Philippine Paramedical and Technical School Incorporated - Cebu

8/14/2019 Philippine Paramedical and Technical School Incorporated - Cebu

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Anatomy of the Cell

PHILIPPINE PARAMEDICAL AND TECHNICAL SCHOOL INCORPORATED - CEBU


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Cell Structure and TheirFunctions

Functions of the Cell

Basic unit of lifeProtection and support

Movement

CommunicationCell metabolism and energy release

Inheritance



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3 Main Regions of a Cell

Cell Membrane

Cytoplasm

Nucleus



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Cell Membrane

Cell membrane or plasmamembrane-the outermostcomponent of a cell

The structure of plasmamembrane contains 2 lipids

(fat) layers arranged tail to

tail in which protein

molecules float



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How substances move acrossthe Plasma Membrane

Substances need to pass through the

membrane to enter or leave the celland they do so in a number of ways.Some of these processes require no

energy i.e. they are passive, whileothers require energy i.e. they areactive.



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Passive processes include:a) diffusion and

b) osmosis,

while active processes include:c) active transport,

d) phagocytosis,

e) pinocytosis and

f) exocytosis.



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Movement through cellmembrane: Diffusion

Tendency for solutesto move from an area

of higherconcentration to anarea of lowerconcentration of that

solute in a solution



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Movement through cell

membrane Mediated Transport Mechanisms

Facilitated diffusion

>moves substances from a higher to lowerconcentration of that substance

Active transport

>moves substances from regions of lowerconcentration to those of higher concentration

against a concentration gradient Secondary active transport

>active transport one substance establishing aconcentration gradient



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Movement through cell membrane:

Osmosis

Diffusion ofwater across a

selectivelypermeablemembranefrom a regionof higher

waterconcentrationto one of lowerwater

concentration



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Active transport When a substance is transported from a

low concentration to a high concentrationi.e. uphill against the concentrationgradient, energy has to be used. This is

called active transport. Active transport is important in

maintaining different concentrations of theions sodium and potassium on either side

of the nerve cell membrane. It is also important for removing valuable

molecules such as glucose, amino acidsand sodium ions from the urine.



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Phagocytosis Phagocytosis is sometimes calledcell eating.

It is a process that requires energyand is used by cells to move solid

particles like bacteria across theplasma membrane.

Finger-like projections from the

plasma membrane surround thebacteria and engulf them.



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Once within the cell, enzymes

produced by the lysosomes of the cell(described later) destroy thebacteria.

The destruction of bacteria and otherforeign substance by white blood cellsby the process of phagocytosis is a

vital part of the defense mechanismsof the body.



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Pinocytosis

Pinocytosis or cell drinking is avery similar process to phagocytosisbut is used by cells to move fluidsacross the plasma membrane.

Most cells carry out pinocytosis.



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Endocytosis Uptake of material through the cell membrane

by the formation of a membrane-bound sac

called a vesicle Invaginates to form a vesicle containing the

material to be taken into the cell

Vesicle is then taken into the cell

Phagocytosis-used for endocytosis whensolid particles are ingested

Pinocytosis-much smalles vesicles areformed that contain liquid rather thanparticles



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Exocytosis

Process within the cell which creates a

membrane-bound sac called secretoryvesicle, which fuses with the cellmembrane and the material in the vesicleis eliminated from the cell

Endocytosis is similar to this process butoccurs in an opposite direction howeverboth require energy in the foto formvesicles



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The Cytoplasm Within the plasma

membrane is the

cytoplasm. It consistsof a clear jelly-like fluidcalled the

a) cytosol or intracellularfluid in which

b) cell inclusions

c) organelles and

d) microfilaments andmicrotubules are found.



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Cytosol

The cytosol consistsmainly of water inwhich variousmolecules are

dissolved orsuspended.

It includes proteins,fats andcarbohydrates as wellas sodium,potassium, calcium

and chloride ions.



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Cell inclusions

These are large particles of fat,

glycogen and melanin that havebeen produced by the cell.

They are often large enough to beseen with the light microscope. For

example the cells of adipose tissue(as in the insulating fat layer underthe skin) contain fat that takes upmost of the cell.



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Organelles Nucleus Nucleoli and ribosomes

Rough and smoothendoplasmic reticulum

Golgi apparatus

Secretory vesicles

Lysosomes andperoxisomes

Mitochondria

Cytoskeleton

Centrioles

Cilia, flagella and microvilli



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A. Ribosomes

Ribosomes are tinyspherical organelles that

make proteins by joiningamino acids together.Many ribosomes arefound free in the cytosol,

while others are attachedto the rough endoplasmicreticulum.



