1. A Study of Tissues

2. #1. I can list several structural characteristics of epithelial tissue.

3. Characteristics of Epithelial Tissue Cellularity. Epithelial tissue is composed almost entirely of close-packed cells. Specialized contacts. Epithelial cells fit close together to form continuous sheets. Polarity. All epithelia have an apical surface which is exposed to the body exterior or a cavity of an internal organ and an attached basal surface. Polarity refers to the fact that cells at the apical surface differ from cells at the basal surface.

4. Characteristics continued. Supported by connective tissue. All epithelial sheets rest upon and are supported by connective tissue. Innervated but avascular. Innervated (supplied by nerve fibers. Avascular ( contains no blood vessels). Regeneration. Epithelium has a high regenerative capacity. As long as epithelial cells receive adequate nutrition they can replace lost cells rapidly by cell division.

5. #2. I can list several functional characteristics of epithelial tissue.

6. Functions of epithelial tissue Protection; epithelium of the skin protects underlying tissues from mechanical and chemical injury and bacterial invasion. Absorption; the digestive tract is specialized to absorb substances as is the epithelial tissue of the kidneys. Filtration; specialty of the epithelial tissue of kidneys. Excretion; specialty of the epithelial tissue of kidneys and glands. Secretion; specialty of the epithelial tissue of kidneys and glands. Sensory reception; epithelial tissue contains nerve endings that respond to various stimuli acting on the skin surface.

7. #3. I can distinguish between the different epithelial tissue micrographs or microscope slides.

8. Classification of epithelia tissue. Based of the number of cell layers.  Simple epithelia; composed of a single cell layer.  Stratified epithelia; consists of two or more cell layers stacked one on top of each other. Based on shape.  Squamous; flattened and scale like.  Cuboidal; boxlike, as tall as they are wide.  Columnar; tall and column shaped.

9. Simple squamous.

10. Simple cuboidal.

11. Simple columnar.

12. Psuedostratified.

13. Stratified epithelia.

14. #4. I can match the various epithelial tissues with their chief functions and their locations.

15. Simple squamous. Description; single layer of flattened cells. Location; kidney glomeruli, air sacs of lungs, lining of the heart, blood vessels, lymphatic vessels and lining of ventral cavity. Function; allows passage of materials by diffusion and filtration and secretes lubricating substances in serosa.

16. Simple Squamous.

17. Simple cuboidal. Description; single layer of cube like shaped cells. Location; kidney tubules, ducts and secretary portions of glands, and ovary surface. Function; secretion and absorption.

18. Simple Cuboidal.

19. Simple columnar epithelium. Description; single layer of tall cells. Some bear cilia. Location; nonciliated type lines most of the digestive tract; the ciliated variety lines small bronchi, uterine tubes, and some regions of the uterus. Function; absorption, secretion of mucus, enzymes, and other substances; ciliated type propels mucus (or reproductive cells) by ciliary action.

20. Simple Columnar.

21. Psuedostratified columnar. Description; single layer of cells of differing heights, nuclei seen at different levels and may bear cilia. Location; nonciliated type in ducts of large glands, parts of male urethra; ciliated variety lines the trachea and most of the upper respiratory tract. Function; secretion, particularly of mucus; propulsion of mucus by ciliary action.

22. Psuedostratified.

23. Stratified squamous. Description; thick membrane composed of several cell layers; basal cells are cuboidal or columnar; surface cells are flattened and keratinized (dead). Location; nonkeratinized type form the moist lining of the esophagus, mouth and vagina; keratinized type form the epidermis of the skin. Function; protects underlying tissues.

24. Stratified Squamous.

25. Stratified cuboidal. Description; generally two layers of cube-like cells. Location; largest ducts of sweat glands, mammary glands and salivary glands. Function; protection.

26. Stratified Cuboidal.

27. Stratified columnar. Description; several cell layers; basal cells usually cuboidal; superficial cells elongated and columnar. Location; rare in the body; small amounts in male urethra and large ducts of some glands. Function; protection and secretion.

