CONNECTIVE TISSUE

CONNECTIVE TISSUE

1. FUNCTIONS: Binds together and supports other tissues; protects and insulates organs; compartmentalises structures; is the body's main transport system (blood)

   • STRUCTURE: Ground substance (material that supports the cells and fibres; can be anything from a liquid to a gel to a solid (bone); Fibres (support the connective tissue); Cells (large variety)
     • FIBRES
       • Collagen Fibres provide toughness and strength
       • Elastin Fibres provide stretch and recoil (elasticity)
       • Reticular Fibres provide support and attachment
     • CELLS
       • OSTEOocytes are found in BONE
       • CHONDROcytes are found in CARTILAGE
       • ERYTHROcytes and LEUKOcytes are found in BLOOD
       • FIBROblasts produce FIBRES
       • ADIPOcytes are found in FAT tissue

2. BLOOD

   • Red and white blood cells in a fluid matrix (plasma); cells are blood specific; red/white blood cells and plateletc.
   • Transports respiratory gases, nutrients, wastes and other substances (body's transport system); located in blood vessels
   • Fibres come in during blood clotting

3. CARTILAGE

   • HYALINE; firm matrix; densely packed with collagen (forms hard gel); cells are CHONDROcytes or CHONDROblasts and are inside Lacunae (gaps/containers); firm but flexible (FOUND in nose tip, trachea pipe and ends of bones) ***Has poor blood circulation= takes a long time to heal
   • ELASTIC ; similar to hyaline but has MORE elastic fibres; maintains shape of a structure; great flexibility (FOUND in external ear, and epiglottis)
   • FIBROCARTILAGE; Similar matrix as of hyaline but thick collagen fibres predominate; absorbs compressive shock; tensile strength (FOUND in intervertebral discs, discs of knee joints

4. FIBROUS (proper)

   • LOOSE AREOLAR ; gel-like matrix(wobbly); protein fibres are collagen and elastin; cells are fibroblasts, macrophages, mast cells, some white blood cells; acts as a bubble wrap around the organs; important for inflammation (connective tissue gets inflamed, not muscle)
     • Found under epithelia of body, packages organs, surrounds capillaries
   • ADIPOSE TISSUE; Closely packed adipocytes (nuclei pushed to side of cell by large fat droplet); acts as a fuel source; protects/cushions (heat loss, injury)
     • Found underneath the skin, abdomen, breast, kidneys (holds them in place), around heart, eyeballs
   • DENSE REGULAR dense= packed with collagen fibres; regular= fibres parallel to each other
     • COLLAGEN; Mostly collagen fibres (parallel to each other); some elastin fibres; FIBROblast is major cell type.
       • Attaches muscles to bones/muscles,and bone to bone, withstands great tension (when pulling force is applied)
       • Found it tendons (attach muscle to bone), most ligaments(connect bone to bone around joints), aponeuroses
     • ELASTIC; Contains many elastin fibres; can stretch and recoil; maintains pulsatile flow of blood in arteries
       • Found in walls of large arteries, vertebral column ligaments, bronchial tube walls
   • DENSE IRREGULAR irregular= fibres run in different directions (can be manipulated in different directions)
     • Irregularly arranged collagen fibres; some elastic fibres; FIBROblast major cell type; withstands tension exerted in MANY directions (hence IRREGULAR); provides structural strength
       • Found in fibrous capsules of organs&joints, dermis of skin

5. BONE

   • Hard, calcified matrix; lots of collagen fibres; cells are OSTEOcytes (or osteoblasts) and are inside Lacunae; very vascular; bones have rings like tree trunks; collagen and calcium salts (what makes bones hard) are arranged into rings called LAMELLAE; osteocytes are found between these rings; red bone marrow produces both R&W blood cells
   • Bone supports and protects (by enclosing); provides levers for muscles; stores calcium, minerals, fat; marrow important for blood cell production (hematopoiesis)