Tissues, Glands & Membranes

7/29/2019 Tissues, Glands & Membranes

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Tissues Glands &Membranes

Neriza G. Mamasabulod, RN, MAN


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Tissue

A tissue is a group of cells with

similar structure and function, as

well as the extracellular

substances located between the

cells.

HISTOLOGY is the study of

tissues


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Functions of the Epithelia

Protection-ex. Epithelium of the oral

cavity, which protect the underlyingstructures from abrasion

Acting as barriers-prevents entry oftoxic molecules or microorganisms

into the body Passage of substances-ex. O2 &

CO2 exchanged through the lungs

Secretion-ex. Sweat glands &mucous glands

Absorption of substances-ex.Epithelial cells of the intestine whichabsorbs digested food molecules,

vitamins & ions


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Types of Tissue

Epithelial tissue-covers surfaces,lines cavities & forms glands.

Connective tissue-supports &forms the framework of all parts

of the body.

Muscle tissue-contracts &

produces movement.

Nervous tissue-conducts nerveimpulses.


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Epithelial Tissue- covers surfaces, usually

has a basement

membrane, has littleextracellular material, and

has no blood


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Classification ofEpithelia

Simple epitheliumhas one layerof cells, whereas stratefied

epithelium has more than one

Pseudostratified columnarepitheliumis simple epitheliumthat appears to have two or more

cell layers Transitional epitheliumis

stratified epithelium that can be

greatly stretched.


7/49Characteristic of E ithelium


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Typesof

Epithelium

(a)Simple

Squamous

Epithelium-

single layerof thin, flat

cells


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(b) Simple Cuboidal Epithelium- single layer of cubelike cells


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(c) Simple Columnar Epithelium- singlela er of tall thin cells


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(d) PseudostratifiedColumnar Epithelium-prefix pseudo means

false, appears to bestratified but not.

Consist of one layer of

cells attached to a

basement membrane.


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(e) StratifiedSquamous

Epithelium-

thick,consists

of many

layer


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(f)Transitional

Epithelium-greatly

stretch


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Structural and FunctionalRelationships

Simple epitheliumis involved withdiffusion, secretion, or absorption.

Stratified epitheliumserves a

protective role. Squamous cellsfunction in diffusionor filtration. Cuboidal or columnarcells, which contain more organelles,

secrete or absorb. A smooth free surface reduces

friction. Microvilliincrease surfacearea, and ciliamove materials over

the cell surface.


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Cont

Desmosomesmechanically bindcells together, tight junction form

a permeability barrier, and gap

junctions allow intercellularcommunication.

Hemidesmosomesmechanically

bind cells to the basementmembranes.


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Glands

A gland is a single cell or a

multicellular structure that

secretes

Exocrine glands have ducts, and

endocrine glands do not


18/49Structure of Exocrine Glands


19/49Cont glands


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CONNECTIVE TISSUE Connective tissue holds cell and

tissues together.

It has an extracellular matrix

consisting of protein fibers, ground

substance, and fluid Collagen fibers are flexible but resist

stretching, reticular fibers form a fiber

network, and elastic fibers recoil Blast cells form the matrix, cyte cells

maintain it and clast cells break it

down


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Functions of Connective Tissue Connective tissues enclose and separate-ex.

Separate muscles, arteries, veins & nerves fromone another.

Connect tissues to one another-ex. Tendons arestrong cables or bands that attach muscle tobones & ligaments.

Support and movement-ex. Skeleton providesrigid support for the body, semirigid cartilagesupports structures such as the nose, ears &surfaces of joints.

Storing-adipose tissue (fat) stores high-energymolecules.

Cushion and insulation-adipose tissue (fats)

protects the tissues it surrounds & insulate toconserve heat

Transport of blood-such as gases, nutrients,hormones, enzymes & cells of immune system.

