Unit Two Anatomy Review Chapter 7 Consists of elongated muscle cells in contraction o Skeletal o Cardiac o Smooth Skeletal Muscle 7.1 Skeletal muscle tissue- contains connective tissue, nerves and blood vessel Directly or indirectly attached to bone Has connective tissue Functions: 1. Move Skeleton 2. Maintain Posture and Body Position 3. Support Soft Tissue 4. Guard Entrances and Exits 5. Maintain Body Temperature Organization of Skeletal Muscle Tissue- 7.2 Contains skeletal muscle tissue, connective tissue, blood vessels and nerves Muscle cell called a muscle fiber, referring to muscle cell- mylocytes Connective Tissue Organization: 1. Epimysium- covers entire muscle (outerlayer), layer of collagen fiber, separates muscle from tissue and organs 2. Perimysium- divide muscles into fascicles or bundles of muscle fibers, divides into compartments. Bundles and nerves supply fascicles with blood, oxygen and such 3. Endomysium- covers each muscle fiber, ties fibers together, has capillaries and nerve fibers. Surrounds skeletal fibers, stem cells among fibers repair damaged muscle tissue, capillaries supply blood to muscle fibers and nerve fibers that control muscle Connective Tissue Attachments: Ends of muscle, collagen fibers come together to form a bundle called a tendon or broad sheet called aponeurosis Collagen fibers from all three layers of connective tissue to form ends: o Tendon- bands of collagen fibers attach skeletal muscles to bones o Aponeurosis- connect different skeletal muscle Blood vessel in skeletal muscle necessary to supply high energy, under voluntary contraction o Stimulation by CNS o Axons (nerve fibers)- run through connective tissue layers to innervate individual muscle fibers
Skeletal Muscle Fibers- 7.3 Long Fiber- multinucleate Repeating pattern gives striated appearance Sarcolemma- muscle cell’s plasma membrane Sarcoplasm- cytoplasm, surrounded by sarcolemma Openings along surface of sarcolemma that leads to networks of tubules called transverse tubule o Allow electrical impulses from sarcoplasm to reach cell’s interior o Unified contraction of entire fiber Myofibrils Cylinder-shaped structures running length of muscle fiber Encircled by t tubules Bundles of thick and thin myofilaments o Actin- thin o Myosin- thick Active shortening creates contraction, attached to sarcolemma to shorten entire cell, myofibrils have mitochondria to make ATP for muscle contraction Sarcoplasmic Reticulum Specialized smooth endoplasmic reticulum, forms network around each myofibril tightly around each T tubule Expanded portion on either side of T tubule is the terminal cisterna, high concentrations of calcium, cytosol has low concentration of calcium Triad- combination of two terminal cisternae and t tubule Skeletal muscle fibers actively transport calcium ions into terminal cisternae of sarcoplasmic reticulum, contraction begins when stored calcium ions released into cytosol of sarcoplasm Sarcomeres
You've reached the end of your free preview.
Want to read all 26 pages?