Biomedical Physiology Lab Exam 1 Experiment 1 Electronic Instrumentation Introduction Recording Oscillograph Precision measurement and recording instruments used for physiological experimentation 10 01 2015 Kymograph Produce permanent records for a variety of physiological events o First machine to record physiological events o Invented by Carl Ludwig o Can only record one event at a time o Messy BIOPAC electronic recording oscillograph used to measure skeletal muscle contraction smooth muscle contraction cardiopulmonary measurements and renal function Recording channel which is made up of 3 parts o Sensing device sensing device that senses physiological information and sends it to the computer Connected directly to subject Electrode Transducer to another detects electrical events transforms data or converts one form of energy Has a directly proportional relationship with mechanical impulse intensity and electrical impulse intensity Myograph Type of transducer that converts mechanical energy from a muscle contraction into electrical energy Myographs we use can measure forces from 5g 1000g 5g range relate to small contractions associated with cardiac or smooth muscle 1000g range relate to skeletal muscle contractions o Processor takes signal from transducer alters it and amplifies it and contains coupler and an amplifier Coupler modifies electrical signal so it can be recognized by the remaining components of the recording channel Basically alters signal Amplifier amplifies signal from coupler because the electrical signal captured by the sensing device is generally too weak to produce a signal that we can measure Example MP35 o Recorder Reproducer portion of the recording channel that makes a permanent record Quantifies height and length of an electrical event o Stimulators used to deliver electrical stimulus to the experimental setup Threshold stimulus lowest possible stimulus that will elicit a response Stimulus has three components Intensity The strength of the stimulus in volts or fractions of volts Frequency How often a stimulus is given during a period of time and is expressed in Hertz or impulses per second Duration Length of stimulus Lab 1 Questions and Answers What are the three components of a recording channel Sensing device processor and recorder What are the three components of an electrical stimulus Intensity duration frequency What does a transducer do Converts one form of energy to another Why is it important to balance and calibrate the BIOPAC device s signal and deflection on the record What is a recording oscillograph Measures and records physiological signals What are your TAs names Jasmine and Pam T F MP35 is the transducer False Balancing zeros out the data to begin and calibration syncs the sensing Biomedical Physiology Lab Exam 1 10 01 2015 Experiment 2 Neuromuscular Physiology Muscle cells contribute to the functionality of nearly every organ system Most dominant type skeletal muscle o Striated tissue that comprises 80 of vertebrate soft tissue Motor Unit Functional unit of skeletal muscle activity that consists of o Neuron motor nerve cell o Motor units are larger in larger muscles o Connection and innervation would be best understood in a drawing so Im working on that pg 29 paragraph 2 During normal muscle movement a motor neuron is activated and an impulse is propagated down its axon The impulse spreads out in the axonal branches and terminals The impulse then crosses the synaptic cleft and causes activation of all muscle fibers of the motor unit o Exciting all of the muscle s motor units can activate all of its fibers Individual motor neurons possess different thresholds o The first neurons excited are those of the lowest thresholds These are the smallest diameter neurons and usually innervate the fewest muscle fibers Increasing the strength of the stimulus step by step will bring more and more neurons motor units as well into action o Muscle twitch will be at maximal force o This process is called Motor Unit Summation o Adding stronger stimuli will result in no effect During a nerve s absolute refractory period the nerve is stimulated and the impulse generated by the nerve lasts about 1 5msec o A second stimulus during this period will not cause a second impulse to be produced o After this period a stimulus will indeed cause an impulse to fire Skeletal muscle contraction lasts longer than a nerve impulse but the refractory period for the muscle membrane still only 5msec o Temporal or wave summation is achieved when the tension developed in a muscle fiber during a muscle twitch will be GREATER in a second twitch compared to a first twitch because the second stimulus was applied before the muscle had relaxed completely after the first twitch despite the fact that both stimuli were identical in strength i e because the second twitch began while some tension remained the final tension is summed o Tetany is achieved when the muscle had no chance to relax at all and reaches maximum sustained contraction During tetany all the motor units are firing as rapidly as possible and the maximum tension of the muscle is generated The sarcomere makes up the structural unit of the muscle cell It is composed of actin and myosin which are arranged between Z lines Six Actin filaments surround a single myosin filament Each myosin molecule shaped like a golf club have a tail that anchors it to the core of the thick filament and the club head sticks out towards actin molecules o This arrangement is advantageous for forming cross bridges between actin and myosin Myofibrils constitute effective contractile elements of the muscle cell and are composed of many sarcomeres Sarcolemma muscle cell membrane o Envelopes the myofibrils and also invaginates deep into the center of the cell These invaginations are called T tubules transverse tubules and are located at the Z lines of amphibian muscle or A I zone of mammalian muscle T tubules come into close contact with lateral sacs Lateral sacs expanded elements of the sarcoplasmic reticulum Triad where two lateral sacs and a t tubule come together in the region of the Z line The stimulation of motor neurons like in the sciatic nerve results in action potentials that are conducted to the nerve terminals from which a neurotransmitter is released The transmitter diffuses across the neuromuscular junction and binds to receptors at sites on the muscle cell membrane idk why they didn t just say sarcolemma This interaction produces local