Notes in 2. Physiology

To Subscribe, use this Key

Status	Last Update	Fields
Published	02/10/2024	Tissues detect hormones through the presence of specific {{c1::receptors}} for that chemical on/in the cells.
Published	02/10/2024	Endocrine vs Neural vs Neuroendocrine communicationRelease ‒ Travel ‒ Distance of site of action{{c1::Endocrine ‒ hormones released by cell, trav…
Published	02/10/2024	While the response of a target cell to any one hormone is highly specific, the same hormone can have different effects in different target cells.…
Published	02/10/2024	{{c1::Endocrine}} glands are ductless and secrete hormones to the internal environment
Published	02/10/2024	{{c1::Exocrine}} glands have ducts and deliver their secretions to the external environment including GI tracte.g. bile, saliva, sweat
Published	02/10/2024	{{c1::Autocrine}} secretions: cells secrete chemicals that bind to receptors on the same cell e.g. cytokines.
Published	02/10/2024	{{c1::Paracrine}} secretions: chemicals diffuse in ECF to affect neighbouring cells e.g. histamine.
Published	02/10/2024	Structures of the body that have pure endocrine function include:{{c1::thyroid gland}}, {{c1::adrenal gland}}, {{c1::pituitary gland}}, {{c1::hypothal…
Published	02/10/2024	Endocrine hormones have their action terminated, often via {{c1::negative}} feedback loops
Published	02/10/2024	Endocrine hormones are often released in short bursts, meaning {{c1::24 hr}} monitoring is clinically required to get a realistic picture
Published	02/10/2024	Classification of endocrine hormones: [1] {{c1::Peptide/protein}} hormones  [2] {{c1::Amine}} hormones  [3] {{c1::Steroid}} hormones&nbsp…
Published	02/10/2024	Peptide/Protein hormones are composed of {{c1::chains of amino acids}}
Published	02/10/2024	All Amine hormones are derived from {{c1::tyrosine}} except Melatonin which is dervied from {{c1::tryptophan}}
Published	02/10/2024	All Steroid hormones are derived from {{c1::cholesterol}}
Published	02/10/2024	Peptide Hormones are synthesised as {{c1::preprohormones}} in advance of need then are cleaved into {{c1::prohormones}} and stored in vesicles un…
Published	02/10/2024	{{c1::C-peptide}} is the inactive fragment cleaved from the {{c2::insulin prohormone}}.
Published	02/10/2024	Levels of {{c1::C-peptide}} in plasma or urine are often measured to indicate endogenous insulin production from the pancreas (produced in equal amoun…
Published	02/10/2024	Peptide hormones are {{c1::water}} soluble, which also means that they cannot cross the cell membrane.
Published	02/10/2024	Most peptide hormones target either {{c1::G-PCR}} or {{c1::tyrosine kinase linked}} receptors on the cell membrane
Published	02/10/2024	GPCR and Tyrosine kinase linked receptors are pathways that {{c1::phosphorylate}} existing proteins in the cell and modify their functione.g. open or …
Published	02/10/2024	GPC receptor has a {{c1::rapid}} response compared to Tyrosine Kinase Linked receptor which has a {{c1::slower, longer lasting}} response
Published	02/10/2024	Hydrophilic Amine Hormones (Catecholamines) include {{c1::dopamine}}, {{c1::norepinephrine}}, and {{c1::epinephrine}}
Published	02/10/2024	Lipophilic Amine Hormones (Thyroid hormones) include {{c1::thyroxine}} and {{c1::triiodothyronine}}
Published	02/10/2024	Unlike the other types of hormones, {{c1::steroid}} hormones are synthesized directly as needed, rather than being stored and released.