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B. Endoplasmicreticulum The endoplasmic

reticulum (ER) is anetwork of membranes

that form channelsthroughout the cytoplasmfrom the nucleus to theplasma membrane.Various molecules aremade in the ER and

transported around thecell in its channels. Thereare two types of ER:smooth ER and rough ER.



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Smooth ERis

where the fats inthe cell are madeand in some cells,where chemicals

like alcohol,pesticides andcarcinogenicmolecules areinactivated.



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The Rough ERhasribosomes attachedto its surface. Thefunction of the

Rough ER istherefore to makeproteins that aremodified stored andtransported by the

ER



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C. Mitochondria (singular

mitochondrion) areoval or rod shaped

organelles scatteredthroughout thecytoplasm. Theyconsist of two

membranes, the innerone of which is foldedto increase its surfacearea.


PHILIPPINE PARAMEDICAL AND TECHNICAL SCHOOL INCORPORATED CEBU


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D. Golgi Apparatus

The Golgi bodies in a celltogether make up the Golgiapparatus.

Golgi bodies are found near

the nucleus and consist offlattened membranesstacked on top of each otherrather like a pile of plates

It modifies and sorts theproteins and fats made bythe ER, then surroundsthem in a membrane asvesicles so they can be

moved to other parts of thecell.




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E. Lysosomes

are large vesicles that containdigestive enzymes.

These break down bacteriaand other substances that are

brought into the cell byphagocytosis or pinocytosis.

also digest worn-out ordamaged organelles, thecomponents of which can then

be recycled by the cell to makenew structures.




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Microfilaments AndMicrotubules

Some cells canmove and change

shape andorganelles andchemicals aremoved around thecell. Threadlike

structures calledmicrofilamentsand microtubulesthat can contractare responsible for

this movement.




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Microfilaments AndMicrotubules These structures also form the projections from

the plasma membrane known as flagella

(singular flagellum) as in the sperm tail, andcilia found lining the respiratory tract and usedto remove mucus that has trapped dustparticles.

Microtubules also form the pair of cylindricalstructures called centrioles found near thenucleus. These help organise the spindle used incell division.




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The Nucleus The nucleus is the

headquarters ofthe cell.

It regulates all cell

activity. It consists of a

nuclear envelope,(the outer

membrane) andnucleoplasm. In the nucleoplasm

you can seechromatin and the

nucleolus.




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Gene containing

The genetic material orDeoxyribonucleic acid (DNA)

= the blue print that contains all instructions

needed for building the whole body= has instructions for building proteins

= necessary for cell production

A cell that has lost or ejected itsnucleus (for whatever reason) isprogrammed only to die.

The shape of the nucleus conformsthe sha e of the cell



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The Nuclear Envelope Double membrane barrier of the

nucleus

Between the two membranes is afluid field moat or a space

The nuclear envelope is selectively

permeable It encloses a jelly like fluid called

nucleoplasm in which the nuclei and

the chromatin are suspended




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The Nucleoli

Small, dark-staining, essentially

round bodies Sites where ribosomes are assembles

= the ribosomes, which eventually

migrate into the cytoplasm, servesas the actual sites of proteinsynthesis




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Chromatin

When a cell is not dividing, its DNA is

combined with Protein and gorms ofloose network of bumpy threadscalled chromatin




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Whole-cell Activity Cell metabolism sum of all the chemical

reactions in the cell

Protein synthesis production of proteinthrough transcription and translation

Cell Division formation of 2 daughter

cells from a single parent cell Differentiation process by which cellsdevelop specialized structures andfunctions




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Mitosis Interphase>time between cell divisions Prophase>chormatin condenses into chromosomes

Metaphase>chromosomes align in the center in association

with the spindle fibers Anaphase

>chromatids separate to form 2 sets ofchromosomes;chromosomes assisted by spindlefibers move toward centrioles

Telophase>chromosomes disperse, and cytoplasm begins to

divide to form 2 cells




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Cellular Aspects of Aging Cellular clock>after a certain passage of time or a number of cell

division results in death of a given line

Death genes>there are death genes which turn on late in life

DNA damage>resulting in cell degeneration and death

Free radicals>susceptible to damage, mutations and ultimately

cell damage Mitchondrial damage>result in loss of proteins critical to mitochondrial

function




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CHAPTER 1: HISTOLOGY TISSUESMitosis

Process by which a cell divides and produces two daughter cell from a single

parent cell.

