chapter 3

  1. tissue
    group of similar cells with a common embryological origin that do specialized tasks
  2. four types of tissue
    • Epithelial
    • Connective
    • Muscle
    • Nervous
  3. Epithelial
    • Covers body surfaces
    • lines hollow organs, body cavities, & ducts; forms glands
  4. cell junctions
    points of contact between adjacent plasma membranes
  5. tight
    Form fluid tight seals between cells
  6. anchoring
    Fasten cells to one another or to the extracellular material
  7. gap
    Permit electrical or chemical signals to pass from cell to cell
  8. three types of cell junctions
    • gap
    • anchoring
    • tight
  9. epithelial tissue characteristics
    • 1. Apical surface is the exposed surface
    • 2. Basal surface is attached to the basement membrane, which is composed of a: Basal lamina which is formed from secretions from the epithelium & the reticular lamina which is formed from connective tissue secretions
    • 3. avascular (no blood vessels)
    • 4. innervated (has nervous tissue)
    • 5. high mitotic rate
  10. types of epithelial
    • simple
    • stratisfied
    • pseudostratisfied
  11. simple epithelial
    single layer of cells

    • squamous
    • cuboidal
    • columnar
  12. stratisfied
    multiple layers of cells, but classified by the top layer

    • squamous
    • cuboidal
    • columnar
    • transitional
  13. pseudostratisfied
    single layer of cells, but due to the placement of the nuclei, it looks like its stratisfied
  14. glandular epithelium
    • ´╗┐exocrine glands
    • endocrine glands
  15. exocrine glands
    ducted glands leading to an epithelial surface
  16. types of exocrine glands
    • holocrine gland
    • merocrine gland
    • apocrine gland
  17. holocrine gland
    Epithelial cells lining the gland accumulate the secretory product inside, die, & are secreted as a whole unit - sebaceous(oil) gland of the skin
  18. merocrine gland
    Exocytotic release of secretory product- salivary & most sweat
  19. apocrine gland
    Release via the pinching off(budding) of the apical surface of the epithelial cell
  20. endocrine glands
    ductless glands; the secretory products are secreted into the extracellular matrix & diffuse into the blood stream
  21. connective tissue
    • 1. Made up of cells, ground substance, & fibers
    • 2. innervated
    • 3. vascularized
    • 4. The matrix is composed of the ground substance (glue) + fibers; matrix can vary in its consistency - fluid, gelatinous, calcified
    • 5. The matrix is derived from secretions from both the CT cells & adjacent cells
  22. connective tissue
    • 1. Fibroblasts- matrix secreting cells for loose & dense CT
    • 2. Osteoblasts- matrix secreting cells in bone
    • 3. Chondroblasts- matrix secreting cells in cartilage
    • 4. Adipocytes- fat cells for insulation & energy
    • 5. Macrophages- phagocytes
    • 6. Plasma cells - antibody production
    • 7. Blood cells- red & white
  23. connective tissue
    composition-ground substance
    • 1. Hyaluronic acid - binds cells together, joint lubrication
    • 2. Chondroitin sulfate & keratan sulfate - support & adhesiveness in cartilage, bone, blood vessels
    • 3. Dermatan sulfate - support & adhesiveness in skin
  24. connective tissue
    composition-fibers (matrix)
    • 1. Collagen fibers - collagen protein; typically occur in bundles; bone, cartilage, tendons, & ligaments
    • 2. Elastic fibers - elastin protein; freely branching; skin, blood vessels
    • 3. Reticular fibers - collagen + glycoproteins; branching, supporting network of many organs

