Body Tissues

1. Body Tissues

2. Four Main Types of Body Tissues • Sometimes I refer to them as basic tissue types • Epithelium • Connective • Muscular • Nervous

3. Epithelium • Lining, covering, and glandular tissue of the body. • Functions: • Protection • Absorption • Filtration • Secretion

4. Special Characteristics of Epithelium • Fits closely together to form continuous sheets. • Membranes always have one free, unattached surface. • Apical surface • Lower surface of the epithelium rests on the basement membrane. • No blood supply of their own. (depend on diffusion) • Can regenerate easily if well nourished.

5. Types of Epithelium • Simple- one layer of cells • Stratified- more than one layer of cells. • Pseudostratified- single layer, but appears stratified because some cells are shorter than others.

7. Simple Squamous • Single layer of thin squamous cells • On a basement membrane • Fit closely together • Usually found where filtration or exchange of substances occurs.

9. Stratified Squamous • Most common stratified epithelium in the body • Several layers of squamous cells • Cells closest to free edge are squamous shaped, but those closest to the basement membrane appear cuboidal. • Found in cites that receive a lot of abuse or friction • Esophagus, mouth, outer portion of the skin

11. Simple Cuboidal • One layer of cuboidal cells • On a basement membrane • Common in glands and ducts • Walls of kidneys, surface of ovaries

13. Stratified Cuboidal • At least two layers of cuboidal cells • Rare in the body • Found mainly in the ducts of large glands

15. Simple Columnar • Single layer of tall cells that fit closely together. • Lines entire length of digestive tract • Goblet cells-produce lubricating mucus are often seen here. • Mucosae (mucous membranes)- epithelial membranes that line body cavities open to the body exterior

17. Stratified Columnar • Surface cells are columnar • Basal cells vary in size and shape. • Fairly rare in the body • Found mainly in the ducts of large glands.

19. Pseudostratified Columnar • Single layer of cells • Some cells are shorter than others, making nuclei appear at different heights. • Functions in absorption and secretion. • Ciliated pseudostratified are found in the respiratory tract. • Cilia propel mucus upward and away from the lungs

21. Transitional • Highly modified • Stratified squamous epithelium • Basal layer cells are cuboidal or columnar • In urinary system

23. Connective Tissue • Connects body parts • Found everywhere in the body • Most abundant and widely spread tissue type • Well vascularized, has its own blood supply. • Extracellular matrix- nonliving substance found outside the cells.

24. Matrix • Matrix is what makes connective tissues different from other tissues. • Produced by connective tissue cells and secreted outside of the cell. • Composed of water and proteins • Because of its matrix, connective tissue is able to form soft packing tissue around other organs to bear weight and withstand abuse.

25. Bone • Osseous tissue • Composed of bone cells (osteocytes) sitting in cavities called lacunae • Surrounded by layers of a hard matrix • Protect and support other body organs

27. Hyaline Cartilage • Most widespread cartilage • Less hard and more flexible than bone. • Has abundant collagen fibers • Glassy matrix • Found in larynx, attaches ribs to breastbone, covers the end of bones where joints form.

29. Elastic Cartilage • Less hard and more flexible than bone. • Found where elasticity is desired. • Supports external ear

31. Fibrocartilage • Forms the cushion-like disks between the vertebrae of the spinal column

32. Areolar Tissue • Most widely distributed connective tissue in the body. • Soft, pliable, cobwebby tissue • Cushions and protects body organs • Helps hold internal organs together

34. Adipose Tissue • Fat tissue • Oil occupies most of a fat cell’s volume and pushes the nucleus to the side • Forms subcutaneous tissue beneath the skin. • Insulates the body and protects it from heat and cold.

36. Blood • Vascular tissue • Consists of blood cells surrounded by a nonliving matrix called plasma • Transport vehicle for the cardiovascular system.

38. Muscular Tissue • Highly specialized to contract or shorten to produce movement • Muscle cells are ellongated and therefore called fibers

39. Skeletal Muscle • Packaged by connective tissue sheets attached to the skeleton. • Can be controlled- voluntary • Form the flesh of the body • The result of their action is gross body movements or changes in facial expressions. • Cells are long, cylindrical, multinucleate, and have striations (stripes)

41. Smooth Muscle • Visceral muscle • No striations are visible • Single nucleus and are spindle shaped (pointed at each end) • Found in the walls of hallow organs • When smooth muscle contracts the cavity of the organ becomes smaller(constricts) or enlarges(dilates) • Peristalsis- food moving through the small intestine – muscle contracting in a wavelike motion

43. Cardiac Muscle • Found only in the heart • Has striations • Uninucleate • Branching • Fit tightly together at gap junctions called intercalated disks. • Involuntary

45. Nervous Tissue • All neurons receive and transmit electrochemical impulses from one part of the body to another.