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84 Cards in this Set
- Front
- Back
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The Hypothalamus regulates (6)
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Regulates
1) food intake and maintains blood glucose levels 2) sleep-wake cycles and other biological rhythms 3) body temperature (Thermoregulation) 4) blood pressure 5) water intake 6) water balance (Extracellular fluid osmolarity) |
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What connects the hypothalamus and posterior pituitary?
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a thin stalk called the infundibulum
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what is neurohypophysis?
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posterior pituitary
Neuro (Greek neuron, nerve or sinew) Hypophysis (an under growth) = Pituitary |
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what is adenohypophysis?
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anterior pituitary
Adeno (Greek aden, gland) Hypophysis (an under growth) = Pituitary |
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The pituitary develops from?
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The pituitary develops from both the roof of the mouth (stomodeum) and the floor of the brain
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The Adenohypothesis develops from?
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The Adenohypothesis (anterior pituitary) develops as an upgrowth (Rathke’s pouch) from the roof of the primitive mouth (stomodeum)
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what type of hormones are created in the hypothalamus?
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all are peptide hormones, except for dopamine (catecholamine)
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what are the 6 hormones released by the anterior pituitary?
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1) Growth hormone (GH)
2)Thyroid-stimulating hormone (TSH) 3)Adrenocorticotropic hormone (ACTH) 4) Luteinizing hormone (LH) 5) Follicle-stimulating hormone (FSH) 6) Prolactin (PRL) |
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what hormone contains the sequence for Melanocyte-stimulating hormone (α-MSH)
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ATCH
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What class do the Anterior pituitary pituitary hormones belong to?
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All are peptide hormones
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what are the 5 cell types that produce anterior pituitary hormones?
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1)soma-totrophs
2)thyro-trophs 3)cortico-trophs 4)gonado-trophs 5)mammo-trophs |
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where are anterior pituitary hormones released?
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Anterior Pituitary Hormones are released into the systemic circulation (blood) and travel to distant target tissues
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what are tropic hormones?
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stimulate the growth and activity of their target tissue
anterior pituitary hormones are tropic |
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what induces feed back inhibition of anterior pituitary hormones?
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anterior pituitary hormones are tropic and stimulate the growth and activity of their target tissue.
The target gland usually produces a hormone that causes feedback inhibition of the anterior pituitary hormone |
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_____ neurons send their axons down the _____ to the posterior pituitary where they release their hormone
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"Magnocellular" neurons send their axons down the "infundibulum" to the posterior pituitary where they release their hormone
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where are Magnocellular neurons located?
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Magnocellular Neurons in in the PVN & SON of the hypothalamus
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The posterior pituitary secretes vasopressin(ADH) and oxytocin into the ____
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system blood stream
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what happens in the RER of PVN & SON of Magnocellular Neurons in in the of the hypothalamus
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protein synthesis of prepropeptides of vasopresin and oxytocin
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how are ADH and Oxytocin traported from the hypothalamus to the posterior pituitary?
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transported by axoplasmic transport down the infundibulum to the posterior pituitary
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Secretion of ADH is stimulated by:
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increased extracellular fluid 1)increased (ECF) osmolarity
2)decreased ECF volume 3)decreased blood pressure (BP) 4) angiotensin II 5) hypoglycemia |
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Secretion of ADH is inhibited by:
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1) Atrial Natriuretic Peptide (ANP)
2) ethanol 3)hyperglycemia? |
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What is the function of vassopressin/ADH?
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maintains fluid osmolarity
ADH increases blood volume and blood pressure regulates Blood and ECF volume (normal range serum osmolarity* ~282-303 mOs/kg) |
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what is the normal range of serum/fluid osmolarity?
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~282-303 mOs/kg
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How is Blood and ECF Volume Regulated?
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ADH
Renin-Angiotensin-Aldosterone (RAAS) Natriuretic Peptides (ANP, BNP, CNP) |
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how does ANP and other Natriuretic Peptides (ANP, BNP, CNP) affect blood pressure and volume?
