Chapter 3 Connective Tissues Pages 93 97 Connective

Chapter 3 Connective Tissues Pages 93 -97

Connective Tissue �The most abundant type of tissue! �Collagen is a major protein found in connective tissue �Also the most common protein found in the body �Functions: �Provides protection �Binds body tissues together �Supports the body © 2015 Pearson Education, Inc.

Vascularity – blood supply �Variations in blood supply �Some are well vascularized �Some have a poor blood supply or are avascular; � Examples include: tendons, ligaments � As a result, these take longer to heal © 2015 Pearson Education, Inc.

The Extracellular Matrix (ECM) �a unique and distinguishing characteristic of connective tissue �Nonliving material that surrounds living cells �Gelatinous-like material �Secreted by the connective tissue cells �Composed of two main components: �Ground Substance �Fibers © 2015 Pearson Education, Inc.

Ground Substance � Secreted by connective tissue cells � Similar to cytosol in composition and function � Composed of: � mostly water � adhesion proteins � polysaccharides

Fibers �Secreted by connective tissue cells �Three types: 1. Collagen (white) fibers � Allow CT to withstand pulling/tension 2. Elastic (yellow) fibers � Contain elastin- allows stretching 3. Reticular fibers (a type of collagen) � Short fibers that create a mesh-like network

Connective Tissue Types �From most rigid to softest, (or most fluid): �Bone �Cartilage �Dense connective tissue �Loose connective tissue �Blood © 2015 Pearson Education, Inc.

BONE �Known as osseous tissue �Produced by Osteocytes (bone cells) �A Hard matrix of calcium salts �Functions to protect and support the body © 2015 Pearson Education, Inc.

Figure 3. 19 a Connective tissues and their common body locations. BONE Bone cells in lacunae Central canal Lacunae Lamella (a) Diagram: Bone Photomicrograph: Cross-sectional view of ground bone (165×)

CARTILAGE �more flexible than bone �Found in only a few places in the body �Produced by Chondrocytes (cartilage cell) �Three types of cartilage: �Hyaline (most abundant; larynx, intercostal, bone ends) �Elastic (external ear and epiglottis) �Fibrocartilage (intervertebral discs; pubic symphysis) © 2015 Pearson Education, Inc.

Figure 3. 19 b Connective tissues and their common body locations. HYALINE CARTILAGE Chondrocyte (cartilage cell) Chondrocyte in lacuna Lacunae Matrix (b) Diagram: Hyaline cartilage Photomicrograph: Hyaline cartilage from the trachea (400×)

Figure 3. 19 c Connective tissues and their common body locations. FIBROCARTILAGE Chondrocytes in lacunae Collagen fibers Collagen fiber (c) Diagram: Fibrocartilage Photomicrograph: Fibrocartilage of an intervertebral disc (150×)

DENSE CONNECTIVE TISSUE �Strong, ropelike structures �Main matrix element is collagen fiber made by fibroblasts �Locations: � Tendons—attach skeletal muscle to bone � Ligaments—attach bone to bone at � Dermis—lower layer of the skin �Found where strength of interconnection is required © 2015 Pearson Education, Inc.

Figure 3. 19 d Connective tissues and their common body locations. DENSE CONNECTIVE TISSUE: Ligament And Tendon Ligament Tendon Collagen fibers Nuclei of fibroblasts (d) Diagram: Dense fibrous Photomicrograph: Dense fibrous connective tissue from a tendon (475×)

LOOSE CONNECTIVE TISSUE �softer tissues; less fibrous �provide cushioning, reduce friction, allow stretching �Three types: �Areolar: wraps and secures organs � Lamina propria: areolar layer that underlies all mucous membranes �Adipose: fat cells; energy storage; insulation �Reticular: provides structural framework for organs/glands © 2015 Pearson Education, Inc.

Figure 3. 19 e Connective tissues and their common body locations. AREOLAR CONNECTIVE TISSUE Mucosa epithelium Lamina propria Elastic fibers Collagen fibers Fibroblast nuclei Fibers of matrix Nuclei of fibroblasts (e) Diagram: Areolar Photomicrograph: Areolar connective tissue, a soft packaging tissue of the body (270×)

Figure 3. 19 f Connective tissues and their common body locations. ADIPOSE TISSUE Nuclei of fat cells Vacuole containing fat droplet (f) Diagram: Adipose Photomicrograph: Adipose tissue from the subcutaneous layer beneath the skin (570×)

Figure 3. 19 g Connective tissues and their common body locations. RETICULAR CONNECTIVE TISSUE Spleen White blood cell (lymphocyte) Reticular cell Blood cell Reticular fibers (g) Diagram: Reticular Photomicrograph: Dark-staining network of reticular connective tissue (400×)

BLOOD �Blood cells = red and white �surrounded by fluid matrix known as blood plasma �Soluble fibers are visible only during clotting �Function: transport vehicle for the CV system; delivers: � Nutrients � Wastes � Respiratory gases (oxygen and carbon dioxide) © 2015 Pearson Education, Inc.

Figure 3. 19 h Connective tissues and their common body locations. BLOOD Blood cells in capillary Neutrophil (white blood cell) Red blood cells White blood cell Red blood cells (h) Diagram: Blood Monocyte (white blood cell) Photomicrograph: Smear of human blood (1290×)