Endocrine system quiz - revision notes

Questions and Answers

What is the term for a cell-produced substance that has an effect on the cell by which it is secreted?

Autocrine

Which type of hormone activates protein kinases by producing cAMP as a second messenger?

Peptide hormone

What is the term for a regulatory substance produced in an organism and transported in tissue fluids to stimulate specific cells or tissues into action?

Hormone

Which type of hormone is thyroid hormone?

Steroid Signup and view all the answers

Which type of hormone is adrenaline?

Catecholamine Signup and view all the answers

Which type of hormone is insulin?

Peptide Signup and view all the answers

Which type of hormones are water soluble?

Catecholamines (adrenalin, noradrenaline, melanin) Signup and view all the answers

Which type of hormones are lipid soluble?

steroids, thyroid hormone Signup and view all the answers

Where do lipid soluble hormones bind to alter gene expression?

Cytosol or nucleus Signup and view all the answers

What is the main mode of transport for lipid soluble hormones into a cell?

Diffusion through the blood and plasma membrane Signup and view all the answers

What is the primary effect of lipid soluble hormones on the production of proteins?

Activating or suppressing protein production Signup and view all the answers

Which molecule is responsible for converting ATP to cAMP in the cytosol as a second messenger?

Adenylyl cyclase Signup and view all the answers

What is the primary role of the hormone-receptor complex that activates the membrane protein G protein?

Activating adenylyl cyclase Signup and view all the answers

What is the function of phosphodiesterase in the hormone signaling pathway?

Deactivates cAMP Signup and view all the answers

What is the term for the effect where the response only occurs when there is a recent or simultaneous presence of a second hormone?

Permissive effect Signup and view all the answers

What is the term for the effect when the effect of two hormones acting together is greater than the sum of their individual effects?

Synergistic effect Signup and view all the answers

What is the term for the effect when one hormone opposes the actions of another hormone?

Antagonistic effect Signup and view all the answers

What is the term for the diminution or counteraction of an effect by its own influence on the process giving rise to it?

Negative feedback mechanism Signup and view all the answers

Which type of feedback mechanism enhances or amplifies an effect by its own influence on the process which gives rise to it?

Positive feedback mechanism Signup and view all the answers

In the context of hormone regulation, which mechanism describes the inhibition of further secretion of a hormone due to its high level in the blood?

Negative feedback mechanism Signup and view all the answers

What is the primary cause of gigantism?

Excessive growth hormone in childhood Signup and view all the answers

Which physical characteristics are commonly associated with gigantism?

Large hands and feet, prominent jaw, and forehead Signup and view all the answers

What is the usual nature of the pituitary gland condition in gigantism?

Adenoma, a tumour Signup and view all the answers

Which of the following symptoms is commonly associated with acromegaly?

Swollen hands and feet Signup and view all the answers

What is a common consequence of acromegaly on hands?

Numbness due to compressed nerves Signup and view all the answers

Which facial features are typically affected by acromegaly?

Larger brow, nose, and lower jaw Signup and view all the answers

Which symptom of Addison’s Disease is a result of the lack of aldosterone?

Frequent urination Signup and view all the answers

What is the primary cause of cortisol underproduction in Addison’s Disease?

Autoimmune destruction of adrenal gland Signup and view all the answers

Which hormone stimulates the production of melanin by melanocytes in Addison’s Disease?

ACTH Signup and view all the answers

Which region of the hypothalamus initiates hunger and thirst?

Tuberal region Signup and view all the answers

Which section of the hypothalamus controls vasoconstriction of skin blood vessels and inhibition of sweating?

Posterior hypothalamus - preoptic especially Signup and view all the answers

What supplies blood to the hypothalamus through the primary plexus of the hypophyseal portal system?

Superior hypophyseal arteries Signup and view all the answers

Which artery supplies the posterior pituitary gland?

Inferior hypophyseal artery Signup and view all the answers

What is the primary mode of connection between the pituitary gland and the hypothalamus?

Nerve fibers Signup and view all the answers

Which bone is located superior to the pituitary gland?

Sphenoid bone Signup and view all the answers

Which hormone is primarily responsible for stimulating the production of melanin by melanocytes?

Melanocyte stimulating hormone (MSH) Signup and view all the answers

Which hormone is associated with the regulation of lactation?

Prolactin (PRL) Signup and view all the answers

Which cell type in the anterior pituitary is responsible for the secretion of adrenocorticotropic hormone (ACTH)?

Corticotrophs Signup and view all the answers

Which hormone is primarily responsible for stimulating the production of melanin by melanocytes?

Adrenocorticotropic hormone (ACTH) Signup and view all the answers

Which region of the hypothalamus initiates hunger and thirst?

Arcuate nucleus Signup and view all the answers

Which hormone is synthesized and secreted by gonadotrophs?

Follicle stimulating hormone (FSH) Signup and view all the answers

What hormone is released by somatotrophs?

Growth hormone (GH) Signup and view all the answers

Which hormone is released by thyrotrophs?

