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Questions and Answers
Endocrine glands secrete hormones directly into the bloodstream, whereas exocrine glands use ducts to transport their secretions.
Endocrine glands secrete hormones directly into the bloodstream, whereas exocrine glands use ducts to transport their secretions.
True (A)
The endocrine system is responsible for rapid, short-lived coordination of body functions, similar to the nervous system.
The endocrine system is responsible for rapid, short-lived coordination of body functions, similar to the nervous system.
False (B)
Hormones secreted by endocrine glands only affect cells and tissues that are located close to the gland.
Hormones secreted by endocrine glands only affect cells and tissues that are located close to the gland.
False (B)
Neurotransmitters, paracrine signals, and hormones all operate through the bloodstream to reach target cells.
Neurotransmitters, paracrine signals, and hormones all operate through the bloodstream to reach target cells.
The production of most anterior lobe hormones is controlled by positive feedback mechanisms, leading to a rapid increase in hormone levels.
The production of most anterior lobe hormones is controlled by positive feedback mechanisms, leading to a rapid increase in hormone levels.
Steroid hormones exert their effects by binding to cell surface receptors, which then activate intracellular signaling cascades.
Steroid hormones exert their effects by binding to cell surface receptors, which then activate intracellular signaling cascades.
Calcitonin increases blood calcium levels by promoting calcium release from bones and increasing calcium absorption in the intestines.
Calcitonin increases blood calcium levels by promoting calcium release from bones and increasing calcium absorption in the intestines.
Type 1 diabetes is primarily caused by the body's inability to respond to insulin, whereas type 2 diabetes results from the autoimmune destruction of insulin-producing cells in the pancreas.
Type 1 diabetes is primarily caused by the body's inability to respond to insulin, whereas type 2 diabetes results from the autoimmune destruction of insulin-producing cells in the pancreas.
Steroid hormones exert their effects by directly interacting with ribosomes to initiate protein synthesis.
Steroid hormones exert their effects by directly interacting with ribosomes to initiate protein synthesis.
Nonsteroid hormones directly enter the target cell to initiate a response.
Nonsteroid hormones directly enter the target cell to initiate a response.
Adenylate cyclase is activated directly by the binding of a nonsteroid hormone to its receptor on the plasma membrane.
Adenylate cyclase is activated directly by the binding of a nonsteroid hormone to its receptor on the plasma membrane.
CAMP directly alters DNA transcription to cause cellular changes.
CAMP directly alters DNA transcription to cause cellular changes.
Positive feedback mechanisms maintain hormone levels in the blood within a narrow, stable range.
Positive feedback mechanisms maintain hormone levels in the blood within a narrow, stable range.
In a negative feedback loop, a decrease in the blood concentration of a regulated substance will inhibit the secretion of the corresponding hormone.
In a negative feedback loop, a decrease in the blood concentration of a regulated substance will inhibit the secretion of the corresponding hormone.
MRNA interacts with the cell nucleus to produce specific proteins.
MRNA interacts with the cell nucleus to produce specific proteins.
The primary role of G proteins in nonsteroid hormone action is to directly activate cellular enzymes.
The primary role of G proteins in nonsteroid hormone action is to directly activate cellular enzymes.
The anterior lobe directly controls the posterior lobe through hormonal signals.
The anterior lobe directly controls the posterior lobe through hormonal signals.
Hypothalamic hormones reach the anterior lobe via systemic arteries.
Hypothalamic hormones reach the anterior lobe via systemic arteries.
Releasing hormones diminish the production and release of anterior lobe hormones.
Releasing hormones diminish the production and release of anterior lobe hormones.
Growth hormone (GH) solely inhibits the division and growth of body cells.
Growth hormone (GH) solely inhibits the division and growth of body cells.
Increasing available energy for synthesis reactions, GH inhibits the release of fat by adipose tissue.
Increasing available energy for synthesis reactions, GH inhibits the release of fat by adipose tissue.
