Describe the four properties of muscular tissue. List the general functions of muscular tissue
What features distinguish the three types of muscular tissue?
The study of tissues is called histology, and is most often performed using a microscope to look at the cells and related structures. There are four general tissue types: epithelial, connective, muscular, and nervous tissue. Each of the general tissue types has different characteristics and can be distinguished by its appearance.
Answer and Explanation: 1
The four properties of muscular tissue are: Extensibility, elasticity, excitability, and contractility. Extensibility is the ability to stretch to a certain point without damage. Elasticity is the ability to return to its original shape and size after being stretched. A good example of extensibility and elasticity can be seen with silly bands, the rubber bands that are made into shapes. You can stretch them (to a point) without damage (extensibility) and when you release them, they return to the original shape (elasticity). Excitability means that a muscle can respond to stimulus from the nervous system, and contractility means that it can produce force when getting shorter.
There are three types of muscle tissue: Skeletal muscle, cardiac muscle, and smooth muscle. Most people when talking about muscle think about skeletal muscle tissue - it is the tissue that is the primary component of all skeletal muscles in the body, such as the biceps brachii and the gluteus maximus muscles. Underneath a microscope, skeletal muscle tissue is distinguished by long cylindrical shaped cells, with many nuclei, and striations (stripes) that are caused by the arrangement of the myofilaments that help with contraction. Skeletal muscle tissue is voluntary in function - you can choose to use it or relax it. Cardiac muscle tissue is also striated (it has the same myofilament arrangement as skeletal muscles, structures known as sarcomeres), but the cells of cardiac muscle tissue are much shorter, have only one nucleus (sometimes two) per cell, and the cells are branched. Viewed under a microscope, dark lines are visible at the junction of cardiac muscle cells known as intercalated discs, which are where the heart muscle cells can communicate with each other. Cardiac muscle tissue is involuntary, you cannot consciously control the function. The third type of muscle tissue is known as smooth muscle, another type of involuntary muscle tissue. Cells of smooth muscle are spindle shaped - they are wider in the middle than at the ends, and they have only one nuclei present per cell. The myofilaments that cause contraction in smooth muscle tissue are arranged differently than they are in cardiac and skeletal muscle, so smooth muscle tissue lacks that stripes that they contain.
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fromChapter 27 / Lesson 1
What are the three types of muscles in the body? Learn about the classification of muscles, their locations, functions, and structure.