Stages of MitosisThe process of mitosis is divided into 6 stages. The Interphase, Prophase,Metaphase, Anaphase, Telophase, and cytokinasis. At Interphase, there isonly one cell, but after cytokinasis there are two identical cells. Beforemitosis can take place, the cell need to store enough energy to drive thechemical processes during the cell division. During this period of time, thereis intense cellular activity. The cell grows in size. The length of the growphase varies between a few hours to a few months. We the cell has storedenough energy, it is ready to divide itself.

1. Interphase

DNA has replicated, but has not formed the condensed structure ofchromosome. They remain as loosely coiled chromatin. The nuclearmembrane is still to protect the DNA molecules from undergoingmutation.

Chromatin - The complex of DNA and proteins that makes up a eukaryotic chromosome. When thecell is not dividing, chromatin exists as a mass of very long, thin fibers that are not visible with a light

microscope.




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2. ProphaseThe DNA molecules progressively shorten and condense by coiling, toform chromosomes. The nuclear membrane and nucleolus are no longervisible. The spindle apparatus has migrate to opposite poles of the cell

Nucleolus - noo-KLEE-oh-lus) (plural, nucleoli) A specialized structure in the nucleus,formed from various chromosomes and active in the synthesis of ribosomes.




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3. MetaphaseThe spindle fibres attach themselves to the centromeres of thechromosomes and align the chromosomes at the equatorial plate.

Centromeres - The constricted region of a chromosome where the two chromatids areattached.




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5. AnaphaseThe spindle fibres shorten and the centromere splits, separated sisterchromatids are pulled along behind the centromeres.

sister chromatids - (KROH-muh-tidz) Replicated forms of a chromosome joinedtogether by the centromere and eventually separated during mitosis or meiosis II.




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6. CytokinasisThis is the last stage of mitosis. It is the process of splitting the daughtercells apart. A furrow forms and the cell is pinched in two. Each daughtercell contains the same number and same quality of chromosomes

Source: http://library.thinkquest.org/



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Epithelial TissuesEpithelial tissue covers the whole surface of the body. It is made up of cellsclosely packed and ranged in one or more layers. This tissue is specialized toform the covering or lining of all internal and external body surfaces.

Epithelial tissue that occurs on surfaces on the interior of the body is knownas endothelium. Epithelial cells are packed tightly together, with almost nointercellular spaces and only a small amount of intercellular substance.Epithelial tissue, regardless of the type, is usually separated from theunderlying tissue by a thin sheet of connective tissue; basement membrane.The basement membrane provides structural support for the epithelium andalso binds it to neighboring structures.

Types of Epithelial TissuesEpithelial tissue can be divided into two groups depending on the number oflayers of which it is composes.

Epithelial tissue which is only one cell thick is known as simple

epithelium.

If it is two or more cells thick such as the skin, it is known as stratifiedepithelium.



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Simple epitheliumSimple epithelium can be subdivided according to the shape andfunction of its cells.

Squamous (pavement) epithelium.Squamous cells have the appearance of thin, flat plates. The shapeof the nucleus usually corresponds to the cell form and help toidentify the type of epithelium. Squamous cells, for example, tend tohave horizontal flattened, elliptical nuclei because of the thinflattened form of the cell. They form the lining of cavities such asthe mouth, blood vessels, heart and lungs and make up the outer

layers of the skin.



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Simple Cuboidal EpitheliumAs their name implies, cuboidal cells areroughly square or cuboidal in shape. Each cell has a sphericalnucleus in the centre. Cuboidal epithelium is found in glands and in

the lining of the kidney tubules as well as in the ducts of the glands.They also constitute the germinal epithelium which produces the eggcells in the female ovary and the sperm cells in the male testes.



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Simple Columnar EpitheliumColumnar epithelial cells occur in one or more layers. The cells areelongated and column-shaped. The nuclei are elongated and areusually located near the base of the cells. Columnar epithelium

forms the lining of the stomach and intestines. Some columnar cellsare specialized for sensory reception such as in the nose, ears andthe taste buds of the tongue. Goblet cells (unicellular glands) arefound between the columnar epithelial cells of the duodenum. Theysecrete mucus or slime, a lubricating substance which keeps thesurface smooth.



