Lecture 4 Cellular organization.pptx
- 1. 4-1 The Tissue Level of Organization ā¢ Group of similar cells ā common function ā¢ Histology ā study of tissues ā¢ Pathologist ā looks for tissue changes that indicate disease
- 2. 4-2 4 Basic Tissues (1) ā¢ Epithelial Tissue ā covers surfaces because cells are in contact ā lines hollow organs, cavities and ducts ā forms glands when cells sink under the surface ā¢ Connective Tissue ā material found between cells ā supports and binds structures together ā stores energy as fat ā provides immunity to disease
- 3. 4-3 4 Basic Tissues (2) ā¢ Muscle Tissue ā cells shorten in length producing movement ā¢ Nerve Tissue ā cells that conduct electrical signals ā detects changes inside and outside the body ā responds with nerve impulses
- 4. 4-4 Epithelial Tissue -- General Features ā¢ Closely packed cells forming continuous sheets ā¢ Cells sit on basement membrane ā¢ Apical (upper) free surface ā¢ Avascular---without blood vessels ā nutrients diffuse in from underlying connective tissu e ā¢ Rapid cell division ā¢ Covering / lining versus glandular types
- 5. 4-5 Basement Membrane ā¢ holds cells to connective tissue
- 6. 4-6 Types of Epithelium ā¢ Covering and lining epithelium ā epidermis of skin ā lining of blood vessels and ducts ā lining respiratory, reproductive, urinary & GI t ract ā¢ Glandular epithelium ā secreting portion of glands ā thyroid, adrenal, and sweat glands
- 7. 4-7 Classification of Epithelium ā¢ Classified by arrangement of cells into layers ā simple = one cell layer thick ā stratified = many cell layers thick ā pseudostratified = single layer of cells where all cells do nāt reach apical surface ā¢ nuclei at found at different levels so it looks multilayered ā¢ Classified by shape of surface cells ā squamous =flat ā cuboidal = cube-shaped ā columnar = tall column ā transitional = shape varies with tissue stretching
- 8. 4-8 Simple Squamous Epithelium ā¢ Single layer of flat cells ā lines blood vessels (endothelium), body cavities (mesothelium) ā very thin --- controls diffusion, osmosis and filtration ā nuclei centrally located ā¢ Cells in direct contact with each other
- 9. 4-9 Examples of Simple Squamous ā¢ Section of intestinal showing serosa ā¢ Surface view of lining of peritoneal cavity
- 10. 4-10 Simple Cuboidal Epithelium ā¢ Single layer of cube-shaped cells viewed from the side ā¢ Nuclei round and centrally located ā¢ Lines tubes of kidney ā¢ Absorption or secretion
- 11. 4-11 Example of Simple Cuboidal ā¢ Sectional view of kidney tubules
- 12. 4-12 Simple Columnar ā¢ Single layer rectangular cells ā¢ Unicellular glands =goblet cells secrete mucus ā lubricate GI, respiratory, reproductive and urinary systems ā¢ Microvilli = fingerlike cytoplasmic projections ā for absorption in GI tract (stomach to anus)
- 13. 4-13 Ex. Simple Columnar ā¢ Section from small intestine
- 14. 4-14 Stratified Squamous Epithelium ā¢ Several cell layers thick ā¢ Surface cells flat ā¢ Keratinized = surface cells dead and filled with keratin ā skin (epidermis) ā¢ Nonkeratinized = no keratin in moist living cells at surface ā mouth, vagina
- 15. 4-15 Example of Stratified Squamous ā¢ Section of vagina
- 16. 4-16 Connective Tissues ā¢ Cells rarely touch due to extracellular matrix ā¢ Matrix(fibers & ground substance secreted by cells) ā¢ Consistency varies from liquid, gel to solid ā¢ Does not occur on free surface ā¢ Good nerve & blood supply except cartilage & tendons
- 17. 4-17 Cell Types ā¢ Blast type cells = retain ability to divide & produce matrix (fibroblasts, chondroblasts, & osteoblasts) ā¢ Cyte type cells = mature cell that can not divide or p roduce matrix (chondrocytes & osteocytes)
- 18. 4-18 Connective Tissue Ground Substance ā¢ Supports the cells and fibers ā¢ Helps determine the consistency of the matrix ā fluid, gel or solid
- 19. 4-19 Types of Connective Tissue Fibers ā¢ Collagen (25% of protein in your body) ā tough, resistant to pull, yet pliable ā formed from the protein collagen ā¢ Elastin (lungs, blood vessels, ear cartilage) ā smaller diameter fibers formed from protein elastin surrounded by glycoprotein (fibrillin) ā can stretch up to 150% of relaxed length and return to original shape ā¢ Reticular (spleen and lymph nodes) ā thin, branched fibers that form framework of organs ā formed from protein collagen
