dwarfism & GH
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The hypothalamus regulates homeostasis and the connection between the nervous and endocrine systems. It produces hormones that act on the pituitary gland. The pituitary gland, located at the base of the brain, is divided into anterior and posterior lobes. The anterior lobe regulates growth and reproduction through hormones targeted towards various organs. Growth hormone, produced by the anterior pituitary, stimulates growth through direct and indirect effects. It works through the IGF axis and binding proteins to promote growth in children and cause issues if overproduced. Growth hormone deficiency can be diagnosed through tests and treated with growth hormone injections or surgery.
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dwarfism & GH
- 1. Hypothalamus *Region of the brain * Composed of small nuclei *Act As Conduit between nervous &endocrine sys. *Also regulate homeostatic function. ( hunger , thirst & body temp(
- 3. Pituitary gland anatomyPituitary gland anatomy *Is an endocrine gland * Size of a pea * Located at the base of the brain * Rests in a small bony cavity * Is divided into ??? * Connected to hypothalamus by???
- 4. Anterior & posterior lobeAnterior & posterior lobe *The cells of the Ant. Lobe are embryologically derived from an ??? *The Ant. Pituitary regulate many processes (stress, growth & reproduction ( & Are achieved through ?? *The post. Lobe is composed of the endings of nevre cells *These nerve cells produce two hormone???
- 5. Pituitary Hormones and TheirPituitary Hormones and Their TargetsTargets The hormones of the anterior pituitary are synthesized in the cytoplasm of the cells as ???? The hormones of the post pituitary are released into the circulation in response to???? http://wps.aw.com/wps/media/objects/443/454188/st1003.html
- 6. Growth hormoneGrowth hormone Growth hormone is a protein hormone of about 190 amino acids that is synthesized and secreted by cells called somatotrophs in the anterior pituitary It is a major participant in control of several complex physiologic processes, including growth and metabolism.
- 7. Control of SecretionControl of Secretion GHIH (or) SST (somatostatin) (-) Anterior Pituitary: Hypothalamus: GHRH (+) GH (somatotropin) Liver: IGF (somatomedins) (+) (-)
- 8. GROWTH HORMONE direct effectsindirect effects lipolysis in fat cells + carbohydrate metabolism + Insulin-like Growth Factor + fat cells muscle chondrocytes Protein synthesis cartilage formation lipogenesis Increases FFA, glycerol, and sugars in circulation
- 9. Brain Pituitary Liver IGF IGF binding proteins (IGFBPs) Growth Growth Hormone (GH) GH/IGF/IGFBP AxisGH/IGF/IGFBP Axis
- 10. IGFBPs—two main typesIGFBPs—two main types IGFBP-3 most abundant form of IGFBP main carrier of IGF in circulation promotes IGF mediated somatic growth high IGFBP-3 associated w/ growth stimulation IGFBP-1 typically present in small amounts high IGFBP-1 associated w/ growth inhibition
- 15. Signs and symptomsSigns and symptoms •Obvious sign is kids being much shorter then kids of the same age and gender •Children with pituitary dwarfism have a slow rate of growth •Children of this disorder still have normal intelligence and capabilities
- 16. Diagnostic proceduresDiagnostic procedures •blood test for protien markers •Pediatric nurses chart : The growth curve of children with pituitary dwarfism shows no growth or minimal growth.
- 17. DiagnosisDiagnosis X-rays to determine bone age can also help with the diagnosis
- 18. DiagnosisDiagnosis .MRI of the brain can also be used to view the hypothalamus and pituitary gland
- 21. Treatments .Surgical intervention is another option which may include: -surgical operation on pituitary gland itself. -Bone lenghthining usually on the femur and tibia.
- 23. PrognosisPrognosis • Depends on whether there’s any permanent damage and the age of the child • Earlier treated, the better chance child will grow to average adult height • Growth improvement of the injections slowly decrease
Editor's Notes
- The hypothalamus is a region of the brain composed of many small nuclei with diverse functions By synthesizing and secreting neurohormones, the nuclei of the hypothalamus act as a conduit between the nervous and endocrine systems via the pituitary gland (hypophysis), regulating homeostatic functions such as hunger, thirst, body temperature, and circadian rhythms
- the hypothalamus releases hormone which have an activating or inhibitory effect on their target organ, hence they are named Releasing or Inhibitory Hormones respectively Releasing Hormones: Thyrotropin Releasing Hormone (TRH) Growth Hormone Releasing Hormone (GH-RH) Gonadotrophin Releasing Hormone (GnRH) Corticotropin Releasing Hormone (CRH) Prolactin Releasing Hormone (PRL-RH) nhibitory Hormones: Growth Hormone Inhibiting Hormone aka Somatostatin (GH-IH) Gonadotrophin Inhibiting Hormone (GnIH) Dopamine (PRL-IH)
- the pituitary gland, or hypophysis -meaning undergrowth- , is an endocrine gland about the size of a pea. It is a protrusion off the bottom of the hypothalamus at the base of the brain, and rests in a small, bony cavity (sella turcica) covered by a dural fold (diaphragm sellae)the pituitary gland is divided into a larger frontal region (adenohypophysis) <<<<a smaller posterior region (neurohypophysis). And intermediate lobe. ##. In humans the intermediate lobe does not exist as a distinct anatomic structure but rather remains only as cells dispersed within the anterior lobeThe gland is connected to the hypothalamus by the pituitary stalk. which is composed of neurons of the axons and the hypophyseal-portal veins. .
