Cryptic coloration sexual territorial advertising p i

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: te TSH 4. TSH continues to stimulate thyroid to overg row. 5. Overgrown thyroid forms a goiter. Pars Intermedia In most vertebrates, a portion of the pituitary anterior lobe adjacent to the posterior lobe develops into an intermediate lobe . ß Principle activity is secreting melanocyte -stimulating hormone (MSH) ß MSH promotes hyperpigmentation from increased melanin production in melanocytes in skin and hair. • Cryptic coloration • Sexual/ territorial advertising P I A Pars Intermedia Alternate processing of the same pro-hormone polypeptide: Pro- opiomelanocortin (POMC) [pro- opioid -melanotropin -corticotropin ] • In anterior pituitary , POMC cleaved to form endorphins ( opioids ) + adrenocorticotrophic hormone (ACTH) • In intermediate lobe , ACTH fragment is further cleaved to form a-MSH • In humans, intermediate lobe is greatly reduced, but present. Syndromes that cause an overproduction of ACTH (pregnancy, adrenal insufficiency [ Addisons disease]) also result in elevated MSH and hyperpigmentation . • Red-headed, poorly tanning people often have normal MSH levels, but decreased MSH-receptors. Heyer Endocrine Pathologies I. Abnormal hormone titer — • Primary pathology: caused the endocrine gland secreting that hormone • Secondary pathology: caused by a factor (e.g., trophic hormone) regulating that gland – Hypersecretion of hormone • Idiopathic: gland “turned on ” for no obvious reason • Tumor hyperplasia of secretory cells • Secondary: hypersecretion of trophic hormone – Hyposecretion of hormone • Enzyme defect in biosynthesis of the hormone • Autoimmune destruction of of secretory cells • Receptor defect/insufficiency responding to trophic hormone • Secondary: hyposecretion of trophic hormone II. Abnormal hormone response — • Number of receptors in target organ: desensitization • Mutant defective receptors in target organ • Defective transduction pathway step III. Exogenous hormones 9...
View Full Document

This note was uploaded on 09/02/2011 for the course BIOL 6a taught by Professor Staff during the Fall '10 term at DeAnza College.

Ask a homework question - tutors are online