Musculoskeletal System (Part A-3) Module 7 -Chapter 10 Overview Muscles Attachments Bones Bone types Surface features of bones Divisions of the skeletal system Joints or Articulations Susie Turner, M.D. 1/8/13 Contractile cells Called fibers (because cells can be very long) Characteristics include: Ability to be excited by a stimulus Stimulus in our body is a nerve impulse Contract & then relax Return to their original size and shape. Muscle Tissue 1
Nerve Impulse Electrical impulse transmitted thru certain tissues Especially nerve fibers & muscles Na+ & K+ ions flowing in and out of cell s plasma membrane cause this. Provide movement of an organ or body part Contribute to posture Produce body heat Highly metabolic tissue Functions 2
Muscle Tissue 3 Types Skeletal muscle Cardiac muscle Smooth muscle Differences Structure of their cells Location in body Function All root words or prefixes of myo or mys and sarco refer to muscle Skeletal Muscle Tissue Under voluntary control Rapid Contractions Striated (Striped) Appear striped under microscope Ex; muscles that move eyeballs, tongue, & bones 3
Involuntary control Cardiac Muscle Tissue Rely on pacemaker cells for contraction AND Autonomic Nervous System Striated like skeletal muscle But unique because branched. Produce rhythmic activity Ex; only found in heart Smooth Muscle Tissue Involuntary or visceral muscles Activated by the Autonomic Nervous System Rhythmic contractions (like peristalsis) Not striated (so called smooth) 4
Smooth Muscle Tissue Found Walls of hollow organs such as the stomach, urinary bladder, and intestines Walls of trachea and bronchi Walls of arteries and veins Skeletal Muscle Attachments Muscles are attached to bone by fleshy or fibrous connections Fleshy Attachments Muscle fibers arise directly from bone Weaker than fibrous Fibrous Attachments Muscle fibers are attached to fibrous connective tissue which attaches to bone 5
Fibrous Attachments Mix with the covering of bone Called periosteum 2 Types 1. Tendons Fibrous cords 2. Aponeuroses Fibrous sheets Sheets of fibrous attachment Can also attach muscle to muscle Ex; Epicranial Aponeurosis Aponeurosis 6
Tendons Cords or strap of fibrous attachment Most common attachment type Ex; Bicep brachii tendons Bone to Bone Attachments Ligaments Flexible bands of fibrous tissue Hold bones together Ex; Cruciate Ligament Cross inside knee joint Cruci = cross Help to prevent anterior-posterior bone displacement 7
Important Skeletal Muscle Facts Origin Insertion Action Innervation Muscle Attachments Origin Immovable or stationary attachment to bone Insertion Movable attachment to bone Action Functions of that particular muscle Innervation Nerve that goes to that particular muscle to make it move Insertion Origin 8
Muscle Organization Muscle Cell (Fiber) Muscle Fascicle Muscle Connective Tissue Muscle Cell (Fiber) Soft and fragile Thousands of fibers are bundled together with connective tissue to form muscles 9
Muscle Connective Tissue Wrappings Support and bind muscle fibers Provide strength to muscle Provide route for entrance and exit of nerves, blood vessels Muscles Muscle Fascicle Several muscle fibers wrapped together in a bundle covered with C.T. Muscle Several fascicles wrapped together covered with C.T. 10
Naming of Muscles 1. Direction of Muscle Fibers 2. Relative Size of the Muscle 3. Location of the Muscle 4. Number or Origins Also called Heads 5. Shape of the Muscle 6. Action of the Muscle Direction of Muscle Fibers Name referenced to an imaginary line Usually vertical along midline Ex; Rectus (straight) Fibers & Fasicles run parallel to midline Ex; Rectus Abdominus 11
Naming Skeletal Muscles Relative size of the muscle Maximus; medius; minimus; brevis; longus; major; minor Ex; Gluteus maximus Naming Skeletal Muscles Location of the muscle May be named for the associated bone Ex: Biceps femoris Femur is the thigh bone 12
Naming of Muscles Number of origins Also called heads Biceps; triceps; quadriceps Ex: Triceps Brachii Naming Skeletal Muscles Shape of the muscle Ex; Trapezius Shaped like a trapezoid? 13
Naming of Muscles Action of the muscle Flexor; extensor; adductor, supinator, pronator Ex; Pronator teres Muscles Pg. 267, Figure 10-1 Picture on left Deltoid, triceps brachii, trapezius, gluteus maximus, biceps femoris, gastrocnemius, soleus, Achilles tendon. Picture on right Biceps brachii, pectoralis major, rectus abdominus, brachioradialis, masseter, orbicularis oculi, sternocleidomastoid, brachialis, 14