Where do you find CT?

What are the fibers in CT? What cells hang out in CT?

Connective Tissue Holding it all together!

Connective tissue is found everywhere! Main types: 1. Connective tissue proper –  We will focus on this one most of next week! 2. Cartilage 3. Bone 4. Blood

Properties 1. common origin  Mesenchyme  Mesenchyme is an embryonic tissue  From the mesoderm Ectoderm Endoderm 2. degrees of vascularity 3. great degree of “non-living” extracellular matrix  What do we mean non-living?

Connective Tissue – essential functions 1.Binds structures 2.Provides support and protection 3.Insulation 4.Transportation 5.Energy storage

Structural elements: 1.Ground substance (matrix) 2.Fibers 3.Cells Wide range of varying tissue! Different structures  different functions!

Ground Substance (matrix) Unstructured material Fills spaces/contains fibers Composed of: 1.interstitial fluid 2.cell adhesion proteins  glue like function 3.Proteoglycans  protein core (point of attachment) “GAGs” glycosaminoglycans 1.(interlock trapping water)

Major Cell Types: Blasts vs. Cytes Fibroblasts- cells that produce fibers by secreting proteins into the matrix of CT tissue Macrophages- originate as WBCs specialized cell  phagocytosis Mast Cells- release heparin  prevents blood clotting, release histamine  promotes reactions associated with inflammation and allergies.

Fibroblast—laying matrix

CONNECTIVE TISSUE-3 FIBER TYPES A. Collagenous fibers- Thick threads of protein (collagen) Grouped in long parallel bundles, they are flexible, but only slightly elastic. Great tensile strength (ligaments and tendons)

B. Elastic fibers- Composed of protein elastin These fibers branch, forming complex networks. weaker than collagenous fiber  however they stretch and can return back to there shape

Elastic Fibers

C. Reticular Fibers Very thin collagenous fibers Highly branched, form supporting networks (LIKE A NET)

Reticular Fibers

When it comes to CT you can have a variety of types…. Loose CT 1.areolar tissue 2.Reticular tissue 3.Adipose tissue Dense   Regular  Irregular  Cartilage types

I. Loose Connective Tissue Loose Connective Tissue Forms delicate thin membranes throughout the body Main cell  Fibroblasts separated by a gel- like matrix Binds skin to underlying organs and fills spaces between muscles Lies beneath epithelium

2 Adipose Tissue FAT , develop when certain cells store fat in droplets within their cytoplasm. Beneath the skin, stored in many other locations as well. Cushions, insulates, stores energy.

3 regular or irregular Dense Connective Tissue  regular or irregular Closely packed, thick, collagenous fibers and a close network of elastic fibers. Relatively few cells  most of which are fibroblasts. VERY STRONG TISSUE

4 Cartilage Rigid CT  provides support, frameworks, and attachments, protects underlying tissue forms structural models for developing bone. Cartilage matrix  abundant, largely composed of colagenous fibers embedded in a gel-like ground substance.

Cartilage  a special case SPECIAL CARTILAGE CELLS  CHONDROCYTES, occupy small chambers called lacunae

Cartilage structures are enclosed in a covering of CT  perichondrium (contains the blood vessels that deliver nutrients) THE INTERCELLULAR MATRIX DISTINGUISHES THE TYPE OF CARTILAGE!

Hyaline Cartilage *most common type *very fine collagenous fibers (looks like white glass) Location: end of bones, joints, soft part of nose, trachea

Elastic Cartilage Dense network of elastic fibers Much more flexible than hyaline cartilage Location: framework of ear, parts of larynx

Fibrocartilage Tough tissue, contains many collagenous fibers -shock absorber for structures subjected to pressure. Location: vertebrae (discs), knees, pelvic girdle.