Published	02/10/2024	Steroid hormones being poorly soluble in water they are transported bound to carrier proteins such as {{c1::albumin}}. → stabilises their transport th…
Published	02/10/2024	Which steroid hormone is produced by the Gonads?{{c1::sex steroids}}
Published	02/10/2024	Which steroid hormone is produced by the Placenta?{{c1::hCG}} and {{c1::sex steroids}}
Published	02/10/2024	Which steroid hormone is produced by the Kidneys?{{c1::Vitamin D3}}
Published	02/10/2024	Which steroid hormone is produced by the Adrenal Cortex?{{c1::Corticosteroids}}
Published	02/10/2024	Activation of the intracellular receptors by steroid hormones leads to a change in {{c1::gene expression}} at the level of the nucleus, which affects …
Published	02/10/2024	There is a small amount of {{c1::unbound-free}} steroid/thyroid hormone in the plasma compared to {{c1::bound-complexed}} steroid/thyroid ho…
Published	02/10/2024	The Law of Mass Action dictates that as {{c1::free hormone leaves the plasma (taken up by cells) more hormone is released from the carriers.}}
Published	02/10/2024	Which hormone is physiologically active in the body, free or complexed?{{c1::free hormone}}
Published	02/10/2024	Why are lipophilic (Amine Thyroid, Steroid) hormones bound to carrier proteins in plasma?[1] {{c1::Increase in solubility which required for transport…
Published	02/10/2024	Peptide and Catecholamine hormones vs Steroid and Thyroid hormonesSolubility ‒ Transport ‒ Half life ‒ Action Duration{{c1::1. Peptide and catech…
Published	02/10/2024	In most endocrine pathways, secretion is responsive to {{c1::negative}} feedback reflexes e.g. parathyroid hormone
Published	02/10/2024	Neuroendocrine pathways also respond to {{c1::neural}} feedback loops e.g. release of adrenaline via activation of sympathetic system
Published	02/10/2024	The {{c1::hypothalamus}} and {{c1::pituitary}} are the principal organisers of the endocrine system.
Published	02/10/2024	As the hypothalamus is made up of neural tissue any chemicals released into the blood from it must be {{c1::neurohormones}}.
Published	02/10/2024	The hypothalamus is connected to the pituitary gland via a {{c1::stalk/infundibulum}}
Published	02/10/2024	The hypothalamus is connected to the {{c2::posterior}} pituitary via {{c1::hypothalamic axons and nerve terminals}}
Published	02/10/2024	The hypothalamus is connected to the {{c2::anterior}} pituitary via {{c1::hypothalamic-hypophyseal portal system}}
Published	02/10/2024	The anterior pituitary gland is an {{c1::endocrine}} tissue with {{c1::epithelial}} origin, also known as adenohypophysis
Published	02/10/2024	The posterior pituitary gland is a {{c1::neuroendocrine}} tissue with {{c1::neural}} origin,also known as neurohypophysis
Published	02/10/2024	The posterior pituitary makes up {{c1::1/3}} of the gland while the anterior pituitary makes up {{c1::2/3}} of it
Published	02/10/2024	{{c1::Tropic hormones}} are hormones that govern the release of another hormone
Published	02/10/2024	All hormones released by the {{c1::hypothalamus}} and {{c1::posterior pituitary}} are {{c2::neurohormones}}
Published	02/10/2024	All hormones released by the {{c1::anterior}} pituitary are {{c2::endocrine hormones}}
Published	02/10/2024	Two forms of hypothalamic neurohormones: {{c1::non-tropic}} and {{c1::tropic}}
Published	02/10/2024	Non-tropic hypothalamic neurohormones are {{c1::neurohormones produced in the hypothalamus and travel to posterior pituitary (via axons of hypoth…
Published	02/10/2024	Tropic hypothalamic neurohormones are {{c1::neurohormones secreted into capillaries travelling to anterior pituitary to govern the release of its…
Published	02/10/2024	{{c1::Posterior}} pituitary contains {{c2::magnocellular}} neurons which have their cell bodies in the hypothalamus