GH-releasing hormone (GHRH) stimulates GH secretion, while GH-inhibiting hormone (GHIH) inhibits GH secretion.
GH-releasing hormone (GHRH) stimulates GH secretion, while GH-inhibiting hormone (GHIH) inhibits GH secretion.
GHIH production is triggered by strenuous exercise and low levels of blood glucose.
GHIH production is triggered by strenuous exercise and low levels of blood glucose.
Acromegaly results from GH hypersecretion before full height is attained, while gigantism occurs after.
Acromegaly results from GH hypersecretion before full height is attained, while gigantism occurs after.
Individuals with pituitary dwarfism, caused by GH hyposecretion, always exhibit disproportionate body parts alongside their small stature.
Individuals with pituitary dwarfism, caused by GH hyposecretion, always exhibit disproportionate body parts alongside their small stature.
Increased levels of thyroid hormones directly stimulate the release of thyrotropin-releasing hormone (TRH) from the hypothalamus.
Increased levels of thyroid hormones directly stimulate the release of thyrotropin-releasing hormone (TRH) from the hypothalamus.
Adrenocorticotropic hormone (ACTH) primarily controls the secretion of hormones produced by the thyroid gland.
Adrenocorticotropic hormone (ACTH) primarily controls the secretion of hormones produced by the thyroid gland.
Increased blood cortisol levels stimulate CRH secretion, leading to increased ACTH secretion.
Increased blood cortisol levels stimulate CRH secretion, leading to increased ACTH secretion.
Gonadotropin-releasing hormone (GnRH) from the anterior pituitary directly stimulates the release of FSH and LH.
Gonadotropin-releasing hormone (GnRH) from the anterior pituitary directly stimulates the release of FSH and LH.
In males, follicle-stimulating hormone (FSH) stimulates testosterone production in the interstitial cells of the testes.
In males, follicle-stimulating hormone (FSH) stimulates testosterone production in the interstitial cells of the testes.
In females, luteinizing hormone (LH) stimulates the development of ovarian follicles, which contain ova and produce estrogen.
In females, luteinizing hormone (LH) stimulates the development of ovarian follicles, which contain ova and produce estrogen.
Prolactin initiates milk production by mammary glands before childbirth, preparing the mother for lactation.
Prolactin initiates milk production by mammary glands before childbirth, preparing the mother for lactation.
Neural communication involves hormones being directly released into the bloodstream to reach distant target cells.
Neural communication involves hormones being directly released into the bloodstream to reach distant target cells.
Paracrine signaling effects are restricted to cells that are nearby the secreting cell, distinguishing it from endocrine signaling which affects distant cells.
Paracrine signaling effects are restricted to cells that are nearby the secreting cell, distinguishing it from endocrine signaling which affects distant cells.
In neuroendocrine communication, a neurotransmitter is released by a neuron and directly affects adjacent muscle tissue by binding to a receptor.
In neuroendocrine communication, a neurotransmitter is released by a neuron and directly affects adjacent muscle tissue by binding to a receptor.
Prolactin secretion is controlled by a positive-feedback mechanism involving prolactin-releasing hormone (PRH) and prolactin-inhibiting hormone (PIH) from the hypothalamus.
Prolactin secretion is controlled by a positive-feedback mechanism involving prolactin-releasing hormone (PRH) and prolactin-inhibiting hormone (PIH) from the hypothalamus.
The posterior pituitary lobe directly synthesizes antidiuretic hormone (ADH) and oxytocin which are then stored.
The posterior pituitary lobe directly synthesizes antidiuretic hormone (ADH) and oxytocin which are then stored.
Eicosanoids, including prostaglandins and leukotrienes, primarily function to regulate long-term growth processes rather than inflammation and immune responses.
Eicosanoids, including prostaglandins and leukotrienes, primarily function to regulate long-term growth processes rather than inflammation and immune responses.
