Lecture2-Muscle and Heart.pdf

Course Outline 0. Introduction to Biosensing and Bioinstrumentation (BSBI) (What is BSBI, why study BSBI, well- known applications of BSBI) 1. Electrical signals in biology (in neurons, muscles, cardiac cells, eyes, skin, gut) and instruments to measure them (EE...

Course Outline 0. Introduction to Biosensing and Bioinstrumentation (BSBI) (What is BSBI, why study BSBI, well- known applications of BSBI) 1. Electrical signals in biology (in neurons, muscles, cardiac cells, eyes, skin, gut) and instruments to measure them (EEG, EMG, ECG, EOG, ERG, EDA, EGG) 2. Mechanical signals in biology (in lungs, heart, blood vessels) and instruments to measure them 3. Chemical signals in biology (in blood, urine, saliva, mucus, tissues, sweat) and instruments to measure them 4. Thermal signals in biology and temperature sensors 5. Common medical diagnostic instruments (CT Scan, MRI, XRD, Raman Spectroscopy) 6. Wearable electronics: Artificial synapses, Memristors – Dr. Ravindra Bukke SMME  Electric signals in the heart https://www.youtube.com/watch?v=TnFoJ7Hhi-M Ca2+ion channels K+ion channels (calcium comes in) (potassium goes out) Leaky ion channels  ECG https://www.youtube.com/watch?v=xIZQRjkwV9Q  How muscles generate force Cellular & Molecular structure of muscles https://www.pharmacy180.com/article/structure-of-skeletal-muscle-fibers-3522/ How muscles generate force Structure of a muscle cell physio-pedia.com/Muscle_Cells_Myocyte  How muscles generate force Myofibrils (organelles) within muscle cell https://en.wikipedia.org/wiki/Sarcoplasm  How muscles generate force Molecular changes that result in muscle contraction https://en.wikipedia.org/wiki/Myofibril How muscles generate force Actin and Myosin Introduction How muscles generate force Role of Calcium  How muscles generate force Role of ATP 1. At the end of the previous round of movement and the start of the next cycle, the myosin head lacks a bound ATP and it is attached to the actin filament in a very short-lived conformation known as the ‘rigor conformation’. 2. ATP binding to the myosin head domain induces a small conformational shift in the actin-binding site that reduces its affinity for actin and causes the myosin head to release the actin filament. 3. ATP binding also causes a large conformational shift in the ‘lever arm’ of myosin that bends the myosin head into a position further along the filament. ATP is then hydrolysed, leaving the inorganic phosphate and ADP bound to myosin. https://www.mbi.nus.edu.sg/mbinfo/what-steps-are-involved-in-the-myosin-powerstroke/  How muscles generate force Role of ATP 4. The myosin head makes weak contact with the actin filament and a slight conformational change occurs on myosin that promotes the release of the inorganic phosphate. 5. The release of inorganic phosphate reinforces the binding interaction between myosin and actin and subsequently triggers the ‘power stroke’. The power stroke is the key force- generating step used by myosin motor proteins. Forces are generated on the actin filament as the myosin protein reverts back to its original conformation. 6. As myosin regains its original conformation, the ADP is released, but the myosin head remains tightly bound to the filament at a new position from where it started, thereby bringing the cycle back to the beginning. https://www.mbi.nus.edu.sg/mbinfo/what-steps-are-involved-in-the-myosin-powerstroke/  How muscles generate force Sliding Filament Theory Proposed in two groundbreaking papers in 1954. A. F. Huxley and R. Niedergerke (1954) and H. E. Huxley and J. Hanson (1954) Using high-resolution microscopy, they observed changes in the sarcomeres as muscle tissue shortened They described the position of myosin and actin filaments at various stages of contraction in muscle fibers and proposed how this interaction produced contractile force pharmacy180.com/article/structure-of-skeletal-muscle-fibers-3522/