Published	02/10/2024	Magnocellular neurons store and release two peptide neurohormones:[1] {{c1::Vasopressin/ADH}} = maintains water balance[2] {{c1::Oxytocin}} = stimulat…
Published	02/10/2024	Oxytocin and Vasopressin behave as typical {{c1::peptide}} hormonesi.e. synthesis and storage in vesicles, cell surface receptors etc
Published	02/10/2024	All hypothalamic neurohormones acting on anterior pituitary cells are {{c1::tropic}} hormonesi.e. stimulate/inhibit release of AP hormones
Published	02/10/2024	There are at least 5 hypothalamic “releasing hormones” – {{c1::Thyrotropin Releasing Hormone (TRH)}} – {{c1::Corticotropin Releasing Hormone (CRH)}} –…
Published	02/10/2024	There are 2 hypothalamic “inhibiting hormones” – {{c1::Growth Hormone Inhibiting Hormone (GHIH) aka somatostatin}} – {{c1::Dopamine aka Prolactin Inhi…
Published	02/10/2024	All hypothalamic neurohormones are peptides except {{c1::Dopamine aka Prolactin Inhibiting Hormone (PIH)}}
Published	02/10/2024	Hypothalamo-hypophyseal portal system is a {{c1::network of tiny vessels which transfer tropic hormones from hypothalamus to anterior pituitary}}two c…
Published	02/10/2024	The production of anterior pituitary hormones is controlled by the hypothalamic {{c1::“releasing” or “inhibiting” tropic}} hormonese.g. Thyrotrop…
Published	02/10/2024	6 hormones are released from the anterior pituitary gland, all are {{c1::peptides}}.
Published	02/10/2024	The anterior pituitary hormones are:1. {{c1::Thyroid Stimulating Hormone (TSH) aka thyrotropin}}2. {{c1::Adrenocorticotropic Hormone (ACTH) aka cortic…
Published	02/10/2024	All the anterior pituitary hormones are tropic and trophic hormones except {{c1::prolactin}}Tropic = control secretion of other endocrine glandsT…
Published	02/10/2024	Anterior pituitary feedback control is a complex, multi-tiered pathway involving up to 3 integration centres:1) {{c1::hypothalamus}} 2) {{c1::anterior…
Published	02/10/2024	In the Anterior pituitary feedback control each hormone feeds back to {{c1::inhibit}} hormone secretion by integrating centres earlier in the ref…
Published	02/10/2024	Feedback coming from the endocrine target to the hypothalamus is known as a {{c1::long}}-loop feedback
Published	02/10/2024	Feedback coming from the anterior pituitary to hypothalamus is known as a {{c1::short}}-loop feedback
Published	02/10/2024	In the Anterior pituitary feedback control, hormones themselves act as {{c1::negative}} feedback signal
Published	02/10/2024	{{c1::hyposecretion}}: too little hormone secreted
Published	02/10/2024	{{c1::hypersecretion}}: too much hormone secreted
Published	02/10/2024	Primary endocrine disorders are those in which the defect is in {{c1::the cells that secrete the hormone}}
Published	02/10/2024	Secondary endocrine disorders are those in which the defect is in {{c1::too little or too much tropic hormone from pituitary}}
Published	02/10/2024	Tertiary endocrine disorders are those in which the defect is in {{c1::the hypothalamus}}
Published	02/10/2024	{{c1::Hyporesponsiveness}} is a disorder that occurs due to alterations in receptor for hormone, disordered post-receptor events, failure of metabolic…
Published	02/10/2024	{{c1::Hyperresponsiveness}} is an endocrine disorder that occurs due to permissive effects, one hormone enhances the activity of another hormone.&nbsp…
Published	02/10/2024	Prolonged exposure to {{c1::low}} [hormone] in plasma often leads to {{c2::up-regulation}} of receptor number(increases tissue sensitivity/response to…
Published	02/10/2024	Prolonged exposure to {{c1::high}} [hormone] in plasma often leads to {{c2::down-regulation}} of receptor number(decreases tissue sensitivity/response…
Published	02/10/2024	A {{c1::Permissive}} effect is when the presence of one hormone enhances the effect of another. Give an example if possible.