- The cells constituting the anterior lobe of the pituitary gland are embryologically derived from an outpouching of the roof of the pharynx known as Rathke’s pouch The anterior pituitary regulates several physiological processes including stress, growth, and reproduction.Its regulatory functions are achieved through the secretion of various peptide hormones that act on target organs The posterior lobe is composed of the endings of nerve cells located in specialized regions of the hypothalamus. These nerve cells produce two hormones oxytocin and vasopressin (antidiuretic hormone) , that are carried down the nerves and stored in the nerve endings that compose the posterior pituitary gland.
- The hormones of the anterior pituitary are synthesized in the cytoplasm of the cells as large, inactive molecules called prohormones. These prohormones are stored in granules, within which they are cleaved into active hormones and are secreted into the circulation The hormones of the post pituitary are released into the circulation in response to nerve signals that originate in the hypothalamus and are transmitted to the posterior pituitary
- Production of growth hormone is modulated by many factors, including stress, exercise, nutrition, sleep and growth hormone itself. However, its primary controllers are two hypothalamic hormones and one hormone from the stomach: Growth hormone-releasing hormone(GHRH) is a hypothalamic peptide that stimulates both the synthesis and secretion of growth hormone. Somatostatin (SS) is a peptide produced by several tissues in the body, including the hypothalamus. Somatostatin inhibits growth hormone release in response to GHRH and to other stimulatory factors such as low blood glucose concentration. Ghrelin is a peptide hormone secreted from the stomach. Ghrelin binds to receptors on somatotrophs and potently stimulates secretion of growth hormone.
- GH- makes energy available for growth IGF- induces cells to grow (brings cells into G1)
- As depicted in this slide, GH from the anterior pituitary is released in circulation and stimulates the synthesis and secretion of IGF-I from the liver. The IGF-I peptide then directly stimulates target cell growth In the last 2 decades, it has been recognized that the GH/IGF system is more complex, owing to the discovery of multiple IGFBPsIGFBPs bind the circulating IGF-I peptide with high affinity & specificity They function as carriers of the IGF-I peptide They prolong the half-life of IGF-I in circulation And they regulate IGF-I access to its cellular receptor
- There are multiple IGFBPs in mammals IGFBP-3 is one of these IGFBPs, and it is the most important carrier of IGF-I in the blood circulation IGFBP-3 is the most abundant form of IGFBP and it promotes IGF-I mediated somatic growth High levels of IGFBP-3 is thus associated with growth stimulation Also shown here is IGFBP-1, which is present only at very low or undetectable levels in “growing” mammals However, when animals are under “catabolic states” such as prolonged stress, the levels of IGFBP-1 will increase several-fold Such increases in this protein are associated with growth inhibition
- The following slide is an animation of how IGFBP-3 promotes IGF-I access to its cellular receptor
- Unlike the Previous animation, the actions of IGFBP-1 is very different Instead of promoting IGF-I ligand binding to its receptor, IGFBP-1 in mammals HAS a higher binding affinity for IGF than the receptor itself, and thus it “disallows” access of IGF-I to the receptor IGFBP-1 is thus associated with growth inhibition, thereby blocking its access to its cellular receptor
- Following puberty, GH levels decline during adulthood and decrease further with aging. Decline in lean body mass and metabolic rate as well as increased adipose tissue associated with aging may be attributed to declining GH levelsGH increases lean body mass through the increase of muscle protein synthesis.
- .if u open their heads to look at their brains u will see normal brains inside
- .x ray can be used to show the difference between bone age and child age, by hand x ray …depending on the defirences between adult bone hand and child bone hand .
- .it is used to show tumors, some inflamations,atrophy.or hyperplasia and this is useful to diagnose the disease.
- .pituitary tumor mri image
- .fortunatly treatment of gh deficincy is easy when it diagnosed early(in young age) .its the first choice for treatment
- . External fixator wich called (ilizarov) is used to jump start bone development and hopefully activate more growth. .doctors break the bone shaft and use the fixator to lenghth it.
- .because some damages are iireversable .