Tissue

• Group of cells similar in structure and function

• Four types of tissue – Epithelial, Connective, Muscle, and Nervous

Epithelial Connective Nervous Muscle

Epithelial

• Covers surfaces• Functions include protection,

absorption, filtration, excretion, secretion, and sensory reception

• Distinguishing characteristics include polarity, cellularity, specialized contacts, support by connective tissue, avascularity, regeneration

• Types include cuboidal, squamous, and columnar in both simple and stratified

Simple

Simple Epithelia

• Single layers of cells• Four main types which

include squamous, cuboidal, columnar, and pseudostratified

Simple Squamous

• Single layer• Flattened cells• Disc Shaped nuclei• Sparse cytoplasm• Simplest epithelia

Simple Cuboidal

• Single layer• Cube-like cells• Large spherical central

nuclei• Functions are to

secrete and absorb

Simple Columnar

• Single layer• Tall cells• Round to oval nuclei• Some cells bear cilia• Layer may contain

goblet cells• Absorbs, secretes

mucus, enzymes, and other substances

• Ciliated type propels mucus

Pseudostratified Columnar

• Single layer of cells• Differing heights of cells

and nuclei• Some cells do not reach

free surface• May contain goblet cells

and bear cilia• Functions are secretion

mostly of mucus but also propulsion of mucus

Stratified Epithelia

• Contains multiple layers of cells

• 4 main types which include squamous, cuboidal, columnar, and transitional

Stratified Squamous

• Thick membrane with several layers of cells

• Basal cells are cuboidal or columnar

• Surface cells are flattened• In Keratinized type surface

cells are full of keratin and dead.

• Basal cells are active in mitosis

• Function is to protect tissues

Stratified Cuboidal

• Mostly two layers• Cubelike cells• Protects• Rare in the body

Stratified Columnar

• Several layers• Basal cells mostly

cuboidal• Superficial cells

elongated and columnar• Protects and Secretes

Transitional Epithelium

• Resembles stratified squamous and stratified cuboidal

• Basal cells cuboidal or columnar

• Surface cells dome shaped or squamouslike

• Depends on organ stretch

Connective Tissue

• Found in all parts of body• Performs variety of functions

like protecting, supporting, and binding other tissues.

• Main types include connective tissue proper, cartilage, bone, and blood.

• Characteristics include many types of cells, great deal of noncellular, nonliving material between cells of connective tissue

• Connective tissues have a rich supply of blood vessels

Mesenchyme Embryonic

• Gel-like ground substance with fibers and start shaped mesenchymal cells

• Found in embryo• Functions gives rise to

other connective tissue types

Areolar

• Gel-like matrix with three fiber types, cells, fibroblasts, macrophages, mast cells, and some white blood cells.

• Wraps organs and cushions them

Adipose

• Matrix, very sparse, closely packed adipocytes , with nucleus pushed to side by fat droplet

• Provide reserve fuel, insulates, supports and protects organs

Reticular

• Network of reticular fibers in a loose ground substance

• Cells lie on network• Fibers form stroma that

supports other cell types

Dense Regular

• Mostly collagen fibers with few elastin fibers

• Major cell is fibroblast• Attaches muscle to

bone, muscle to muscle, or bone to bone

• Withstands great tensile stress when force is applied in one direction

Dense Irregular

• Mainly irregularly arranged collagen fibers and some elastic fibers

• Major cell is the fibroblast

• Withstand tension in several directions

• Provides structural strength

Cartilage Hyaline

• Amorphous but firm• Collagen fibers form

imperceptible network• Supports and reinforces• Has cushioning

properties• Can resist compressive

stress

Cartilage elastic

• Similar to hyaline• More elastic fibers in

matrix• Maintains shape of

structure with flexibility

Fibrocartilage

• Matrix is similar to hyaline but less firm

• Thick collagen fibers• Tensile strength can

absorb compressive shock

Osseous

• Hard, calcified matrix, with many collagen fivers

• Very well vascularized• Supports and protects• Marrow inside bones is

site for bone formation

Blood

• Red and white blood cells

• Contained in a fluid matrix

• Transport substances

Nervous Tissue

• Composed of two major cell populations, Neuroglia and Neurons

• Neurons are branching cells

• The neuroglia are special supporting cells that protect, support, and insulate the more delicate neurons

Muscle Tissue

• Muscle tissue is specialized in contracting and producing body movement

• There are three main types of muscle tissue which include skeletal muscle, cardiac muscle, and smooth muscle

Skeletal Muscle

• Long cylinders• Multinucleate cells• Used for voluntary

movement, locomotion, and facial expression

Cardiac Muscle

• Branching, striated, usually uninucleate cells

• When contracting it shoots blood into circulation by involuntary control

Smooth Muscle

• Spindle shaped cells• Central nuclei• No striation• Cells form close sheets• Smooth muscle moves

substances and/or objects along internal passageways