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decrease blood pressure (vasodilation) and
decrease blood volume (diuresis, decreases Na+, inhibits ADH & aldosterone release) |
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What type of receptors do ADH interact with in the kidney?
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Kidney: V2 receptors
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What type of receptors do ADH interact with in Vascular smooth muscle?
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Vascular smooth muscle: V1 receptors
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The Hormone-receptor complex is usually coupled to effector proteins by what?
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guanosine triphosphate (GTP) binding proteins = G-proteins
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what are effector proteins?
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associated with mechanisms of hormone action and 2nd messengers.
effector proteins are usually enzymes that when activated produce a second messenger which amplifies the original hormonal signal and orchestrates the physiologic actions |
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what are 2 typical effector proteins?
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adenylyl cyclase
phospholipase C |
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How is the secretion of anterior pituitary hormones regulated by the hypothalamus?
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hypothalamic releasing and release-inhibiting hromones that act on anterior pituitary cells are secreted into the hypothalamic-hypophyseal portal blood supply that connects the hypothalamus and AP. AP hormones then may be secreted into the systemic circulation where they can affect their target tissue.
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What are the hypothalamic releasing hormones?
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1) Growth hormone-releasing hormone (GHRH)
2) Thyrotropin-releasing hormone (TRH) 3) Corticotropin-releasing hormone (CRH) 4) Gonadotropin-releasing hormone (GnRH) 5) prolactin-releasing factor (PRF) |
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What are the hypothalamic inhibiting hormones?
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1) Growth hormone-inhibiting hormone (GHIH) (somatostatin)
2) Prolactin-inhibiting hormone (PIH) (dopamine) |
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(somatostatin) is also know as
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Growth hormone-inhibiting hormone (GHIH)
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(dopamine) is also know as
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Prolactin-inhibiting hormone (PIH)
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what does (GHRH) do?
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Growth hormone-releasing hormone (GHRH)
affect: stimulates pituitary cell: stomato-trophs result: release GH |
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what does (TRH) do?
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Thyrotropin-releasing hormone (TRH)
affect: stimulates pituitary cell: thyro-trophs result: release TSH |
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what does (CRH) do?
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Corticotropin-releasing hormone (CRH)
affect: stimulates pituitary cell: cortico-trophs result: release ACTH |
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what does (GnRH) do?
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Gonadotropin-releasing hormone (GnRH)
affect: stimulates pituitary cell: gonado-trophs result: release LH, FSH |
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what does (PRF?) do?
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prolactin-releasing factor (PRF)
affect: stimulates pituitary cell: mammo-trophs result: release prolactin |
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what does PIH do?
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prolacin-inhibiting hormone (PIH)
effect: inhibit anterior pituitary cell type: mammo-troph result: No prolactin release |
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what does GHIH do?
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somatostatin
growth hormone-inhibiting hormone (GHIH) effect: inhibit ant pituitary cell type: somato-troph result: No GH release |
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What are the hypothalamic hormones released by the posterior pituitary?
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vasopressin/ADH
oxytocin |
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what is the target tissue of vasopressin?
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kidney and vascular smooth muscle
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what is SIADH stand for?
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SIADH: Syndrome of Inappropriate ADH Secretion
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what is the cause of SIADH?
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excess ADH
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What is the RAPID physiological response of ADH on the kidney?
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aquaporin 2 (AQP2) inserted into the apical membrane of the distal tubule and collecting duct to increase H20 permeability
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What is the DELAYED physiological response of ADH on the kidney?
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protein kinase A activates CREB transcription factors bind to CRE and increase AQP2 synthesis
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How does ADH effect the osmotic gradient in the kidney?
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renal cortex osmolarity = no change
Renal medulla osmolarity = increased by by increasing urea recycling from the inner medullary collecting ducts. |
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What is Ghrelin?
where is it synth/secreted? what is it's function? |
peptide hormone from the p/D1 cells of stomach
regulates/stimulates appetite and GH secetion? |
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what is the effect of Ghrelin on GH?
