Additional research papers will be used to supplement specific topics and will be listed with each topic. 1. Diagram a mechanical model of muscle. What actual structures in muscle may the individual components in the model correspond to? (R. p. 9-10) 2. Draw a diagram illustrating the length-tension relationship of muscle for active contraction and passive stretch. (R. p. 11) What is the contri...

muscle contraction (Huxley and Niedergerke, 1954; Huxley and Hanson, 1954), dictates a trade-off between the ability of a muscle to generate isometric force and its length. This intrinsic trade-off is the result of the need for overlap between thick and thin filaments upon extension of the sarcomere and of the limitations imposed by the physical interference of thin filaments and thick filament...

We studied effects of increasing the length of porcine trachealis muscle on 5.5 microM carbachol (CCh)-evoked phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] synthesis and other parameters of phosphatidylinositol (PI) turnover. PI(4,5)P2 resynthesis rates in muscle held at 1.0 optimal length (L(o)), measured over the first 6 min of CCh stimulation, were 140 +/- 12 and 227 +/- 14% of values fo...

Accurate measurements of muscle length changes are essential for understanding the biomechanics of musculoskeletal systems, and can provide insights into muscular work, force, and power. Muscle length has typically been measured in vivo using sonomicrometry, a method that measures distances by sending and receiving sound pulses between piezoelectric crystals. Here, we evaluate an alternative me...

Effects on force of changes of the position of extensor digitorum longus muscle (EDL) relative to surrounding tissues were investigated in rat. Connective tissue at the muscle bellies of tibialis anterior (TA), extensor hallucis longus (EHL) and EDL was left intact, to allow myofascial force transmission. The position of EDL muscle was altered, without changing EDL muscle-tendon complex length,...

The mechanical power output was measured from scaphognathite (SG = gill bailer) muscle L2B of the crab Carcinus maenas (L.). The work was determined from the area of the loop formed by plotting muscle length against force when the muscle was subjected to sinusoidal length change (strain) and phasic stimulation in the length cycle. The stimulation pattern (10 stimuli per burst, burst length = 20...

We investigated the role of the integrin-associated proteins focal adhesion kinase (FAK) and paxillin as mediators of mechanosensitive signal transduction in tracheal smooth muscle. In muscle strips contracted isometrically with ACh, we observed higher levels of tyrosine phosphorylation of FAK and paxillin at the optimal muscle length ( L o) than at shorter muscle lengths of 0.5 or 0.75 L o. Pa...

The effects of changing the length of the cat soleus muscle on electromyographic (EMG) signals, muscle force and the corresponding EMG-force relationship were assessed using distributed stimulation of ten ventral root filaments and irregular interpulse intervals. EMG-force relationships were first determined for four muscle lengths using a protocol of simultaneous addition and rate modulation o...