Lecture+37_Endocrine2-6

18 12 p 679 fig 18 11 p 677 hipwwwanatomyatlasesorg

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: from again? •  And how are those hormones regulated? •  And where are the regulators released from? –  growth hormone–releasing hormone (GHRH) –  growth hormone–inhibi=ng hormone (GHIH or somatosta=n) Major inputs Blood amino acids, Blood fatty acids Exercise, stress, blood glucose Ghrelin Diurnal rhythm Minor inputs Hypothalamus Somatostatin (growth hormone–inhibiting hormone; GHIH) Growth hormone– releasing hormone (GHRH) Anterior pituitary somatotrope Growth hormone Liver IGF-I Growth-promoting actions cell division protein synthesis ( blood amino acids) bone growth Metabolic actions unrelated to growth fat breakdown (blood fatty acids) glucose uptake by muscles (blood glucose) glucose output by liver (blood glucose) Fig. 18-10, p. 676 GH Dysregula=on: Timing MaIers Gigan4sm •  Caused by excess GH secre=on during childhood •  Epiphyseal plate is s=ll present in long bones •  Long bones are s=ll able to grow longer Acromegaly •  Caused by excess GH secre=on during adulthood •  Long bones are not able to elongate because epiphyses have fused •  All bones grow thicker, soX =ssues proliferate Gigan4sm Acromegaly Fig. 18- 12, p. 679 Fig. 18- 11, p. 677 hIp://www.anatomyatlases.org/ Circadian Rhythms •  Like many hormones, GH secre=on displays a diurnal rhythm –  How does the hypothalamus “know” what =me it is? •  The suprachiasma4c nucleus (SCN) of the hypothalamus is the body’s biological clock. –  Slow changes in the concentra=on of clock proteins in the SCN cause 24h- ish cycles of neural ac=vity –  Specialized ganglion cells from the re4na project directly to the SCN, causing photentrainment: sebng the clock to match light/dark cycles at 24h exactly Photoentrainment and “free run”...
View Full Document

Ask a homework question - tutors are online