Ch. 17 Endocrine System Flashcards
Endocrine glands (BLANK).
A) secrete hormones that travel through a duct to the target organs.
B) release neurotransmitters into the synaptic cleft.
C) secrete chemical messengers that travel in the bloodstream.
D) include sebaceous glands and sweat glands.
C. Secrete chemical messengers that travel in the bloodstream.
Explanation: Endocrine glands are ductless glands that release hormones into the extracellular fluid. These hormones then enter the bloodstream and travel to target cells throughout the body.
Incorrect:
A – Describes exocrine glands, not endocrine glands.
B – Refers to neural communication, not endocrine signaling.
D – Sebaceous and sweat glands are exocrine, not endocrine.
Chemical signaling that affects neighboring cells is called (BLANK).
A) Autocrine.
B) Paracrine.
C) Endocrine.
D) Neuron.
B. Paracrine.
Explanation: Paracrine signaling involves chemical messengers that act on nearby cells, rather than traveling through the bloodstream like endocrine signals.
Incorrect:
A – Autocrine signals act on the same cell that secreted them.
C – Endocrine signals act on distant cells via the bloodstream.
D – “Neuron” is not a type of chemical signaling.
A newly developed pesticide has been observed to bind to an intracellular hormone receptor. If ingested, residue from this pesticide could disrupt levels of (BLANK).
A) Melatonin.
B) Thyroid hormone.
C) Growth hormone.
D) Insulin.
B. Thyroid hormone.
Explanation: Thyroid hormone is one of the few lipid-soluble hormones that binds to intracellular receptors, allowing it to enter the cell and alter gene expression directly.
Incorrect:
A – Melatonin is water-soluble and binds to membrane-bound receptors.
C – Growth hormone binds to cell surface receptors.
D – Insulin is a protein hormone that also binds to membrane receptors.
A small molecule binds to a G protein, preventing its activation. What direct effect will this have on signaling that involves cAMP?
A) The hormone will not be able to bind to the hormone receptor.
B) Adenylyl cyclase will not be activated.
C) Excessive quantities of cAMP will be produced.
D) The phosphorylation cascade will be initiated.
B. Adenylyl cyclase will not be activated.
Explanation: G protein activation is required to stimulate adenylyl cyclase, which then converts ATP to cAMP. Blocking the G protein means the signaling cascade never starts.
Incorrect:
A – Hormone binding to the receptor is upstream of G protein activation.
C – Without G protein activation, cAMP won’t be produced, let alone in excess.
D – The phosphorylation cascade is downstream and won’t be triggered without cAMP.
A student is in a car accident, and although not hurt, immediately experiences pupil dilation, increased heart rate, and rapid breathing. What type of endocrine system stimulus did the student receive?
A) Humoral.
B) Hormonal.
C) Neural.
D) Positive feedback.
C. Neural.
Explanation: The student experienced a classic “fight-or-flight” response, which is a neural stimulus triggering the adrenal medulla to release epinephrine and norepinephrine in response to stress.
Incorrect:
A – Humoral stimuli involve changes in blood ion/nutrient levels, not immediate stress response.
B – Hormonal stimuli involve one hormone triggering another, which takes longer.
D – Positive feedback is a type of regulation, not a stimulus source.
The hypothalamus is functionally and anatomically connected to the posterior pituitary lobe by a bridge of (BLANK).
A) Blood vessels.
B) Nerve axons.
C) Cartilage.
D) Bone.
B. Nerve axons.
Explanation: The posterior pituitary is connected to the hypothalamus via nerve axons that travel through the infundibulum, allowing it to store and release hormones (oxytocin and ADH) produced in the hypothalamus.
Incorrect:
A – Blood vessels connect the hypothalamus to the anterior pituitary, not the posterior.
C & D – Not involved in endocrine connections.
Which of the following is an anterior pituitary hormone?
A) ADH.
B) Oxytocin.
C) TSH.
D) Cortisol.
C. TSH (Thyroid-Stimulating Hormone).
Explanation: TSH is produced by the anterior pituitary and stimulates the thyroid gland to release thyroid hormones.
Incorrect:
A & B – ADH and oxytocin are produced by the hypothalamus and released by the posterior pituitary.
D – Cortisol is secreted by the adrenal cortex, not the pituitary.
How many hormones are produced by the posterior pituitary?
A) 0.
B) 1.
C) 2.
