New objectivesName the four major tissue typesGive the chief locations of the various tissue

types in the bodyDescribe the process of tissue repairDefine neoplasm and distinguish between

benign and malignant neoplasmsExplain the significance of the fact that some

tissue types (muscle and nerve) are largely amitotic after the growth stage is over

TissuesTissues- groups of cell that are similar in

structure and functionThere are four primary tissues

1. epithelium-covering2.connective-support3. nervous-control4. muscle-movementTissues are organized into organs and organs are

made up of a variety of tissues. The arrangement of tissue determines each organ’s structure and function

Epithelial tissue=epithelium“epithe=laid on, covering it is the lining,

covering and glandular tissue of the body

Functions:ProtectionAbsorption FiltrationSecretion

Special characteristics of epitheliumEpithelial cells usually fit together closely in a

continuous sheet neighboring cells are bound by desmosomes and tight junctions

The membrane always has a free unattached surface or edge (apical surface) which is exposed to the body’s exterior or the cavity of an internal organ. May be smooth or contain microvili

The lower surface of an epithelium rests on a basement membrane

Epithelial tissues have no blood supply of their own and rely on diffusion from the capillaries in the underlying connective tissue for food and oxygen

If well nourished, these cells regenerate themselves easily

Simple=one layer

Stratified= more than one cell layer

Named for cells on the free layer (apical surface)

Simple squamous= forms membranes where filtration occurs allows for rapid diffusion ex) alveoli, capillaries, serosae (lining of the ventral cavity)Simple cuboidal= glands and ducts ex) salivary glands, pancreas, kidney tubulesSimple columnar=goblet cells produce lubricating mucus. Ex)lining of digestive tract, mucous membranes (epithelial membranes that line body cavities open to the body exteriorPseudostratisfied columnar=all of these cells rest on the basement membrane. Nuclei are at different heights giving the illusion of being stratisfied. Allow for absorption and secretion and are often ciliated. Ex) line respiratory tract

Stratified squamousStratified squamous= most common stratified

epithelium in the body. The cells on the apical surface are squamous, whereas those nearest the basement membrane are cuboidal or columnar.

They are found in sites that receive a good deal of friction, such as the esophagus, mouth and dermis layer of skin

Stratified cuboidal &stratified columnarStratified cuboidal= usually two cell layers

with the apical cells being cuboidal in shapeStratified columnar= apical cells are

columnar but basal cells vary in size and shape

Both are very rare and found mainly in the ducts of large glands

Glandular epitheliumA gland consists of one or more cells that

make and secrete a particular productSecretions, the product secreted that typically

contains protein molecules in an aqueous fluid-active process

Endocrine glands- lose their connection to the surface (duct); they are often called ductless glands. Their secretions (hormones) diffuse directly into blood vessels that weave throughout the gland

ex) adrenal, thyroid and pituitary glands

Exocrine glands retain their ducts, and their secretions empty through the ducts to the epithelial surface

Ex) sweat and oil glands, liver, and pancrease

Connective tissueConnects body parts and is found throughout

the body. It is the most abundant and widely spread of all tissue types.

Involved in protecting, supporting, and binding together other body tissue

Common characteristicsVariation in blood supply most connective tissue

is vascularized =good blood supply Exceptions are tendons, ligaments(poor blood supply),

and cartilage (avascular)

Extracellular matrixExtracellular matrix nonliving substances

outside of the cells that make up the connective tissue in addition to the varying cells.

It is produced by the connective tissue cells and then is secreted to their exteriors

Comprised of two main parts : Ground substance-water, adhesion proteins,

polysaccharides (liquidgel solid) absorbs water/reserve

Fibers- collagen (white), elastic (yellow)

Types of connective tissue:1.Bone2.Cartilage3.Dense connective tissue 4.Loose connective tissue5.Blood

Bone= osseous tissue Composed of bone cells sitting in cavities, lacunae and surrounded by layers of a very hard matrix containing calcium salts in addition to large amounts of collagen fibers.Rock Hard!!!

Cartilage types1. Hyaline “glass”: most widespread has rubbery matrix (many collagen fibers) blue white appearanceLarynx (voice box), attaches ribs to sternum

(breast bone), covers bone ends to form joints, skeleton of fetus

2. Fibrocartilage-highly compressible forms cushion-like discs between vertebrae

3.Elastic cartilage- ear

Loose connectiveAreolar tissue- most

widely distributed “glue” hold the internal organs in proper place

Adipose tissue-fatInsulates body and protects

Reticular tissue-is the “bed” that supports blood cells (lymph nodes, spleen, bone marrow)

Blood= vascular tissueconsists of blood cells surround by plasma (fluid matrix)

Muscle Tissue: 3 typesSkeletal- form the muscular system and are

associated with voluntary movementsCardiac- heart muscle under involuntary

controlSmooth muscle a.k.a visceral muscle- no

visible striations found in the walls of hollow organs such as the stomach, bladder, uterus, and blood vessels.Responsible for peristalsis

Nervous Tissue: OMG what do I do?!?Comprised of neurons which receive and

conduct electrochemical impulses. Make up the brain, spinal cord, and nerves

Tissue Repair (Wound Healing)Two ways:

Regeneration- the replacement of destroyed tissue by the same kind of cells

Fibrosis- involves repair by dense connective tissue, by the formation of scar tissue

Type of repair depends on:1. The type of tissue damaged 2. The severity of the cut

Regeneration capabilities depend on tissue type: epithelial, mucous membrane, fibrous

connective, and bone +Skeletal muscle, cardiac muscle, and nervous -

Developmental aspects of cells and tissues Every living thing starts as one cell

(diploid organisms=zygote) that divides & divides & divides & divides & divides & divides & divides & …..

Most cells (not neurons) undergo mitosis until the end of puberty

When adult body size is reached most stop after this time only certain cells routinely divide (skin, intestinal cells, liver cells can)

Amitotic tissueAmitotic tissue –tissue comprised of cells that

lose the ability to divide when they are fully mature ex.) cardiac muscle and neuronsThey are severely handicapped as a result of

injury because they are often replaced with scar tissue

Aging-process

Begins once maturity has been reached (or at birth)

Suggestions as to what causes aging (no one knows):Chemical insults (alcohol, drugs, &CO) in blood

&/or absence of glucose and oxygenRadiation (xrays and UV waves)genetics

Aging eventsEpithelial membranes thin and are easily

damaged. Skin loses elasticity and sagsExocrine glands become less active and produce

less oil, mucous, sweat, and hormonesMetabolism becomes less efficient as does

reproductionConnective tissue changes (bone becomes more

porous and weakens)Healing/repair process slowsMuscles atrophy

Neoplasm- when cells fail to honor normal controls on cell division and multiply wildly , an abnormal mass of proliferating cells. Can be benign or malignant

Hyperplasia-when certain body tissues or organs enlarge because there is some local irritant or condition that stimulates the cells. Ex) breast enlargement during pregnancy

Atrophy- decrease in size, can occur in an organ or body area that loses its normal stimulation. Ex) used muscles that lost there nerve supply

Read A Closer LookCancer -The Intimate Enemy pg 100-101Read Summary for part I, II, & IIIAnswer all multiple choice questions in

complete sentencesAnswer all short answer questionsExtension “At the clinic” bonus