Lab Exercise #8 Connective Tissue

Characteristics of Connective Tissues Specialized cells Solid extracellular protein fibers Fluid extracellular ground substance These latter two extracellular features are called Matrix

The Matrix The extracellular components of connective tissues (fibers and ground substance): majority of volume determines specialized function e.g. connective tissue proper  syrupy liquid cartilage  gel-like matrix blood  fluid matrix bone  crystalline solid

Classification of connective tissues

Lab #8. Connective Tissue Today’s Lab Lab #8. Connective Tissue

Connective Tissue Connective tissue proper Fluid connective tissue Supportive connecting tissue

Connective tissues Bone Connective tissue proper Loose connective tissue Areolar Adipose Reticular Dense connective tissue Dense regular Dense irregular Elastic tissue Fluid CT Blood Supporting CTs Cartilage Hyaline cartilage Elastic cartilage Fibrocartilage Bone

Areolar tissue A loose CTP

Areolar

Areolar: what to look for Fibroblasts Collagen fibers Elastic fibers Mast cells and macrophages Found? Throughout body, under dermis, divides skin from underlying tissues

Fibroblasts Resting fibroblasts typically have so little cytoplasm that the cells appear, by light microscopy, as "naked" nuclei

Fibroblast

Adipose tissue Another lose CTP (note nucleus)

Adipose: what to look for Lots of cytoplasm Slim nuclei pushed off the side Found? You know where

Reticular tissue The third type of loose CTP

Reticular tissue

Reticular: what to look for Reticular fibers (network) Found? Internal framework in many sort organs (liver, spleen) supporting the parenchyma

Dense CTP Dense regular – strength in one direction Dense irregular – strength in all directions Elastic tissue - pliable

Dense regular

Dense regular: what to look for Thick parallel bundles of collagen Small fibroblasts in between bundles Found? Tendons, ligaments, deep fascia.

Dense irregular

More dense irregular

Dense irregular: what to look for Mesh of collagen fibers (irregular looking) Interspersed fibroblasts Found? Dermis of skin, periosteum, perichondrium

Elastic tissue

Elastic tissue: what to look for Elastic fibers (instead of collagen fibers) in large bundles Fibroblasts Found? Between vertebrae, in blood vessel walls (underneath endothelium)

Fluid CT Blood

Blood: what to look for RBCs White blood cells (darker): monocytes, lymphocytes, granulocytes Platelets

Supportive CT Cartilage – gelatinous, padding Hyaline cartilage Elastic cartilage Fibrocartilage

Hyaline cartilage Glasslike because fibers not visible

More hyaline There are collagenous and elastic fibers lying in the cartilage matrix but they are invisible because their “refractive index” is the same as that of the matrix (like cornea)

More hyaline

Hyaline cartilage

Hyaline Hyaline cartilage (lavender matrix), with perichondrium (pink) outside it. The latter is a dense regular collagenous CT. Cartilage cells = chondrocytes, and they are lying in the lacunae.

Hyaline cart.: what to look for Perichondrium Chondroblasts (make the matrix fibers and ground) Chondrocytes and lacunae Where? Most joints, nasal septum

Elastic cartilage

Elastic cart: what to look for Many elastic fibers in matrix Perichondrium Chondroblasts Chondrocytes in lacunae

Fibrocartilage

Fibrocartilage: what to look for Irregular, wispy collagen fibers Chondrocytes Found? Intervertabral discs of spine, pads in knee joint

Supportive CT: Bone

Detail of lacuna, showing radiating canaliculi Detail of lacuna, showing radiating canaliculi. Tissue fluid from the capillaries and connective tissue of the Haversian canal can seep through these spaces and channels, bringing nutrients to the stellate osteocytes residing there.

Bone: what to look for Osteon (whole circular structure) Concentric lamellae (of matrix) Central canal (at center of lamellae) Osteoblasts Osteocytes in lacunae Canaliculi Found? Bones!

Exercises Look at all slides Draw an example of each tissue (11) on paper provided 6 CTP (3 loose, 3 dense) 1 Fluid CT (blood) 4 Supportive CT (3 cartilage, 1 bone) Due next Tuesday (6/3)

Turn in next Tuesday Drawings of 11 tissues Lab Report 8 (A,B,E)