Published	02/10/2024	An {{c1::Antagonistic}} effect is when the presence of one hormone reduces the effect of another. Give an example if possible.
Published	02/10/2024	Energy intake is determined by the balance of activity in two hypothalamic centres:• {{c1::Feeding}} Centre - promotes feelings of hunger and dri…
Published	02/10/2024	Glucostatic theory – food intake is determined by {{c1::blood glucose}}: as {{c1::[BG]}} increases, the drive to eat decreases (- Feeding Centre;&nbsp…
Published	02/10/2024	Lipostatic theory – food intake is determined by {{c1::fat stores}}: as {{c1::fat stores}} increase, the drive to eat decreases (- feeding centre; + S…
Published	02/10/2024	{{c1::Leptin}} is a peptide hormone released by fat stores which depresses feeding activity.
Published	02/10/2024	3 categories of energy output:• {{c1::Cellular work}} – transporting molecules across membranes; growth and repair; storage of energy (eg. fat, g…
Published	02/10/2024	{{c1::Anabolic}} pathways = Build Up. Net effect is synthesis of large molecules from smaller ones, usually for storage purposes.
Published	02/10/2024	{{c1::Catabolic}} pathways =  Break Down. Net effect is degradation of large molecules into smaller ones, releasing energy for work.
Published	02/10/2024	After eating we enter an Absorptive State where ingested nutrients supply the energy needs of the body and excess is stored. This is an {{c1::anabolic…
Published	02/10/2024	Between meals and overnight the pool of nutrients in the plasma decreases and we enter a Post-absorptive State (aka Fasted State) where we r…
Published	02/10/2024	Most cells can use fats, carbohydrates or protein for energy but the brain can only use {{c1::glucose}}
Published	02/10/2024	How is BG maintained in the post-absorptive state to avoid hypoglycaemia?BG is maintained by synthesising glucose from {{c1::glycogen (glycogenol…
Published	02/10/2024	Normal range of [BG] = {{c1::4.2-6.3mM (80-120mg/dl)}}
Published	02/10/2024	Hypoglycaemia =  [BG] {{c1::< 3mM}}
Published	02/10/2024	BG is maintained by two key endocrine hormones produced in the pancreas: {{c1::Insulin}} and {{c1::Glucagon}}
Published	02/10/2024	{{c2::Glycogenolysis}} and {{c2::Gluconeogenesis}} are metabolic processes done to raise [BG] maintained by the hormone {{c1::glucagon}}
Published	02/10/2024	{{c2::Glycogenesis}}, {{c2::Lipogenesis}} and uptake of {{c2::glucose}} are metabolic processes done to lower [BG] maintained by the hormone {{c1…
Published	02/10/2024	When insulin is not present (T1DM) or the body is unresponsive to it (T2DM), {{c1::muscle}} and {{c1::adipose}} tissue can't take …
Published	02/10/2024	99% of the pancreas operates as an {{c1::exocrine}} gland releasing enzymes and NaHCO3 via ducts into the alimentary canal to support digestion.
Published	02/10/2024	Only 1% of the pancreas has {{c1::endocrine}} function. Its hormones are produced in the {{c1::Islets of Langerhans}}.
Published	02/10/2024	The four types of Islet of Langerhans cells are {{c1::alpha}}, {{c1::beta}}, {{c1::delta}} & {{c1::F}} cells
Published	02/10/2024	{{c2::Alpha}} cells in Islet of Langerhans produce {{c1::glucagon}}
Published	02/10/2024	{{c2::Beta}} cells in Islet of Langerhans produce {{c1::insulin}}
Published	02/10/2024	{{c2::Delta}} cells in Islet of Langerhans produce {{c1::somatostatin}}
Published	02/10/2024	{{c2::F}} cells in Islet of Langerhans produce {{c1::pancreatic polypeptide}}
Published	02/10/2024	In a fed state, insulin dominates and [BG] decreases due to an increase in processes of {{c1::glucose oxidation}}, {{c1::glycogen synthesis}}, {{c1::f…
Published	02/10/2024	In a fasted state, glucagon dominates and [BG] increases due to an increase in processes of {{c1::glycogenolysis}}, {{c1::gluconeogenes…
Published	02/10/2024	{{c1::Insulin}} is a peptide hormone produced by pancreatic beta cells, stimulates glucose uptake by cells.
