CH10 Lecture Notes - The Muscular System_ BIO-168-OA01-ML FL21 Human Anatomy and Physiology I w_ lab

This preview shows page 1 - 3 out of 6 pages.

9/25/21, 1:15 AMCH10 Lecture Notes - The Muscular System: BIO-168-OA01-ML FL21 Human Anatomy and Physiology I w/ lab (P) (4 cr) - Bridge…1/6CH10 Lecture Notes - The MuscularSystemThe Muscular SystemMuscle is one of the 4 primary types of tissue. It is subdivided into skeletal, cardiac and smoothmuscle.I. Skeletal Muscle Tissue and the Muscular System1. Skeletal muscles are the muscles attached to the skeletal system, which allow us to move. Themuscular system includes only skeletal muscles.2. Skeletal muscles are made up of muscle tissue (composed of muscle cells or fibers), connectivetissues, nerves and blood vessels.3. The 5 functions of skeletal muscles are:1. To produce skeletal movement.2. To maintain posture and body position.3. To support soft tissues.4. To guard the entrances and exits of the body.5. To maintain body temperature by generating body heat.II. Functional Anatomy of Skeletal MuscleBlood Vessels and Nerves1. Skeletal muscles are voluntary muscles, controlled by nerves from the central nervous system.2. An extensive vascular system supplies large amounts of oxygen to muscles, and carries awaywastes.Skeletal Muscle FibersSkeletal muscle cells (fibers) are very different from typical cells. The long fibers develop through thefusion of mesodermal cells (myoblasts) until they become very large and contain hundreds of nuclei.III. Tension ProductionTension Production by Muscle FibersAs a whole, a muscle fiber is either contracted or relaxed (the all-or-none principal).Tension Production by Skeletal Muscles
9/25/21, 1:15 AMCH10 Lecture Notes - The Muscular System: BIO-168-OA01-ML FL21 Human Anatomy and Physiology I w/ lab (P) (4 cr) - Bridge…2/61. Skeletal muscle motion results from the coordinated action of many fibers in a muscle.2. The amount of tension a whole muscle can produce depends on:1. The internal tension produced by the muscle fibers2. The external tension the muscle fibers exert on their elastic extracellular fibers (series elasticelements such as tendons)3. The total number of muscle fibers stimulated3. A single motor neuron can control hundreds of muscle fibers (a motor unit) that contract at thesame time.4. In a whole muscle or group of muscles, smooth motion and increasing tension are produced byslowly increasing the size or number of motor units stimulated. This is called recruitment ormultiple motor unit summation.5. Maximum tension is achieved when all motor units reach tetanus, but this can only be sustainedfor a very short time. Sustained tension is less than maximum tension, allowing some motor unitsto rest in rotation.

Upload your study docs or become a

Course Hero member to access this document

Upload your study docs or become a

Course Hero member to access this document

End of preview. Want to read all 6 pages?

Upload your study docs or become a

Course Hero member to access this document

Term
Spring
Professor
N/A
Tags
muscle tension

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture