Integumentary System Chapter 5
Classification of Body Membranes Membrane – thin, sheet-like structure that may have important functions in the body. Membranes cover and protect the body surface, line body cavities, and cover the inner surfaces of the hollow organs, such as the digestive, reproductive, and respiratory passageways.
Classification of Body Membrane http://seniorjournal.com/images/Symbols/Health/7-10-30-SynovialJoint.jpg • Some membranes anchor organs to each other or to bones and others cover the internal organs • In certain areas of the body membranes secrete lubricating fluids and reduce friction during organ movement. • Example: Joints
Epithelial Membranes Cutaneous Serous Mucous
1. Cutaneous (Skin) • Primary organ of the integumentary system. • Superficial layer of epithelial cells and an underlying layer of supportive connective tissue.
2. Serous Membranes Epithelial and connective tissue layers Serous membranes secrete a thin, watery fluid that helps reduce friction and serves as a lubricant. Peritoneum: Abdominal Cavity Parietal: Lines body cavities Visceral: Covers surface or organs Pleura: Thoracic Cavity
3. Mucous Membranes Line the respiratory, digestive, urinary, and reproductive tracts Function depends on location Secrete mucous – keeps membrane moist and soft.
Connective Tissue Membranes Synovial membranes lining the spaces between bones (joints) that move Theses membranes are smooth and slick and secrete synovial fluid that helps reduce friction Bursae – cushions
The Skin In one inch of skin we have about 500 sweat glands, over 1000 nerve endings, yards of tiny blood vessels, nearly 100 oil (sebaceous) glands, 150 sensors for pressure, 75 for heat and 10 for cold, and millions of cells.
The Skin Made of the epidermis, dermis, and subcutaneous tissue (fatty tissue-hypodermis)
Epidermis • Stratum germinativum – innermost layer. • They undergo mitosis and reproduce themselves • Move upward to replace other cells • Cytoplasm is replaced by keratin - waterproof • Produces the pigment melanin Stratum corneum – tough outer layer
Epidermis • Blisters – cells of the epidermis are tightly packed together. • When links are weakened or destroyed, the skin falls apart. • Caused by burns, friction, or exposure to irritants • Can occur within the epidermis or at the dermal-epidermal junction
Dermis Mostly connective tissue (cells scattered far apart) Mix of strong, tough fibers and stretchable elastic
Dermis • With age the elastic fibers decrease and the amount of fat stored decreases • wrinkles develop http://rds.yahoo.com/_ylt=A0WTb_xJGFtLPeAAOsWjzbkF/SIG=11o72gr1i/EXP=1264347593/**http%3A//mingle2.com/topic/show/178723
Dermis • Dermal papillae • peglike projections • dermal-epidermal junction (bind 2 layers) • form ridges and grooves – make fingerprinting possible