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Ciliated Columnar EpitheliumThese are simple columnar epithelial cells, but in addition, theyposses fine hair-like outgrowths, cilia on their free surfaces. Thesecilia are capable of rapid, rhythmic, wavelike beatings in a certain

direction. This movement of the cilia in a certain direction causesthe mucus, which is secreted by the goblet cells, to move (flow orstream) in that direction. Ciliated epithelium is usually found inthe air passages like the nose. It is also found in the uterus andFallopian tubes of females. The movement of the cilia propel theovum to the uterus.



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Stratified EpitheliumWhere body linings have to withstand wear and tear, the epitheliaare composed of several layers of cells and are then calledcompound or stratified epithelium. The top cells are flat and

scaly and it may or may not be keratinized (i.e. containing a tough,resistant protein called keratin). The mammalian skin is an exampleof dry, keratinized, stratified epithelium. The lining of the mouthcavity is an example of an unkeratinized, stratified epithelium.



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Functions of Epithelial Tissue

ProtectionEpithelial cells from the skin protect underlying tissue from

mechanical injury, harmful chemicals, invading bacteria and fromexcessive loss of water.

SensationSensory stimuli penetrate specialized epithelial cells. Specializedepithelial tissue containing sensory nerve endings is found in theskin, eyes, ears, nose and on the tongue.

SecretionIn glands, epithelial tissue is specialized to secrete specific chemicalsubstances such as enzymes, hormones and lubricating fluids.

Absorption

Certain epithelial cells lining the small intestine absorb nutrients fromthe digestion of food.

ExcretionEpithelial tissues in the kidney excrete waste products from the bodyand reabsorb needed materials from the urine. Sweat is also excretedfrom the body by epithelial cells in the sweat glands.



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DiffusionSimple epithelium promotes the diffusion of gases, liquids andnutrients. Because they form such a thin lining, they are ideal for thediffusion of gases (e.g. walls of capillaries and lungs).

CleaningCiliated epithelium assists in removing dust particles and foreignbodies which have entered the air passages.

Reduces FrictionThe smooth, tightly-interlocking, epithelial cells that line the entire

circulatory system reduce friction between the blood and the walls ofthe blood vessels.

Source: http://www.botany.uwc.ac.za



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Connective TissuesA material made up of fibers forming a framework and support structure forbody tissues and organs. Connective tissue surrounds many organs. Allconnective tissue is derived from mesoderm, the middle germ cell layer in the embryo.

ClassificationConnective tissue proper

Loose IrregularDense IrregularDense Regular

Skeletal connective tissuesOsseous (bone) tissueCartilaginous tissue

Special varieties of connective tissueWhite adiposeBrown adiposePigmentaryMucous (jelly form)Reticular



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LOOSE IRREGULAR

Specifics:cell-rich, poor in intercellular matter (fibers and amorphous matter [ground

substance])

Localization:forms stroma of many organs, vascular tunica adventitia; lies underneath

epithelia - forms lamina propria of mucous membranes and submucosa, isabundantly represented among muscle cells and fibers

CELLS fibroblasts

Five subtypes: Young Mature fibrocytes Myofibroblasts fibroclasts

develop from poorly differentiated mesenchymal cells; stellate or spindle-shaped cells with little cytoplasm; functions - formation of collagen and elasticfibers, ground substance of connective tissue, synthesis of enzymes digestingfibers and ground-substance, as collagenase, elastase, hyaluronidase;

elaboration of biologically active substances



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macrophagesdescendants of blood monocytes, large cells with round or bean-shaped nucleiand abundant cytoplasm, rich in lysosomes, phagosomes, irregularcytoplasmic membrane contour; functions - endocytosis, antigen presentation,

production of a whole host of biologically active factors

mast cellsdevelop from a dedicated bone marrow predecessor; large cells, cytoplasmfilled with basophilic granules containing histamine, heparin, serotonin,chymase, triptase; their function is related to release of granule contents andto effects of these substances on the organism, to secondary uptake of the

substances, to elaboration of a number of bioactive compounds; mast cellgranules on staining show what is known as metachromasia, i.e. they changecolor of the dye

adventitious cellscome from mesenchyme, represent a poorly differentiated component of thelatter; they have numerous cytoplasmic membrane processes

pericytesdevelop from poorly differentiated mesenchymal cells; cells of basal layer incapillaries