  25. Mesenchyme
    composed of mesenchymal cells & reticular fibers; forms all other kinds of CT
  26. Embryonic connective tissue
    • mesenchyme
    • mucous CT
  27. Mucous CT
    fibroblasts & collagen fibers; found in the fetus
  28. Mature CT
    Loose CT
    • Areolar CT
    • Adipose
    • Reticular CT
  29. Areolar CT
    composed of a variety of cell types along with all types of fibers; it provides strength, elasticity, & support
  30. adipose tissue
    composed of adipocytes; it provides insulation, energy, support, & protection; subcutaneous layer of the skin, yellow marrow of long bones
  31. reticular CT
    composed of reticular cells & reticular fibers; forms the stroma(framework) of organs, binds smooth muscle cells
  32. Mature CT
    Dense CT
    • Dense regular CT
    • dense irregular CT
    • elastic CT
  33. dense regular CT
    • composed of fibroblasts & bundles of collagen fibers;
    • provides strong attachments between various structures;
    • tendons (muscle to bone), ligaments (bone to bone)
  34. dense irregular CT
    composed of fibroblasts & randomly arranged collagen fibers; it provides strength; found in membrane capsules around organs
  35. elastic CT
    composed of fibroblasts & elastic fibers; allows stretching of organs
  36. mature CT- Cartilage
    • 1. Composed of a dense network of collagen & elastic fibers embedded in chondroitin sulfate
    • 2. Collagen gives cartilage its strength
    • 3. Chondroitin sulfate gives cartilage its resilience
    • 4. Cells of mature cartilage are called chondrocytes & they are located in spaces called lacunae
    • 5. Surface of most cartilage is surrounded by the perichondrium, a layer of dense, irregular CT
    • 6. Cartilage has no blood vessels or nerves except for those in the perichondrium
  37. three types of cartilage
    • hyaline cartilage
    • fibrocartilage
    • elastic cartilage
  38. Hyaline Cartilage
    composed of thin collagen fibers that are not visible and the standard chondrocytes in lacunae
  39. fibriocartilage
    composed of bundles collagen fibers that are visible and the standard chondrocytes in lacunae
  40. elastic cartilage
    composed of elastic fibers that are visible and the standard chondrocytes in lacunae
  41. Mature CT-Bone
    • 1. Bone tissue is classified as either compact or spongy
    • 2. The basic unit of compact bone is the osteon or Haversian system
    • 3. It is comprised of a central (Haversian) canal that contains blood vessels & nerves
    • 4. Surrounding the canal are lamellae, which are concentric rings of calcified matrix which are secreted by osteoblasts which form the bone.
    • 5. The osteoblasts mature into osteocytes which are now embedded between the lamellae in spaces called lacunae, which are analogous to cartilage lacunae
    • 6. The lacunae are connected by channels called canaliculi, which allow nutrients & wastes to be transported into & out of the bone.
    • 7. Spongy bone do not possess osteons, but trabeculae, which are columns of bone containing lamellae, ostecocytes, lacunae, & canaliculi - no central canal
    • 8. Bone provides support, protection, movement, & houses blood forming tissue
  42. Mature CT-Blood
    • 1. Blood is a CT with a liquid matrix called plasma, which is
    • composed of water & dissolved solutes
    • 2. Erythrocytes are red blood cells necessary for the transport of oxygen & carbon dioxide
    • 3. Leukocytes are white blood cells which provide immunity
    • 4. Platelets function in blood clotting
  43. epithelial membranes
    • 1. Epithelial membranes are composed of an epithelial layer & an underlying layer of CT
    • 2. The principal epithelial membranes are mucous & serous
    • 3. Mucous membranes (mucosa) line body cavities that are exposed to the exterior (examples are digestive and respiratory tracts), providing a barrier to infection, lubrication, and even enzymes for chemical reactions
    • 4. Serous membranes (serosa) line body cavities that are not exposed to the exterior & cover the organs within the cavities
    • 5. The mesothelium of the serosa secretes serous fluid, providing lubrication so that the organs can easily glide against one another.
    • 6. The serosa can be divided into the parietal layer which lines the cavity, the visceral layer which covers the organs
  44. Skeletal Muscle
    • 1. Attached to bones by tendons
    • 2. They are striated- alternating light & dark bands of structures within the cells
    • 3. It is voluntary, since its contractions are under conscious control
  45. Cardiac Muscle
    • 1. Forms the bulk of the heart wall
    • 2. They are striated - alternating light & dark bands of structures within the cells
    • 3. It is involuntary, since its contractions are not under conscious control
    • 4. Cardiac muscle fibers are connected to one another at their ends by thickenings of the plasma membrane, called intercalated discs
    • 5. The intercalated discs contain both adhering & gap junctions
    • 6. The gap junctions allow electrical impulses to move rapidly through the heart, providing a smooth continuous contraction that is necessary for pumping blood
  46. Smooth Muscle
    • 1. It is located in the walls of hollow organs (blood vessels, digestive tract)
    • 2. They are not striated, involuntary, & some possess gap junctions
    • 3. They provide for involuntary movement of material & mixing
  47. Nervous Tissue
    • 1. Nervous tissue is composed of two cell types: neurons & neuroglia
    • 2. Neurons are the structural & functional units of the nervous system. They respond to stimuli & control the body to react to that stimuli.
    • 3. Structurally the neuron is composed of a cell body, dendrites (specialized structures that receive & conduct nerve impulses (information) to the cell body, & an axon (which conveys the information to the next cell)

    • 4.
    • Neuroglia are support cells that maintain proper neuron functions
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chapter 3