Connective Tissues Most diverse & abundant tissue

Main Role Strength against forces Protect organs Maintain organ shape Provide frame for muscle pull

2 Components Cells + matrix Cells Matrix ~ ground substance Fibers + “Protein Glue” + Water Non-living

Origin of ConnectiveTissue Just notice that the cells, thus tissue, thus system originates from the mesoderm, as you learned previously

Connective Tissue Cells Fibrocyte Chondrocyte Osteocyte Hematopoietic stem cell (in bone marrow) red blood cell makers

Types of Fibers Reticular keeps cells in place Collagen resists stretch Elastic allows stretch

Tissues Described By : Amount of fibers : # of cells Arrangement of fibers in matrix Type(s) of fiber in matrix Ability, function or location

Types Connective proper Cartilage Blood Bone

Connective Tissue Proper (1/4) Loose few fibers : more cells

Loose & Adipose Fiber type: almost none Function: Energy storage, protection Location Under skin Around organs Behind eyeballs Fastens kidneys

Function: scaffold for cell migration Location: lymph organs Loose & Reticular Fibers: reticular Function: scaffold for cell migration Location: lymph organs Lymph nodes bone marrow spleen

Loose & Areolar Fiber Type: collagen, reticular, elastic Function: retains water; connects epithelium to …? Location Under epithelia Around organs Surround capillaries

Dense more fibers : few cells Connective Tissue Proper (1/4) Dense more fibers : few cells  

Dense & Regular Description Parallel direction collagen & some elastic fibers High stretch strength Poor vascular supply Function stress in one direction Location Tendons & ligaments Bundle ends of muscles

Dense & Irregular Description Multi direction collagen & elastic fibers Resist stretch Function Withstand tension structural strength Location Dermis of skin digestive tract joints and organs Tension = “pulling” Sclera of eye Leather

Dense & Elastic Description Function Location Elastic fibers, very little collagen High elasticity Function Allow stretch Location Alveoli of lungs Arteries

*Cartilage (1/4) 3 types Description Avascular, no nerves Matrix up to 80% water

A. Hyaline (Glassy) Description a few collagen fibers Function Resist repetitive stress Support & reinforce cushion Location End of long bones Costal cartilage of ribs nose, trachea, & larynx

B. Elastic Description More elastic fibers A Few collagen Function Maintain shape Great flexibility Location external ear Epiglottis

C. Fibrous Description Thick collagen fibers Function Tensile strength Absorb compression Location Intervertebral discs Pubis symphysis Disc of knee joint

*Blood Tissue (1/1) Description Cells + fluid matrix + dissolved fibers Function transport gases, nutrients, & waste Location blood vessels