1. How are these cells different? A.A. B.B. C.C. D.D. pancake Circle, bricks, boxes Vertical, long, compact Puzzle pieces, vertical

2. Connective Tissue

3. General Characteristics Support, protection, binding Most diverse Widely distributed within ECM – Lots of distance between bone cells Vascularized – Exceptions: tendons/ligaments, Cartilage ECM = fibers/ground substance Rigid (bone, cartilage) or loose (adipose, dense)

4. 3 common features 1.Cellular component Blast cells are responsible for secreting extracellular and fibrous components 2.Extracellular matrix: Non-living ground substance secreted by cellular component (see next slide) Ex: solid in bone is created by osteoblasts 3. Fiber component: usually produced by cellular component (fibroblasts) a)Collagen b)Elastin

5. Extracellular Matrix ECM Function: supports cells, binds them together, stores water, provides a medium through which substances are exchanged between the blood and cells

6. Connective Tissue Fibers Collagenous Fibers Elastic Fibers Made of what protein? Collagen (thick threads) Elastin What shape? Long, parallel bundles Thin, branch into networks StrengthTensile (strong)Weaker Flexibility Some, not like elastic Stretch Found where? Fibroblasts produce connective tissue fibers secreted in the extracellular matrix.

7. Connective Tissue I.Loose II.Adipose III.Dense IV.Cartilage V.Bone VI.Blood

8. I. Loose Connective Tissue First glance:

9. Loose, gel-like ECM with collagenous and elastic fibers Function: Binds organs together, holds tissue fluids Where: – beneath skin – between muscles – beneath epithelial tissues

10. II. Adipose Tissue First glance:

11. Adipocyte cells store fat in droplets Enlarge around other cell types Function: cushions, insulates, stores energy Where: beneath skin, behind eyeballs, surface of heart

12. III. Dense Connective Tissue First glance:

13. Few cells, but they are closely packed; Blood supply is slow Thick collagenous fibers but also elastic: flexible but withstand pulling Function: Binds organs together Where: tendons, ligaments, deeper layers of skin Why don’t Achilles tendon injuries repair easily? – Blood supply is slow  repair from blood is slow

14. IV. Cartilage First glance:

15. Rigid Function: support, frameworks, attachments; protection; models for developing bones Collagen fibers Chondrocytes found in chambers called lacunae Lacunae is surrounded by ECM with collagenous fibers Looks smooth, rubbery

16. Types of cartilage Type depends on the ECM A.Hyaline: (Shown previously) -Fine collagenous fibers in ECM -Important for bone growth -Where? End of bones, in joints, nose, rings of resp. passages B.Elastic C.Fibrocartilage

17. B. Elastic cartilage Elastic fiber network  more flexible Where? External ears, part of larynx

18. C. Fibrocartilage Many collagenous fibers Absorbs shock for structures under pressure Where? Pads between bones (discs in vertebrae); cushions bones in pelvic girdle, knees

19. V. Bone First glance:

20. Where? Bones of skeleton Function? Support (internal body structures), protect (cranial, thoracic cavities), provide framework (muscles attach) Rigid: mineral salts between cells ECM has collagenous fibers: Flexible, reinforce mineral salts in bone

21. Lamellae: layers of bone matrix; concentric circles around canals Central canals: empty cavity at center Osteocytes: bone cells, found in lacunae Lacunae: house bone cells, evenly spaced between lamellae

23. Osteocytes and EXM layers (concentric) for osteon – Many osteons cemented together form bone Each central canal has a blood vessel: gives nutrient supply Canaliculi: cellular processes that connect with membranes of nearby cells – Materials move rapidly between blood vessels and bone cells – Bone is very active that heals faster than cartilage

24. VI. Blood First glance:

25. Function: transports materials between interior body cells and those that exchange material with external environment – Ex: gas exchange in the lungs Maintains stable environmental conditions Parts of blood: formed elements suspended in ECM – ECM = blood plasma – Formed elements = red blood cells, white blood cells, platelets Made in red marrow, hollow parts of bone