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stimulates GH secretion
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The extracellular growth hormone receptor domain ___ upon GH binding and activates.
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dimerizes
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When is the extracellular growth hormone receptor domain considered active?
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when it binds GH and dimerizes
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Apon activation/dimerization of the extracellular growth hormone receptor domain what occurs to the intracellular domain?
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the intracellular domain binds and activates JAK
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What is JAK?
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Janus Family tyrosine kinase
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What does the activated JAK complex phosphorylate?
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STAT transcription factors and kinases that produce phyiological changes in the cell
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What activates STAT
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phosphorylation by the activated JAK complex to form a STAT homodimer
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STAT is a transcription factor for what gene?
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IGF-1 gene
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STAT stands for
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signal transducers and activator of transcription (STAT)
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What are the direct action of GH on metabolism?
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(+) Glycogenolysis
(+) Lipolysis (+) Gluconeogenesis Inhibition of some (-) insulin actions (diabetogenic) |
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What are the indirect action of GH on metabolism?
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Stimulates the production of
insulin-like growth factor 1 (IGF-1) by the liver and other tissues |
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what mediates the growth effects of GH and is it direct or indirect?
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The indirect effect of growth is mediated by IGH.
IGF-1 binds to IGF receptors to stimulate growth |
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what is IGF and where is it produced?
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insulin-like growth factor (IGF) is produced in the liver
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Why is GH difficult to measure clinically?
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GH is not released constantly, but released in pulses (at onset of sleep/night highest)
GH has a short half life |
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Since random blood sampling is not accurate, how can you test for the presence of hormone?
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Endocrine function test to measure the response to a stimulus
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GH secreting tumors/ excess GH before puberty leads to ...
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Giantism
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GH secreting tumors/ excess GH before puberty leads to ...
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Acromegaly
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sometimes you give a patient GH and they dont respond. what does this mean?
How would you treat? |
most likely cause = defective GH receptors which leads to GH insensitivity
treatment= biosynthetic IGF-1 |
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What is often the first symptom of a pituitary tumor?
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visual distrubances due to tumor impinging on the optic nerve
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What can cause feedback inhibition of GH secretion?
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IGF-1
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What stimulates the production of IGF-1?
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GH
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Where is GH produced?
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GH is produced by anterior pituitary somato-trophs
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What hypothalamic hormones control GH?
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GHRH & GHIH (somatostatin)
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GH growth effects are mainly produced by:
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IGF-1 (somatomedin)
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For GH to produce growth (height) what must be present in the long bones?
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epiphyseal growth plate
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GH Hyposecretion during childhood
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pituitary dwarfism (proportional, childlike body)
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GH Hypersecretion during childhood (pre-puberty)
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giantism - very tall, normal proportions
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GH Hypersecretion as adult
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acromegaly - growth of hands, feet, facial features & thickening of skin
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Lack of growth with normal GH and low IGF-1
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Laron dwarfism: GH receptor defect
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What type of hormones are released from the hypothalamus, anterior pituitary, and posterior pituitary?
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hypothalamus and pituitary gland secrete peptide hormones (membrane receptor, g-protein, adenylate cyclase)
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How does the hypothalamus regulate ECF?
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through the release of ADH from the anterior pituitary gland
FLAT PEG |
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What is the function of cAMP response element binding proteins (CREB)?
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Delayed physiological response: synthesis of new AQP2
CREB is activated by protein kinase A to increase Aquaqporin 2 transcription for future insertion into the distal tubule and collecting duct. |
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what is the function of IGF-1 (somatomedin)?
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GH stimulates growth indirectly through the release of IGF-1 (somatomedin). IGF-1 binds to IGF receptors to stimulate growth.
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what is the function and another name for GHIH
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GHIH = somatostatin
somatostain inhibits release of GH from the anterior pituitary somatotrophs |
