Friday October 16, 2015 AIM: How is Connective tissue categorized? Do Now: Homework: Read chapter 4, Really… Read it! Work on Homework packet I a gave out yesterday.

Anatomy and Physiology Chapter 4 Tissue: The Living Fabric 2: Connective Tissue

Connective tissue proper Cartilage Bone Blood Found throughout the body Most abundant and widely distributed in primary tissues Connective tissue proper Cartilage Bone Blood

Connective Tissue Figure 4.6

Functions of Connective Tissue Binding and support Protection Insulation Transportation Examples – bone & cartilage support and protect body organs (skeleton); fat protects organs and provides reserve energy fuel

Characteristics of Connective Tissue Connective tissues have: Mesenchyme (embryonic tissue) as their common tissue of origin Potential to develop into bone, cartilage, blood Varying degrees of vascularity (avascular, poorly vascularized, rich supply of blood) Nonliving extracellular matrix, consisting of ground substance and fibersweight bearing, tension) Most have nerve supply

Connective Tissue: Embryonic Mesenchyme – embryonic connective tissue Gel-like ground substance with fibers and star-shaped mesenchymal cells Gives rise to all other connective tissues Found in the embryo

Structural Elements of Connective Tissue Ground substance – unstructured material that fills the space between cells Fibers – collagen, elastic, or reticular Cells – fibroblasts, chondroblasts, osteoblasts, and hematopoietic stem cells

Interstitial (tissue) fluid (extracellular matrix) 1. Ground Substance Interstitial (tissue) fluid (extracellular matrix) Adhesion proteins – fibronectin and laminin CT ‘glue’ – cells attach themselves to matrix Proteoglycans – glycosaminoglycans (GAGs) Trap water, forms fluid or gel Functions as a molecular sieve through which nutrients diffuse between blood capillaries and cells Dissolved substances must pass through from capillaries to cells

Ground Substance: Proteoglycan Structure Figure 4.7

2. Fibers Collagen – tough; provides high tensile strength Made of fibrils – stronger than steel White fibers Elastic – long, thin fibers that allow for stretch Elastin, allow recoil Skin, lungs, blood vessel walls Yellow fibers Reticular – branched collagenous fibers that form delicate networks

2. Fibers Reticular – branched collagenous fibers that form delicate networks Short and very thin or fine collagenous fibers (continuous with collagen fibers) Branch extensively, forming tight network called reticulum. Surround small blood vessels and support soft tissue of organs Form internal framework of glands Join connective tissues to other types of tissues (basement membrane of epithelial tissues and around capillaries. Reticular fibers are inelastic and made of collagen called reticulin.

3. Cells Undifferentiated, actively mitotic – secrete ground substance and fibers (blasts = forming) Fibroblasts – connective tissue proper Chondroblasts – cartilage Osteoblasts – bone Hematopoietic stem cells – blood Others: White blood cells, plasma cells, macrophages, and mast cells, fat cells

Areolar Connective Tissue: Model Figure 4.8

AIM: How is connective tissue categorized AIM: How is connective tissue categorized? Do Now: Homework: Read chapter 4. Should be half way done at least. Work on Homework packet – due Tomorrow.

Two subclasses of Connective Tissue Proper Loose Connective Tissue - Areolar Adipose Reticular Dense Connective Tissue Dense Regular Dense Irregular Elastic

Connective Tissue Proper: Loose Areolar connective tissue Gel-like matrix with all three connective tissue fibers (collagen, elastic, reticular) Cells - Fibroblasts, macrophages, mast cells, and some white blood cells Widely distributed throughout the body

Locations & Structural features of Areolar CT – type of loose CT Epithelia of body (forms lamina propria of mucous membranes; packages organs, surrounds capillaries. Structural feature: loose arrangement of fibers. Rest of matrix occupied by ground substance (appears as empty space under microscope) Edema – when body region is inflamed, areolar soaks up excess fluid like sponge, becomes puffy

Connective Tissue Proper: Loose Figure 4.9a

Connective Tissue Proper: Loose Adipose connective tissue Matrix similar to areolar connective tissue with closely packed adipocytes (fat cells) Chicken wire appearance Reserve food (fuel) stores, insulates against heat loss, and supports and protects Found under skin, around kidneys, within abdomen, and in breasts Local fat deposits serve nutrient needs of highly active organs

Connective Tissue Proper: Loose Figure 4.9b

Connective Tissue Proper: Loose Reticular connective tissue Loose ground substance with reticular fibers Reticular cells lie in a fiber network Forms a soft internal skeleton, or stroma, that supports other cell types (WBC, mast, macrophages) Found in lymph nodes, bone marrow, and the spleen

Connective Tissue Proper: Loose Figure 4.9c

Connective Tissue Proper: Dense Regular Parallel collagen fibers with a few elastic fibers Parallel to direction of pull (tendons, ligaments) Major cell type is fibroblasts b/n fiber bundles Attaches muscles to bone or to other muscles, and bone to bone Found in tendons, ligaments, and aponeuroses, fascia

Connective Tissue Proper: Dense Regular Figure 4.9d

Connective Tissue Proper: Dense Irregular Irregularly arranged thick collagen fibers with some elastic fibers Major cell type is fibroblasts Withstands tension in many directions providing structural strength Found in the dermis, submucosa of the digestive tract, and fibrous organ capsules

Connective Tissue Proper: Dense Irregular Figure 4.9e

Connective Tissue: Hyaline Cartilage Most abundant type Amorphous, firm matrix with imperceptible network of collagen fibers Chondrocytes lie in lacunae (cavities) Function: Supports, reinforces, cushions, and resists compression LOC: Forms the costal cartilage Found in embryonic skeleton, the end of long bones, nose, trachea, and larynx

Connective Tissue: Hyaline Cartilage Figure 4.9f

Connective Tissue: Elastic Cartilage Similar to hyaline cartilage but with more elastic fibers Maintains shape and structure while allowing flexibility Supports external ear (pinna) and the epiglottis

Connective Tissue: Elastic Cartilage Figure 4.9g

Connective Tissue: Fibrocartilage Matrix similar to hyaline cartilage but less firm with thick collagen fibers Provides tensile strength and absorbs compression shock Found in intervertebral discs, the pubic symphysis, and in discs of the knee joint

Connective Tissue: Fibrocartilage Cartilage Figure 4.9h

Connective Tissue: Bone (Osseous Tissue) Hard, calcified matrix with collagen fibers found in bone Osteocytes are found in lacunae and are well vascularized Fxn: Supports, protects, and provides levers for muscular action Stores calcium, minerals, and fat Marrow inside bones is the site of hematopoiesis

Connective Tissue: Bone (Osseous Tissue) Figure 4.9i

Connective Tissue: Blood Red and white cells in a fluid matrix (plasma) Contained within blood vessels Functions in the transport of respiratory gases, nutrients, and wastes

Connective Tissue: Blood Figure 4.9j