Tissues Carry out all chemical activities needed to sustain life Cells are the building blocks of all living things Tissues are groups of cells that are similar in structure and function Slide 3.1 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Body Tissues Cells are specialized for particular functions Tissues Groups of cells with similar structure and function Four primary types Epithelium Connective tissue Nervous tissue Muscle Slide 3.41 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Epithelial Tissue FUNCTIONS Protection Absorption Filtration Secretion Excretion Sensory receptiion Forms layer over body & inner surfaces Comes in 3 shapes – squamous, cuboidal, columnar Comes in several patterns Simple, stratified or pseudostratified, transitional,and glandular

Epithelial Tissues Found in many different areas of the body Body coverings Body linings Glandular tissue Slide 3.42 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Epithelium Characteristics Cells fit closely together Tissue layer always has one free surface (apical) The lower surface is bound by a basement membrane (basal) Avascular (have no blood supply) Regenerate easily if well nourished Slide 3.43 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

More Characteristics Specialized contact between cells Tight junctions--no spaces (digestive tract) Desmosomes—anchoring and stress bearing (skin) Gap Junctions—spaces (smooth muscle)

Classification of Epithelium Number of cell layers Simple – one layer Stratified – more than one layer Figure 3.16a Slide 3.44a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Classification of Epithelium Shape of cells Squamous – flattened Cuboidal – cube-shaped Columnar – column-like Figure 3.16b Slide 3.44b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Simple Epithelium: Squamous Single layer of flat cells Usually forms membranes Lines body cavities Lines lungs and capillaries Figure 3.17a Slide 3.45 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Squamous Cells

Simple Squamous Cells

Simple Epithelium: Cuboidal Single layer of cube-like cells Common in glands and their ducts Excretory, secretory, or absorptive Forms walls of kidney tubules Covers the ovaries Figure 3.17b Slide 3.46 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Simple Cuboidal

Simple Cuboidal Cells

Simple Epithelium: Columnar Single layer of tall cells May have cilia on apical surface Often includes goblet cells, which produce mucus Lines digestive tract Figure 3.17c Slide 3.47 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Simple Columnar Cells

Simple Epithelium: Pseudostratified Single layer, but some cells are shorter than others Often looks like a double cell layer Sometimes ciliated, such as in the respiratory tract May function in absorption or secretion Figure 3.17d Slide 3.48 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Stratified Epithelium: Stratified Squamous Cells at the free edge are flattened Found as a protective covering where friction is common Locations Skin Mouth Esophagus Figure 3.17e Slide 3.49 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Stratified Cells / Skin / Most Common

Stratified Epithelium: Transitional Shape of cells depends upon the amount of stretching Lines organs of the urinary system Bladder lining Figure 3.17f Slide 3.51 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Transitional Cells

Glandular Epithelium: Glands SECRETE FLUIDS MADE BY THE CELLS UNI OR MULTICELLULAR Endocrine gland Ductless Secretions are HORMONES Exocrine gland Have ducts to the epithelial surface Include sweat and oil glands Slide 3.52 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Secretions of Excretory Glands Sebaceous = oil or sebum Mucin = mucus Serous = watery Sudoriferous = sweat Ceruminous = wax or cerumen Ciliary = tears Mammary = mother’s milk

EXOCRINE GLANDS

MEROCRINE EXOCYTOSIS

HOLOCRINE RUPTURE AND REGENERATE SEBACEOUS GLANDS

Connective Tissue Loose – supports epithelium and many organs Fibrous – found in tendons (connects muscles to bones), ligaments (connect bones to other bones at joints) Cartilage & bone – rigid connective tissues in which structural proteins or calcium salts are deposited in the intercellular matrix Blood – cells are separated by a liquid portion called plasma

Structural Substances of Connective Tissue Ground Substance Fibers Collagen (white fibers) Elastic Fibers (yellow fibers) Reticular Fibers Cells Fibroblasts - Others Chondroblasts WBCs Hematopoietic stem cells Plasma cells Osteoblast Mast cells Macrophages

Areolar Connective Tissue Loose connective tissue presence in lungs, arteries and bladder allows organs to expand

Adipose Tissue (loose connective tissue) “Fat” Cells

Dense Regular Connective Tissue Have collagen fibers as its main matrix Between collagen fibers are rows of fibroblasts (fiber forming cells.) Tendons secure muscle to bone Ligaments secure one bone to another Also makes up lower layers of skin

Bone calcium salts give bone rigidity protein fibers provide elasticity and strength

Bones Sometimes calledOsseous tissue Bone cells sit in cavities called lacunnae Bone cells are surrounded by very hard matrix of fibers and calcium salts.

Cartilage is retained at the ends of long bones at the end of the nose in framework of ear within walls of respiratory ducts within intervertebral disks

Blood erythrocytes(carry oxygen in HgB) & leukocytes (aid in fighting infections)

Blood Smear

Muscle Tissue Composed of cells called muscle fibers Contain actin and myosin filaments whose interactions accounts for movements 3 Types * Skeletal * Cardiac * Smooth

Skeletal Muscle attached via tendons to bones Moves body parts Skeletal Muscle attached via tendons to bones Moves body parts. Fibers are cylindrical & long nuclei are located at the periphery of the fiber & are striated

Cardiac Muscle found only in wall of the heart responsible for the heartbeat fibers have striations single centrally located nucleus fibers are branched

Smooth Muscles fibers lack striations spindle shaped fibers form layers nuclei form an irregular pattern in tissue found in walls of viscera –intestine, stomach, blood vessels

Nervous Tissue Contain nerve cells called neurons Found in brain & spinal cord Neuron has 3 parts 1. Dendrites –conducts impulses to cell body 2. Cell body-contains major concentration of cytoplasm and nucleus 3. Axon-conducts impulses away from the cell body

Nerve Tissue long axons & dendrites called nerve fibers bound by connective tissue to form nerves.