Action potentials travel down axons of neurosecretory neurons from the cerebrum to the posterior lobe, triggering the release of hormones into the bloodstream.
Action potentials travel down axons of neurosecretory neurons from the cerebrum to the posterior lobe, triggering the release of hormones into the bloodstream.
Due to their high concentrations in the blood, hormones require specialized transport mechanisms to reach target cells effectively.
Due to their high concentrations in the blood, hormones require specialized transport mechanisms to reach target cells effectively.
Steroid hormones, derived from amino acids, typically bind to receptors on the plasma membrane of target cells to initiate a rapid signaling cascade.
Steroid hormones, derived from amino acids, typically bind to receptors on the plasma membrane of target cells to initiate a rapid signaling cascade.
Increased water concentration in the blood leads to increased ADH secretion, promoting greater water retention by the kidneys.
Increased water concentration in the blood leads to increased ADH secretion, promoting greater water retention by the kidneys.
The magnitude of a hormone's effect on a target cell is solely determined by the hormone's concentration in the blood, irrespective of the number of available receptors.
The magnitude of a hormone's effect on a target cell is solely determined by the hormone's concentration in the blood, irrespective of the number of available receptors.
Diabetes insipidus results from oversecretion of ADH leading to excessive fluid retention and concentrated urine.
Diabetes insipidus results from oversecretion of ADH leading to excessive fluid retention and concentrated urine.
Because they are lipid-soluble, peptide hormones can easily diffuse through the plasma membrane to exert effects on DNA.
Because they are lipid-soluble, peptide hormones can easily diffuse through the plasma membrane to exert effects on DNA.
Nonfunctional ADH receptors in the kidneys can lead to diabetes insipidus because the kidneys are unable to respond appropriately to ADH.
Nonfunctional ADH receptors in the kidneys can lead to diabetes insipidus because the kidneys are unable to respond appropriately to ADH.
Oxytocin stimulates the contraction of smooth muscle in the bladder during labor which culminates in the birth of the infant.
Oxytocin stimulates the contraction of smooth muscle in the bladder during labor which culminates in the birth of the infant.
In lactating mothers, oxytocin secretion is regulated by a negative-feedback mechanism, where increased nipple stimulation leads to decreased OT release.
In lactating mothers, oxytocin secretion is regulated by a negative-feedback mechanism, where increased nipple stimulation leads to decreased OT release.
Flashcards
Endocrine System
Endocrine System
Provides slow, long-lasting coordination of body functions.
Endocrine Gland
Endocrine Gland
Cells, tissues, and organs that secrete hormones into interstitial fluid.
Hormones
Hormones
Chemical messengers secreted into interstitial fluid that alter cellular functions.
Exocrine Gland
Exocrine Gland
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Neurotransmitters
Neurotransmitters
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Paracrine Signals
Paracrine Signals
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Negative Feedback Mechanism
Negative Feedback Mechanism
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Steroid Hormones
Steroid Hormones
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Neural Communication
Neural Communication
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Paracrine Communication
Paracrine Communication
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Endocrine Communication
Endocrine Communication
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Neuroendocrine Communication
Neuroendocrine Communication
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Prostaglandins
Prostaglandins
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Leukotrienes
Leukotrienes
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Nonsteroid Hormones
Nonsteroid Hormones
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Hormone-Receptor Complex
Hormone-Receptor Complex
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Hormone-Receptor & DNA
Hormone-Receptor & DNA
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mRNA and Protein Synthesis
mRNA and Protein Synthesis
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Nonsteroid Hormones and Messengers
Nonsteroid Hormones and Messengers
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First Messenger
First Messenger
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Adenylate Cyclase Activation
Adenylate Cyclase Activation
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cAMP Formation
cAMP Formation
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Anterior Pituitary Regulation
Anterior Pituitary Regulation
