to Practice Questions -

    Solve targeted endocrine system practice questions that reinforce concepts of glands, hormones, and regulatory pathways.

  6. Evaluate Quiz Performance and Learning Gaps -

    Interpret your results from the endocrine glands quiz to identify strengths and focus areas for further review.

Cheat Sheet

  1. Hormone Classification: Steroid vs Nonsteroid -

    Hormones are classified as lipophilic steroids derived from cholesterol or hydrophilic nonsteroids (peptides, proteins, glycoproteins, amines). Nonsteroid hormones bind to plasma membrane receptors and often utilize second messengers like cAMP - for example, epinephrine activates adenylate cyclase to increase cAMP levels. Recognizing these differences helps you predict hormone solubility and signaling pathways [Source: Guyton & Hall, 14th Edition].

  2. FLAT-PEG Mnemonic for Anterior Pituitary Hormones -

    Use the FLAT-PEG mnemonic to remember the seven anterior pituitary hormones: FSH, LH, ACTH, TSH (FLAT) and PRL, endorphins, GH (PEG). This method streamlines memorization by grouping tropic and non-tropic hormones. For example, ACTH drives cortisol release while GH promotes growth and metabolism [Source: University of Michigan Medical School].

  3. Negative Feedback Regulation -

    Most endocrine pathways use negative feedback to maintain homeostasis by reducing upstream hormone release when downstream levels rise - e.g., high cortisol inhibits CRH and ACTH secretion in the HPA axis. Identifying these loops helps you predict clinical scenarios like Cushing's syndrome or hypothyroidism. Sketching simple feedback diagrams can solidify your understanding [Source: Endocrine Society Clinical Practice].

  4. Key Hypothalamic-Pituitary Axes -

    The HPA (CRH→ACTH→cortisol), HPT (TRH→TSH→T3/T4), and HPG (GnRH→LH/FSH→sex steroids) axes coordinate major stress, metabolic, and reproductive functions. Mapping each axis end-to-end, including releasing factors and end hormones, clarifies where disorders can arise. A quick chart can help you match stimuli, hormones, and feedback sites [Source: Harvard Medical School].

  5. Major Gland Functions -

    The adrenal cortex secretes mineralocorticoids (aldosterone), glucocorticoids (cortisol), and androgens, while the medulla releases catecholamines (epinephrine, norepinephrine). The thyroid gland produces T3/T4 for basal metabolic rate regulation, and pancreatic islets secrete insulin and glucagon for glucose homeostasis. Familiarize yourself with each gland's cell types and hormones to ace matching questions [Source: NIH Endocrine System Overview].

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