90 Questions
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
Which type of hormone is adrenaline?
Catecholamine
Which type of hormone is insulin?
Peptide
Which type of hormones are water soluble?
Catecholamines (adrenalin, noradrenaline, melanin)
Which type of hormones are lipid soluble?
steroids, thyroid hormone
Where do lipid soluble hormones bind to alter gene expression?
Cytosol or nucleus
What is the main mode of transport for lipid soluble hormones into a cell?
Diffusion through the blood and plasma membrane
What is the primary effect of lipid soluble hormones on the production of proteins?
Activating or suppressing protein production
Which molecule is responsible for converting ATP to cAMP in the cytosol as a second messenger?
Adenylyl cyclase
What is the primary role of the hormone-receptor complex that activates the membrane protein G protein?
Activating adenylyl cyclase
What is the function of phosphodiesterase in the hormone signaling pathway?
Deactivates cAMP
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
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
What is the term for the effect when one hormone opposes the actions of another hormone?
Antagonistic effect
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
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
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
What is the primary cause of gigantism?
Excessive growth hormone in childhood
Which physical characteristics are commonly associated with gigantism?
Large hands and feet, prominent jaw, and forehead
What is the usual nature of the pituitary gland condition in gigantism?
Adenoma, a tumour
Which of the following symptoms is commonly associated with acromegaly?
Swollen hands and feet
What is a common consequence of acromegaly on hands?
Numbness due to compressed nerves
Which facial features are typically affected by acromegaly?
Larger brow, nose, and lower jaw
Which symptom of Addison’s Disease is a result of the lack of aldosterone?
Frequent urination
What is the primary cause of cortisol underproduction in Addison’s Disease?
Autoimmune destruction of adrenal gland
Which hormone stimulates the production of melanin by melanocytes in Addison’s Disease?
ACTH
Which region of the hypothalamus initiates hunger and thirst?
Tuberal region
Which section of the hypothalamus controls vasoconstriction of skin blood vessels and inhibition of sweating?
Posterior hypothalamus - preoptic especially
What supplies blood to the hypothalamus through the primary plexus of the hypophyseal portal system?
Superior hypophyseal arteries
Which artery supplies the posterior pituitary gland?
Inferior hypophyseal artery
What is the primary mode of connection between the pituitary gland and the hypothalamus?
Nerve fibers
Which bone is located superior to the pituitary gland?
Sphenoid bone
Which hormone is primarily responsible for stimulating the production of melanin by melanocytes?
Melanocyte stimulating hormone (MSH)
Which hormone is associated with the regulation of lactation?
Prolactin (PRL)
Which cell type in the anterior pituitary is responsible for the secretion of adrenocorticotropic hormone (ACTH)?
Corticotrophs
Which hormone is primarily responsible for stimulating the production of melanin by melanocytes?
Adrenocorticotropic hormone (ACTH)
Which region of the hypothalamus initiates hunger and thirst?
Arcuate nucleus
Which hormone is synthesized and secreted by gonadotrophs?
Follicle stimulating hormone (FSH)
What hormone is released by somatotrophs?
Growth hormone (GH)
Which hormone is released by thyrotrophs?
Thyroid stimulating hormone (TSH)
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
Which hormone stimulates the secretion of gastric acid by the parietal cells of the stomach and aids in gastric motility?
Gastrin
What is the primary function of the pancreas's exocrine system?
Producing enzymes involved in hydrolysing proteins, fats, and carbs
Where are the parathyroid glands located?
On the posterior thyroid gland
Which hormone induces smooth muscle relaxation in the stomach and gallbladder?
Vasoactive Intestinal Peptide
What is the primary function of the hormone glucagon?
Stimulating glycogen breakdown and release of glucose into the bloodstream
Which hormone is primarily responsible for stimulating the production of melanin by melanocytes?
Melanocyte stimulating hormone (MSH)
What is the primary function of the adrenal cortex?
Secretion of aldosterone, cortisol, and androgens
Where do the Adrenal Glands lie?
On the upper poles of the kidneys
What is the developmental origin of the Thyroid Gland?
Begins as a dorsal endodermal thickening
What is the consequence of a patent thyroglossal duct?
Formation of a thyroglossal cyst
What is the foetal remnant found at the posterior tongue?
Foramen caecum
What does the medulla of the adrenal gland produce?
Adrenaline and noradrenaline
What happens if the thyroglossal duct closes up incompletely?
Formation of a thyroglossal cyst
Which hormone condition would lead to down regulation?
Excess hormone
What is the primary origin of the anterior pituitary?
Ectoderm of Rathke’s pouch
Which hormone is responsible for the majority of the growth promoting effects of growth hormone (GH)?
Insulin-like growth factor (IGF-I)
Which cells secrete a hormone in response to the releasing hormone in the anterior pituitary gland?
Thyrotrophs
What is the primary origin of the posterior pituitary?
Neural ectoderm from the floor of the diencephalon
Which hormone is secreted from the liver and other tissues in response to GH, mediating indirect effects?
Insulin-like growth factor (IGF-I)
What is the primary source of the majority of the growth promoting effects of GH?
Target cells
Which cells in the anterior pituitary gland are responsible for secreting a hormone in response to the releasing hormone?
Somatotrophs
What is the primary function of the hormone IGF-I?
Stimulating triglyceride breakdown
Which cells in the anterior pituitary gland are responsible for secreting a hormone in response to the releasing hormone?
Corticotrophs
Which hormone stimulates osteoblasts at the epiphyseal plate and increases uptake of amino acids for protein synthesis?
IGF-1
What stimulates the hypothalamus to secrete corticotropin-releasing hormone (CRH)?
Low glucose levels
What inhibits the production of Growth Hormone (GH)?
Growth Hormone Inhibiting Hormone (GHIH)
Which hormone is secreted in response to the releasing hormone in the anterior pituitary gland?
Adrenocorticotropic hormone (ACTH)
Which hormone is primarily responsible for the majority of the growth promoting effects of Growth Hormone (GH)?
Insulin-like Growth Factor 1 (IGF-1)
What stimulates the hypothalamus to secrete Growth Hormone Releasing Hormone (GHRH)?
Presence of testosterone and oestrogen
What stimulates the production of TRH in the hypothalamus?
Low levels of T3 and T4
What is the primary function of cortisol?
Increases glucose production
What is the primary effect of TSH on the thyroid gland?
Production of T3 and T4
What stimulates gonadotrophs in the anterior pituitary to secrete LH and FSH?
GnRH
Which hormone stimulates ovulation and the formation of the corpus luteum in females?
LH
What hormone stimulates sperm production in males?
FSH
What hormone is secreted by the hypothalamus just before menstruation to stimulate lactotrophs in the anterior pituitary gland?
PRH
What hormone diminishes just before menstruation, leading to the secretion of prolactin?
Dopamine
What stimulates the production of Melanocyte-Stimulating Hormone (MSF) in the skin in response to UV light?
MSF-releasing factor (MRF) from the hypothalamus
Which cells in the hypothalamus are responsible for synthesizing oxytocin and ADH into vesicles?
Paraventricular and supraoptic nuclei
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
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
Where do hormones pass into before reaching their target organs?
Capillary plexus of the infundibular vein
What stimulates the release of oxytocin during delivery of a baby?
Cervical stretching
What is the primary stimulus for the release of ADH (Vasopressin)?
High blood osmolarity
What is the primary effect of ADH binding to cells lining the DCT and the collecting duct?
Activation of adenylyl cyclase
What is the additional effect of ADH besides promoting water reabsorption?
Vasoconstriction
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.
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