2What are tissues?Tissues are collections of specialized cells and cell products that perform a limited number of functions.
3Four Basic Tissue Types Epithelial – lining and secretory tissueConnective – supportive and nutritive tissueMuscular – contracts to produce movementNervous – integration and control
4Characteristics of Epithelial Tissue Cellularity– epithelia are composed almost entirely of cells bound closely together by interconnections called cell junctions.Polarity-epithelial tissue have an exposed surface (apical cells) that either faces the exterior of the body or some internal space and a base (basal cells).Attachment—the base of the epithelium is bound to a thin basal lamina or basement membrane.
5More characteristics of Epithelial Tissue Avascularity—epithelia are avascular, which means that they lack blood vessels. They have to get their nutrients by diffusion or absorptionRegeneration—epithelial cells that are damaged or lost are continuously replaced by the stem cells in the epithelium
6Functions of Epithelial Tissue Four major functions:Provide physical protectionControl permeabilityProvide sensation (They have a large sensory nerve supply.)Produce specialized secretions (Glands)
7Naming Epithelial Tissue based on shape Epithelium is named according to shape, structure, and arrangement of cells.Shapes of Epithelium•squamous - thin and flat cells•cuboidal - cube shaped cells•columnar - column shaped cells
8Naming Epithelial Tissue based on layers simple - single layer of cellsstratified - multilayered cells
10What do you HAVE to know?-Structure, function, and location of seven epithelial tissue types-what each tissue type looks like enough to be able to identify the type from a picture
11The 7 Epithelial Tissue Types that you have to know are . . . Simple SquamousSimple CuboidalSimple ColumnarStratified SquamousStratified Cuboidal (sometimes referred to as Transitional)Pseudostratified Ciliated ColumnarKeratinized (or Cornified) Stratified Squamous
12Simple Squamous Epithelium Structure-The thinnest tissue of the body. One layer, flattened (squashed) nucleus.Function-Allows transport across membranes in lungs and capillaries. Secretes fluid in serous membranes (e.g. pericardial and pleural membranes, mesenteries).Location-Lines cardiovascular system, covers organs, forms glomerular capsules in kidney.
26Stratified Cuboidal (sometimes referred to as “Transitional”) Structure- many layered (usually 2), cube like cells, spherical (round) nucleiFunction-absorption, secretionLocation- mammary and some sweat glands.
28Keratinized Stratified Squamous Structure- there is a layer of dead cells above the stratified squamous cells (nearest the apical surface).Function-protection of areas of external, sometimes extreme abrasionLocation- Palms of hands and soles of feet.
30Summary of Epithelial Tissue Look for basement membrane and apical surface (could be a lumen).Determine how many layers there are between the basement membrane and the free or apical surface.Simple=one layer, stratified=multiple layers, pseudostratified=looks like stratified, but are all connected to the basement membraneLook at the shape of the cells nearest the apical surface.Name the cells according to the shapes.
34Tissue Notes Part 2 Muscle and Connective Tissue
35Muscle Tissue Is specialized for contraction Produces all body movement
363 Types of Muscle Tissue Smooth Muscle: Skeletal muscle: found in walls of hollow, contracting organs (blood vessels; urinary bladder; respiratory, digestive and reproductive tracts)Skeletal muscle:body muscles responsible for movementCardiac muscle:only in the heart
37Skeletal Muscle Cells Skeletal muscle cells: are long and thin are usually called muscle fibersdo not dividenew fibers are produced by stem cells (satellite cells)
38Skeletal MuscleStriated, voluntary, and multinucleatedFigure 4–18a
39MUSCLE TISSUE SKELETAL Voluntary movement Long and cylindrical Transverse striationEach fiber is multi-nuclear
40Smooth Muscle Cells Smooth muscle cells: are small and tapered can divide and regenerate
41Smooth Muscle Tissue Nonstriated, involuntary, and single nucleus Figure 4–18c
47Connective TissueThe essential characteristic that distinguishes connective tissue from the other three tissue types is that it consists of cells separated from each other by an extracellular MATRIX.
48Cell types in a Matrix -blast: create the matrix -cytes: maintain the matrix-clasts: breakdown the matrix
49Major Components of the Matrix Protein fibersCollagen-very strong and flexible but not elasticReticular-thin and “fillers” of spaceElastin-elasticGround Substance with non-fibrous proteins and other molecules.BoneCartilageFluidBlood
50Classification of Connective Tissue Fibrous Connective TissueLoose Connective TissueAreolarDense Connective TissueRegular-very strong in one direction (tendons and ligaments)Irregular-less strength but in many directions (dermis of skin)
51AreolarStructure- has a viscous matrix with an irregular arrangement of fibersFunction-loose packing, support, and nourishment for the surrounding structuresLocation-widely distributed throughout the body; fascia, which attaches the skin to underlying tissue
53AdiposeStructure-Little extracellular material. The adipocytes, or fat cells, are so full of lipid that the cytoplasm is pushed to the periphery of the cell.Function-Insulation, packing material, energy storage, and protection of organsLocation-mesenteries, subcutanous area (below the skin) and surrounding organs
55Fibrous (Dense or Collagenous) Structure-Matrix composed of collagen fibers running in (somewhat) the same direction.Function-Withstand great pulling forces with great tensile strength and stretch resistance.Location-Tendons and Ligaments
56Dense Fibrous Tendon (connects muscle to bone—muscle stretches) Ligament (connects bone to bone—ligament stretches)
57Cartilage (Hyaline)Structure-Collagen fibers are small and evenly dispersed in the matrix. The cartilage cells, or chondrocytes, are found in spaces, or lacunae, within the rigid matrix.Function-Allows growth of long bones. Provides rigidity with some flexibility.Location-Growing long bones, costal cartilage of ribs, nasal cartilage, articulating surface of bones.
59Bone (Compact)Structure-Hard matrix with osteocytes within lacunae that are distributed around the central canalFunction-Provide strength and support. Forms the outer shell of bonesLocation-Shafts of long bones, outer shell on all bones