Slides 21 - Muscle systems

Slides 21 Muscle systems

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: r legs • Some spiders have leg joints that lack extensor muscles. - Extensor muscles extend the angle between two bones or body surfaces at a joint. - Flexor muscles decrease the angle between two bones or body surfaces at a joint. • Recoil of exoskeletal plates provides energy for extension Figure 12.23 4. Muscle energy metabolism • Muscle activity requires a lot of energy, mainly in the form of ATP - Actomyosin ATPase ‣ Cross-bridge cycling - Na+/K+ ATPase ‣ Reestablish ion gradients - Ca2+ ATPase ‣ Transport Ca2+ into SR Crystal structure Na+/K+ ATPase Crystal structure Ca2+ ATPase with 2 bound Ca2+ ions What fuels do muscles use? White muscle Red muscle Phosphagen system • Working muscle breaks down ATP. • ATP can be replenished by phosphagen system. • Creatine phosphokinase (CPK) breaks down PCr to Cr, transfers P to ADP to regenerate ATP • Some muscles use PCr shuttle Figure 2.41 Glycolysis to lactate • Glycolysis generates pyruvate from glucose. • Produces 2-3 ATP • Pathway produces ATP at very high rates, but at low efficiency • Pyruvate can then either enter mitochondria or be converted to lactate (by lactate dehydrogenase) • Lactate build up is associated with a decrease in muscle pH. • Glycolysis cannot be sustained indefinitely. Aerobic respiration • Occurs in mitochondria • Involves citric acid cycle • Electron transport and ATP production by F1F0 ATPase • Produces ~32 ATP/glucose • Slower than glycolysis, but more efficient • Can use a variety of fuels 5. Exercise physiology Factors that influence muscle fibre types and muscle size • The balance of fibre types within a muscle can vary in repose to: - genetic differences - exercise Exercise physiology & metabolism lab University of Melbourne • The size and number of fibres within a muscle can vary in response to: - genetic differences - exercise - drugs/hormones Fibre type- effects of genes • Transgenic mice (TG) that overexpress PPARδ - transcription factor involved in oxidative muscle development • Have a higher proportion...
View Full Document

This note was uploaded on 01/22/2014 for the course BIOL 361 taught by Professor Dougaltshuler during the Fall '13 term at University of British Columbia.

Ask a homework question - tutors are online