Connective Tissue *The most abundant of the tissue types* I. Consists of: A. Cells

1. Connective Tissue *The most abundant of the tissue types* I. Consists of: A. Cells B. Matrix ~ amorphus substance - ground substances (glycosaminoglycad ~ repeating units of hexose(6C) sugar with nitrogen; glycoproteins - fibers (3) - provide strength and support

2. 3 types of fibers: 1. Collagen Fibers: 60% of protein in bone and cartilage; 50-90% of dry weight of skin, ligaments, tendons, and dentine (stain pink) tough fibers found in bone, cartilage, tendons, and ligaments 2. Elastic Fibers (stain purple) -can stretch -found in skin, blood vessels, lungs 3. Reticular Fibers (stain purple) -provide support -found in blood vessels, fat cells, nerve fibers, and muscle

3. II. Connective Tissue features - abundant matrix with few cells - usually does not occur on free surfaces - has a nerve supply (except cartilage) - vascular (except cartilage) - may be fluid, semifluid, gelatinous, fibrous, or calcified matrix. Cells of connective tissue secrete the matrix of the tissue.

4. III. Connective Tissue Cells - mature cells end in -cyte Ex. osteocyte, chondrocyte - immature cells end in -blast Ex. Fibroblast, chondroblast, osteoblast - destroying cells end in -clast Ex. osteoclast CT Cell Types: 1. fibroblasts – secrete fibers; most numerous 2. macrophages – phagocytic WBC - wanders through CT to fight infections 3. Plasma Cells – secrete antibodies to aid in immunity

5. Cell Types, cont. 4.Mast cells – produce histamine to dilate blood vessels in reaction to injury and infection; secrete heparin to prevent excessive blood clotting 5. Adipocytes – store energy in form of fat 6. Leukocytes – white blood cells - increase in number to fight infection

6. Connective Tissue Types A. Loose Connective Tissue 1. Areolar Connective: 2. Adipose Connective 3. Reticular Connective B. Dense Connective Tissue 1. Dense Regular 2. Dense Irregular 3. Elastic Connective C. Cartilage 1. Hyaline cartilage 2. Fibrocartilage 3. Elastic cartilage D. Osseous (bone) E. Vascular (blood)

7. Areolar • gel-like matrix with fibroblasts, macrophages, mast cells and collagen and elastic fibers; • beneath epithelium, covering ventral organs; • functions in diffusion of nutrients and gases; wraps and cushions organs

9. Adipose • Closely packed adipocytes (fat cells) with nuclei pushed to one side within matrix • Location=under skin and around kidneys and eyeballs, breasts • Functions: energy store, insulation, protection

11. Reticular • Network of reticular fibers within loose ground substance and reticulocytes • Location = basement membranes and lymphatic organs (lymph nodes, thymus, spleen) • Function = support

13. Dense Regular • Primarily collagen fibers (pink) with few fibroblasts (you can only see nuclei) • Location = tendons, ligaments • Functions = attachment, tensile strength • Poor blood supply=slow to no healing

16. Dense Irregular • Primarily collagen fibers randomly arranged • Location = dermis of skin, heart valves • Function = primarily provides tensile strenth

17. Elastic Connective • Primarily elastin fibers (purple) • Location – lung tissue, wall of aorta, • Funciton = durability with stretch

19. Hyaline Cartilage • Amorphous (chondroitin and glucosamine) matrix that surround cells = chondrocytes (within lacunae) • Locations = embryonic skeleton, costal cartilages, cartilage of the nose, trachea, and larynx • Function = support • Avascular = no healing

21. Fibrocartilage • Less firm than elastic cartilage • Locations = intervertebral discs, pubic symphysis • Functions = tensile strength plus shock absorber

22. Elastic Cartilage • Amorphous matrix that surrounds cells called chondrocytes; elastic fibers present • Locations = external ear, epiglottis • Functions = maintenance of shape plu flexibility

23. Osseus (bone) • Hard, calcified matrix with collagen fibers and cells = osteocytes within lacunae • Location = bones of skeleton • Functions = protection, support, movement, calcium store, and hematopoiesis • Highly vascular = fast healing

24. Vascular (blood) • Red cells (erythrocytes), white cells (leukocytes), and platelets (thrombocytes) in a fluid matrix called plasma • Location = within heart and blood vessels • Function = transport of gases, nutrients, and wastes

25. Skeletal Muscle Tissue • Structure: long thin cells (fibers) with many nuclei; alternating areas of light and dark (striations) • Locations: attached to bones • Function: move bones of skeleton • Control: voluntary = conscious

26. Cardiac Muscle Tissue • Structure: network of cells with one centrally located nucleus; intercalated discs (where 2 cells meet); striations • Location: heart • Function: to pump blood from heart to lungs and from lungs to heart • Control: involuntary = unconscious

27. Smooth Muscle Tissue • Structure: spindle-shaped cells with one centrally located nucleus; no striations • Location: walls of hollow visceral organs; walls of blood vessels; attached to hair follicles in the dermis • Function: movement of food through digestive tract; vasoconstriction • Control: involuntary = unconscious

28. Nervous Tissue • Structure: Primary cells = neurons which respond to changes in their surroundings (stimuli) • Neurons are surrounded by neuroglia (supporting cells) • Locations:Brain, Spinal Cord, Nerves • Function: Coordination or integration of body parts (to transmit signals from body parts to brain and from brain back to body parts) • No reproduction of neurons, only neuroglia can divide