NRSC 2100 1st Edition Lecture 23 Energy Balance the control of food intake Eating is partly controlled by the digestive tract the hypothalamus and cognitive factors The digestive system brings macromolecules into the body via breakdown hydrochloric acid pepsin etc and absorption of essential nutrients and energy molecules Three classes lipids fats amino acids building blocks of proteins and glycogens starches and sugars Lipids provide approximately 85 of stored energy adipose cells whereas amino acids 14 5 and glycogens liver 0 5 provide the rest Long term Regulation of Feeding Behavior Energy Balance Prandial state Anabolism Energy storage as glycogen and triglycerides fats during and shortly after food intake Postabsorptive state Catabolism Breaking down complex macromolecules from storage Lipostatic Hypothesis Proposed by Gordon Kennedy 1953 Leptin discovered by Jeffrey Friedman s group in 1994 Genetic Leptin deficiency dysregulation of body fat can be reversed by leptin treatment Studies indicating role of lateral and ventromedial hypothalamus Lateral hypothalamus lesions anorexia Ventromedial nucleus lesions obesity Leptin Regulation of Hypothalamus Lateral hypothalamus lesions anorexia Ventromedial nucleus lesions obesity Leptin Regulation of Hypothalamus Peripheral adipose cells release leptin into blood supply which eventually reaches the brain These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Leptin receptors located on neurons in hypothalamic Arcuate nucleus Response to Elevated Leptin Activated arcuate neurons release MSH and CART peptides anorectic peptides reduce appetite Activates paraventricular nucleus neurons which releases ACTH and TSH humoral and project to intermediolateral gray matter of spinal cord sympathetic activation Inhibits lateral hypothalamus reduces feeding behaviors somatic Response to Decreased Leptin Activated arcuate neurons release NPY and AgRP peptides orexigenic peptides increase appetite Inhibit paraventricular nucleus neurons which reduces ACTH and TSH humoral and activate parasympathetic system Stimulate lateral hypothalamus increase feeding behaviors somatic
View Full Document
Unlocking...