Published	02/10/2024	Insulin is synthesized as a large preprohormone, {{c1::preproinsulin}}, which is then converted to {{c1::proinsulin}} in the endoplasmic reticulum and…
Published	02/10/2024	Any excess glucose is stored as {{c1::glycogen}} in liver and muscle, and as {{c1::triacylglycerols (TAG)}} in liver and adipose tissue
Published	02/10/2024	Beta-cells have a specific type of {{c1::K+}} ion channel that is sensitive to the [{{c1::ATP}}] within the cell
Published	02/10/2024	Control of insulin secretion by [BG]When [BG] ↑ = {{c1::goes into cell and metabolism ↑}} = {{c1::[ATP] ↑ closing KATP channels}} = {{c1::in…
Published	02/10/2024	Control of insulin secretion by [BG]When [BG] ↓ = {{c1::[ATP] ↓ KATP channels are open}} = {{c1::extracellular [K+] ↑ hyperpolarizing t…
Published	02/10/2024	Primary action of insulin is binding to {{c1::tyrosine kinase}} receptors on the cell membrane of insulin-dependent tissues to increase glucose uptake…
Published	02/10/2024	In muscle and adipose tissue, insulin stimulates the mobilization of specific glucose transporters, {{c1::GLUT-4}}, which reside in the cytoplasm of t…
Published	02/10/2024	Most types of tissue do NOT require insulin to take up glucose, ONLY {{c1::muscle}} and {{c1::adipose}} tissue are insulin dependent.
Published	02/10/2024	In normality, muscle and adipose tissue make up around {{c1::60}}% of the body→ very large proportion of the body is dependent on insulin for its gluc…
Published	02/10/2024	In other tissues, glucose uptake is via other GLUT-transporters, which are insulin-independent.GLUT-{{c1::1}} → basal glucose uptake in many tissues e…
Published	02/10/2024	Liver takes up glucose by GLUT-{{c1::2}} transporters, which are insulin independent, by going down a concentration gradient
Published	02/10/2024	Although insulin has no direct effect on the liver, glucose transport into hepatocytes is affected by insulin {{c1::status}}
Published	02/10/2024	Insulin status and the Liver ‒ in a fed stateThe liver takes up glucose because insulin activates {{c1::hexokinase}} which lowers [glucose]ic creating…
Published	02/10/2024	Insulin status and the Liver ‒ in a fasted stateThe liver synthesises glucose via {{c1::glycogenolysis}} and {{c1::gluconeogenesis}}, increasing …
Published	02/10/2024	Some anabolic processes associated with insulina) Increases glycogen synthesis in muscle and liver by stimulating {{c1::glycogen synthase}} and inhibi…
Published	02/10/2024	Insulin has a permissive effect on which hormone?{{c1::Growth Hormone}}
Published	02/10/2024	Insulin promotes K+ ion entry into cells by stimulating {{c1::Na+/K+ ATPase}}.
Published	02/10/2024	Insulin has a half-life of {{c1::5}} minutes and is degraded principally in the liver and kidneys.
Published	02/10/2024	Once insulin action is complete insulin-bound receptors are internalised by {{c1::endocytosis}} and destroyed by insulin {{c1::protease}}, some recycl…
Published	02/10/2024	Stimuli which increase insulin release1. Increased {{c1::[BG]}} 2. Increased {{c1::[amino acids]plasma}} 3. {{c1::Glucagon (insulin required to take u…
Published	02/10/2024	Stimuli that inhibit insulin release 1. Decreased {{c1::[BG]}} 2. {{c1::Somatostatin (GHIH)}} 3. {{c1::Sympathetic alpha-2}} effects 4…
Published	02/10/2024	Intravenous glucose increases insulin by {{c1::direct effect of increased glucose on beta cells.}}
Published	02/10/2024	Oral glucose increases insulin by both {{c1::direct effect of increased glucose on beta cells}} and {{c1::vagal stimulation of beta cells including in…
Published	02/10/2024	{{c1::Glucagon}} is a peptide hormone produced by alpha cells of the pancreatic islets, it raises blood glucose by acting on the liver.
