Histology: The Study of Histology: The Study of TissuesTissues

Mrs. HartleyMrs. Hartley

Anatomy and PhysiologyAnatomy and Physiology

Types of TissuesTypes of Tissues

• Epithelial Tissue – Covering and Epithelial Tissue – Covering and LiningLining

• Connective Tissue – Support and Connective Tissue – Support and ManufactureManufacture

• Muscle Tissue – MovementMuscle Tissue – Movement

• Nerve Tissue – Signaling and SupportNerve Tissue – Signaling and Support

Epithelial TissueEpithelial Tissue

• Cells closely joined togetherCells closely joined together with little or with little or no intercellular material between cellsno intercellular material between cells

• Blood vessels cannot penetrate between Blood vessels cannot penetrate between them therefore they are them therefore they are avascularavascular

• Covers body surfaces, lines body cavities Covers body surfaces, lines body cavities and organs and forms glandsand organs and forms glands

• May perform secretion, absorption, and May perform secretion, absorption, and serve as protection in certain areasserve as protection in certain areas

Covering & Lining Covering & Lining EpitheliumEpithelium• Cover external body surfaces and lines inner Cover external body surfaces and lines inner

walls of cavities and organswalls of cavities and organs• Cells are stationary and anchored by their basal Cells are stationary and anchored by their basal

surfacessurfaces• 3 general shapes can are recognized3 general shapes can are recognized

– Squamous = flatSquamous = flat– Cuboidal = cube-shaped (= in height & width)Cuboidal = cube-shaped (= in height & width)– Columnar = cylindrical (greater in height)Columnar = cylindrical (greater in height)Two cell arrangementsTwo cell arrangements

simple = single layersimple = single layerstratified = multiple layersstratified = multiple layers

Simple SquamousSimple Squamous

• Simple = one layerSimple = one layer• Squamous = flatSquamous = flat• Flattened cells arranged in a Flattened cells arranged in a

single layersingle layer• Centrally located nucleusCentrally located nucleus• Found where layers must be Found where layers must be

thin to permit diffusion of thin to permit diffusion of materialsmaterials

• Lines the walls of Lines the walls of blood blood vessels, forms walls of vessels, forms walls of capillaries, forms walls of air capillaries, forms walls of air sacs in lungs, linings of the sacs in lungs, linings of the body cavitiesbody cavities

• Outermost section of frog Outermost section of frog skin viewed from the topskin viewed from the top

Simple CuboidalSimple Cuboidal

• Single layer of cube-Single layer of cube-shaped cellsshaped cells

• Centrally located Centrally located nucleusnucleus

• Often contain Often contain ciliacilia and/or and/or microvillimicrovilli along along their free bordertheir free border

• Forms the walls of small Forms the walls of small tubes, or ducts, that tubes, or ducts, that carry secretions from carry secretions from one part of the body to one part of the body to anotheranother

• i.e. i.e. kidneys, liver, and kidneys, liver, and many glandsmany glands

Simple Columnar EpitheliumSimple Columnar Epithelium

• Single layer of elongated, Single layer of elongated, cylindrical cellscylindrical cells

• Nuclei lie near basement Nuclei lie near basement membranemembrane

• Frequently Frequently secrete a secrete a product (abundance of ER product (abundance of ER and Golgiand Golgi))

• Lining the walls of the Lining the walls of the uterus and uterus and digestive digestive organs such as the organs such as the stomach and small stomach and small intestineintestine

• Small intestine = Small intestine = microvillimicrovilli

Pseudostratified ColumnarPseudostratified Columnar

• Appears multi-layered Appears multi-layered but is notbut is not

• Uniformity among cell Uniformity among cell shapes and locations shapes and locations of nucleiof nuclei

• Long Long ciliacilia that create that create currents for the currents for the movement of mucusmovement of mucus

• Lines parts of the Lines parts of the respiratory tractrespiratory tract such such as the as the tracheatrachea and and bronchibronchi

Transitional EpitheliumTransitional Epithelium

• Multiple-layered arrangement of cells of Multiple-layered arrangement of cells of cubelike or irregular shapecubelike or irregular shape

• Have the capacity to Have the capacity to expand in size and expand in size and recoilrecoil giving the tissue the ability to stretch giving the tissue the ability to stretch ((elasticityelasticity))

• Lines the insides of organs that require Lines the insides of organs that require elasticityelasticity and extensibility for normal function and extensibility for normal function

• Urinary bladder and the uretersUrinary bladder and the ureters (tubes that (tubes that travel from the kidneys to the bladder)travel from the kidneys to the bladder)

Left: Empty BladderLeft: Empty BladderRight: Full BladderRight: Full Bladder

Glandular EpitheliumGlandular Epithelium

• Closely packed cells highly specialized to Closely packed cells highly specialized to manufacture and secrete productsmanufacture and secrete products

• Particular type = glandParticular type = gland• Exocrine glandsExocrine glands: : empty their products into ductsempty their products into ducts

which transport the product onto the body which transport the product onto the body surface or into a cavity where it will provide some surface or into a cavity where it will provide some benefit (benefit (sweat, oil, salivary)sweat, oil, salivary)

• Endocrine glandsEndocrine glands: : secrete their productssecrete their products into the into the extracellular space and extracellular space and into the bloodstreaminto the bloodstream where it is distributed throughout the body where it is distributed throughout the body (pituitary, thyroid, adrenal, the endocrine system)(pituitary, thyroid, adrenal, the endocrine system)

Exocrine GlandsExocrine GlandsLeft: Salivary GlandsLeft: Salivary GlandsRight: Sweat GlandsRight: Sweat Glands

Endocrine GlandsEndocrine GlandsLeft: PituitaryLeft: PituitaryRight Bottom: Adrenal GlandsRight Bottom: Adrenal Glands

Stratified SquamousStratified Squamous

• Multi-layered arrangement of flat cellsMulti-layered arrangement of flat cells

• Covers areas of the body that take Covers areas of the body that take constant wear and tearconstant wear and tear and must resist and must resist that wear and tearthat wear and tear

• Surface layer is squamous, deepest layers Surface layer is squamous, deepest layers may have cuboidal or columnar cells that may have cuboidal or columnar cells that have become flattenedhave become flattened

• Outer layer of skin to protect from Outer layer of skin to protect from abrasionsabrasions

Your AssignmentYour Assignment

• Create a picture atlas of tissues.Create a picture atlas of tissues.• You will be able to use this atlas on the You will be able to use this atlas on the

test! So make it good!test! So make it good!• Each page will have the tissue name, the Each page will have the tissue name, the

function, location, and a picture.function, location, and a picture.• You may use the text or this slideshow You may use the text or this slideshow

which is found on my website.which is found on my website.• You will be graded by test and by You will be graded by test and by

completion of the atlas…do not get completion of the atlas…do not get behind!behind!