- 20. 4-20 Mature Connective Tissue ā¢ Loose connective tissue ā¢ Dense connective tissue ā¢ Cartilage ā¢ Bone ā¢ Blood ā¢ Lymph
- 21. 4-21 Loose Connective Tissues ā¢ Loosely woven fibers throughout tissues ā¢ Types of loose connective tissue ā areolar connective tissue ā adipose tissue ā reticular tissue
- 22. 4-22 Areolar Connective Tissue ā¢ Black = elastic fibers, ā¢ Pink = collagen fibers ā¢ Nuclei are mostly fibroblasts
- 23. 4-23 Adipose Tissue ā¢ Peripheral nuclei due to large fat storage droplet ā¢ Deeper layer of skin, organ padding, yellow marrow ā¢ Reduces heat loss, energy storage, protection
- 24. 4-24 Reticular Connective Tissue ā¢ Network of fibers & cells that produce framework of organ ā¢ Holds organ together (liver, spleen, lymph nodes, bone marrow)
- 25. 4-25 Dense Connective Tissue ā¢ More fibers present but fewer cells ā¢ Types of dense connective tissue ā dense regular connective tissue ā dense irregular connective tissue
- 26. 4-26 Dense Regular Connective Tissue ā¢ Collagen fibers in parallel bundles with fibroblasts between bundles of collagen fibers ā¢ White, tough and pliable when unstained (forms tendons) ā¢ Also known as white fibrous connective tissue
- 27. 4-27 Dense Irregular Connective Tissue ā¢ Collagen fibers are irregularly arranged (interwoven) ā¢ Tissue can resist tension from any direction ā¢ Very tough tissue -- white of eyeball, dermis of skin
- 28. 4-28 Cartilage ā¢ Network of fibers in rubbery ground substance ā¢ Resilient and can endure more stress than loos e or dense connective tissue ā¢ Types of cartilage ā hyaline cartilage ā fibrocartilage ā elastic cartilage
- 29. 4-29 Hyaline Cartilage ā¢ Bluish-shiny white rubbery substance ā¢ Chondrocytes sit in spaces called lacunae ā¢ No blood vessels or nerves so repair is very slow ā¢ Reduces friction at joints as articular cartilage
- 30. 4-30 Fibrocartilage ā¢ Many more collagen fibers causes rigidity & stiffness ā¢ Strongest type of cartilage (intervertebral discs)
- 31. 4-31 Elastic Cartilage ā¢ Elastic fibers help maintain shape after deformations ā¢ Ear, nose, vocal cartilages
- 32. 4-32 Growth & Repair of Cartilage ā¢ Grows and repairs slowly because is avascular ā¢ Interstitial growth ā chondrocytes divide and form new matrix ā occurs in childhood and adolescence ā¢ Appositional growth ā chondroblasts secrete matrix onto surface ā produces increase in width
- 33. 4-33 ā¢ Spongy bone ā sponge-like with spaces and trabeculae ā trabeculae = struts of bone surrounded by red bone marrow ā no osteons (cellular organization) ā¢ Compact bone ā solid, dense bone ā basic unit of structure is osteon (haversian system) ā¢ Protects, provides for movement, stores mineral s, site of blood cell formation Bone (Osseous) Tissue
- 34. 4-34 Compact Bone ā¢ Osteon = lamellae (rings) of mineralized matrix ā calcium & phosphate---give it its hardness ā interwoven collagen fibers provide strength ā¢ Osteocytes in spaces (lacunae) in between lamellae ā¢ Canaliculi (tiny canals) connect cell to cell
- 35. 4-35 ā¢ Connective tissue with a liquid matrix = the plasma ā¢ Cell types = red blood cells (erythrocytes), white blood cells (leukocytes) and cell fragments called platelets ā¢ Provide clotting, immune functions, carry O2 and CO2 Blood
- 36. 4-36 Muscle ā¢ Cells that shorten ā¢ Provide us with motion, posture and heat ā¢ Types of muscle ā skeletal muscle ā cardiac muscle ā smooth muscle
- 37. 4-37 Skeletal Muscle ā¢ Cells are long cylinders with many peripheral nuclei ā¢ Visible light and dark banding (looks striated) ā¢ Voluntary or conscious control
- 38. 4-38 Cardiac Muscle ā¢ Cells are branched cylinders with one central nuclei ā¢ Involuntary and striated ā¢ Attached to and communicate with each other by intercalated discs and desmosomes
- 39. 4-39 Smooth Muscle ā¢ Spindle shaped cells with a single central nuclei ā¢ Walls of hollow organs (blood vessels, GI tract, bladder) ā¢ Involuntary and nonstriated
- 40. 4-40 Nerve Tissue ā¢ Cell types -- nerve cells and neuroglial (supporting) cells ā¢ Nerve cell structure ā nucleus & long cell processes conduct nerve signals ā¢ dendrite --- signal travels towards the cell body ā¢ axon ---- signal travels away from cell body