Connective (Most abundant tissue in body) Loose (areolar, adipose, reticular) 2. Dense (dense irregular, white fibrous) 3. Cartilage (hyaline, elastic, fibrocartilage) 4. Bone 5. Blood 6. Mesenchyme Functions Support B. Attachment C. Storage (calcium, energy) D. Protection (skull, ribs, kidneys) E. Movement (muscle attachments) F. Blood formation and transport

make Thin, wire-like, flexible Common, long, white, wavy Short, branching (netting) CT Glue Chondroitin sulfate 1.7

Blood vessels? Nerves? 128

16-day-old embryo (dorsal surface view) Muscle and connective Figure 4.13 Embryonic germ layers and the primary tissue types they produce. 16-day-old embryo (dorsal surface view) Muscle and connective tissue (mostly from mesoderm) Ectoderm Mesoderm Nervous tissue (from ectoderm) Endoderm Mesenchyme -ameboid cells Embryonic Stem cells Flexible Epithelium Pg 146

Figure 4.8k Connective tissues. -Liquid ground substance (Plasma) -Transport -Made by red bone marrow Figure 4.8k Connective tissues. (k) Others: blood Description: Red and white blood cells in a fluid matrix (plasma). Plasma Function: Transport of respiratory gases, nutrients, wastes, and other substances. Neutrophil Location: Contained within blood vessels. Red blood cells Lymphocyte Photomicrograph: Smear of human blood (1860x); two white blood cells (neutrophil in upper left and lymphocyte in lower right) are seen surrounded by red blood cells. Pg 137

Loose CT’s -Sheets of filler tissue -Gelatinous -Beneath skin, in membranes, surrounds vessels, nerves and ducts 131

Figure 4.8b Connective tissues. -Adipocytes filled with triglycerides -Energy, insulation, protection (b) Connective tissue proper: loose connective tissue, adipose Description: Matrix as in areolar, but very sparse; closely packed adipocytes, or fat cells, have nucleus pushed to the side by large fat droplet. Function: Provides reserve food fuel; insulates against heat loss; supports and protects organs. Nucleus of fat cell Location: Under skin in the hypodermis; around kidneys and eyeballs; within abdomen; in breasts. Adipose tissue Vacuole containing fat droplet Triglycerides Photomicrograph: Adipose tissue from the subcutaneous layer under the skin (350x). Mammary glands Pg 131

Figure 4.8c Connective tissues. Supports soft organs (glands, bone marrow, lymphatic organs) Figure 4.8c Connective tissues. (c) Connective tissue proper: loose connective tissue, reticular Description: Network of reticular fibers in a typical loose ground substance; reticular cells lie on the network. Function: Fibers form a soft internal skeleton (stroma) that supports other cell types including white blood cells, mast cells, and macrophages. White blood cell (lymphocyte) Location: Lymphoid organs (lymph nodes, bone marrow, and spleen). Reticular fibers Spleen Photomicrograph: Dark-staining network of reticular connective tissue fibers forming the internal skeleton of the spleen (350x). Pg 132

Figure 4.8e Connective tissues. -Forms most of dermis -Forms capsules around organs, muscles and joints (deep fascia) Dense CT’s (e) Connective tissue proper: dense connective tissue, dense irregular Description: Primarily irregularly arranged collagen fibers; some elastic fibers; major cell type is the fibroblast. Nuclei of fibroblasts Function: Able to withstand tension exerted in many directions; provides structural strength. Location: Fibrous capsules of organs and of joints; dermis of the skin; submucosa of digestive tract. Collagen fibers Fibrous joint capsule Photomicrograph: Dense irregular connective tissue from the dermis of the skin (400x). Pg 133

Figure 4.8d Connective tissues. Forms tendons, ligaments, white of the eye (White Fibrous) (d) Connective tissue proper: dense connective tissue, dense regular Description: Primarily parallel collagen fibers; a few elastic fibers; major cell type is the fibroblast. Collagen fibers Function: Attaches muscles to bones or to muscles; attaches bones to bones; withstands great tensile stress when pulling force is applied in one direction. Location: Tendons, most ligaments, aponeuroses. Nuclei of fibroblasts Shoulder joint Ligament Photomicrograph: Dense regular connective tissue from a tendon (500x). Tendon Pg 132

Figure 4.8f Connective tissues. In walls of blood vessels and lungs (f) Connective tissue proper: dense connective tissue, elastic Description: Dense regular connective tissue containing a high proportion of elastic fibers. Function: Allows recoil of tissue following stretching; maintains pulsatile flow of blood through arteries; aids passive recoil of lungs following inspiration. Elastic fibers Location: Walls of large arteries; within certain ligaments associated with the vertebral column; within the walls of the bronchial tubes. Aorta Photomicrograph: Elastic connective tissue in the wall of the aorta (250x). Heart Pg 134

Clicker Question: Which of the following statements regarding epithelial tissues are true? 1. Has a good blood supply. 2. Food in the stomach would touch the apical surface of the epithelial tissue there. 3. Simple arrangements of epithelia are associated with filtration and absorption. 4. Pseudostratified epithelia consist of at least 2 layers of cells stacked on top of one another. A. 1,2,4 B. 2,3,4 C. 1, 2, 3 D. 2,3

Clicker Question: Which of the following statements regarding connective tissue are true? 1. The 3 main components of connective tissue are: ground substance, fibers and proteoglycans. 2. All connective tissue has a good blood supply. 3. Collagen fibers provide a lot of strength within connective tissue. 4. Connective tissue can have a nerve supply. A. 1, 3, 4 B. 2, 4 C. 2, 3, 4 1, 2, 3