GTC BIO 2117 EXAM READY - VERIFIED QUESTIONS AND
ANSWERS - COMPREHENSIVE LATEST VERSION
Q: What is the primary function of the endocrine system?
ANSWER To regulate body functions through the secretion of
hormones into the bloodstream.
Q: How do endocrine glands differ from exocrine glands?
ANSWER Endocrine glands are ductless and secrete hormones directly
into the blood; exocrine glands secrete products into ducts that lead to
body surfaces or cavities.
Q: What is a target cell?
ANSWER A cell that possesses specific receptors for a particular
hormone and can respond to it.
Q: What is up-regulation?
ANSWER An increase in the number of hormone receptors on a target
cell, increasing its sensitivity.
Q: What is down-regulation?
ANSWER A decrease in the number of hormone receptors, decreasing
cell sensitivity to prevent overstimulation.
Q: What are the two major chemical classes of hormones?
ANSWER Amino acid-based (peptides, proteins, amines) and steroid
hormones (derived from cholesterol).
Q: Which hormones can pass directly through the plasma membrane of
a target cell?
ANSWER Steroid hormones and thyroid hormones (because they are
lipid-soluble).
Q: What is the role of a second messenger in amino acid-based
hormone action?
, ANSWER It relays the signal from the plasma membrane receptor to
the inside of the cell, activating intracellular enzymes (e.g., cAMP).
Q: How do steroid hormones typically alter cell activity?
ANSWER They enter the nucleus and directly affect gene
transcription/translation to produce specific proteins.
Q: What is a negative feedback loop?
ANSWER A mechanism where increasing hormone levels inhibit
further hormone release to maintain homeostasis.
Q: What is a positive feedback loop? Give an example.
ANSWER A mechanism where hormone release causes an action that
stimulates more hormone release (e.g., oxytocin during childbirth).
Q: Where is the hypothalamus located?
ANSWER At the base of the brain, below the thalamus.
Q: What is the anatomical connection between the hypothalamus and
the posterior pituitary?
ANSWER The infundibulum (or hypothalamic-hypophyseal tract).
Q: Does the posterior pituitary synthesize hormones?
ANSWER No, it stores and releases hormones (ADH and oxytocin)
produced by the hypothalamus.
Q: What is the function of Antidiuretic Hormone (ADH)?
ANSWER To promote water reabsorption in the kidneys, reducing urine
output and preventing dehydration.
Q: What triggers the release of ADH?
ANSWER Increased blood osmolarity (high solute concentration) or
decreased blood volume/pressure.
Q: What is the function of Oxytocin?
ANSWER It stimulates uterine contractions during labor and milk
ejection (let-down) during lactation.
Q: What are the three parts of the anterior pituitary (adenohypophysis)?
,ANSWER Pars distalis, pars intermedia, and pars tuberalis.
Q: What regulates the release of anterior pituitary hormones?
ANSWER Releasing and inhibiting hormones from the hypothalamus
delivered via the hypophyseal portal system.
Q: What is Growth Hormone (GH) primary function?
ANSWER To stimulate growth of body tissues, especially bone and
muscle, and to mobilize fats.
Q: What are the two main effects of GH?
ANSWER Anabolic effects (protein synthesis) and lipolytic effects (fat
breakdown).
Q: What causes gigantism?
ANSWER Hypersecretion of GH during childhood.
Q: What causes acromegaly?
ANSWER Hypersecretion of GH during adulthood.
Q: What causes pituitary dwarfism?
ANSWER Hyposecretion of GH during childhood.
Q: What is the function of Thyroid-Stimulating Hormone (TSH)?
ANSWER To stimulate the thyroid gland to produce and release T3 and
T4.
Q: What is the function of Adrenocorticotropic Hormone (ACTH)?
ANSWER To stimulate the adrenal cortex to release glucocorticoids
(mainly cortisol).
Q: What do Follicle-Stimulating Hormone (FSH) and Luteinizing
Hormone (LH) regulate?
ANSWER The gonads (ovaries and testes) for gamete production and
sex hormone secretion.
Q: What hormone from the anterior pituitary targets the mammary
glands?
ANSWER Prolactin (PRL).
, Q: Where is the thyroid gland located?
ANSWER Just inferior to the larynx, anterior to the trachea.
Q: What are the two main hormones produced by the thyroid follicles?
ANSWER Thyroxine (T4) and Triiodothyronine (T3).
Q: What element is essential for the synthesis of T3 and T4?
ANSWER Iodine.
Q: What is the primary effect of T3 and T4?
ANSWER To increase the basal metabolic rate (BMR) and regulate
growth and development.
Q: What is calcitonin and what does it do?
ANSWER A hormone produced by parafollicular cells (C cells) of the
thyroid that lowers blood calcium levels by inhibiting osteoclasts.
Q: Where are the parathyroid glands located?
ANSWER On the posterior surface of the thyroid gland.
Q: What is the function of Parathyroid Hormone (PTH)?
ANSWER To increase blood calcium levels and decrease blood
phosphate levels.
Q: What are the three target organs of PTH?
ANSWER Bones (stimulates osteoclasts), kidneys (increases calcium
reabsorption and activates vitamin D), and intestines (indirectly via
vitamin D).
Q: Where is the adrenal cortex located?
ANSWER The outer layer of the adrenal gland, situated atop the kidney.
Q: What are the three zones of the adrenal cortex, from superficial to
deep?
ANSWER Zona glomerulosa, zona fasciculata, and zona reticularis.
Q: What hormone is secreted by the zona glomerulosa?
