Match Tissue Type to Function 1.Epithelial 2.Connective 3.Nervous 4.Muscle A.Supports, protects, binds other tissues together B.Internal communication C.Contracts to cause movement D.Forms boundaries between different environments, protects, secretes, absorbs, filters
Epithelial Tissue (Epithelium) Two main types (by location): 1.Covering and lining epithelium 2.Glandular epithelium oblet%20cells%20.jpg Forms boundaries b/w different environments
Characteristics of Epithelial Tissue 1.Cells have polarity 2.Are composed of closely packed cells 3.Supported by a connective tissue reticular lamina (under the basal lamina) 4.Avascular but innervated 5.High rate of regeneration
Classification of Epithelia Ask two questions: 1.How many layers? 1 = simple epithelium >1 = stratified epithelium
Classification of Epithelia 2.What type of cell? Squamous Cuboidal Columnar Note: if stratified, name according to apical layer of cells!
Overview of Epithelial Tissues For each of the following types of epithelia, note: – Description – Function – Location
Simple Epithelia Single cell layer (usually very thin) Concerned with: – Absorption – Secretion – Filtration NOT concerned with: protection Simple squamous, simple cuboidal, simple columnar, pseudo stratified columnar
Simple Squamous Epithelium Description Function Location Photomicrograph: Simple squamous epithelium forming part of the alveolar (air sac) walls (125x). Note: ENDOTHELIUM AND MESOTHELIUM
Description Function Location (b) Simple cuboidal epithelium Photomicrograph: Simple cuboidal epithelium in kidney tubules (430x). Simple Cuboidal Epithelium
(c) Simple columnar epithelium Photomicrograph: Simple columnar epithelium of the stomach mucosa (860X). Simple Columnar Epithelium Description Function Location
(c) Simple columnar epithelium Pseudostratified Columnar Epithelium Description Function Location Photomicrograph: Pseudostratified ciliated columnar epithelium lining the human trachea (570x).
Stratified Epithelium 2+ cell layers Regenerate from below More durable than simple epithelia Major role: Protection
Stratified Squamous Epithelium Description Function Location Photomicrograph: Stratified squamous epithelium lining the esophagus (285x).
Stratified Cuboidal Epithelium Description Function Location
Stratified Columnar Epithelium Stratified_columnar_epithelium,_urethra-SPL.jpg Description Function Location
Transitional Epithelium Description Function Location Photomicrograph: Transitional epithelium lining the urinary bladder, relaxed state (360X); note the bulbous, or rounded, appearance of the cells at the surface; these cells flatten and become elongated when the bladder is filled with urine.
Glandular Epithelia Gland: one or more cells that secretes and aqueous fluid Classified by: – Site of product release Endocrine Exocrine – Relative number of cells forming the gland Unicellular Multicellular
Glands Endocrine Ductless glands Secrete hormones that travel through lymph or blood to target organs Examples: Thyroid Gland, Pituitary Gland Covered in Ch. 16 Exocrine Secrete products into ducts Secretions released onto body surfaces (skin) or into body cavities Examples: mucous, sweat, oil, and salivary glands More numerous!
Multicellular Exocrine Glands Composed of a duct and a secretory unit Classified according to: 1.Duct type Simple Compound 2.Structure of secretory units tubular alveolar tubuloalveolar
Figure 4.5 Compound duct structure (duct branches) Simple tubular Example Intestinal glands Simple branched tubular Example Stomach (gastric) glands Compound tubular Example Duodenal glands of small intestine Compound alveolar Example Mammary glands Simple alveolar Example No important example in humans Simple branched alveolar Example Sebaceous (oil) glands Compound tubuloalveolar Example Salivary glands Tubular secretory structure Alveolar secretory structure Surface epitheliumDuctSecretory epithelium Simple duct structure (duct does not branch)
Modes of Secretion Merocrine Products are secreted by exocytosis pancreas, sweat and salivary glands Holocrine Products are secreted by rupture of gland cells sebaceous (oil) glands
Connective Tissue Most abundant and widely distributed tissue type Four main classes 1)Connective Tissue Proper 2)Cartilage 3)Bone Tissue 4)Blood See Table 4.1
Major Functions of Connective Tissue 1)Binding and Support 2)Protection 3)Insulation 4)Stores reserve fuel 5)Transports
Characteristics of Connective Tissue Connective tissues have: – Mesenchyme as their common tissue of origin – Varying degrees of vascularity – Cells separated by nonliving extracellular matrix (ground substance and fibers) 3 Structural Elements – Ground substance – Fibers – Cells
Structural Elements of Connective Tissue Ground substance – Medium through which solutes diffuse between blood capillaries and cells – Components: Interstitial fluid Adhesion proteins ( “ glue ” ) Proteoglycans – Protein core + large polysaccharides – Trap water -> viscosity
Structural Elements of Connective Tissue Connective Tissue Fibers – Collagen (white fibers) Strongest and most abundant type Provides high tensile strength – Elastic (yellow fibers) Networks of long, thin, elastin fibers that allow for stretch/recoil – Reticular Short, fine, highly branched collagenous fibers
