MSK Tissue Organization
Page 1: Title Slide
MSK Tissue Organization
Abigail Fredrickson, D.O.
Page 2: Connective Tissue
Connective tissue is one of the most abundant tissues in the body.
Widely distributed throughout the body.
Composed of two basic elements:
Extracellular matrix
Cells
Functions include:
Protection and support of organs and the body
Binding organs together
Storing energy as fat
Helping provide immunity
Page 3: Connective Tissue Cells
Types of connective tissue cells:
Fibroblasts: secrete fibers and ground substance
Osteoblasts: bone-forming cells
Chondroblasts: cartilage-forming cells
Macrophages: immune cells that engulf and digest pathogens
Plasma cells: produce antibodies
Mast cells: involved in inflammatory responses
Adipocytes: fat cells for energy storage
White blood cells: key role in body’s immune response
Page 4: Collagen Fibers
Collagen fibers are strong and resist pulling forces but are not stiff.
Collagen protein:
Most abundant protein in the body
Various types of collagen present in different tissues
**Types of connective tissue: **
Dense regular connective tissue: parallel bundles of collagen
Dense irregular connective tissue: irregularly arranged collagen bundles
Page 5: Fiber Types
Collagen Fibers:
Elastic Fibers:
Reticular Fibers:
Types of connective tissue fibers include collagen, elastic, and reticular fibers.
Page 6: Elastic Fibers
Elastic fibers have a smaller diameter than collagen fibers.
They branch and join together to form a fibrous network.
Elasticity:
Enable stretching and returning to original shape.
Protein composition:
Elastin
Fibrillin (a glycoprotein): adds strength and stability
Page 7: Reticular Fibers
Reticular fibers are collagen fibers arranged in fine bundles, coated with glycoprotein
Produced by fibroblasts.
Form branching networks that provide:
Support and strength for soft organs
Framework (stroma) for soft organs
Help to form the basement membrane
Page 8: Mature Connective Tissue Classifications
Loose connective tissue:
Areolar
Adipose tissue
Reticular
Dense connective tissue:
Dense regular
Dense irregular
Elastic
Cartilage:
Hyaline
Fibrocartilage
Elastic
Bone
Liquid connective tissue:
Blood
Lymph
Page 9: Musculoskeletal Connective Tissue
Types of connective tissue: liquid, loose, dense, cartilaginous, osseous.
Components:
Collagen:
Offers tensile strength
Type I: most abundant protein in the body found in ligaments, tendons, fascial tissues, and fibrous capsules
Type II: found in cartilage and intervertebral discs
Type III: found in arteries, liver, spleen, etc.
Elastic tissue: permits flexibility
Page 10: Hyaline Cartilage
Appears as resilient gel as ground tissue, bluish-white appearance.
Contains chondrocytes found in lacunae, surrounded by a perichondrium.
Location:
Ends of long bones
Anterior ribs
Nose, larynx, trachea/bronchi/bronchioles
Fetal skeleton
Function:
Provides smooth surfaces for movement at joints, flexibility, and support.
Most common cartilage type, known to be the weakest.
Page 11: Fibrocartilage
Chondrocytes scattered among thick bundles of collagen, lacking a perichondrium.
Location:
Pubic symphysis
Intervertebral discs
Menisci
Some tendons
Function:
Provides support, joins structures together with strength and rigidity.
Recognized as the strongest type of cartilage.
Page 12: Bone Tissues
Types of bone:
Compact bone: Contains osteons and lamellae
Spongy bone: Contains trabeculae and marrow
Location: Bone
Function:
Provides support and protection, stores minerals, houses blood-forming tissue, acts as levers for muscle movement.
Page 13: Bone Histology
35% organic materials:
Collagen: provides flexible strength
Proteoglycans
65% inorganic materials:
Hydroxyapatite: provides weight-bearing strength, composed of calcium and phosphate.
