BIO 240 1st Edition Lecture 16 Outline of Last Lecture C. Clinical Application – ACL TearD. Clinical Application – Shoulder Injuries E. Clinical Application – OsteoarthritisF. Clinical Application – Rheumatoid arthritis Outline of Current Lecture I. Muscle TissueA. General characteristicsB. Functions C. Cell typesD. Specific characteristicsCurrent LectureI. Muscle TissueA. General characteristics1. Excitability They can receive and respond to stimuli. They’re wired; the nervous system provides the electrical wires, which are where the excitatory signals come from. Part of the heart is wireless. 2. Contractility Shortens and thickens.3. Extensibility The ability to stretch. 4. Elasticity The ability to return to their original shape. B. Functions1. Movement - (true of skeletal and smooth muscle – smooth muscle move things inside of your body)2. Maintain posture - (only skeletal muscle)3. Heat production – as muscles burn energy they produce heat4. Energy storage – specifically ATPC. Cell types = Fibers1. Cardiac myocytes = cardiac muscle tissue2. Smooth myocytes = smooth muscle tissue3. Skeletal myocytes = skeletal muscle tissue****Muscle cell = muscle fiber = myocyteThese 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.D. Specific Characteristics1. Cardiac musclei. Involuntaryii. Uni-nucleated iii. Striatediv. Quadriangular shaped cellsv. Intercalated discs** (Specific to cardiac muscle) IPMPs that occur on every cardiac muscle cell allowing cell to cell communication by allowing chemicals to rapidly flow throughout the cardiac tissue. vi. Synctium System of intercalated disks that makes sure the heart is in sync.2. Smooth musclei. Involuntaryii. Uni-nucleatediii. Smooth (not striated)iv. Shape tapers at endsv. Are mobile – can break off from the tissue and go serve as a “bandaid” at tears that need patching. vi. 2 layers thicka. Circular layer inner layer of smooth muscle; can be multiple cell layers thick. It surrounds the lumen of organs and constricts its diameter. b. Longitudinal layer outer layer of smooth muscle that lays the length of the organ (longitudinally); can be multiple cell layers thick. It lies lengthwise along the outer surface of hollow organs and shortens the length when contraction occurs. vii. Found around hollow organs and around exocrine glands and blood vessels viii. Peristalsis The longitudinal and circular layers working in harmony to produce wave like contractions of smooth muscle thatmove food and other substances through the hollow organs of thebody. 3. Skeletal musclei. Associated connective tissues:a. Tendons Attaches muscle to bone. b. Connective tissue sheets Sheaths of connective tissue that cover all skeletal muscle. There are 3 types:i. Epimysium Dense irregular connective tissue that wraps around the entire muscleii. Perimysium Dense fibrous connective tissue thatcovers fascicles.iii. Endomysium Areolar connective tissue that wraps around and covers the myocytes. ii. Voluntaryiii. Multi-nucleatediv.
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