Vertebrate/Human Tissues

1. 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)

2. Review of Cell Struture

3. 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)

4. Collagen

5. Collagen & Elastin

6. 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

7. Basal Lamina

8. Basement Membrane epithelial cell

9. 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

10. Epithelial Tissues Pseudostratified columnar

11. Epithelial Tissues - Examples

12. 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).

13. 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

14. Connective Tissue Types

15. Connective Tissue Types

16. Areolar & Adipose Tissue

17. Dense Regular, Dense Irregular, & Elastic Conn. Tissue

18. Hyaline, Fibro-, & Elastic Cartilage

19. Bone, Blood, & Mesenchyme

20. 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

21. Muscle Tissues

22. 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

23. Neuron

24. Neuron & Glial Cells