Tissue Types Overview  Tissue Definitions  Epithelial Tissue Simple and Stratified  Connective Tissue Characteristics Bone, Cartilage, Loose Conn. Dense Connective  Blood  Muscle Tissue Skeletal, Cardiac, and Smooth  Nervous Tissue  Tissue Repair  Tissue Development and Aging

Table 4.1

Connective Tissue: Cartilage  Three types of cartilage: Hyaline cartilage Elastic cartilage Fibrocartilage

Connective Tissue Types: Cartilage  Hyaline cartilage Found in larynx, joints, connecting ribs, tip of nose

Connective Tissue Types: Cartilage  Elastic cartilage Found in the external ear, auditory tube, larynx

Connective Tissue Types: Cartilage  Fibrocartilage Figure 3.19c Found between vertebrae in the spine

Connective Tissue Types: Dense  Dense connective tissue Found in tendons, ligaments, lower layers of skin

Figure 4.8d (d) Connective tissue proper: dense connective tissue, dense regular Description: Primarily parallel collagen fibers; a few elastic fibers; major cell type is the fibroblast. 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. Photomicrograph: Dense regular connective tissue from a tendon (500x). Shoulder joint Ligament Tendon Collagen fibers Nuclei of fibroblasts

Figure 4.8e (e) Connective tissue proper: dense connective tissue, dense irregular Description: Primarily irregularly arranged collagen fibers; some elastic fibers; major cell type is the fibroblast. 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. Photomicrograph: Dense irregular connective tissue from the dermis of the skin (400x). Collagen fibers Nuclei of fibroblasts Fibrous joint capsule

Figure 4.8f (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. Location: Walls of large arteries; within certain ligaments associated with the vertebral column; within the walls of the bronchial tubes. Elastic fibers Aorta Heart Photomicrograph: Elastic connective tissue in the wall of the aorta (250x).

Figure 3.19f Connective Tissue Types: Adipose  Adipose tissue A signet ring Found around organs (e.g. kidneys), eyballs, hips, and breast

Connective Tissue Types: Reticular  Reticular connective tissue Found in spleen, bone marrow, and lymph nodes

Connective Tissue Types: Blood  Blood

Tissue Types Overview  Tissue Definitions  Epithelial Tissue Simple and Stratified  Connective Tissue Characteristics Bone, Cartilage, Dense Connective, Loose Connective  Blood  Muscle Tissue Skeletal, Cardiac, and Smooth  Nervous Tissue  Tissue Repair  Tissue Development and Aging

Muscle Tissue  Function is to produce movement  Three types Skeletal muscle Cardiac muscle Smooth muscle

Muscle Tissue Types: Skeletal  Skeletal muscle Figure 3.20a Found in all muscle connected to bones

Muscle Tissue Types: Cardiac  Cardiac muscle Figure 3.20b Found exclusively in the heart

Muscle Tissue Types: Smooth  Smooth muscle Found in walls of hollow organs like stomach, bladder, uterus, blood vessels, intestines

Tissue Types Overview  Tissue Definitions  Epithelial Tissue Simple and Stratified  Connective Tissue Characteristics Bone, Cartilage, Dense Connective, Loose Connective  Blood  Muscle Tissue Skeletal, Cardiac, and Smooth  Nervous Tissue  Tissue Repair  Tissue Development and Aging

Nervous Tissue Found in brain, spinal cord, and extensions all over the body

Tissue Repair  Types of Repair Regeneration  Replacement of destroyed tissue by the same kind of cells Fibrosis  Repair by dense fibrous connective tissue (scar tissue)  Determination of method Type of tissue damaged Severity of the injury

Events in Tissue Repair 1. Inflammatory Reaction sets the stage Mast cells release histamines Release of histamines cause vasodilation  temperature,  swelling Clotting proteins Walling-off of injured area, scab Leukocytes: neutrophils, macrophages 2. Organization restores blood supply Formation of granulation tissue Fibroblasts bind with collagen Phagocytosis by macrophages 3. Regeneration of surface epithelium Fibrosed area matures, contracts Scar tissue forms

Regeneration of Tissues  Tissues that regenerate easily Epithelial tissue Fibrous connective tissue and bone  Tissues that regenerate poorly Skeletal muscle  Tissues that are replaced largely with scar tissue Cardiac muscle Nervous tissue within the brain and spinal cord

Development of Tissues Regenerative Non-regenerative (amitotic) 3 Primitive Germ Layers: Endoderm: Forms gut tube, digestive system Mesoderm: Forms muscle, mesenchyme (embryonic connective tissue) -> osteoblasts, fibroblasts, chondrocytes -> bone, blood, other connective tissue Ectoderm: Forms nervous tissue, skin

Aging of Tissues Some Tissue Changes in Aging Skin loses elasticity, epithelia membranes thin Exocrine glands less active; skin dries Decreased endocrine function and slowing of metabolism Bones become porous Muscles atrophy Normal tissue changes Hyperplasia (enlargement) Atrophy (reduction) Abnormal tissue changes Neoplasms

Summary  Tissue Definitions  Epithelial Tissue Simple and Stratified  Connective Tissue Characteristics Bone, Cartilage, Dense Connective, Loose Connective  Blood  Muscle Tissue Skeletal, Cardiac, and Smooth  Nervous Tissue  Tissue Repair  Tissue Development and Aging