Thyroid stimulating hormone (TSH) Signup and view all the answers

Which hormone suppresses the release of gastrointestinal hormones, decreases the rate of gastric emptying, and reduces smooth muscle contractions and blood flow within the intestine?

Somatostatin Signup and view all the answers

Which hormone stimulates the secretion of gastric acid by the parietal cells of the stomach and aids in gastric motility?

Gastrin Signup and view all the answers

What is the primary function of the pancreas's exocrine system?

Producing enzymes involved in hydrolysing proteins, fats, and carbs Signup and view all the answers

Where are the parathyroid glands located?

On the posterior thyroid gland Signup and view all the answers

Which hormone induces smooth muscle relaxation in the stomach and gallbladder?

Vasoactive Intestinal Peptide Signup and view all the answers

What is the primary function of the hormone glucagon?

Stimulating glycogen breakdown and release of glucose into the bloodstream Signup and view all the answers

Which hormone is primarily responsible for stimulating the production of melanin by melanocytes?

Melanocyte stimulating hormone (MSH) Signup and view all the answers

What is the primary function of the adrenal cortex?

Secretion of aldosterone, cortisol, and androgens Signup and view all the answers

Where do the Adrenal Glands lie?

On the upper poles of the kidneys Signup and view all the answers

What is the developmental origin of the Thyroid Gland?

Begins as a dorsal endodermal thickening Signup and view all the answers

What is the consequence of a patent thyroglossal duct?

Formation of a thyroglossal cyst Signup and view all the answers

What is the foetal remnant found at the posterior tongue?

Foramen caecum Signup and view all the answers

What does the medulla of the adrenal gland produce?

Adrenaline and noradrenaline Signup and view all the answers

What happens if the thyroglossal duct closes up incompletely?

Formation of a thyroglossal cyst Signup and view all the answers

Which hormone condition would lead to down regulation?

Excess hormone Signup and view all the answers

What is the primary origin of the anterior pituitary?

Ectoderm of Rathke’s pouch Signup and view all the answers

Which hormone is responsible for the majority of the growth promoting effects of growth hormone (GH)?

Insulin-like growth factor (IGF-I) Signup and view all the answers

Which cells secrete a hormone in response to the releasing hormone in the anterior pituitary gland?

Thyrotrophs Signup and view all the answers

What is the primary origin of the posterior pituitary?

Neural ectoderm from the floor of the diencephalon Signup and view all the answers

Which hormone is secreted from the liver and other tissues in response to GH, mediating indirect effects?

Insulin-like growth factor (IGF-I) Signup and view all the answers

What is the primary source of the majority of the growth promoting effects of GH?

Target cells Signup and view all the answers

Which cells in the anterior pituitary gland are responsible for secreting a hormone in response to the releasing hormone?

Somatotrophs Signup and view all the answers

What is the primary function of the hormone IGF-I?

Stimulating triglyceride breakdown Signup and view all the answers

Which cells in the anterior pituitary gland are responsible for secreting a hormone in response to the releasing hormone?

Corticotrophs Signup and view all the answers

Which hormone stimulates osteoblasts at the epiphyseal plate and increases uptake of amino acids for protein synthesis?

IGF-1 Signup and view all the answers

What stimulates the hypothalamus to secrete corticotropin-releasing hormone (CRH)?

Low glucose levels Signup and view all the answers

What inhibits the production of Growth Hormone (GH)?

Growth Hormone Inhibiting Hormone (GHIH) Signup and view all the answers

Which hormone is secreted in response to the releasing hormone in the anterior pituitary gland?

Adrenocorticotropic hormone (ACTH) Signup and view all the answers

Which hormone is primarily responsible for the majority of the growth promoting effects of Growth Hormone (GH)?

Insulin-like Growth Factor 1 (IGF-1) Signup and view all the answers

What stimulates the hypothalamus to secrete Growth Hormone Releasing Hormone (GHRH)?

Presence of testosterone and oestrogen Signup and view all the answers

What stimulates the production of TRH in the hypothalamus?

Low levels of T3 and T4 Signup and view all the answers

What is the primary function of cortisol?

Increases glucose production Signup and view all the answers

What is the primary effect of TSH on the thyroid gland?

Production of T3 and T4 Signup and view all the answers

What stimulates gonadotrophs in the anterior pituitary to secrete LH and FSH?

GnRH Signup and view all the answers

Which hormone stimulates ovulation and the formation of the corpus luteum in females?

LH Signup and view all the answers

What hormone stimulates sperm production in males?

FSH Signup and view all the answers

What hormone is secreted by the hypothalamus just before menstruation to stimulate lactotrophs in the anterior pituitary gland?

PRH Signup and view all the answers

What hormone diminishes just before menstruation, leading to the secretion of prolactin?

Dopamine Signup and view all the answers

What stimulates the production of Melanocyte-Stimulating Hormone (MSF) in the skin in response to UV light?

MSF-releasing factor (MRF) from the hypothalamus Signup and view all the answers

Which cells in the hypothalamus are responsible for synthesizing oxytocin and ADH into vesicles?