28. Stratified Columnar.

29. Transitional. Description; resembles both stratified squamous and stratified cuboidal; basal cells cuboidal or columnar; surface cells dome-shaped or squamous-like, depend on degree of organ stretch. Location; lines the ureters, bladder, and part of the urethra. Function; stretches readily and permits distension of urinary organ by contained urine.

30. Transitional.

31. Review of Epithelial Tissue

32. #5 I can indicate common characteristics of connective tissue and their functions.

33. Common characteristics of connective tissue. Common origin; all connective tissue arise from the same embryonic tissue. Degrees of vascularity; range from avascular to highly vascularized. Extracellular matrix; connective tissue is composed largely of a nonliving extra-cellular matrix.

34. Structural elements of connective tissue. Connective tissue have three main elements’  Ground substance; fills the space between cells and contains fibers.  Fibers; provide support. Three types of fibers: 1) collagen, 2) elastic, and 3) reticular.  Cells; fibroblast (connective tissue proper), chondroblast (cartilage), osteoblast ( bone), and hemocytoblast (blood).

35. Structural elements image

36. #6 I can distinguish between dense, adipose and hyaline cartilage micrograph or microscope slides.

37. Dense regular connective tissue. Description; primarily parallel collagen fibers, a few elastic fibers; major cell type is the fibroblast. Location; tendons, most ligaments, and aponeuroses. Function; attaches muscles to bones or to muscles; attaches bones to bones; withstands great tensil stress when pulling force is applies in one direction.

38. Dense regular image.

39. Dense irregular tissue. Description; primarily irregularly arranged collagen fibers; some elastic fibers; major cell type is the fibroblast. Location; dermis of the skin; submucosa of the digestive tract; fibrous capsules of organs and joints. Function; able to withstand tension exerted in many directions; provides structural strength.

40. Dense Irregular; image

41. Adipose tissue. Description; closely packed adipocytes (fat cells); nucleus pushed to the side by large fat droplet. Location; under skin, around the kidneys and eyeballs; in bones and within abdomen and breasts. Function; provides reserve food fuel; insulates against heat loss; supports and protects organs.

42. Adipose; image

43. Hyaline cartilage. Description; firm matrix of collagen fibers; chrondroblasts produce the matrix and when mature (chondrocytes) lie in lacunae. Location; forms most of the embryonic skeleton; ends of long bones and joint cavity; costal cartilage of ribs; cartilage of nose, trachea, and larynx. Function; support, cushions and resists compressive stress.

44. Hyaline; image

45. #7 I can note the general characteristics of nervous tissues.

46. Nervous tissue. Nervous tissues is made up of two major cells types.  Neurons.  Supporting cells.

47. Neurons. Highly specialized cells that generate and conduct nerve impulses. They are branched cells. The branches are referred to as processes and allow the cells to transmit electrical impulses over substantial distances,

48. Supporting cells. These are nonconducting cells that Support. Insulate. Protect. neurons.

49. Nervous tissue (neurons). Description; branching cell processes that may be quite long and extend from the cell body. Location; brain, spinal cord and nerves. Function; transmit electrical signals from sensory receptors and to effectors (muscles and glands) which control their activity.

50. Nervous tissue; image

51. #8 I can compare and contrast the structures and body locations of the three types of muscle tissue.

52. Skeletal Muscle. Description: Long, cylindrical, multinucleate cells; obvious striations. Location: In skeletal muscles attached to bones or occasionally to skin. Function: Voluntary movement; locomotion; facial expression. Voluntary control.

53. Skeletal muscle; muscle

54. Cardiac Muscle. Description: Branching, striated, generally uninucleate cells that interdigitate at specialized junctions (intercalated discs). Location: The walls of the heart. Function: As it contracts, it propels blood into the circulation; involuntary control.

55. Cardiac Muscle; Image

56. Smooth Muscle. Description: Spindle-shaped cells with central nuclei, cells arranged closely to form sheets, no striations. Location: Mostly in the walls of hollow organs. Function: Propels substances of objects along internal passageways; involuntary control.

57. Smooth muscle; image

58. #9 I can identify a micrograph of a tissue as one of the four main types found in the human body.

59. Major tissue types comparison.