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endothelial cellsare formed from poorly differentiated mesenchymal cells, line from the insideall of the blood vessels and lymphatics; produce many bioactive substances

pigmentary cellscome from neural crest, contain a pigment called melanin in their cytoplasm adipose cells develop from non-differentiated cells of mesenchyme; structure

and function are discussed later

plasma cellsare from the B cell lineage, produce antibodies, are characterized by well-

developed rough endoplasmic reticulum and Golgi complex in cytoplasm; Golgicomplex is pale on regular staining - perinuclear halo

leukocytesleukocytes that left circulation



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INTERCELLULAR MATTERFIBERS:collagen fibers are composed of a protein collagen. Structure - five levels oforganization:

1. polypeptide chain, consists of repeating sequences of 3 amino acids, 2 ofthem are proline or lysine and glycine, and the 3rd - any other

2. molecule - three polypeptide chains form a collagen molecule3. protofibril - several collagen molecules, cross-linked by covalent bonds4. microfibril - a union of several protofibrils forms them5. fibril - a combination of bundles of protofibrils

collagen is heterogeneous with regard to amino acid composition, number ofcross-links, attached carbohydrate side-chains and degree ofhydroxylation; on this basis collagen is divided into 15 subtypes collagenfibers are firm and do not stretch

elastic fibers structure: on the fiber exterior there are microfibrils, composed of

microfibrilary protein, the interior is formed primarily by a protein called elastin;elastic fibers stretch well, then easily regaining their original shape

reticular fibers - a subtype of collagen fibers, are well impregnated with silversalts, hence the alternative term for them is argyrophilic fibers



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GROUND (AMORPHOUS) SUBSTANCE: glycosaminoglycans (non-sulfated and sulfated) - hyaluronic acid proteoglycans (glycosaminoglycans with proteins) - chondroitin-4-sulfate,

chondroitin-6-sulfate, dermatan sulfate, heparan sulfate, heparin

glycoproteins - fibronectin, laminin, etc. ground substance is jelly-like in consistence; cells and fibers areembedded in it

DENSE IRREGULAR

Specifics: many fibers, few cells, fibers are irregular in orientation

Localization: reticular layer of dermis; periosteum, perichondrium

CELLSthe major component of the relatively scarce cellular population is fibroblasts;occasional mast cells and macrophages may also be found

INTERCELLULAR MATTERFIBERS: numerous collagen and elastin fibers

GROUND (AMORPHOUS) SUBSTANCE: moderate amounts ofglycosaminoglycans and proteoglycans



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DENSE REGULAR

Specifics: many fibers, scarce cells, fibers are regularly oriented - arranged inbundles

Localization: tendons, ligaments, capsules, fasciae, and fibrous membranes

CELLSvery few cells are present, most of them are fibroblasts; some mast cells and

macrophages as well

INTERCELLULAR MATTERFIBERS: in abundance, collagen and elastic; have a regular orientation, form

thick bundles (fascicles)

GROUND (AMORPHOUS) SUBSTANCE: glycosaminoglycans and proteoglycansin very limited amounts

TENDONin tendons collagen fiber fascicles are invested with thin layers of loose irregular

connective tissue; the thinnest (first-order) fascicles are surrounded byendotendineum; second-order fascicles are surrounded by peritendineum, thetendon itself is a third-order fascicle



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CONNECTIVE TISSUES WITH SPECIAL PROPERTIES

ADIPOSE TISSUE

Specifics:basically composed of fat cells and thin layers of loose irregular connectivetissuewhite adipose tissue

Localization: present everywhere

CELLSwhite adipose cells (white adipocytes) cytoplasm is dominated by a singlelarge fat vacuole; cell nucleus and other organelles are pushed by thevacuole to the periphery there is loose irregular connective tissue betweengroups of adipocytes

INTERCELLULAR MATTERFIBERS: small numbers of collagen and elastic fibers

GROUND SUBSTANCE: glycosamino- and proteoglycans in small amounts



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BROWN ADIPOSE TISSUE

Localization: between scapulae, around kidneys and thyroid glandbrown adipose tissue is more widely represented in fetuses, its quantity is

greatly reduced after birth

CELLSbrown adipose cells (brown adipocytes) many small fat droplets are scatteredthroughout the cytoplasm; nucleus and organelles are in the cell center;multiple mitochondria are present the brown color of cells is due tosignificant amounts of iron-containing pigments - cytochromes; in brown

adipocyte mitochondria the free energy released from the oxidation of fattyacids and glucose is not stored in the form of ATP, rather it is dissipated asheat; therefore the function of this tissue is heat production and regulation ofbody's thermal balance there are also small numbers of fibroblasts and othercell types of loose irregular connective tissue

