Vertebrate/Human Tissues  Epithelial = sheet of cells; attached to basement “membrane” of collagen and other protein (covers surfaces; avascular)  Connective = cells scattered in an acellular matrix (binds, supports, & protects; vascular or avascular)  Nervous / Neural = neurons and their supporting cells (transports electric signals; technically vascular)  Muscle = elongate cells that contract (causes more rapid movement; vascular)

Review of Cell Struture

Extracellular Fibrous Proteins  Collagen = complex triple-coil proteins - Type I Collagen = unbranched; more “tough” (form “collagen fibers”) - Type II Collagen = unbranched (form most basic “cartilage fibers”) - Type III Collagen = branched; more flexible (form “reticular fibers”) - Type IV Collagen = branched; (form much of basal lamina of epithelia)  Elastin = Proteins that coil; can pull straight & return to coiled shape (elastic fibers)

Collagen

Collagen & Elastin

Epithelial Tissues  Basement membrane = 2-layered sheet to which epithelial cells are attached Basal lamina = type IV collagen & other components secreted by epithelial cells Reticular lamina = type III collagen & other components secreted by underlying connective tissue cells  basal surface = basement membrane (b. m.) surface (attached to connective tissue)  apical surface = surface opposite b.m., exposed externally or to an internal cavity

Basal Lamina

Basement Membrane epithelial cell

Epithelial Tissues - Cells  simple = one layer of cells  stratified = more than one layer of cells  cuboidal = cells about as wide as tall  columnar = cells taller (apical-basal) than wide  squamous = cells wider than tall (a. to bas.)  pseudostratified columnar epithelium = technically simple because all cells contact b.m., few “cuboidal” cells at b.m., columnar cells reach from b.m. to apical surface  transitional epithelium = stratified irregular cells, some apical cells large & binucleate

Epithelial Tissues Pseudostratified columnar

Epithelial Tissues - Examples

Connective Tissues Defined by the abundant extracellular matrix. (Blood is often the odd one.)  Most connective tissue (all except mature blood) have collagen fibers.  All connective tissues have cells and ground substance.  Ground substance is primarily water with proteins and carbohydrates. It may be very fluid (blood), semisolid (cartilage), or solid (bone).

Connective Tissue Cells  Fibroblasts = fibrous connective tissue cells with tapered ends  Adipocytes = fat cells; store fats  Chondrocytes = rounded cartilage cells (chondroblasts → chondrocytes)  Osteocytes = bone cells w/ small processes (osteoblasts → osteocytes)  Osteoclasts = dissolve bone; bone remodeling  Mesenchyme cells = stem cells that divide to repair or grow tissue

Connective Tissue Types Conn. Tissue (example) Most Common Cells FibersGround Substance Areolar (in hypodermis) Fibroblasts, Few adipocytes Much type I collagen & elastin Gel-like Adipose (in hypodermis) Few fibroblasts, Adipocytes Much type I collagen & elastin Gel-like Reticular (in spleen) Fibroblasts, Many leucocytes Much type III collagen (reticular) Gel-like Dense Regular (in tendons) Fibroblasts Much type I collagen Small amount of gel-like Dense Irregular (in dermis) Fibroblasts Much type I collagen Gel-like Elastic (in arteries) Fibroblasts Much elastin & some type I collagen Gel-like

Connective Tissue Types Conn. Tissue (example) Most Common Cells FibersGround Substance Hyaline Cartilage (larynx cartilages) Chondrocytes Type II collagen; No elastic Chondroitin sulfate semi-solid gel Fibrocartilage (knee meniscus) Chondrocytes Type I AND type II collagen;; Little or no elastic Chondroitin sulfate semi-solid gel Elastic Cartilage (ear cartilages) Chondrocytes Type II collagen AND much elastin Chondroitin sulfate semi-solid gel Bone (bones) Osteocytes Much type I collagen; No elastin CaPO 4 BloodLeucocytes; Erythrocytes ABSENT Liquid/fluid (plasma) Mesenchyme (developmental) Mesenchyme Multiple types of collagen Gel-like

Areolar & Adipose Tissue

Dense Regular, Dense Irregular, & Elastic Conn. Tissue

Hyaline, Fibro-, & Elastic Cartilage

Bone, Blood, & Mesenchyme

Muscle Tissues Defined by the the ability to contract using fibers (actin & myosin).  Skeletal Muscle = long, unbranched, multinucleate cells with distinct lines; voluntary  Cardiac Muscle = short, branched, uninucleate cells with distinct lines; involuntary  Smooth Muscle = short, unbranched, uninucleate cells without distinct lines; involuntary

Muscle Tissues

Nervous/Neural Tissues Cells that send electrical then chemical signals and any associated cells.  Neuron = Cells with long processes that can receive and send signals. Axon Dendrites  Glial Cells = Cells that support or assist neurons

Neuron

Neuron & Glial Cells