Structural Elements of Connective Tissue Cells (see table 4.1) – Mitotically active and secretory cells = “ blasts ” Fibroblasts, chondroblasts, osteoblasts, hematopoietic stem cells – Mature cells = “ cytes ” Chondrocytes, osteocytes –Other cell types Fat cells, white blood cells, mast cells, and macrophages
Loose Connective: Areolar Description Function Location Photomicrograph: Areolar connective tissue, a soft packaging tissue of the body (300x). CONNECTIVE TISSUE PROPER
Loose Connective: Adipose Description Function Location Photomicrograph: Adipose tissue from the subcutaneous layer under the skin (350x). CONNECTIVE TISSUE PROPER
Loose Connective: Reticular Description Function Location Photomicrograph: Dark-staining network of reticular connective tissue fibers forming the internal skeleton of the spleen (350x). CONNECTIVE TISSUE PROPER
Dense Connective: Dense Regular Description Function Location Photomicrograph: Dense regular connective tissue from a tendon (500x). CONNECTIVE TISSUE PROPER
Dense Connective: Dense Irregular Description Function Location Photomicrograph: Dense irregular connective tissue from the dermis of the skin (400x). CONNECTIVE TISSUE PROPER
Dense Connective: Elastic Description Function Location Photomicrograph: Elastic connective tissue in the wall of the aorta (250x). CONNECTIVE TISSUE PROPER
Connective Tissue: Cartilage Stands up to both compression and tension No nerve fibers, avascular 80% water Chondroblasts – produce new matrix Chondrocytes – mature cartilage cells – Found in small groups in lacunae
Hyaline Cartilage Description Function Location Photomicrograph: Hyaline cartilage from the trachea (750x). CARTILAGE
Elastic Cartilage Description Function Location Photomicrograph: Elastic cartilage from the human ear pinna; forms the flexible skeleton of the ear (800x). CARTILAGE
Fibrocartilage Description Function Location Photomicrograph: Fibrocartilage of an intervertebral disc (125x). Special staining produced the blue color seen. CARTILAGE
Connective Tissue: Bone Description Function Location Photomicrograph: Cross- sectional view of bone (125x).
Connective Tissue: Blood Description Function Location Photomicrograph: Smear of human blood (1860x); two white blood cells (neutrophil in upper left and lymphocyte in lower right) are seen surrounded by red blood cells.
Nervous Tissue Description Function Location Photomicrograph: Neurons (350x)
Muscle Tissue Highly cellular, well vascularized Movement Types 1.Skeletal 2.Cardiac 3.Smooth
Skeletal Muscle Description Function Location Photomicrograph: Skeletal muscle (approx. 460x). Notice the obvious banding pattern and the fact that these large cells are multinucleate. MUSCLE TISSUE
Cardiac Muscle Description Function Location Photomicrograph: Cardiac muscle (500X); notice the striations, branching of cells, and the intercalated discs. MUSCLE TISSUE
Smooth Muscle Description Function Location Photomicrograph: Sheet of smooth muscle (200x). MUSCLE TISSUE
Epithelial Membranes Cutaneous membrane (skin) Mucous membranes – Mucosae Line body cavities open to the exterior (e.g., digestive and respiratory tracts) Serous Membranes – Serosae—membranes (mesothelium + areolar tissue) in a closed ventral body cavity Parietal serosae line internal body walls Visceral serosae cover internal organs
Figure 4.11b Mucosa of nasal cavity Mucosa of lung bronchi Mucosa of mouth Esophagus lining (b) Mucous membranes line body cavities open to the exterior.
Figure 4.11c Parietal pericardium Visceral pericardium (c) Serous membranes line body cavities closed to the exterior. Parietal peritoneum Visceral peritoneum Parietal pleura Visceral pleura
Steps in Tissue Repair Inflammation Organization and Restored Blood Supply Regeneration and Fibrosis
Figure 4.12, step 1 Scab Blood clot in incised wound Epidermis Vein Inflammatory chemicals Inflammation sets the stage: Severed blood vessels bleed and inflammatory chemicals are released. Local blood vessels become more permeable, allowing white blood cells, fluid, clotting proteins and other plasma proteins to seep into the injured area. Clotting occurs; surface dries and forms a scab. Migrating white blood cell Artery 1
Figure 4.12, step 2 Regenerating epithelium Area of granulation tissue ingrowth Fibroblast Macrophage Organization restores the blood supply: The clot is replaced by granulation tissue, which restores the vascular supply. Fibroblasts produce collagen fibers that bridge the gap. Macrophages phagocytize cell debris. Surface epithelial cells multiply and migrate over the granulation tissue. 2
Figure 4.12, step 3 Regenerated epithelium Fibrosed area Regeneration and fibrosis effect permanent repair: The fibrosed area matures and contracts; the epithelium thickens. A fully regenerated epithelium with an underlying area of scar tissue results. 3
Developmental Aspects Primary germ layers: ectoderm, mesoderm, and endoderm – Formed early in embryonic development – Specialize to form the four primary tissues Nerve tissue arises from ectoderm Muscle and connective tissues arise from mesoderm Epithelial tissues arise from all three germ layers