D) 6.
A. 0.
Explanation: The posterior pituitary does not produce any hormones. It stores and releases two hormones—ADH and oxytocin—that are made by the hypothalamus.
Which of the following hormones contributes to the regulation of the body’s fluid and electrolyte balance?
A) Adrenocorticotropic hormone.
B) Antidiuretic hormone.
C) Luteinizing hormone.
D) All of the above.
B. Antidiuretic hormone (ADH).
Explanation: ADH helps regulate fluid balance by promoting water reabsorption in the kidneys, reducing urine output and conserving body water.
Incorrect:
A – ACTH stimulates cortisol release, not fluid regulation directly.
C – LH is involved in reproductive function, not fluid/electrolyte balance.
D – Not all listed hormones are related to fluid/electrolyte balance.
This is a disorder in adults caused when abnormally high levels of GH trigger growth of bones in the face, hands, and feet.
A) Aldosterone.
B) Acromegaly.
C) Gigantism.
D) Hyperglycemia.
B. Acromegaly.
Explanation: Acromegaly is a disorder that occurs in adults when the pituitary gland produces excessive growth hormone (GH) after the growth plates have closed. This leads to abnormal growth of bones in areas such as the face, hands, and feet.
Incorrect:
A – Aldosterone is a mineralocorticoid hormone produced by the adrenal cortex that regulates sodium and potassium levels, not related to bone growth.
C – Gigantism is caused by excess GH in children, before the growth plates close, leading to overall increased height and size.
D – Hyperglycemia refers to high blood sugar levels, which can result from various metabolic issues, not abnormal bone growth.
Which region of the diencephalon is inferior to the thalamus that functions in neural and endocrine signaling?
A) Posterior pituitary gland.
B) Anterior pituitary gland.
C) Infundibulum.
D) Hypothalamus.
D. Hypothalamus.
Explanation: The hypothalamus is located inferior to the thalamus in the diencephalon and plays a central role in both neural and endocrine signaling. It produces hormones that regulate the anterior pituitary and stores hormones like ADH and oxytocin, which are released by the posterior pituitary.
Incorrect:
A – Posterior pituitary gland releases hormones but does not produce them and is not the primary controller of neural-endocrine functions.
B – Anterior pituitary gland secretes hormones but is regulated by the hypothalamus and is not part of the diencephalon.
C – Infundibulum is the stalk connecting the hypothalamus to the pituitary, not a functional brain region in itself.
Which of the following statements about the thyroid gland is true?
A) It is located anterior to the trachea and inferior to the larynx.
B) The parathyroid glands are embedded within it.
C) It manufactures three hormones.
D) All of the above.
D. all of the above.
Explanation: All listed statements are correct: Location: Anterior to trachea, below larynx. Parathyroids are embedded on the posterior surface. It produces T3, T4, and calcitonin.
The secretion of thyroid hormones is controlled by (BLANK).
A) TSH from the hypothalamus.
B) TSH from the anterior pituitary.
C) Thyroxine from the anterior pituitary.
D) Thyroglobulin from the thyroid’s parafollicular cells.
B. TSH from the anterior pituitary.
Explanation: TSH from the anterior pituitary stimulates the thyroid to release T3 and T4.
Incorrect:
A – TSH is not secreted by the hypothalamus; TRH is.
C – The anterior pituitary does not secrete thyroxine.
D – Parafollicular cells produce calcitonin, not thyroglobulin.
The development of a goiter indicates that (BLANK).
A) The anterior pituitary is abnormally enlarged.
B) There is hypertrophy of the thyroid’s follicle cells.
C) There is an excessive accumulation of colloid in the thyroid follicles.
D) The anterior pituitary is secreting excessive growth hormone.
C. There is an excessive accumulation of colloid in the thyroid follicles.
Explanation: A goiter often results from iodine deficiency, preventing the production of T3 and T4, which causes colloid to build up in the thyroid follicles.
Incorrect:
A & D – Not relevant to goiter formation.
B – Hypertrophy may occur, but colloid buildup is the direct cause.
Iodide ions cross from the bloodstream into follicle cells via (BLANK).
A) Simple diffusion.
B) Facilitated diffusion.
C) Active transport.
D) Osmosis.
C. Active transport.
Explanation: Iodide is transported against its concentration gradient into follicular cells, requiring active transport.
When blood calcium levels are low, PTH stimulates (BLANK).
