Skeletal System/Tissues/Joints/Skeletal Muscle (Skeletal System/Tissues…
Skeletal System/Tissues/Joints/Skeletal Muscle
Major Functions of Skeletal System
Support. Framework for soft tissues.
Movement. Assists along with muscles
Protection. Cranium, vertebrae, rib cage all protect vital organs.
Mineral Storage. Calcium & Phosphate
Production of Blood Cells. Inside bones (Red Marrow).
Energy Storage. Yellow Marrow serves as fat-nutrient storage.
Major Structural Components
Bone tissue includes all of the cells plus extracellular matrix
Tendons: Link Muscle to Bone (Dense Regular C.T.)
Ligaments: Link Bone to Bone (Dense Regular C.T.)
Meniscus of Knee
Articular Cartilage. Covers ends of Long Bones
Epiglottis, Outer Ear
Covers ALL bones
Perforating Canals: Joins two central canals of Osteons
Covered in PERIOSTEUM: Dense Irregular C.T.
Ends of Long Bones, in Coxal Bones, and Fills Spaces Between Compact Bone
Trabeculae are the little structural bits (spindles) of bone that make up spongy bone
ENDOSTEUM: Covers trabeculae.
Long Bone Components
Medullary Cavity (Yellow Marrow)
Compact Bone (Diaphysis)
Spongy Bone (Epiphyses) (Red Marrow)
Epiphyses (proximal/distal ends)
Periosteum: Covers Compact Bone. 2 layers. Outside is D.I.C.T. Inside layer is osteogenic. Place for tendons and ligaments to attach.
Gelatinous, soft tissue
Blood Cell forming
Fills all bones until age ~7
Remains in axial skeleton in adults
Epiphyses of Long Bones (adults)
Diaphysis of Long Bones (adults)
OSTEOGENIC: Stem cells. Found in Periosteum & Endosteum. Creates Osteoblasts.
OSTEOBLASTS: Create osteocytes. Builds up bone tissue.
OSTEOCYTE: In lacunae. Retired osteoblasts. Maintains bone tissue.
OSTEOCLASTS: Found in Endosteum. Fusion of several Leukocytes. Has Microvilli which secrete enzymes to break down bone. Large, multinucleate. Mobile. Phagocyte.
Very Short Interconnecting Fibers
SUTURE: No movement. Example: joints of skull bones
SYNDESMOSIS: Little movement. Bundles of Dense CT. Ex: Distal tibiofibular tarsals.
GOMPHOSIS: No movement. Ex: where tooth meets alveolus periodontal ligaments.
SYNCHONDROSIS: No movement. Hyaline Cartilage. Ex: Epiphyseal plate, 1st Rib and Manubrium.
SYMPHYSIS(SES): Slight movement. Fibrocartilage (& Hyaline). Ex: Pubic Symphysis, Intervertebral joints.
SYNOVIAL: Movement. Joint Capsule. Hyaline cartilage. Joint cavity filled with synovial fluid. Ex: Elbow joints, joints of phalanges, knee joint.
Synovial Joint Compents
Joint Capsule: 2 layers. Outer layer is continuous with periosteum and is Dense Irregular CT. Inner layer consists of Areolar CT and is the synovial membrane.
Hyaline Cartilage: Not covered in synovial membrane, covers ends of bones.
Joint Cavity: Filled with Synovial Fluid, made by the synovial membrane and nourishes cartilage. Absorbs shock.
Bursa(e): Fibrous sac (Dense Irregular CT) filled with synovial fluid. Located by joints.
Specialized Bursa: Tendon Sheath. Where lots of tendons move through a small space. Ex: Wrist, ankle, fingers, toes.
Types of Synovial Joints
PLANE JOINT: Bones glide against one another. Ex: Carpals, tarsals, intercarpal joints.
HINGE JOINT: Permits motion only in one place. Ex: Elbow, Interphalangeal joints of hand
PIVOT JOINT: Articular surface of one bone pivots around another. Ex: Proximal radioulnar joint.
CONDYLOID(LAR) JOINT: A condyle articulates with a notch or cavity. Ex: Fingers, metacarpals
SADDLE JOINT: Two bones fit, slide against one another. Ex: Thumb.
BALL & SOCKET: Ball shaped surface of one bone connects to cavity-like depression of another bone. Medial and lateral rotation. Ex: Shoulder, Hip.
Open & Close Body Passages. (Sphincter Muscle)
Contractility. Creates force or tension while pulling on attach point.
ACTIN: Protein. Thin filament
MYOSIN: Protein. Thick filament
Excitability. Responds to a stimulus and produces electrical signal.
Extensibility. Ability to stretch within limits.
Elasticity. Ability to return to original shape after contraction or extension
Connective Tissue Layers
Inside muscle tissue
RETICULAR FIBERS. Loose C.T. Creates space. Blood Cells within
Around muscle FASCICLE (a bundle of cells).
Dense Irregular CT. Has Blood vessels.
Around muscle organ
Dense Irregular CT.
Deep Fascia surrounds several muscles, they work together.
Components of Skeletal Muscle Fiber
Sarcolemma: Plasma Membrane
Myofibrils: Long cylindrical organelles
Transverse "T" Tubule: Sarcolemma goes in muscle fiber, and around myofibrils.
Sarcoplasmic Reticulum: Smooth E.R. Terminal Cistern, a storage place for calcium.
Unit Of Contraction in Skeletal Muscle
Sarcomere: Z-line to Z-line
Z-Line/disc: "Zig zags" of actin
Thin Filament: Actin
Thick Filament: Mysosin
A-Band: Myosin borders "dark band"
I-Band: Actin borders "light band"
M-Line: Anchor for Myosin