Paraventricular and supraoptic nuclei Signup and view all the answers

What is the primary mode of transport for hormones from the hypothalamus to the axon terminals for storage?

Axonal transport along the hypothalamo-hypophyseal tract Signup and view all the answers

What is the pathway for the release of oxytocin and ADH into the bloodstream when a stimulus excites the hypothalamus?

Vesicles undergo exocytosis and hormones are released into the blood stream Signup and view all the answers

Where do hormones pass into before reaching their target organs?

Capillary plexus of the infundibular vein Signup and view all the answers

What stimulates the release of oxytocin during delivery of a baby?

Cervical stretching Signup and view all the answers

What is the primary stimulus for the release of ADH (Vasopressin)?

High blood osmolarity Signup and view all the answers

What is the primary effect of ADH binding to cells lining the DCT and the collecting duct?

Activation of adenylyl cyclase Signup and view all the answers

What is the additional effect of ADH besides promoting water reabsorption?

Vasoconstriction Signup and view all the answers

Study Notes

Hormone Functions and Types

Autocrine signaling involves a cell-produced substance influencing its own function.
Water-soluble hormones often activate protein kinases via cAMP as a second messenger.
Hormones can function as signaling molecules, affecting specific cells or tissues.
Thyroid hormones are classified as lipid-soluble hormones.
Adrenaline is a water-soluble hormone belonging to the catecholamines group.
Insulin is a peptide hormone categorized as water-soluble.
Water-soluble hormones typically include peptide hormones and catecholamines.
Lipid-soluble hormones include steroid hormones and thyroid hormones.

Mechanisms of Hormone Action

Lipid-soluble hormones bind to nuclear receptors, altering gene expression.
Diffusion is the main transport method for lipid-soluble hormones into cells.
Lipid-soluble hormones primarily increase protein synthesis through gene transcription.
Adenylate cyclase converts ATP to cAMP, a crucial second messenger in signal transduction.
G protein activation occurs when the hormone-receptor complex interacts with membrane proteins.

Hormonal Interactions and Feedback Mechanisms

Synergistic effect occurs when two hormones together produce an outcome greater than their individual effects.
Permissive effect requires a second hormone’s presence for the primary response to occur.
Antagonistic effect is when one hormone counteracts the action of another hormone.
Feedback inhibition occurs when high hormone levels inhibit further secretion of that hormone.
Positive feedback mechanisms enhance the effects of hormonal processes.

Gigantism and Acromegaly

Gigantism results from excessive growth hormone (GH) production usually due to pituitary adenoma.
Common signs of gigantism include excessive height and large hands/feet.
Acromegaly symptoms include enlarged hands and feet, with thickened facial features.
Addison's Disease results in the absence of aldosterone, leading to symptoms like low blood pressure and dehydration.

Hypothalamus and Pituitary Gland Regulation

The lateral hypothalamus initiates hunger and thirst responses.
The posterior hypothalamus manages vasoconstriction and temperature regulation.
Portal circulation to the anterior pituitary is supplied by the hypophyseal portal system.
The pituitary gland connects to the hypothalamus via stalk-like infundibulum.
The sphenoid bone is located superior to the pituitary gland.
Melanocyte-stimulating hormone (MSH) regulates melanin production.

Hormones Produced by the Pituitary Gland

Corticotrophs produce Adrenocorticotropic hormone (ACTH).
Somatotrophs release growth hormone (GH).
Thyrotrophs release Thyroid Stimulating Hormone (TSH).
Gastrin stimulates gastric acid secretion and increases gastric motility.
Glucagon increases blood glucose levels by promoting hepatic glycogenolysis.

Thyroid, Parathyroid, and Adrenal Functions

The thyroid gland originates from the foregut endoderm and regulates metabolism.
Parathyroid glands are located posterior to the thyroid gland, vital for calcium homeostasis.
The adrenal cortex produces corticosteroids, including cortisol, which regulates stress response.
Adrenal medulla produces catecholamines such as epinephrine and norepinephrine, enhancing the fight-or-flight response.

Growth Hormone and Its Mechanism

Insulin-like growth factor 1 (IGF-1) mediates most growth-promoting effects of GH.
Growth hormone promotes protein synthesis and encourages growth at epiphyseal plates.
The hypothalamus secretes growth hormone-releasing hormone (GHRH) to initiate GH release.

Neuroendocrine Regulation

Oxytocin and antidiuretic hormone (ADH) are synthesized in the hypothalamus and stored in the posterior pituitary.
Hormonal signaling involves the hypothalamus sending hormones down axons for release into the bloodstream.
Stimulation during childbirth triggers oxytocin release, facilitating labor.

Additional Hormonal Considerations

ADH promotes water reabsorption in the kidneys and regulates blood osmolality.
TRH production in the hypothalamus stimulates TSH release from the anterior pituitary, affecting thyroid activity.

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Description

Test your knowledge of endocrine, paracrine, and autocrine signaling with this quiz. Explore the functions and characteristics of these signaling mechanisms, as well as their roles in regulating the body's processes.