1. Connective tissue

2. § Connective Tissue (CT) Overview
Most abundant and variable tissue type
3 structural elements –
Consists mostly of (a) G________; (b) F_______
(c) with widely spaced cells
Functions of CT:
Binding of organs --Ex. a tendon connects muscle to bone
Support, protection, movement -- Ex. bones
Storage – (energy, electrolytes) Ex. Fats/bones
Transport -- Ex. Blood

3. § 1. Ground Substance of C.T.
Gelatinous or rubbery material found in between cells – Function?
Consists of 3 classes of large molecules
Glycosaminoglycans (GAGs) –
Polysacharides that attract sodium & hold water
Ex.--
Proteoglycan is bottlebrush-shaped molecule
Forms thick gel that slows the spread of pathogens
Cell adhesive glycoproteins
Allow themselves bind to matrix elements 3

4. § 2. Fibers of C.T. Collagen fibers--called white fibers (Fig. 5.13)
Most abundant protein of the body
Thick, tough, resist stretch yet flexible
Ex. tendons, ligaments & dermis
Elastic fibers--called yellow fibers
made of E______; recoil like rubberband (elasticity)
Ex. skin, lungs & arteries; ability to recoil
Reticular fibers
Thin collagen fibers coated with glycoprotein
Ex. form framework for spleen & lymph nodes 4

5. Figure 5.13
Collagen
Tendons (collagen)

6. § 3. Cells of C.T. Fibroblasts -- produce fibers & ground substance
WBCs -- wander (mostly in CT) in search of bacteria
Macrophages – large phagocytic cells-- arise from monocytes (WBC); function? phagocytosis
Plasma cells -- arise from lymphocytes; antibody-producing cells
Mast cells – oval shaped; clustered along blood vessels; secrete heparin and histamine
Adipocytes or fat cells --store triglycerides

7. Connective tissue A. Fibrous CT

8. § Five Types of Fibrous C.T.
Divided into 2 broad categories:
Loose CT (3 slides followed)
contains MORE gel-like ground substance between cells
3 types: A--areolar, B--reticular, C--adipose tissue
Dense CT (2 slides followed)
FIBERS fill the spaces between cells
2 types varying in fiber orientation: D--dense regular, E--dense irregular 8

9. § A-- Areolar Tissue Fig. Mesentery
Loose arrangement of collagenous and elastic fibers; scattered cell types; abundant ground substance
Locations-- Underlying all epithelia; surrounding nerves, blood vessels, esophagus, trachea

10. § B-- Reticular Tissue Fig. Spleen
Loose network of R_________ and cells
Forms structural supportive stroma for lymphatic organs
Locations-- lymph nodes, spleen, thymus & bone marrow
Fig. Spleen

11. § C-- Adipose Tissue (Fat)
Large, empty-looking cells dominate with thin margins; nucleus pressed against cell membrane; often very pale
Functions-- Energy storage, insulation, space filled as cushioning
Locations-- Subcutaneous fat beneath skin, breast, heart surface, surrounding organs

12. Figure 5.16b
Fig. Adipose tissue

13. § D-- Dense Regular CT
Structure-- Mainly densely, PACKED, PARALLEL C__________FIBERS; compressed fibroblast nuclei; scanty open space and blood vessels
Locations-- Tendons & ligaments 13

14. D-- Dense Regular CT
Fig. Tendon

15. § E-- Dense Irregular CT
Densely packed collagen fibers running in ________ directions; scanty open space; few visible cells and blood vessels
Function-- Withstands stresses applied in MANY DIFFERENT DIRECTIONS
Locations-- Deeper portion of skin; capsules around organs (ex. Liver, kidney etc); sheaths around cartilages and bones.

16. E-- Dense Irregular CT
Fig. Dermis of the skin 16

17. Connective tissue B. Cartilage, Bone, Blood

18. § Cartilage Supportive CT with rubbery matrix
Chondroblasts produce matrix, surround themselves, and become Chondrocytes
No blood vessels; so diffusion must bring in nutrients & remove wastes; healing . . .
3 types of cartilage depend upon FIBER TYPES
A--hyaline, B--elastic, and C--fibrocartilage

19. § A-- Hyaline Cartilage
Clear, glassy matrix; invisible fine dispersed collagen fibers; chondrocytes in small clusters enclosed in lacunae
Supports airway, eases joint movements
Locations-- Over ends of bones at movable joints; sternal ends of ribs; supportive material in larynx, trachea, bronchi and fetal skeleton

20. Figure 5.19b
Fig. Fetal skeleton

21. § B-- Elastic Cartilage
Hyaline cartilage with weblike mesh of elastic fibers amid the lacunae; always has perichondrium (a sheath of C.T.)
Provides flexible, elastic support
Locations— Ear + Epiglottis

22. Figure 5.20b
Fig. External ear

23. § C-- Fibrocartilage
Cartilage containing extensive parallel Collagen fibers; never has perichondrium; row of chondrocytes in lacunae
Resists compression and absorbs shock in some joints
Locations-- Pubic symphysis, menisci (pads) in knee joint, & intervertebral discs

24. Fig. Intervertebral disc
Figure 5.21b
Fig. Intervertebral disc

25. § Bone (osseous tissue)
Spongy bone looks spongy in appearance
fills heads of long bones
delicate struts of bone
ALWAYS COVERED BY COMPACT BONE
Compact (dense) bone looks solid
No space visible to the naked eye
External surfaces of ALL bones

26. § Compact bone
Calcified matrix in concentric lamellae around central (haversian) canal containing blood vessels
osteocytes in lacunae between lamellae connected by canaliculi— delicate narrowing canals . . .
Physical support; leverage for muscles; mineral storage
Locations-- in skeleton

27. Canaliculi ?
Fig. Compact bone 27

28. § Blood
Variety of cells and cell fragments; some with nuclei & some without
RBC, WBC, platelets
Found in heart and blood vessels

29. Fig. Blood smear 29