A) Urinary excretion of calcium by the kidneys.
B) A reduction in calcium absorption from the intestines.
C) The activity of osteoblasts.
D) The activity of osteoclasts.
D. The activity of osteoclasts.
Explanation: PTH stimulates osteoclasts to break down bone matrix and release calcium into the blood.
Incorrect:
A – PTH reduces calcium excretion in the kidneys.
B – PTH increases calcium absorption via calcitriol.
C – Osteoblasts build bone and store calcium.
Which of the following can result from hyperparathyroidism?
A) Increased bone deposition.
B) Fractures.
C) Convulsions.
D) All of the above.
B. fractures.
Explanation: Hyperparathyroidism causes excessive bone resorption, weakening bones and making them prone to fractures.
Incorrect:
A – Opposite of what occurs. Bone deposition decreases.
C – Convulsions are more associated with hypocalcemia, not hyperparathyroidism.
D – Not all listed effects occur.
The adrenal glands are attached superiorly to which organ?
A) Thyroid.
B) Liver.
C) Kidneys.
D) Hypothalamus.
C. Kidneys.
Explanation: The adrenal glands sit on top of the kidneys, like caps, and are sometimes called suprarenal glands.
What secretory cell type is found in the adrenal medulla?
A) Chromaffin cells.
B) Neuroglial cells.
C) Follicle cells.
D) Oxyphil cells.
A. Chromaffin cells.
Explanation: Chromaffin cells in the adrenal medulla secrete epinephrine and norepinephrine as part of the sympathetic response.
Incorrect:
B – Found in the nervous system.
C – Found in the thyroid follicles.
D – Found in the parathyroid glands.
Cushing’s disease is a disorder caused by (BLANK).
A) Abnormally low levels of cortisol.
B) Abnormally high levels of cortisol.
C) Abnormally low levels of aldosterone.
D) Abnormally high levels of aldosterone.
B. Abnormally high levels of cortisol.
Explanation: Cushing’s disease results from excessive ACTH stimulation, leading to overproduction of cortisol, causing symptoms like fat redistribution and immune suppression.
Incorrect:
A – Describes Addison’s disease.
C – Also seen in Addison’s disease, but not relevant to Cushing’s.
D – Describes hyperaldosteronism.
Which of the following responses is not part of the fight-or-flight response?
A) Pupil dilation.
B) Increased oxygen supply to the lungs.
C) Suppressed digestion.
D) Reduced mental activity.
D. Reduced mental activity.
Explanation: The fight-or-flight response increases mental alertness, not reduces it.
Incorrect: A, B, C – All are typical sympathetic responses.
What cells secrete melatonin?
A) Melanocytes.
B) Pinealocytes.
C) Suprachiasmatic nucleus cells.
D) Retinal cells.
B. pinealocytes.
Explanation: Pinealocytes, located in the pineal gland, produce melatonin, which helps regulate the sleep–wake cycle.
Incorrect:
A – Melanocytes produce melanin in the skin.
C – SCN controls melatonin secretion but doesn’t produce it.
D – Retinal cells detect light but don’t produce melatonin.
The production of melatonin is inhibited by (BLANK).
A) Declining levels of light.
B) Exposure to bright light.
C) The secretion of serotonin.
D) The activity of pinealocytes.
B. exposure to bright light.
Explanation: Bright light inhibits melatonin production by suppressing signals from the suprachiasmatic nucleus to the pineal gland.
The gonads produce what class of hormones?
A) Amine hormones.
B) Peptide hormones.
C) Steroid hormones.
D) Catecholamines.
C. Steroid hormones.
Explanation: Gonads (testes and ovaries) produce steroid hormones like testosterone, estrogen, and progesterone, all derived from cholesterol.
The production of FSH by the anterior pituitary is reduced by which hormone?
A) Estrogens.
B) Progesterone.
C) Relaxin.
D) Inhibin.
D. inhibin.
Explanation: Inhibin is secreted by both testes and ovaries to inhibit FSH secretion, helping regulate gamete production.
The function of the placental hormone human placental lactogen (hPL) is to (BLANK).
A) Prepare the breasts for lactation.
B) Nourish the placenta.
C) Regulate the menstrual cycle.
D) All of the above.
A. Prepare the breasts for lactation.
Explanation: hPL prepares the mammary glands for milk production during pregnancy.
Incorrect:
B – hPL does not directly nourish the placenta.
