Anatomy & Physiology

Anatomy & Physiology Study Guide embryo; areolar tissue; adipose tissue, i.e., white fat and brown fat; and reticular tissue. Most of the volume in dense connective tissue consists of fibers. The two types of dense connective tissue are dense regular connective tissue and dense irregular connective tissue in the adult. • Blood and lymph are connective tissues that contain distinctive collections of cells in a fluid matrix. • Blood contains formed elements: red blood cells (erythrocytes), white blood cells (leukocytes), and platelets. The watery matrix of blood is called plasma. • Arteries carry blood away from the heart and toward capillaries, where water and small solutes move into the interstitial fluid of surrounding tissues. Veins return blood to the heart. • Lymph forms as interstitial fluid enters the lymphatic vessels, which return lymph to the cardiovascular system. Cartilage and bone provide a strong supporting framework: • Cartilage and bone are called supporting connective tissues because they support the rest of the body. The matrix of cartilage is a firm gel that contains chondroitin sulfates (used to form proteoglycans) and cells called chondrocytes. Chondrocytes occupy chambers called lacunae. A fibrous perichondrium separates cartilage from surrounding tissues. The three types of cartilage are hyaline cartilage, elastic cartilage, and fibrous cartilage. • Chondrocytes rely on diffusion through the avascular matrix to obtain nutrients. • Cartilage grows by two mechanisms: interstitial growth and appositional growth. • Bone, or osseous tissue, consists of osteocytes, little ground substance, and a dense, mineralized matrix. Osteocytes are situated in lacunae. The matrix consists of calcium salts and collagen fibers that gives it unique properties. • Osteocytes depend on diffusion through canaliculi for nutrient intake. • Each bone is surrounded by a periosteum with fibrous and cellular layers. Membranes are physical barriers of four types: mucous, serous, cutaneous, and synovial: • Membranes form a barrier or interface. Epithelia and connective tissues combine to form membranes that cover and protect other structures and tissues. • Mucous membranes line cavities that communicate with the exterior. They contain areolar tissue called the lamina propria. • Serous membranes line the body’s sealed internal cavities. They form a fluid called a transudate. • The cutaneous membrane, or skin, covers the body surface. • Synovial membranes form an incomplete lining within the cavities of synovial joints. • Connective tissues create the internal framework of the body: o Internal organs and systems are tied together by a network of connective tissue proper. This consists of the superficial fascia (the subcutaneous layer, or hypodermis, separating the skin from underlying tissues and organs), the deep fascia (dense connective tissue), and the subserous fascia (layer between deep fascia and serous membranes that line body cavities). Achieve Page 46 of 368 ©2018