Protection from microorganisms-such as toxins

Cl ifi i f


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Classification ofConnective Tissue

1. Embryonic connective tissue givesrise to six major categories ofconnective tissue

2. Loose, or areolar, connective

tissueis the loose packingmaterial of the body, which fills thespaces between the organs andholds them in place.

3. Adipose, or fat, tissuefunctionsto store energy. Adipose tissuealso pads and protects parts of thebody and acts as as thermalinsulator.


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4.Dense connective tissueconsists of

matrix containing densely packed

collage fibers (tendons, ligaments, anddermis of the skin)or of matrix containing

densely packed elastic fibers (elastic

ligaments and in the walls of arteries).

5. Cartilageprovides support and is foundin structures such the costal cartilages,

disks between vertebrae, and external

ear.

6. Bonehas a mineralized matrix and formsmost of the skeletons of the body.

7. Bloodhas a liquid matrix and is found inblood vessels.


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(d) Dense Elastic Connective Tissue


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-Is the most abundant type of cartilage& has man functions.


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- Hard Connective Tissue


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Muscle Tissue

1. Muscle tissue is specialized to

contract or shorten, making

movement possible.

2. The three types of muscle

tissue are skeletal, cardiac and

smooth muscles.


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Nervous Tissue

1. Forms the brain, spinal cord

and nerves.

2. Nervous Tissue is specialized to

conduct action potentials

(electrical signals)

3. Neurons conduct action

potentials, and neurogliasupport the neurons


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Membranes: Mucous

MembranesMucous Membranes line cavities

that open to the outside of the

body ( digestive, respiratory,excretory, and reproductive

tracts). They contain glands and

secrete mucus.


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Membranes: SerousMembranes

Serous membranes line trunk

cavities that do not open to the

outside of the body (pleural,pericardial, and peritoneal

cavities). They do not contain

glands but do secrete serousfluid.


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Other Membranes

Other membranes include the

cutaneous membrane (skin)

synovial membranes (line joint

cavities) and periosteum ( aroundthe bone)


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Inflammation

1. The function of the inflammatory

response is to isolate and

destroy harmful agents.

2. The inflammatory response

produces five symptoms:

redness, heat, swelling

(edema), pain, and disturbanceof function.


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Chronic Inflammation

Chronic inflammation results

when the agent causing injury is

not removed or something else

interferes with the healingprocess.

1 A splinter in the skin


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1. A splinter in the skincause damage &introduces bacteria.Mediators of

inflammation arereleased.

2. Mediators ofinflammation causecapillaries to dilatecausing, the skin tobecome red.

3. WBC (ex. neutrophils &macrophages) leave

the dilated bloodvessels & move to thesite of bacterial infx.Where they begin tophagocyte bacteria &

other debris.

Tissue Repair


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Tissue Repair1. Tissue repair is the substitution of

viable cells for dead cells. Labile cells

divide throughout life and can undergo

regeneration. Stable cells do not

ordinarily divide but can regenerate if

necessary. Permanent cells have littleor no ability to divide if killed repair is

by replacement.

2. Tissue repair involves clot formation,

inflammation, formation of granulationtissue, and regeneration or

replacement of tissues in severe

wounds, wound contracture can occur.

1. Fresh wound


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1. Fresh woundcuts theepithelium(epidermis &dermis) & a cloyis formed.

2. Approx. 1 wk.after the injury,a scab ispresent &epithelium isgrowing into the

wound.3. Approx. 2 wks.

the epitheliumhas growncompletely intothe wound.

4. Approx. 1 monththe hascompletelyclosed w/c isreplaced by anew connectivetissue.


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Tissues & Aging

Cells divide more slowly as

people age. Injuries heal more

slowly.

Extracellular matrix containing

collagen and elastic fibers

become les flexible and less

elastic. Consequently, skinwrinkles elasticity in arteries is

reduced, and bones break more

easily.


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Thats all folks !!!

Tissues, Glands & Membranes

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