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| Hormones “orchestrate” responses in other tissues, including other endocrine organs, and these overall effects can be similar or different in different tissues. These signaling pathways are often described as "axes" the two major types are the: '''HPA''' ('''H'''yothalamus-'''P'''ituitary-'''A'''drenal) and '''HPG''' ('''H'''ypothalamus-'''P'''ituitary-'''G'''onad). These hormone effects (like music) can be rapid, slow, brief, diurnal, or long-term. Hormone effects can be mimicked, stimulated, and blocked by therapeutic drugs, nutritional and environmental chemicals. Importantly, fetal endocrine development is required for normal fetal growth and differentiation. | | Hormones “orchestrate” responses in other tissues, including other endocrine organs, and these overall effects can be similar or different in different tissues. These signaling pathways are often described as "axes" the two major types are the: '''HPA''' ('''H'''yothalamus-'''P'''ituitary-'''A'''drenal) and '''HPG''' ('''H'''ypothalamus-'''P'''ituitary-'''G'''onad). These hormone effects (like music) can be rapid, slow, brief, diurnal, or long-term. Hormone effects can be mimicked, stimulated, and blocked by therapeutic drugs, nutritional and environmental chemicals. Importantly, fetal endocrine development is required for normal fetal growth and differentiation. |
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| ==Abnormalities==
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| '''NIH Genes & Disease''' [http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=gnd.chapter.41 Chapter 41 - Glands and Hormones]
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| ===Pineal===
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| * hypoplasia - associated with retinal disease.
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| * tumours - in children are associated with abnormal puberty development.
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| ===Pituitary===
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| * craniopharyngeal canal - Rathke's pouch abnormality, from the anterior part of the fossa hypophyseos of the sphenoid bone to the under surface of the skull.
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| * pituitary tumours (adenomas) - several abnormalities associated with abnormal levels of the hormonal output of the pituitary.
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| ** Growth hormone (GH) adenomas - benign pituitary tumors lead to chronic high GH output levels, that may lead to acromegaly.
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| * Cushing's disease - caused either by a pituitary adenoma produces excess adrenocorticotropic hormone (ACTH, corticotropin) or due to ectopic tumors secreting ACTH or corticotropin-releasing hormone (CRH).
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| === Thyroid ===
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| [[File:Thyroid_pyramidal_lobe.jpg|thumb|Thyroid pyramidal lobe]]
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| [[File:Thyroid uptake scans .jpg|thumb|Thyroid uptake scans]]
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| * Pyramidal lobe - from isthmus (50% of people) attached to hyoid bone distal end of thryoglossal duct.
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| * Congenital hypothyroidism - approximately 1 in 3000 births, associated with neurological abnormalities.
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| * Lingual thyroid gland - failure of thyroid descent.
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| * Thyroglossal cyst - persistance of thyroglossal duct. [http://www.upstate.edu/cdb/grossanat/imgs/tgdfig2.jpg Image - thyroglossal duct]
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| * Thyroglossal fistula - partial degeneration of the thyroglossal duct.
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| * Abnormal development of the thyroid - incomplete or excessive descent.
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| * Childhood hypothyroidism delays ossification and bone mineralization.
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| Iodine Deficiency
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| * A teaspoon of iodine, total lifetime requirement, cannot be stored for long periods by our body, tiny amounts are needed regularly
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| * Areas of endemic iodine deficiency, where soil and therefore crops and grazing animals do not provide sufficient dietary iodine to the populace
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| * food fortification and supplementation - Iodized salt programs and iodized oil supplements are the most common tools in fight against IDD
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| ===Parathyroid===
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| * Usually four glands are present (2 on each side), but three to six glands have been found in human.
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| * Lower parathyroid glands arise from the third pharyngeal pouch and descend with the thymus. Variable descent can lead to a range of adult locations, from just beneath the mandible to the anterior mediastinum.
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| ===Pancreas===
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| * Type 1 Diabetes - juvenile onset diabetes, more severe form of illness, increases risk of blindness, heart disease, kidney failure, neurological disease, T-lymphocyte-dependent autoimmune disease, infiltration and destruction of the islets of Langerhans, Approx 16 million Americans
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| * Type 2 Diabetes - loosely defined as "adult onset" diabetes, becoming more common cases of type 2 diabetes seen in younger people
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| * Risk of developing diabetes - environmental factors (food intake and exercise play an important role, either overweight or obese), Inherited factors (genes involved remain poorly defined)
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| ===Adrenal===
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| * Congenital Adrenal Hyperplasia (CAH) - family of inherited disorders of adrenal steroidogenesis enzymes which impairs cortisol production by the adrenal cortex. Androgen excess leads newborn females with external genital ambiguity and postnatal progressive virilization in both sexes.
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| ** Enzymes most commonly affected: 21-hydroxylase (21-OH), 11beta-hydroxylase, 3beta-hydroxysteroid dehydrogenase.
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| ** Enzymes less commonly affected: 17alpha-hydroxylase/17,20-lyase and cholesterol desmolase.
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| * Pheochromocytomas (PCC) - Catecholamine-producing (neuro)endocrine tumor located in the adrenal medulla. Similar catecholamine-producing tumors outside the adrenal gland are called paragangliomas (PGL).
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| ===Endocrine Disruptors===
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| Exogenous chemicals that interfere with the function of hormones. There are 3 main mechanisms: mimic, block or interfere.
