Classification of connective tissues Lab Exercise 6a-2 Connective Tissue Nervous Muscle Connective Tissue Connective tissues Connective tissue proper Fluid connective tissue Supportive connecting tissue 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 1
Areolar: what to look for Fibroblasts Collagen fibers Elastic fibers Mast cells and macrophages Fibroblasts Resting fibroblasts typically have so little cytoplasm that the cells appear, by light microscopy, as "naked" nuclei Found? Throughout body, under dermis, divides skin from underlying tissues Fibroblast Adipose tissue Another lose CTP (note nucleus) Adipose: what to look for Lots of cytoplasm Slim nuclei pushed off the side Reticular tissue The third type of loose CTP Found? You know where 2
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 Dense regular strength in one direction Dense irregular strength in all directions Elastic tissue - pliable Dense regular: what to look for Dense irregular Thick parallel bundles of collagen Small fibroblasts in between bundles Found? Tendons, ligaments, deep fascia. 3
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 4
Supportive CT Cartilage gelatinous, padding Hyaline cartilage Elastic cartilage Fibrocartilage Hyaline cartilage Glasslike because fibers not visible More hyaline 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) 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. 5
Hyaline cart.: what to look for Elastic cartilage Chondrocytes and lacunae No visible fibers Where? Most joints, nasal septum Elastic Cartilage Elastic cart: what to look for Many elastic fibers in matrix Chondrocytes in lacunae May be stacked up Fibrocartilage Fibrocartilage: what to look for Irregular, wispy collagen fibers Chondrocytes Found? Intervertabral discs of spine, pads in knee joint 6
Supportive CT: Bone 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 Nervous tissue Neuron smear Large, pyramidal cell bodies Long processes extending out Found? Bones! Nervous Tissue 3 Types of Muscle Tissue Skeletal muscle: large body muscles responsible for movement Cardiac muscle: found only in the heart Smooth muscle: found in walls of hollow, contracting organs (blood vessels; urinary bladder; respiratory, digestive and reproductive tracts) Figure 4.10 7
Muscle Tissue: Skeletal Muscle Tissue: Skeletal Long, cylindrical, multinucleate cells with obvious striations Found in skeletal muscles that attach to bones or skin Figure 4.11a Muscle Tissue: Cardiac Muscle Tissue: Cardiac Branching, striated, uninucleate cells interlocking at intercalated discs Figure 4.11b Muscle Tissue: Smooth Muscle Tissue: Smooth Sheets of spindle-shaped cells with central nuclei that have no striations Found in the walls of hollow organs Figure 4.11c 8
Exercises Look at all slides Draw an example of each tissue on paper provided 11 connective tissues: 6 CTP (3 loose, 3 dense) 1 Fluid CT (blood) 4 Supportive CT (3 cartilage, 1 bone) Neurons 3 Muscle tissues Skeletal Striated Smooth Turn in on Thurs 10/25 7 drawings from 6a-1 Epithelia 15 Drawings from 6a-2 Connective+ Review sheet for lab 6a 9