Published	02/10/2024	Glucagon has a half-life of {{c1::5-10}} minutes and is degraded principally in the liver.
Published	02/10/2024	The hormones involved in the glucose counter-regulatory control system include {{c1::glucagon}}, {{c1::epinephrine}}, {{c1::cortisol}},…
Published	02/10/2024	Glucagon is most active in the {{c1::post-absorptive/fasted}} state, where we rely on body stores to provide energy.
Published	02/10/2024	Glucagon receptors are {{c1::G-protein coupled}} receptors linked to the {{c1::adenylate cyclase/cAMP}} system that phosphorylates specific liver enzy…
Published	02/10/2024	Fasted-state metabolism must maintain energy for the brain which can use only {{c1::glucose}} and {{c1::ketones}}.
Published	02/10/2024	Amino acids in the plasma stimulate release of both {{c1::insulin}} and {{c1::glucagon}} hormones
Published	02/10/2024	Changes in [BG] have {{c1::opposite}} effects on insulin and glucagon
Published	02/10/2024	Stimuli that promote glucagon release1. Decreased {{c1::[BG] (<5mM)}} 2. Increased {{c1::[amino acids]}} 3. {{c1::Sympathetic b2 effect}}…
Published	02/10/2024	Stimuli that inhibit glucagon release1. {{c1::glucose}} 2. {{c1::free fatty acids (FFA) and ketones}} 3. {{c1::insulin (fails in diabetes …
Published	02/10/2024	Autonomic innervation of islet cellsParasympathetic (vagal) activity increases insulin and to a lesser extent glucagon,in anticipation of {{c1::…
Published	02/10/2024	Autonomic innervation of islet cellsSympathetic activity promotes glucose mobilization by increasing glucagon, epinephrine and inhibiting insulin…
Published	02/10/2024	{{c1::Somatostatin}} is a peptide hormone, secreted by D-cells of the pancreas (and hypothalamus aka {{c1::GHIH}}).
Published	02/10/2024	Main pancreatic action of Somatostatin is to inhibit activity in the GI Tract by {{c1::slowing down absorption of nutrients}} to prevent exaggera…
Published	02/10/2024	Somatostatin inhibits the secretion of {{c1::GH}} from the anterior pituitary
Published	02/10/2024	Somatostatin strongly suppresses the release of both hormones {{c1::insulin}} and {{c1::glucagon}} in a paracrine fashion
Published	02/10/2024	The entry of glucose into skeletal muscle is increased during exercise, even in the absence of {{c1::insulin}} via an insulin-independent increas…
Published	02/10/2024	In non-active muscle, insulin binds to its receptor, which then leads to glucose transporters, GLUT-{{c1::4}}, migrating to the cell membrane, allowin…
Published	02/10/2024	In active muscle i.e. during exercise, GLUT-4 transporters can migrate to the membrane without insulin being present, so exercise causes glucose uptak…
Published	02/10/2024	After a period of starvation, the brain adapts to be able to use {{c1::ketone bodies}}.
Published	02/10/2024	The usage of ketone bodies as an energy source by the brain and muscles serves to spare {{c1::protein}} which would be broken down to provide gluconeo…
Published	02/10/2024	Ketone body uptake is not possible without the presence of a functional pancreas because this process is {{c1::insulin dependent}}
Published	02/10/2024	Type 1 Diabetes/Insulin Dependent Diabetes Mellitus (IDDM) involves an {{c1::autoimmune destruction of the pancreatic b-cells ability to produce …
Published	02/10/2024	Type I diabetic patients have an absolute need for insulin, without it they become excessively wasted, develop {{c1::ketoacidosis}}, coma and die.