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| '''Mimic''' - effects of natural hormones by binding receptors
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| * Diethylstilbestrol - (DES or diethylstilbetrol) a drug prescribed to women from 1938-1971 to prevent miscarriage in high-risk pregnancies. Acts as a potent estrogen (mimics natural hormone) and therefore a potential endocrine disruptor. Female fetus, increased risk abnormal reproductive tract and cancer. Male fetus, abnormal genitalia. Banned by USA FDA in 1979 as a teratogen, previously used as livestock growth promoter.
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| '''Block''' - binding of a hormone to receptor or hormone synthesis
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| * Finasteride - chemical used to prevent male pattern baldness and enlargement of prostate glands. An anti-androgen (blocks synthesis of dihydrotestosterone) and therefore a potential endocrine disruptor, exposed pregnant women can impact on male fetus genetial development.
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| * Vinclozolin - a dicarboximide fungicide, perinatal exposure in rats inhibits morphological sex differentiation. In adult rats, shown to cause gonad tumours (Leydig cell) and atrophy. Chemical has androgen-antagonist (antiandrogenic) activity, metabolies compete with natural androgen
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| '''Interfere''' - with hormone transport or elimination
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| * Polychlorinated biphenyl pollutants - (PCBs) Rats exposed to PCBs have low levels of thyroid hormone. Compete for binding sites of thyroid hormone transport protein. Without being bound to this protein, thyroid hormones are excreted from the body (McKinney et al. 1985; Morse et al. 1996)
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| ==References==
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| <references/>
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| * Endocrinology: An Integrated Approach Nussey, S.S. and Whitehead, S.A. London:Taylor & Francis; c2001 [http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=endocrin&part=A3&rendertype=box&id=A11 Major hormone types]
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| * Genes and Disease, Bethesda (MD): National Library of Medicine (US), NCBI [http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=gnd.chapter.41 Chapter 41 - Glands and Hormones]
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| ===Search ===
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| * '''Bookshelf''' [http://www.ncbi.nlm.nih.gov/sites/entrez?db=Books&cmd=search&term=endocrine endocrine] | [http://www.ncbi.nlm.nih.gov/sites/entrez?db=Books&cmd=search&term=pineal_gland pineal gland] | [http://www.ncbi.nlm.nih.gov/sites/entrez?db=Books&cmd=search&term=hypothalmus hypothalamus] | [http://www.ncbi.nlm.nih.gov/sites/entrez?db=Books&cmd=search&term=pituitary_gland pituitary gland] | [http://www.ncbi.nlm.nih.gov/sites/entrez?db=Books&cmd=search&term=thyroid_gland thyroid gland] | [http://www.ncbi.nlm.nih.gov/sites/entrez?db=Books&cmd=search&term=parathyroid_gland parathyroid gland] | [http://www.ncbi.nlm.nih.gov/sites/entrez?db=Books&cmd=search&term=thymus_gland thymus gland] | [http://www.ncbi.nlm.nih.gov/sites/entrez?db=Books&cmd=search&term=endocrine_pancreas endocrine pancreas] | [http://www.ncbi.nlm.nih.gov/sites/entrez?db=Books&cmd=search&term=adrenal_gland adrenal gland]
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| * '''Pubmed''' [http://www.ncbi.nlm.nih.gov/sites/gquery?itool=toolbar&cmd=search&term=endocrine_development endocrine development]
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| ==Histology== | | ==Histology== |
Introduction
The endocrine system resides within specific endocrine organs and both organs and tissues with other specific functions. Epithelia (ectoderm and endoderm) form the majority of the “ductless” endocrine glands like gastrointestinal and skin associated “ducted” glands. Differentiation of several also organs involves a epithelial/mesenchye interaction, seen in repeated in many differentiation of many different tissues. The endocrine glands produce hormones, which are distributed by the vascular system to the many body tissues, subsequently these organs are richly vascularized.
Hormones “orchestrate” responses in other tissues, including other endocrine organs, and these overall effects can be similar or different in different tissues. These signaling pathways are often described as "axes" the two major types are the: HPA (Hyothalamus-Pituitary-Adrenal) and HPG (Hypothalamus-Pituitary-Gonad). These hormone effects (like music) can be rapid, slow, brief, diurnal, or long-term. Hormone effects can be mimicked, stimulated, and blocked by therapeutic drugs, nutritional and environmental chemicals. Importantly, fetal endocrine development is required for normal fetal growth and differentiation.
Histology
Adult
Pituitary - adenohypophysis
Pituitary - adenohypophysis
Pituitary - neurohypophysis
Adrenal - Cortex and Medulla
Adrenal - Zona Reticularis and Medulla
Embryonic
Stage 22 - Pancreatic duct
Terms
adrenocorticotropin - (ACTH or corticotropin) anterior pituitary, peptide hormone
antidiuretic hormone - (ADH) hypothalamus, peptide hormone
atrial natriuretic factor - (ANP) heart, , peptide hormone
calcitonin - (CT) C cells of thyroid, peptide hormone
follicle stimulating hormone - (FSH) pituitary, protein hormone
growth hormone - (GH) pituitary, peptide hormone
human chorionic gonadotropin - (hCG) pancreas glycoprotein hormone with 2 subunits (alpha and beta joined non covalently). Similar in structure to luteinizing hormone (LH), hCG exists in multiple hormonal and non-endocrine agents (regular hCG, hyperglycosylated hCG and the free beta-subunit of hyperglycosylated hCG). PMID: 19171054
lutenizing hormone - (LH) pituitary, protein hormone
melaocyte stimulating hormone - (MSH) pituitary, peptide hormone
prolactin - (PRL) pituitary, peptide hormone
parathyroid hormone - (PTH) parathyroid, peptide hormone
thyroid hormone - (TH) thyroid,amino acid derivative
thyroid stimulating hormone - (TSH) pituitary, protein hormone
