KIN 330 1st Edition Lecture 3Outline of Current Lecture I. Muscle TissueA. TypesB. Special CharacteristicsII. Muscle functionsIII. Microscopic Anatomy of Muscle FibersA. MyofibrilsB. StriationsC. SarcomereD. Sarcoplasmic ReticulumE. T tubulesF. Neuromuscular JunctionsIV. Muscle ContractionV. Action PotentialsVI. Homeostatic ImbalanceCurrent LectureI. Muscle Tissue: Makes up nearly half of the body’s mass. Muscle tissue transforms chemical energy into directed mechanical energy to exert a force. C. Types: 1. Skeletal: Has muscle fibers that are elongated cells. Under voluntary control; require nervous system stimulation; contract rapidly; tire easily; powerful. Have at least one insertion and origin that can be indirect or direct. 2. Cardiac: Only in heart; striated; can contract without nervous system stimulation; involuntary3. Smooth: In walls of hollow organs; not striated; can contract without nervous system stimulation; involuntaryD. Special Characteristics1. Excitable: can receive and respond to stimuli2. Contractible: can shorten forcibly when stimulated3. Extensible: can be stretched4. Elastic: can recoil to resting lengthII. Muscle functionsA. Movement of bones or fluidsThese 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.B. Maintain posture and body positionC. Stabilize JointsD. Generate HearE. Protect organs, forms valves, controls pupil sizeIII. Microscopic Anatomy of Muscle Fibers: long, cylindrical cells with multiple nuclei.G. Myofibrils: Densely packed, rod-like elements that make up ~80% of cell volume and contain sarcomeres. H. Striations: Perfectly aligned, repeated series of dark and light bands. I. Sarcolemma: Plasma MembraneJ. Sarcoplasm: Cytoplasm with glycosomes for glycogen storage and myoglobin for O2 storage. Region between 2 successive Z discsK. Sarcomere: Smallest functional contractile unit that contains myofilamentsL. Sarcoplasmic Reticulum: Network of smooth endoplasmic reticulum surrounding each myofibril. Functions in regulation of Ca2+M. T tubules: continuations of sarcolemma that increase a muscle fiber’s surface area. They are associated with paired terminal cisterns to form triads that encircle sarcomeres. N. Neuromuscular Junctions: Includes axon terminals, synaptic cleft and junctional folds. Where nerve impulses arrive at axon terminals and Ach is released into a synaptic cleft that initiates an action potential. IV. Muscle ContractionA. Sliding Filaments: During a contraction, thin filaments slide past thick filaments and a cross bridge forms. Shortening of a muscle fiber occurs when thin filaments are pulled in by actin/myosin binding. B. For a muscle contraction to happen, it must be activated at a neuromuscular junction and there must be excitation-contraction coupling. V. Action Potentials: Depolarization, generation of an action potential, repolarizationVI. Homeostatic ImbalanceA. Rigor Mortis: Cross-bridge detachment requires ATP. 3-4 hours after death muscles begin to stiffin with weak rigidity at 12 hours post