Page 14: Bone Cells
Different types of bone cells include:
Osteoblasts: cells that build bone
Osteocytes: mature bone cells
Osteoclasts: bone-destroying cells.
Bone matrix consists of collagen and inorganic mineral components.
Page 15: Osteoblasts
Osteoblasts are responsible for building bone tissue.
Process of ossification:
Formation of bone by osteoblasts.
Produce vesicles containing collagen and proteoglycans for matrix formation, which holds calcium and phosphate.
Page 16: Osteocytes
Osteocytes are osteoblasts that are surrounded by bone matrix and are less active.
Lacunae: Spaces in which osteocytes sit.
Canaliculi: Spaces connecting lacunae, allowing communication through processes of osteocytes.
Gap junctions facilitate cell-to-cell contact.
Page 17: Osteocyte Structure
Lacunae: Spaces occupied by osteocyte cell body
Canaliculi: Spaces occupied by osteocyte cell processes, enabling intercellular communication.
Gap junctions provide connectivity between osteocytes.
Page 18: Osteoclasts
Osteoclasts are referred to as "Pac-man cells" due to their role in bone resorption.
They are involved in the breakdown of mineralized bone, freeing calcium and phosphate.
These are large, multinucleated cells derived from macrophage lineage.
Maturation and activation are controlled by osteoblasts.
Page 19: Bone Classifications
Types of bone:
Woven vs. lamellar
Spongy vs. compact
Different organizational methods relate to collagen fiber arrangement and the matrix relative to space.
Page 20: Synovial Membranes
Synovial membranes line structures that do not open to the exterior, containing no epithelium.
They line the cavities of freely movable joints.
Components:
Discontinuous layer of synoviocytes closer to the synovial cavity
Outer layer of connective tissue (areolar and adipose)
Synovial fluid:
Provides lubrication and nourishment to cartilage and contains macrophages for immunity.
Page 21: Muscular Tissue
Functions of Muscle Tissue:
Specialized cells for contraction and generation of force
Generates heat as a byproduct of energy usage.
Page 22: Skeletal Muscle
Location: Attached to bones.
Cells: Long and cylindrical in shape, with multiple, peripherally located nuclei.
Lacks special cell-to-cell connections, is striated in appearance.
Control: Both voluntary and involuntary (e.g. reflexes), and does not exhibit spontaneous contraction.
Function: Primarily movement.
Page 23: Cardiac Muscle
Location: Located in the heart.
Cells: Cylindrical and branched with a single, centrally located nucleus.
Features intercalated disks for cell-to-cell attachments, striated in appearance.
Control: Involuntary; exhibits spontaneous contraction.
Function: Pumps blood, allowing propulsion through the circulatory system.
Page 24: Smooth Muscle
Location: Found in walls of hollow organs, blood vessels, eyes, skin, and glands.
Cells: Spindle-shaped with a single, centrally located nucleus.
Features gap junctions in visceral smooth muscle, not striated.
Control: Involuntary with some spontaneous contractions.
Function: Moves food through the gastrointestinal tract, empties the bladder, alters blood vessel diameters, and changes pupil sizes.
Page 25: Muscle Type Comparison
Skeletal Muscle:
Location: Attached to bones
Appearance: Long and cylindrical
Nucleus: Multiple, peripherally located
Striations: Yes
Control: Voluntary and involuntary (reflexes)
Capable of spontaneous contraction: No
Function: Body movement
Smooth Muscle:
Location: Walls of hollow organs and blood vessels
Appearance: Spindle-shaped
Nucleus: Single, centrally located
Striations: No
Control: Involuntary
Capable of spontaneous contraction: Yes (some smooth muscle)
Function: Moving food, regulating blood vessel diameter, etc.
Cardiac Muscle:
Location: Heart
Appearance: Cylindrical and branched
Nucleus: Single, centrally located
Striations: Yes
Control: Involuntary
Capable of spontaneous contraction: Yes
Function: Pumps blood throughout the body.