INTERCELLULAR MATTERFIBERS: small amounts of collagen and elastic fibers

GROUND SUBSTANCE: glycosamino- and proteoglycans in small amounts



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PIGMENTARY TISSUE

Specifics: ordinary loose or dense connective tissue with large numbers ofpigment cells

Localization: vascular tunic of the eye, dermis under mammary glandareolae, birthmarks, and nevi

MUCOUS CONNECTIVE TISSUE

Specifics: few cells and fibers, lots of ground substance

Localization: umbilical cord (Wharton's jelly)

CELLSin general, poorly differentiated fibroblasts in small numbers

INTERCELLULAR MATTERFIBERS: scarce and thin collagen fibers

GROUND SUBSTANCE: generally contains hyaluronic acid



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RETICULAR TISSUE

Specifics: provides a soft structural framework (stroma) for organs ofhemopoiesis and immunity

Localization: spleen, lymph nodes, tonsils, lymphoid follicles, and red bonemarrow

CELLSreticular cells (a subtype of fibroblasts) these cells possess processes whichthey connect to each other through forming thereby a network; other cell

types of loose connective tissue are also present in small quantities:macrophages, mast cells, plasma cells, fat cells (adipocytes)

INTERCELLULAR MATTERFIBERS:reticular fibers - a subtype of collagen fibers, are well stained with silversalts; that's why they are also known as argyrophilic fibers; they form ameshwork

GROUND (AMORPHOUS) SUBSTANCE: extracellular fluid



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OSSEOUS TISSUE

CELLS:osteoblasts - take origin from poorly differentiated mesenchymal cells; reside inthe internal layer of periosteum, during bone development osteoblasts are on theperiosteal surface and around interosseous blood vessels; these cells are cuboidal,columnar and polygonal in shape, have a well-developed rough endoplasmicreticulum

function - production of bone intercellular matterosteocytes - a mature form of osteoblasts, they lie in lacunae within a bone andextend protoplasmic processes into small canaliculi in the intercellular matrix

function - weak secretion of bone intercellular matter componentsosteoclasts - macrophages of bone tissue, blood monocytes being theirprecursors; large multinucleated cells; a zone of cytoplasm adjacent to osseoussurface is referred to as ruffled border, multiple cytoplasmic processes andlysosomes are found herefunction - destruction and resorption of bone fibers and ground substance

INTERCELLULAR MATTERFIBERS: collagen fibers

GROUND (AMORPHOUS) SUBSTANCE: the predominant component is calciumphosphate mostly in the form of hydroxyapatite crystals and some in amorphousstate; small amounts of magnesium phosphate and very scarceglycosaminoglycans and proteoglycans are also found


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PERIOSTEUMhas 2 layers:external- fibrous; made of dense irregular connective tissueinternal- cellular (osteogenic); contains many osteoblasts and blood vessels,

some osteocytes as wellfunctions: bone nutrition, longitudinal and transverse growth of bone, itsregeneration

ENDOSTEUMa lining covering a bone from the marrow side, made of loose irregularconnective tissue with osteoblasts and osteoclasts in addition to more

common cell types of this tissue

CARTILAGINOUS TISSUETHREE TYPES OF CARTILAGE ARE DISTINGUISHEDHYALINEELASTICFIBROUS

what distinguishes them is primarily intercellular matter composition



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CELLSchondroblasts - less differentiated cartilage cells, originate from non-differentiated mesenchyme; have a flattened shape; a well-developed roughendoplasmic reticulum in a basophilic cytoplasm;

function - elaboration of cartilage intercellular matter; under certaincircumstances chondroblasts are capable of producing matrix-degradingenzymes - collagenase, elastase, hyaluronidasereside in the internal layer of periosteum and in the depth of matrix - withinlacunes chondroblasts mature into chondrocytes

chondrocytes - differentiated cartilage cells; of round or angular shapes,

with advancing cellular age chondrocytes progressively lose their roughendoplasmic reticulum;function - elaboration of cartilage intercellular matter; under certaincircumstances chondroblasts are capable of producing matrix-degradingenzymes - collagenase, elastase, hyaluronidasereside in the depth of matrix - within minute special cavities lacunessometimes the number of cartilage cells in one lacune is more than one, it isthe consequence of cell division; quite often the division id accomplishedthrough amitosis; such cellular groups are called isogenic groups



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CARTILAGE AND BONE

hyaline cartilage

Localization: trachea and bronchi, articular surfaces, larynx, costosternaljunctions

