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Bell Ringer 2.01 What is tissue? 2.02 What are some of the different types of tissue found within the human body? 2.03 Why do we need different types of tissue? © 2016 Pearson Education, Inc.

I. Tissue: The Living Fabric A. Individual body cells are specialized and perform specific functions B. Tissues Groups of cells similar in structure & function Four basic tissue types Epithelial Connective Muscle Nervous C. Histology 1. Study of tissues © 2016 Pearson Education, Inc.

Nervous tissue: Internal communication • Brain • Spinal cord • Nerves Figure 4.1 Overview of four basic tissue types: epithelial, connective, muscle, and nervous tissues. Nervous tissue: Internal communication • Brain • Spinal cord • Nerves Muscle tissue: Contracts to cause movement • Muscles attached to bones (skeletal) • Muscles of heart (cardiac) • Muscles of walls of hollow organs (smooth) Epithelial tissue: Forms boundaries between different environments, protects, secretes, absorbs, filters • Lining of digestive tract organs and other hollow organs • Skin surface (epidermis) Connective tissue: Supports, protects, binds other tissues together • Bones • Tendons • Fat and other soft padding tissue © 2016 Pearson Education, Inc.

II. Epithelial Tissue Epithelial tissue (epithelium) is asheet of cells that covers body surfaces or cavities 1. Two main forms: a. Covering and lining epithelia i. On external and internal surfaces ii. Ex. skin b. Glandular epithelia i. Secretory tissue in glands ii. Ex. salivary glands © 2016 Pearson Education, Inc.

3. Main Functions a. Protection b. Absorption c. Filtration d 3. Main Functions a. Protection b. Absorption c. Filtration d. Excretion e. Secretion f. Sensory Reception © 2016 Pearson Education, Inc.

B. Special Characteristics of Epithelial Tissues Epithelial tissue has 5 characteristics Polarity Cells have a top and bottom Apical Surface (top) Basal Surface (bottom) b. Specialized contacts Tissues fit closely together Many form continuous sheets © 2016 Pearson Education, Inc.

c. Supported by connective tissues i. helps reinforce and resist stretching and tearing d. Avascular, but innervated No blood vessels are found in epithelial tissue Nourishment must come from other tissues ii. Epithelia DO have nerve fibers e. Regeneration i. Epithelial cells have high regenerative capacities © 2016 Pearson Education, Inc.

C. Classification of Epithelia 1. All epithelial tissues have two names a. First name indicates number of cell layers i. Simple epithelia are a single layer thick ii. Stratified epithelia are two or more layers thick b. Second name indicates shape of cells i. Squamous: flattened and scale-like ii. Cuboidal: box-like, cube iii. Columnar: tall, column-like © 2016 Pearson Education, Inc.

c. In stratified epithelia, shape can vary in each layer, so cell is named according to the shape in the outermost layer © 2016 Pearson Education, Inc.

Figure 4.2a Classification of epithelia. Apical surface Basal surface Simple Apical surface Basal surface Stratified Classification based on number of cell layers. © 2016 Pearson Education, Inc.

Figure 4.2b Classification of epithelia. Squamous Cuboidal Columnar Classification based on cell shape. © 2016 Pearson Education, Inc.

2. Gland a. One or more cells that makes and secretes an aqueous fluid called a secretion b. Classified by: i. Site of product release: Endocrine: internally secreting Exocrine: externally secreting ii. Relative number of cells forming the gland Unicellular multicellular © 2016 Pearson Education, Inc.

Bell Ringer 2.04 Describe what Simple Cuboidal Epithelia would look like. 2.05 How would you classify epithelium that is multiple layers with column shaped cells? © 2016 Pearson Education, Inc.

III. Muscle Tissue A. Characteristics 1. Highly vascularized 2. Responsible for most types of movement 3. Muscle cells possess myofilaments a. made up of actin and myosin proteins that bring about contraction B. Three types of muscle tissues: 1. Skeletal muscle 2. Cardiac muscle 3. Smooth muscle © 2016 Pearson Education, Inc.

Bell Ringer 2.06 What type of gland secretes hormones? 2.07 What type of muscle tissue is voluntary? © 2016 Pearson Education, Inc.

IV. Connective Tissue A. Connective tissue is the most abundant and widely distributed of primary tissues 1. Major functions a. binding and support b. protecting c. insulating d. storing reserve fuel e. transporting substances (blood) © 2016 Pearson Education, Inc.

2. Four main classes a. Connective tissue proper b. Cartilage c. Bone d. Blood © 2016 Pearson Education, Inc.

Table 4.1-1 Comparison of Classes of Connective Tissues © 2016 Pearson Education, Inc.

Table 4.1-2 Comparison of Classes of Connective Tissues (continued) © 2016 Pearson Education, Inc.

B. Structural Elements of Connective Tissue 1. All connective tissues have three main elements a. Ground substance i. gel-like material between cells b. Fibers i. Collagen Provides Strength ii. Elastic Fibers Allows for stretching iii. Reticular Provides cushioning c. Cells © 2016 Pearson Education, Inc.

2. The first two elements together make up the extracellular matrix (ECM) 3. Composition and arrangement of these three elements vary considerable in different types of connective tissue © 2016 Pearson Education, Inc.

Cell types Extracellular matrix Ground substance Fibers Macrophage Figure 4.7 Areolar connective tissue: A prototype (model) connective tissue. Cell types Extracellular matrix Ground substance Fibers Macrophage • Collagen fiber • Elastic fiber • Reticular fiber Fibroblast Lymphocyte Fat cell Capillary Mast cell Neutrophil © 2016 Pearson Education, Inc.

Fibroblasts found in connective tissue proper C. Cells “Blast” cells Immature form of cell that actively secretes ground substance and ECM fibers 4 Types Fibroblasts found in connective tissue proper Chondroblasts found in cartilage Osteoblasts found in bone Hematopoietic stem cells in bone marrow © 2015 Pearson Education, Inc.

2. “Cyte” Cells a. Mature, less active form of “blast” cell that now becomes part of and helps maintain health of matrix © 2016 Pearson Education, Inc.

3. Other cell types a. Fat cells i. store nutrients b 3. Other cell types a. Fat cells i. store nutrients b. White blood cells i. tissue response to injury c. Mast cells i. initiate inflammatory response d. Macrophages i. Phagocytic cells that “eat” dead cells and bacteria © 2016 Pearson Education, Inc.

Bell Ringer 2.08 Name the 3 types of Loose Connective Tissue 2.09 What does ECM stand for? 2.10 What type of cells help create the ECM? © 2016 Pearson Education, Inc.

V. Nervous Tissue A. Main component of nervous system (brain, spinal cord, nerves) 1. Regulates and controls body functions 2. Made up of two types of cells: a. Neurons b. Neuroglia © 2016 Pearson Education, Inc.

Nervous tissue Nuclei of supporting cells Cell body of a neuron Neuron Description: Neurons are branching cells; cell processes that may be quite long extend from the nucleus-containing cell body; also contributing to nervous tissue are nonexcitable supporting cells. Neuron processes Cell body Nuclei of supporting cells Axon Dendrites Cell body of a neuron Function: Neurons transmit electrical signals from sensory receptors and to effectors (muscles and glands); supporting cells support and protect neurons. Neuron processes Location: Brain, spinal cord, and nerves. Photomicrograph: Neurons (350×) © 2016 Pearson Education, Inc.