ANSWER Mineralocorticoids, primarily aldosterone.
ANSWERS - COMPREHENSIVE LATEST VERSION
Q: What is the primary function of the endocrine system?
ANSWER To regulate body functions through the secretion of
hormones into the bloodstream.
Q: How do endocrine glands differ from exocrine glands?
ANSWER Endocrine glands are ductless and secrete hormones directly
into the blood; exocrine glands secrete products into ducts that lead to
body surfaces or cavities.
Q: What is a target cell?
ANSWER A cell that possesses specific receptors for a particular
hormone and can respond to it.
Q: What is up-regulation?
ANSWER An increase in the number of hormone receptors on a target
cell, increasing its sensitivity.
Q: What is down-regulation?
ANSWER A decrease in the number of hormone receptors, decreasing
cell sensitivity to prevent overstimulation.
Q: What are the two major chemical classes of hormones?
ANSWER Amino acid-based (peptides, proteins, amines) and steroid
hormones (derived from cholesterol).
Q: Which hormones can pass directly through the plasma membrane of
a target cell?
ANSWER Steroid hormones and thyroid hormones (because they are
lipid-soluble).
Q: What is the role of a second messenger in amino acid-based
hormone action?
, ANSWER It relays the signal from the plasma membrane receptor to
the inside of the cell, activating intracellular enzymes (e.g., cAMP).
Q: How do steroid hormones typically alter cell activity?
ANSWER They enter the nucleus and directly affect gene
transcription/translation to produce specific proteins.
Q: What is a negative feedback loop?
ANSWER A mechanism where increasing hormone levels inhibit
further hormone release to maintain homeostasis.
Q: What is a positive feedback loop? Give an example.
ANSWER A mechanism where hormone release causes an action that
stimulates more hormone release (e.g., oxytocin during childbirth).
Q: Where is the hypothalamus located?
ANSWER At the base of the brain, below the thalamus.
Q: What is the anatomical connection between the hypothalamus and
the posterior pituitary?
ANSWER The infundibulum (or hypothalamic-hypophyseal tract).
Q: Does the posterior pituitary synthesize hormones?
ANSWER No, it stores and releases hormones (ADH and oxytocin)
produced by the hypothalamus.
Q: What is the function of Antidiuretic Hormone (ADH)?
ANSWER To promote water reabsorption in the kidneys, reducing urine
output and preventing dehydration.
Q: What triggers the release of ADH?
ANSWER Increased blood osmolarity (high solute concentration) or
decreased blood volume/pressure.
Q: What is the function of Oxytocin?
ANSWER It stimulates uterine contractions during labor and milk
ejection (let-down) during lactation.
Q: What are the three parts of the anterior pituitary (adenohypophysis)?
,ANSWER Pars distalis, pars intermedia, and pars tuberalis.
Q: What regulates the release of anterior pituitary hormones?
ANSWER Releasing and inhibiting hormones from the hypothalamus
delivered via the hypophyseal portal system.
Q: What is Growth Hormone (GH) primary function?
ANSWER To stimulate growth of body tissues, especially bone and
muscle, and to mobilize fats.
Q: What are the two main effects of GH?
ANSWER Anabolic effects (protein synthesis) and lipolytic effects (fat
breakdown).
Q: What causes gigantism?
ANSWER Hypersecretion of GH during childhood.
Q: What causes acromegaly?
ANSWER Hypersecretion of GH during adulthood.
Q: What causes pituitary dwarfism?
ANSWER Hyposecretion of GH during childhood.
Q: What is the function of Thyroid-Stimulating Hormone (TSH)?
ANSWER To stimulate the thyroid gland to produce and release T3 and
T4.
Q: What is the function of Adrenocorticotropic Hormone (ACTH)?
ANSWER To stimulate the adrenal cortex to release glucocorticoids
(mainly cortisol).
Q: What do Follicle-Stimulating Hormone (FSH) and Luteinizing
Hormone (LH) regulate?
ANSWER The gonads (ovaries and testes) for gamete production and
sex hormone secretion.
Q: What hormone from the anterior pituitary targets the mammary
glands?
ANSWER Prolactin (PRL).
, Q: Where is the thyroid gland located?
ANSWER Just inferior to the larynx, anterior to the trachea.
Q: What are the two main hormones produced by the thyroid follicles?
ANSWER Thyroxine (T4) and Triiodothyronine (T3).
Q: What element is essential for the synthesis of T3 and T4?
ANSWER Iodine.
Q: What is the primary effect of T3 and T4?
ANSWER To increase the basal metabolic rate (BMR) and regulate
growth and development.
Q: What is calcitonin and what does it do?
ANSWER A hormone produced by parafollicular cells (C cells) of the
thyroid that lowers blood calcium levels by inhibiting osteoclasts.
Q: Where are the parathyroid glands located?
ANSWER On the posterior surface of the thyroid gland.
Q: What is the function of Parathyroid Hormone (PTH)?
ANSWER To increase blood calcium levels and decrease blood
phosphate levels.
Q: What are the three target organs of PTH?
ANSWER Bones (stimulates osteoclasts), kidneys (increases calcium
reabsorption and activates vitamin D), and intestines (indirectly via
vitamin D).
Q: Where is the adrenal cortex located?
ANSWER The outer layer of the adrenal gland, situated atop the kidney.
Q: What are the three zones of the adrenal cortex, from superficial to
deep?
ANSWER Zona glomerulosa, zona fasciculata, and zona reticularis.
Q: What hormone is secreted by the zona glomerulosa?
ANSWER Mineralocorticoids, primarily aldosterone.