INTERCELLULAR MATTERFIBERS: collagen fibers

GROUND SUBSTANCE: glycosaminoglycans and proteoglycans

elastic cartilage

Localization: pinna of the ear, corniculate and cuneiform cartilages of thelarynx, nasal cartilages

INTERCELLULAR MATTERFIBERS: elastic and collagen fibers

GROUND SUBSTANCE: glycosaminoglycans and proteoglycans


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Tissues, Glands andMembranes



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Functions of Epithelia

Proctecting underlying structures

Acting as barriers

Permitting the passage of substances

Secreting substances

Absorbing substances



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Classification of Epithelia Simple epithelium single layer of

thin flat cells

>lines blood vessels and the heart,

lymphatic vessels, alveoli of thelungs and lining of serousmembranes of body cavities



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Classification of Epithelia

Simple cuboidal single layer of cube-shapedcells some with microvilli or cilia

>for secretion and absorption by cells of thekidney tubules



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Simple columnar single layer of tall,narrow cells, some have cilia ormicrovilli

>respiratory tract, auditory, uterinetubes and uterus, intestines



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Psuedostratified columnar single layer ofcells, some tall and thin and others not

Synthesize and secrete mucus onto free

surface and move mucus or fluid that haveforeign particles

Lines nasal cavity, nasal sinuses, auditorytubes, trachea, bronchi of lungs



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Stratified squamous several layersif cells that are cuboidal at base andflatttens toward the surface

Protects against abrasion, barrier forinfection and reduces water loss frombody

Keratinized and nonkeratinized



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Transitional epithelium stratifiedcells that appear cuboidal when notstretched and squamous when the

organ is stretched by fluid Urinary bladder



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Stratified cuboidal consists of morethan one layer of cuboidal epithelialcells

Found in sweat glands, ovarianfollicular cells and salivary glands



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Stratified columnar consists of morethan one layer of epithelial cells;surface cells more columnar in shape

Rare; found in mammary gland ducts,larynx and a portion of the maleurethra.



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Glands

Multicellular structure that secretessubstances onto a surface, cavity orblood

SimpleCompound

Tubular

Acinus/alveolusEndocrine



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Connective tissue

Characterized by large amounts ofextracellular materials that

separate celss from one another Major components:

Protein fibers

Ground substances consisting ofnonfibrous protein

fluid



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Functions of Connective

Tissue Enclosing and separating Connecting tissues to one another

Supporting and moving Storing

Cushioning and insulating

Transporting

Protecting

Cl ifi ti fPHILIPPINE PARAMEDICAL AND TECHNICAL SCHOOL INCORPORATED - CEBU


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Classifications of

Connective Tissue Loose or areolar

Adipose

Dense

Dense collagenous Dense elastic

Cartilage

Hyalin

Fibrocartilage Elastic Cartilage

Bone

Blood



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Muscle Tissue

Skeletal

Cardiac

Smooth



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Nervous Tissue

Consists of neurons and supportcells

Neuron/nerve cell-responsible forconduction of action potential

Cell body-contains organelles

Dendrites and axons nerve cellextension

neuroglia- support cells of nervoussystem



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Membranes

Thin sheet or layer of tissues that covers astructure or lines a cavity

Mucous membrane various kinds of

epithelium resting on a thick layer ofconnective tissue

Serous membranes membranes consistof simple squamous epithelium resting on

a delicate layer of loose connective tissue



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Membranes

Skin/cutaneous stratified squamousepithelium and dense connectivetissue

Synovial membrane line the insideof joint cavities



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Inflammation

Occurs when tissues are damaged

5 major symptoms:

Redness

Heat

Swelling

Pain

Disturbance of function



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Tissue Repair

Labile cells continue to dividethroughout life

Stable cells dont actively divide;

retain ability to divide after an injury

Permanent cells have little or noability to divide

R ti d



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Regeneration and

replacement Regeneration new cells are thesame tupe as those that weredestroyed

Replacement new type of tissuedevelops eventually causes scarproduction



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Tissue Repair

Edges of a woundclose together getsfilled with blood

Dilation of bloodvessels allows

inflammatoryresponse Epthelium under the

wound is regenerateduntil scab is sloughed

off Granulation tissuereplaces clot



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Tissues and Aging

Cells divide more slowly

RBC synthesis declines

Injuries heal slowly

Less flexible; more fragile

CHAPTER 2: MUSCLE TISSUES



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Structure

We know that living organisms can move on their own or can perform othertypes of movement. Muscle tissue has a ability to relax and contrast and sobring about movement and mechanical work in various parts of the body.There are other movements in the body too which are necessary for thesurvival of the organism such as the heart beat and the movements of thealimentary canal.

