Chapter Four Objectives

Epithelial Tissue

Epithelial Tissue

forms boundaries between different environments, protects, secretes, absorbs, filters

Location: lining of digestive tract organs and other hollow organs, skin surface (epidermis)

Connective Tissue

supports, protects, binds other tissues together

Location: bones, tendons, fat and other soft padding tissue

Nervous Tissue

internal communication

Location: brains, spinal cord, nerves

Muscular Tissue

contracts to cause movement

Location: muscles attached to bones (skeletal), muscles of heart (cardiac), muscles of walls of hollow organs (smooth)

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Characteristics of Epithelial Tissue

connective tissue support and specialized contacts

Specialized Contacts

binds adjacent cells, Tight Junctions, Desmosomes, Gap Junctions, Hemidesomosomes

Connective tissue support

basement membrane, noncellular basal lamina, and

adhesive sheet

Reticular lamina

network of collagen fibers, deep to basal lamina

Six functions of Epithelial tissue

Protection, Absorption, Filtration, Excretion, Secretion, Sensory reception

Stratified epithelia

two or more layers of cells

Simple epithelia

single layer of cells

Squamous

Flattened and scalelike

Cuboidal

Boxlike

Columnar

Tall; column shaped

Simple Squamous Epithelium

Allows materials to pass by diffusion and filtration in sites Location: Lining of ventral body cavity (serosae).

Simple Cuboidal Epithelium

Secretion and absorption

Location: Ovary surface.

Simple Columnar Epithelium

Absorption; secretion of mucus, enzymes, and other substances; Ciliated type propels mucus

Location: gallbladder, and excretory ducts of some glands

Pseudostratified Epithelium

Secrete substances, particularly mucus; Propulsion of mucus by ciliary action

Location: lines the trachea, most of the upper respiratory tract

Stratified Squamous Epithelium

Protects underlying tissues in areas subjected to abrasion

Location: linings of the esophagus, mouth, and vagina

Transitional Epithelium

Stretches readily, permits stored urine to distend urinary organs

Location: Lines the ureters, bladder, and part of the urethra

Gland

One or more cells that makes and secretes an aqueous fluid called a secretion

Exocrine Gland

secrete through ducts onto the surface of the gland

Endocrine Gland

release hormones into the surrounding fluid

Unicellular

The only important glands are mucous cells and goblet cells. Found in epithelial linings of intestinal and respiratory tracts. All produce mucin

Multicellular

Are composed of a duct and a secretory unit. Unbranched or Branched

Three types of secretion of multicellular glands

Merocrine, Apocrine, Holocrine

Merocrine

most common secretes products by exocytosis

Apocrine

accumulates products within but only apex ruptures

Holocrine

accumulates products within, then ruptures, killing the cell

Structural Elements of Connective Tissue

Ground substance, Fibers, Cells

Ground substance

Unstructured material that fills space between cells

Fibers

collagen, elastic, reticular

Collagen fibers

Strongest and most abundant type

Elastic fibers

Networks of long, thin, elastin fibers that allow for stretch and recoil

Reticular fibers

Short, fine, highly branched collagenous fibers. Branch, forming networks that offer more "give"

Cells of Connective tissue

"Blasts" cells, Fat cells, White blood cells, Mast cells, Macrophages

Areolar Loose Connective Tissue

Wraps and cushions organs, Plays important role in inflammation, Holds and conveys tissue fluid

Location: Surrounds capillaries.

Adipose Loose Connective Tissue

Provides reserve food fuel, Insulates against heat loss, Supports and protects organs

Location: Under skin in subcutaneous tissue

Reticular Loose Connective Tissue

supports free blood cells in lymph nodes, the spleen and bone marrow

Location: Lymphoid organs (lymph nodes, bone marrow, and spleen)

Dense Regular Connective Tissue

Attaches muscles to bones or to muscles, Attaches bones to bones

Location: Tendons, most ligaments, aponeuroses.

Dense Irregular Connective Tissue

Withstands tension, Provides structural strength

Location: Dermis of the skin

Elastic Dense Connective Tissue

Allows tissue to recoil after stretching

Location: Walls of large arteries

Blood (Fluid Connective Tissue)

Transport respiratory gasses, nutrients, wastes, and other substances

Location: Contained within blood vessels.

Skeletal muscle tissue

Found in skeletal muscle, Voluntary

Cardiac muscle tissue

Found in walls of heart, Involuntary

Smooth muscle tissue

Mainly in walls of hollow organs other than heart, Involuntary

Main component of the nervous system

Brain, spinal cord, nerves. Regulates and controls body functions

Cutaneous membranes

(the skin) covers the body surface

Mucous membranes

lines body cavities that are open to the exterior

Serous membranes

lines body cavities that are closed to the exterior

Tissue repair involves

regeneration, fibrosis

Regeneration

Same kind of tissue replaces destroyed tissue. Original function restored

Fibrosis

Connective tissue replaces destroyed tissue. Original function lost