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Releasing Hormones (RH)
Releasing Hormones (RH)
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Inhibiting Hormones (IH)
Inhibiting Hormones (IH)
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Growth Hormone (GH) Function
Growth Hormone (GH) Function
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How GH Increases Energy
How GH Increases Energy
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GHRH vs. GHIH
GHRH vs. GHIH
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Gigantism
Gigantism
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Acromegaly
Acromegaly
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Pituitary dwarfism
Pituitary dwarfism
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Thyroid-stimulating hormone (TSH)
Thyroid-stimulating hormone (TSH)
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Thyrotropin-releasing hormone (TRH)
Thyrotropin-releasing hormone (TRH)
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Adrenocorticotropic hormone (ACTH)
Adrenocorticotropic hormone (ACTH)
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Corticotropin-releasing hormone (CRH)
Corticotropin-releasing hormone (CRH)
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Gonadotropins
Gonadotropins
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Follicle-stimulating hormone (FSH) functions
Follicle-stimulating hormone (FSH) functions
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Prolactin (PRL)
Prolactin (PRL)
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Prolactin Regulation
Prolactin Regulation
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Posterior Lobe Control
Posterior Lobe Control
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Posterior Lobe Hormones
Posterior Lobe Hormones
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Antidiuretic Hormone (ADH)
Antidiuretic Hormone (ADH)
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Diabetes Insipidus
Diabetes Insipidus
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Oxytocin (OT)
Oxytocin (OT)
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Oxytocin Positive Feedback
Oxytocin Positive Feedback
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Oxytocin in Males/Non-Pregnant Females
Oxytocin in Males/Non-Pregnant Females
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Study Notes
Endocrine System Overview
- The endocrine system provides slow, long-lasting coordination of body functions.
- Endocrine glands secrete hormones into the interstitial fluid.
- Hormones travel from interstitial fluid into the blood to affect other tissues/organs.
- Exocrine glands carry secretions via a duct.
Endocrine Glands and Hormones
- Nonsteroid hormones are derived from amino acids, peptides, or proteins.
- Steroid hormones are derived from cholesterol.
- The hypothalamus produces tropic hormones that can be both releasing/inhibiting.
- The anterior pituitary gland produces growth hormone (GH), adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), and prolactin (PRL).
- The posterior pituitary gland produces antidiuretic hormone (ADH) and oxytocin (OT).
- The thyroid gland produces thyroid hormones and calcitonin.
- The parathyroid glands produce parathyroid hormone (PTH).
- The adrenal glands produce epinephrine, cortisol, aldosterone, and androgens.
- The pancreas produces insulin and glucagon.
- The ovaries produce estrogens and progesterone.
- The testes produce testosterone.
- The thymus produces thymosins.
Communication Modes
- Neural communication releases neurotransmitters at a synapse to transmit signals.
- Paracrine communication releases paracrine signals (local hormones) affecting neighboring cells within tissues.
- Endocrine communication releases hormones into the blood, distributed throughout the body, acting only on target cells with receptors.
- Neuroendocrine communication involves a neuron releasing a hormone into a blood vessel.
- Eicosanoids are a major class of paracrine signals
- Prostaglandins and Leukotrienes are the two types of eicosanoids
Hormone Action Mechanisms
- Hormones are secreted in small amounts and have low blood concentrations.
- Hormones act on cells that have specific receptors; therefore, large quantities are unnecessary.
- Steroid and thyroid hormones act on DNA and affect gene expression.
- A lipid-soluble hormone diffuses across the phospholipid bilayers of the plasma membrane.
- It combines with intracellular receptors to form a hormone-receptor complex.
- The hormone-receptor complex interacts with DNA, activating specific genes that synthesize messenger RNA (mRNA).
- mRNA leaves the nucleus and interacts with ribosomes, which results in the synthesis of specific proteins.
- Two messengers are needed to produce an effect on a target cell as nonsteroid hormones are not lipid-soluble.
- A nonsteroid hormones binds to receptors on the plasma membrane i.e. a first messenger (hormone-receptor complex).
