1. Tissues

2. Epithelial Tissue
Epithelial tissue: covers internal or external surfaces.
Protection, secretion, absorption, excretion, sensory reception
Characteristics:
Cells close together
Apical surface exposed to environment or hollow internal cavity
Basement membrane attaches to underlying tissues
Absence of blood vessels
Continuous regeneration of surface cells

3. Types of Epithelium
Simple epithelium: thin, single layer of cells covering the basement membrane.
Stratified epithelium: several layers of cells above the basement membrane
Ex: areas exposed to mechanical and chemical stress, such as the mouth.

4. Simple squamous epithelium: found in internal surfaces where absorption takes place, and there is little friction
Ex: Lining of the heart, blood vessels, kidney tubules, air sacs of lungs.

5. Simple cuboidal epithelium: in areas where increased amounts of secretion and absorption occur
Cells are larger and provide more room for organelles
Ex: Pancreas, salivary glands, kidneys

6. Simple columnar epithelium: provides more protection in areas of absorption and secretion
Examples: Stomach lining, intestinal tract

7. Stratified squamous epithelium: thick protective lining found in areas of high mechanical stress
Ex: Lining of the mouth, esophagus, and anus, and skin

8. Pseudostratified ciliated columnar epithelium: mixture of columnar and cuboidal cells that appears layered, but all cells touch the basement membrane
Cilia are present to move mucus
Ex: Lining of the nasal cavity, trachea, and bronchi

9. Transitional epithelium: can stretch and recoil, so its appearance changes
Ex: Urinary bladder

10. Glands: organs that produce secretions
Made of epithelial tissues
Exocrine glands discharge secretions to the outside
Ex: lining of the digestive tract, skin
Endocrine glands secrete directly into tissue fluid or blood
Ex: thyroid, pituitary, etc.

11. Connective Tissue
Connective tissues: a mixture of cells and protein fibers, distributed throughout the body, never exposed to the outside environment
Have diverse functions:
Support and protect other tissues
Transport materials
Storage of energy reserves as fat
Defense against microorganisms

12. Major cell types: Fibroblasts: large in size, produce protein fibers
Macrophages: phagocytize or “eat” damaged cells, bacteria, or viruses
Mast cells: release defensive chemicals during an injury or infection

13. Connective tissue fibers:
Collagen fibers: long, straight, and flexible, add strength
Elastic fibers: give stretch and flexibility to connective tissues
Reticular fibers: thin, form supportive networks

14. Disorder
Molecular Defect
Signs and Symptoms
Chondrodysplasia
Collagen fibers are too wide and asymmetric
Stunted growth; deformed joints
Dystrophic epidermolysis bullosa
Breakdown of collagen fibrils that attach skin layers to each other
Stretchy, easily scarred skin, lax joints
Hereditary osteoarthritis
Substituted amino acid in collagen chain alters shape
Painful joints
Marfan syndrome
Too little fibrillin, and elastic connective tissue protein
Long limbs, sunken chest, lens dislocation, spindly fingers, weakened aorta
Osteogenesis imperfecta type I
Too few collagen triple helices
Easily broken bones; deafness; blue sclera
Stickler syndrome
Short collagen chains
Joint pain; degeneration of retina and fluid around it

15. Loose Connective Tissues
Loose connective tissues: the “packing materials” of the body, filling in spaces to provide cushioning and support

16. Areolar tissue: elastic and has an extensive blood supply
Collagen and elastin for strength
Ex: Between the skin and muscle

17. Adipose tissue: collection of fat cells
Provides padding, shock absorption, and thermal insulation
Ex: Breasts, abdomen, beneath skin

18. Reticular tissue: network of protein fibers that holds other cells in place, such as white and red blood cells
Ex: Spleen, liver, bone marrow, lymph nodes

19. Dense connective tissues: consist mostly of collagen fibers, with little blood supply
Found in tendons and ligaments

20. Cartilage
Cartilage: rigid connective tissue that provides structural framework for various structures
Chondrocytes (cartilage cells) are found within small fluid filled pockets called lacunae.
No blood supply

21. Hyaline cartilage: the most common, providing stiff and flexible support
Matrix is made of densely packed collagen fibers
Ex: Respiratory tract, connecting ribs to sternum, and covering the ends of bones

22. Elastic cartilage: extremely resilient; able to endure distortions while still maintaining original shape
Contains many more elastic fibers than hyaline cartilage
Ex: External ear

23. Fibrocartilage: has very little ground substance, with densely packed collagen fibers
Tough, durable, and resistant to compression
Ex: Spinal cord, knee joint, between bones of pelvis

24. Bone: most rigid connective tissue, with mineral salts and collagen within the matrix
Supports the body, protects, forms muscle attachments, blood cell formation

25. Fluid Connective Tissues
Blood and lymph are the only two types of fluid connective tissues
Transport oxygen, carbon dioxide, nutrients, and wastes throughout the body

26. Nervous Tissue
Nervous tissue: specialized for the conduction of electrical impulses, found in brain and spinal cord
Neurons conduct nervous impulses
Neuroglia support and nourish neurons

27. Muscle Tissue
Muscle tissue: made of arrangements of protein filaments that can contract and generate force

28. Skeletal muscle: attached to bone, cells are long and cylindrical and have many nuclei
Controlled voluntarily
The repeating groups of muscle filaments create bands called striations

29. Cardiac muscle: found only in the heart, consists of branching fibers, cells have a single nucleus
Cells are connected at specialized attachment sites called intercalated discs, and appear striated
Involuntary movement

30. Smooth muscle: tissue is made of cells smaller and more slender than skeletal muscle, found in the walls of internal organs, blood vessels, and bladder
Striations are not present

31. Tissue Membranes
Mucous membranes: line cavities that open to the outside. Have goblet cells that secrete mucous
Ex: oral, nasal cavities, digestive, respiratory, urinary, and reproductive systems

32. Cutaneous membranes: are thick, dry, and relatively waterproof.
Serous membranes: line internal body cavities, secrete serous fluid to reduce friction
Ex: Lungs
Cutaneous membranes: are thick, dry, and relatively waterproof.
Ex: Skin

33. Synovial membranes: line joints and secrete synovial fluid that reduces friction
Ex: The bones of the knee joint