Transcript Chapter 5
Chapter 5 - Tissues Membranes, Muscle Tissues, and Nervous Tissues Types of Membranes • Epithelial Membranes – Thin, sheetlike structures – Usually composed of epithelial and underlying connective tissues – Cover body surfaces and line body cavities – 3 major types • Serous • Mucous • Cutaneous Types of Membranes • Epithelial Membranes – Serous Membranes • Consist of a layer of simple squamous epithelium (mesothelium) and a thin layer of loose connective tissue • Cells of the membrane secrete watery serous fluid which helps lubricate membrane surfaces • Line body cavities that do not open to the outside – Form the inner linings of the thorax and abdomen and cover the organs within these cavities • Reduce friction between organs and cavity walls Types of Membranes • Epithelial Membranes – Mucous Membranes • Consists of epithelium overlying a layer of loose connective tissue – The type of epithelium varies with the location of the membrane • Goblet cells within the membrane secrete mucus • Line the cavities and tubes that open to the outside of the body – Includes oral and nasal cavities, and the tubes of the digestive, respiratory, urinary, and reproductive systems Types of Membranes • Epithelial Membranes – Cutaneous Membranes • More commonly called skin…will be covered in next chapter Types of Membranes • Synovial Membranes – Composed completely of connective tissue – Line joints Muscle Tissues • General Characteristics – Have elongated cells commonly termed muscle fibers – Contractile…can shorten and thicken • As muscle tissues contract, they pull at their attached ends which moves body parts – 3 types • Skeletal muscle tissue • Smooth muscle tissue • Cardiac muscle tissue Muscle Tissues • Skeletal Muscle Tissue – Forms muscles that usually attach to bone and that are controlled by conscious effort (so it is often called voluntary muscle tissue) – Consists of cells that are long and narrow (threadlike), have alternating light and dark cross-markings called striations, and many nuclei (multinucleate) – When stimulated by a nerve cell, protein filaments within the muscle cell slide past one another causing the muscle cell to contract • Skeletal muscles move the head, trunk, and limbs and allow us to make facial expressions, to write, to talk, to sing, to chew, to swallow, and to breathe. Skeletal Muscle Tissue Muscle Tissues • Smooth Muscle Tissue – Has cells that lack striations, are shorter than those of skeletal muscle, are spindle-shaped, and have a single, centrally located nuclei – Comprises the walls of hollow internal organs (such as the stomach, intestines, urinary bladder, uterus, and blood vessels) – Usually cannot be stimulated to contract by conscious effort (thus, it is termed involuntary) • Examples of locations/functions: – moves food through the digestive tract – constricts blood vessels – empties the bladder Smooth Muscle Tissue Muscle Tissues • Cardiac Muscle Tissue – Only found in the heart – Has cells that are striated and branched, have one nucleus, and are joined end-to-end, resulting in complex networks • Intercalated discs (a specialized intercellular junction found only in cardiac tissue) are located where cells touch – Is not controlled voluntarily and can continue to function without being stimulated by nerve impulses – Makes up the bulk of the heart and pumps blood through the heart chambers and into blood vessels Cardiac Muscle Tissue Nervous Tissues • Found in the brain, spinal cord, and peripheral nerve cells. • Contain two types of cells – Neurons – Neurological cells Nervous Tissues • Neurons – Basic nerve cells – Highly specialized – Coordinate, regulate, and integrate many body functions – Sense certain types of changes in their surroundings and respond to these changes by transmitting nerve impulses along cellular processes to other neurons or to the muscles and glands they connect with Nervous Tissues • Neurological Cells – Support and bind the components of nervous tissue – Carry on phagocytosis – Help supply nutrients to neurons by connecting them to blood vessels – Play a role in cell-to-cell communications – May give rise to neural stem cells Nervous Tissues