- The hormone-receptor complex activates a membrane G protein, activates a membrane enzyme (adenylate cyclase).
- Adenylate cyclase catalyzes the formation of cAMP (second messenger).
- cAMP activates other enzymes which activates or inactivates cellular enzymes.
Hormone Production Control
- Hormone secretion is mostly regulated by negative-feedback mechanisms.
- Hormone levels are kept relatively stable in the blood.
- Decreased blood concentration of a regulated substance stimulates the endocrine gland and increases hormone secretion.
- The target cells stimulate to increase blood level of the substance back to set point.
- Hormone secretion has tight regulation to avoid hyposecretion (deficient Production) and hypersecretion (excessive production).
- Hormones secreted have fluctuating levels in the bloodstream.
- Secretion in some cases occurs on a daily (circadian) or monthly rhythm dependent on stimili.
- Three types of mechanisms regulate the endocrine glands i.e. hormonal, neual, and humoral control.
- Hormonal control involves tropic hormones to regulate secretion i.e. hypothalamus secretes a tropic hormone that interacts with cells in the anterior lobe of the pituitary gland.
- Neural control has the nervous system stimulate an endocrine gland in order to produce harmones which in turn affect target cells in the body.
- Humoral control has a chemical change in the blood that stimulates endocrine glands to produce harmones affecting target cells.
Pituitary Gland
- The pituitary gland (hypophysis) in attached to the hypothalamus by a short stalk,
- It rests in and is protected in the sella turcica of the sphenoid bone.
- Controlled by the hypothalamus through neurons and hormones that stimulate the anterior/hormone lobes.
- Anterior lobe is regulated by releasing and the portal veins carry hormones from the hypothalamus to directly enter the lobe.
- Releasing hormones stimulate production and inhibiting hormones inhibit the release of anterior lobe hormones.
- The posterior lobe is controlled by a neural-control, negative-feedback mechanism where axons release hormones from terminal boutons into the lobe, and communication is regulated by a neural control mechanism.
Anterior Lobe Hormones
- Growth hormone (GH) stimulates the division and grows of body cells and aids in synthesis of proteins.
- Increases available energy for aerobic respiration during childhood and adolescence which is regulated by the antagonistic functions of GHRH and GHIH.
- Gigantism in caused by GH's oversecretion during growth years reaching 8 ft in height, Acromegaly is similar but occurs during after growth, or pituitary dwarfism occurs caused by GH's undersecretion during growth resulting body well porpotioned but significantly smaller.
- Thyroid-stimulating hormone (TSH) stimulates production regulated by throthpin-regulated which can be affected by disorders in the thyroid. Low TH levels cause it to release by the hypothalamus triggering the TSH release or inhibited by TH releases.
- Adrenocorticotropic hormone (ACTH) is controlled through the levels of CRH. This controls harmones prouduced in the adrenal cortex and is in turn affects the target cells.
- Gonadotropins include follicle stimulating and Lutenizing hormones. Both cause secrtion in the hypothalamus with GnRH
They affect the gonads.
- The onset of puberty occurs due to FSH secretions
- Prolactin (PRL) released from mammary glands stimulates the antagonistic function of prolactin-releasing (PRH) and prolactin-inhibiting harmone (PIH)
Posterior Lobe Hormones
- Two types of hormones are released ADH and Oxytocin whoch are secreted by the neurons of the hypothalamus.
- Antidiuretic hormone (ADH) promotes water retention in Kidneys and maintains blood volume and reduced urine.
- Diabetes insipidus may occur as a condition due to damage to the ADH regulatory mechanisims
- Oxytocin Stimulates and strengthens contraction of the smoooth nuscles of the utereus.
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Description
Explore the endocrine system, contrasting endocrine and exocrine glands. Learn about hormone function, including their effects on target cells and tissues. Understand the roles of neurotransmitters, paracrine signals, and the mechanisms of hormone action, including steroid hormones.