Published	02/10/2024	Diabetic Ketoacidosis occurs because of {{c1::a lack of insulin in the body. The lack of insulin and corresponding elevation of glucagon leads to incr…
Published	02/10/2024	Type 2 Diabetes/Non-Insulin Dependent Diabetes Mellitus (NIDDM) involves {{c1::tissues becoming insensitive and resistant to insulin, muscle and …
Published	02/10/2024	{{c1::Hyperglycaemia}} is the diagnostic criterion for diabetes, detected by performing a “{{c1::Glucose Tolerance Test}}”
Published	02/10/2024	In humans there are 2 periods of rapid growth: 1. {{c1::Infancy}}: Growth in the foetal period and the first 8-10 months of life is largely contr…
Published	02/10/2024	In normal puberty, before the epiphyseal plates fuse, {{c1::GH}} and {{c1::IGF-I}} promote bone elongation and increased height, weight and body mass.…
Published	02/10/2024	{{c1::Sex}} hormones in the later stages of puberty act to close the epiphyses and hence stop bone elongation.
Published	02/10/2024	Hormones involved in the physiology of growth are:{{c1::Growth hormones}}, {{c1::IGF-1}}, {{c1::thyroid hormones}}, {{c1::sex steroids}}, {{c1::glucoc…
Published	02/10/2024	Sex hormones influence is minor until {{c1::puberty}} when they dominate the growth spurt.
Published	02/10/2024	GH influence is minor during foetal life. Babies born {{c1::deficient}} in GH and IGF-1 are of normal size.
Published	02/10/2024	Thyroid hormones, insulin and IGF-II dominate {{c1::intra-uterine}} growth.
Published	02/10/2024	{{c1::Thyroid}} hormones are essential for normal growth, particularly important for development  of the nervous system in utero and early childh…
Published	02/10/2024	Maternal {{c1::iodine}} deficiency during pregnancy (rare) may result in severely retarded intra-uterine growth.
Published	02/10/2024	{{c1::TH}} have a permissive effect on GH. Loss of permissive effect severely impacts on GH action.
Published	02/10/2024	{{c1::Growth Hormone}} Aka {{c1::somatotropin}} is a peptide hormone released from the anterior pituitary. → Released from somatotroph cells.
Published	02/10/2024	Release of GH is controlled via the release of two hypothalamic neurohormones with opposing action:[1] {{c1::Growth Hormone Inhibiting Hormone (GHIH)}…
Published	02/10/2024	GH is necessary for growth and development of the child. From around {{c1::10}} months of age GH becomes the dominant influence on the rate at which c…
Published	02/10/2024	Growth hormone requires permissive action of {{c1::thyroid hormones}} and {{c1::insulin}} before it will stimulate growth.
Published	02/10/2024	GH promotes an increase in both cell size ({{c1::hypertrophy}}) and cell division ({{c1::hyperplasia}}) in its target tissues.
Published	02/10/2024	GH acts on {{c1::tyrosine kinase}} receptors which phosphorylates intracellular targets causing two actions:1. Growth of {{c2::long bones}} (indirect …
Published	02/10/2024	The effect of GH on skeletal growth is almost entirely indirect, being achieved through {{c1::insulin-like growth factor-I (IGF-1)}} aka {{c1::somatom…
Published	02/10/2024	IGF-I is secreted primarily by the liver in response to GH release, and it controls GH release through a {{c1::negative}} feedback loop.
Published	02/10/2024	GH and IGF-I are peptide hormones, but like steroid and thyroid hormones,they are transported in the blood bound to {{c1::carrier}} proteins
Published	02/10/2024	IGF exhibits negative feedback on GH release both via inhibiting {{c1::GHRH}} and stimulating {{c1::GHIH (somatostatin)}}.