C – The menstrual cycle is regulated by ovarian hormones.
If an autoimmune disorder targets the alpha cells, production of which hormone would be directly affected?
A) Somatostatin.
B) Pancreatic polypeptide.
C) Insulin.
D) Glucagon.
D. Glucagon.
Explanation: Alpha cells in the pancreatic islets are responsible for producing glucagon, which raises blood glucose levels during fasting or low energy states. If these cells are destroyed, glucagon secretion would be impaired.
Incorrect:
A – Somatostatin is produced by delta cells, not alpha cells.
B – Pancreatic polypeptide is made by PP cells, which regulate pancreatic secretions and appetite.
C – Insulin is produced by beta cells, not alpha cells.
Which of the following statements about insulin is true?
A) Insulin acts as a transport protein, carrying glucose across the cell membrane.
B) Insulin facilitates the movement of intracellular glucose transporters to the cell membrane.
C) Insulin stimulates the breakdown of stored glycogen into glucose.
D) Insulin stimulates the kidneys to reabsorb glucose into the bloodstream.
B. Insulin facilitates the movement of intracellular glucose transporters to the cell membrane.
Explanation: Insulin binds to receptors on target cells, causing glucose transporters (like GLUT4) to move to the membrane, allowing glucose to enter the cell.
Incorrect:
A – Insulin is not a transport protein itself.
C – This is the action of glucagon, not insulin.
D – Kidney glucose reabsorption involves renal transporters, not insulin.
The walls of the atria produce which hormone?
A) Cholecystokinin.
B) Atrial natriuretic peptide.
C) Renin.
D) Calcitriol.
B. Atrial natriuretic peptide.
Explanation: Atrial natriuretic peptide (ANP) is released from the heart’s atria in response to high blood pressure, promoting sodium and water excretion to lower blood volume and pressure.
Incorrect:
A – Cholecystokinin is secreted by the small intestine.
C – Renin is secreted by the kidneys.
D – Calcitriol is the active form of vitamin D, produced by the kidneys.
The end result of the RAAS is to (BLANK).
A) Reduce blood volume.
B) Increase blood glucose.
C) Reduce blood pressure.
D) Increase blood pressure.
D. increase blood pressure.
Explanation: The renin-angiotensin-aldosterone system (RAAS) increases blood pressure by promoting vasoconstriction and sodium/water reabsorption via aldosterone.
Athletes may take synthetic EPO to boost their (BLANK).
A) Blood calcium levels.
B) Secretion of growth hormone.
C) Blood oxygen levels.
D) Muscle mass.
C. Blood oxygen levels.
Explanation: Erythropoietin (EPO) stimulates red blood cell production, which enhances oxygen-carrying capacity—attractive for endurance athletes.
Incorrect:
A – Calcium levels are regulated by PTH and calcitonin, not EPO.
B – EPO has no effect on growth hormone.
D – Muscle mass is influenced by testosterone, GH, and IGF-1, not EPO.
Hormones produced by the thymus play a role in the (BLANK).
A) Development of T cells.
B) Preparation of the body for childbirth.
C) Regulation of appetite.
D) Release of hydrochloric acid in the stomach.
A. Development of T cells.
Explanation: The thymus secretes thymosins, which are essential for T cell maturation, a critical part of the immune system.
The anterior pituitary gland develops from which embryonic germ layer?
A) Oral ectoderm.
B) Neural ectoderm.
C) Mesoderm.
D) Endoderm.
A. Oral ectoderm.
Explanation: The anterior pituitary develops from an invagination of the oral ectoderm (specifically, Rathke’s pouch).
Incorrect:
B – Neural ectoderm gives rise to the posterior pituitary.
C & D – These germ layers form other endocrine glands (e.g., gonads from mesoderm, thyroid from endoderm).
In the elderly, decreased thyroid function causes (BLANK).
A) Increased tolerance for cold.
B) Decreased basal metabolic rate.
C) Decreased body fat.
D) Osteoporosis.
B. Decreased basal metabolic rate.
Explanation: A decline in thyroid hormone slows down metabolism, resulting in a lower basal metabolic rate.
Incorrect:
A – Reduced thyroid activity decreases heat production, making cold intolerance more likely.
C – Slower metabolism usually leads to increased fat storage.
D – Osteoporosis is more directly linked to declining estrogen or PTH changes, not thyroid hormone alone.