Muscles can be divided into three main groups according to their structure

Smooth muscle tissue.Skeletal muscle tissue.Cardiac (heart) muscle tissue

Types of Muscle Tissue



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Types of Muscle Tissue

Smooth Muscle Tissue

Smooth muscle tissue is made up of thin-elongated musclecells, fibres. These fibres are pointed at their ends and eachhas a single, large, oval nucleus. Each cell is filled witha specialized cytoplasm, the sarcoplasm and is surrounded bya thin cell membrane, thesarcolemma. Each cell has

many myofibrils which lie parallel to one another in thedirection of the long axis of the cell. They are not arranged ina definite striped (striated) pattern, as in skeletal muscles- hence the name smooth muscle . Smooth muscle fibresinterlace to form sheets or layers of muscle tissue ratherthan bundles. Smooth muscle is involuntary tissue, i.e. it is

not controlled by the brain. Smooth muscle forms the musclelayers in the walls of hollow organs such as the digestivetract (lower part of the esophagus, stomach and intestines),the walls of the bladder, the uterus, various ducts ofglands and the walls of blood vessels .


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Functions of Smooth Muscle Tissue

Controls slow, involuntary movements suchas the contraction of the smooth muscletissue in the walls of the stomach and

intestines.

The muscle of the arteries contracts and

relaxes to regulate the blood pressure andthe flow of blood.



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Skeletal Muscle Tissue

Skeletal muscle is the most abundant tissue in thevertebrate body. These muscles are attached to andbring about the movement of the various bones of theskeleton, hence the name skeletal muscles. The wholemuscle, such as the biceps, is enclosed in a sheath of

connective tissue, the epimysium. This sheath foldsinwards into the substance of the muscle to surround alarge number of smaller bundles, the fasciculi. Thesefasciculi consist of still smaller bundles of elongated,cylindrical muscle cells, the fibres. Each fiber is

a syncytium, i.e. a cell that have many nuclei.The nuclei are oval in shaped and are found at theperiphery of the cell, just beneath the thin, elasticmembrane (sarcolemma).



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The sarcoplasm also has many alternating light anddark bands, giving the fibre a striped or striatedappearance (hence the name striated muscle). Withthe aid of an electron microscope it can be seen thateach muscle fibre is made up of many smaller units,

the myofibrils. Each myofibril consists of smallprotein filaments, known asactin and myosinfilaments. The myosin filaments are slightlythicker and make up the dark band (or A-band).



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The actin filaments make up the lightbands (I-bands) which are situated oneither side of the dark band. The actinfilaments are attached to the Z-line. Thisarrangement of actin and myosinfilaments is known as a sacromere.During the contraction of skeletal muscle

tissue, the actin filaments slideinwards between the myosin filaments.

Mitochondria provide the energy for this to take place. This action causesh t i f th (Z li l t th ) hi h i t



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a shortening of the sacromeres (Z-lines move closer together), which in turncauses the whole muscle fibre to contract. This can bring about a shorteningof the entire muscle such as the biceps, depending on the number of musclesfibres that were stimulated. The contraction of skeletal muscle tissue is

very quick and forceful.

Functions of Skeletal Muscle TissueSkeletal muscles function in pairs to bring about the coordinated movementsof the limbs, trunk, jaws, eyeballs, etc.Skeletal muscles are directly involved in the breathing process.



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Cardiac (Heart) Muscle TissueThis is a unique tissue found only in the walls of the heart. Cardiac(Heart) Muscle Tissue shows some of the characteristics of smoothmuscle and some of skeletal muscle tissue. Its fibres , like those ofskeletal muscle, have cross-striations and contain numerous nuclei.However, like smooth muscle tissue, it is involuntary. Cardiacmuscle differ from striated muscle in the following aspects: theyare shorter, the striations are not so obvious, the sarcolemma is

thinner and not clearly discernible, there is only one nucleuspresent in the centre of each cardiac fibre and adjacent fibres branchbut are linked to each other by so-called muscle bridges. The spacesbetween different fibres are filled with areolar connective tissuewhich contains blood capillaries to supply the tissue with the oxygenand nutrients.

Functions of Cardiac (Heart) Muscle TissueCardiac muscle tissue plays the most important role in thecontraction of the atria and ventricles of the heart.It causes the rhythmical beating of the heart, circulating the bloodand its contents throughout the body as a consequence.



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Source: http://www.botany.uwc.ac.za



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