Published	02/10/2024	{{c1::Hyper}}glycaemic properties of GH dominate the {{c1::hypo}}glycaemic action of IGF-I
Published	02/10/2024	Epiphyseal plates close during adolescence under the influence of {{c1::sex steroid}} hormones then no further longitudinal growth is possible.
Published	02/10/2024	As GH levels increase it has an {{c1::autocrine}}, {{c1::inhibitory}} effect on the release of itself from somatotrophs in pituitary
Published	02/10/2024	GH regulates metabolism via:1. Increasing {{c1::gluconeogenesis}} by the liver. 2. Reducing the ability of {{c1::insulin}} to stimulate glucose u…
Published	02/10/2024	Cortisol stimulates protein {{c1::catabolism}} unlike Growth hormone which promotes protein {{c1::anabolism}} by increasing amino acid uptake and prot…
Published	02/10/2024	Growth hormone is {{c1::diabetogenic}} when present in excess because it has an anti-{{c1::insulin}} effect by increasing blood glucose
Published	02/10/2024	Even though growth hormone is anti-insulin it still promotes muscle growth by increasing {{c1::amino acid}} uptake and {{c1::protein}} synthesis
Published	02/10/2024	Majority of GH is released during first 2 hours of sleep ({{c1::deep delta}} stage of sleep)
Published	02/10/2024	Plasma levels of IGF-1 remain relatively constant because it binds much more tightly to carrier proteins than GH so is less vulnerable to {{c1::degrad…
Published	02/10/2024	Stimuli that increase GHRH secretion (and therefore increases GH):[1] Actual or potential {{c1::decrease}} in energy supply to cells[2] Increased {{c…
Published	02/10/2024	Stimuli that increase GHIH/Somatostatin secretion (and therefore decreases GH):[1] {{c1::Glucose}} [2] {{c1::FFA}} [3] {{c1::Ageing}} [4] {{c1::Corti…
Published	02/10/2024	{{c1::Gigantism}} is a GH hypersecretion disorder due to a pituitary tumour before epiphyseal plates of long bones close → excessive growth, may …
Published	02/10/2024	{{c1::Acromegaly}} is a GH hypersecretion disorder due to a pituitary tumour after epiphyseal plates have sealed→ Long bones cannot increase…
Published	02/10/2024	Unsually small stature that is {{c2::hypothalamic}} in origin occurs due to a deficiency in {{c1::GHRH}}
Published	02/10/2024	Unsually small stature that is {{c2::pituitary}} in origin occurs due to a deficiency in {{c1::GH}}
Published	02/10/2024	Loss of {{c1::IGF-1}} inhibition of GH is responsible for increased [GH] (remember negative feedback loop!)
Published	02/10/2024	Excess {{c1::GHRH}} release in children may cause early puberty and stunted growth because long bones fuse early under influence of sex horm…
Published	02/10/2024	Hypothyroid dwarfism occurs due to loss of permissive effect of {{c1::thyroid}} hormone on {{c1::growth}} hormone
Published	02/10/2024	Gestational diabetes can lead to very big babies through excess {{c1::anabolism}} by foetal insulin
Published	02/10/2024	The thyroid gland synthesises the Thyroid Hormones of which there are two physiologically active forms: {{c1::T3 (triiodothyronine)}} and {{…
Published	02/10/2024	The thyroid gland contains two cell types:1. {{c1::C (clear)}} cells which secrete {{c2::calcitonin (Ca2+ regulating hormone)}}. 2. {{c…
Published	02/10/2024	{{c2::Follicular}} cells manufacture the enzymes that make thyroid hormones as well as {{c1::thyroglobulin}}, a large protein rich in tyrosine re…
Published	02/10/2024	Both {{c1::tyrosine}} and {{c1::iodide}}, which are essential to make thyroid hormones, are derived from our diet.
Published	02/10/2024	Iodide enters the follicular cells from the plasma via a {{c1::Na+/I-}} transporter (symport). This coupling enables the cells to take up iodide …
Status	Last Update	Fields