Chapter 4 - Tissues. study of tissues. of cells and tissue for diagnoses. activities. n A tissue is a group of cells

Transcription

1 Chapter 4 - Tissues A tissue is a group of cells Commo embryoic origi Fuctio together to carry out specialized activities Hard (boe), semisolid (fat), or liuid (blood) Histology is the sciece that deals with the study of tissues. Pathologist specialized i laboratory studies of cells ad tissue for diagoses

2 4 Types of Tissues Epithelial Covers body surfaces ad lies hollow orgas, body cavities, duct, ad forms glads Coective Protects, supports, ad bids orgas. Stores eergy as fat, provides immuity Muscular Geerates the physical force eeded to make body structures move ad geerate body heat Nervous Detect chages i body ad respods by geeratig erve impulses

3 Developmet of Tissues Tissues of the body develop from three primary germ layers: Ectoderm, Edoderm, ad Mesoderm Epithelial tissues develop from all three germ layers All coective tissue ad most muscle tissues drive from mesoderm Nervous tissue develops from ectoderm

4 Cell Juctios Cotact poits betwee the plasma membraes of tissue cells 5 most commo types: Tight juctios Adheres juctios Desmosomes Hemidesmosomes Gap juctios

5 Tight Juctios Web-like strads of trasmembrae proteis Fuse cells together Seal off passageways betwee adjacet cells Commo i epithelial tissues of the stomach, itesties, ad uriary bladder Help to retard the passage of substaces betwee cells ad leakig ito the blood or surroudig tissues

6 Adheres Juctios Dese layer of proteis called plaue Resist separatio of cells durig cotractile activities Located iside of the plasma membrae attached to both membrae proteis ad microfilamets of the cytoskeleto Trasmembrae glycoproteis called cadheris isert ito the plaue ad joi cells I epithelial cells, adhesio belts ecircle the cell

7 Desmosomes Cotai plaue ad cadheris that exteds ito the itercellular space to attach adjacet cells together Desmosome plaue attaches to itermediate filamets that cotai protei kerati Prevet epidermal cells from separatig uder tesio ad cardiac muscles cells from pullig apart durig cotractio

8 Hemidesmosomes Resemble half of a desmosome Do ot lik adjacet cells but achor cells to the basemet membrae Cotais trasmembrae glycoprotei itegri Itegris attach to itermediate filamets ad the protei lamii preset i the basemet membrae

9 Gap Juctios Coect eighborig cells via tiy fluid-filled tuels called coexos Cotai membrae proteis called coexis Plasma membraes of gap juctios are separated by a very arrow itercellular gap (space) Commuicatio of cells withi a tissue Ios, utriets, waste, chemical ad electrical sigals travel through the coexos from oe cell to aother

10 Epithelial Tissues Epithelial tissue cosists of cells arraged i cotiuous sheets, i either sigle or multiple layers Closely packed ad held tightly together Coverig ad liig of the body Free surface 3 major fuctios: Selective barrier that regulates the movemet of materials i ad out of the body Secretory surfaces that release products oto the free surface Protective surfaces agaist the eviromet

11 Geeral Features of Epithelial Cells Surfaces of epithelial cells differ i structure ad have specialized fuctios Apical (free) surface Faces the body surface, body cavity, lume, or duct Lateral surfaces Faces adjacet cells Basal surface Opposite of apical layer ad adhere to extracellular materials

12 Geeral Features of Epithelial Cells Basemet membrae Thi double extracellular layer that serves as the poit of attachmet ad support for overlyig epithelial tissue Basal lamia Closer to ad secreted by the epithelial cells Cotais lamii, collage, glycoproteis, ad proteoglycas Reticular lamia Closer to the uderlyig coective tissue Cotais collage secreted by the coective tissue cells

13 Epithelial Cells

14 Epithelial Tissues Ow erve supply Avascular or lacks its ow blood supply Blood vessels i the coective tissue brig i utriets ad elimiate waste High rate of cell divisio for reew ad repair Numerous roles i the body (i.e. protectio ad filtratio) Coverig ad liig epithelium Outer coverig of ski ad some iteral orgas Gladular epithelium Secretig portio of glads (thyroid, adreal, ad sweat glads)

15 Coverig ad Liig Epithelium Normally classified accordig to: Arragemet of cells ito layers Shapes of cells

16 Coverig ad Liig Epithelium Arragemet of cells i layers Cosist of oe or more layers depedig o fuctio Simple epithelium Sigle layer of cells that fuctio i diffusio, osmosis, filtratio, secretio, or absorptio Pseudostratified epithelium Appear to have multiple layers because cell uclei at differet levels All cells do ot reach the apical surface Stratified epithelium Two or more layers of cells that protect uderlyig tissues i areas of wear ad tear

17 Differet Types of Coverig ad Liig Epithelium Cells vary i shape depedig o their fuctio Suamous Thi cells, arraged like floor tiles Allows for rapid passage of substaces Cuboidal As tall as they are wide, shaped like cubes or hexagos May have microvilli Fuctio i secretio or absorptio

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19 Differet Types of Coverig ad Liig Epithelium Columar Much taller tha they are wide, like colums May have cilia or microvilli Specialized fuctio for secretio ad absorptio Trasitioal Cells chage shape, trasitio for flat to cuboidal Orgas such as uriary bladder stretch to larger size ad collapse to a smaller size

20 Simple Epithelium Simple suamous epithelium Simple cuboidal epithelium Simple columar epithelium (ociliated ad ciliated) Pseudostratified columar epithelium (ociliated ad cilated)

21 Simple suamous epithelium Sigle layer of cells that resembles a tiled floor o the surface Nucleus is cetrally located ad appears flatteed oval or sphere Foud at sites for filtratio or diffusio

22 Coverig ad Liig Epithelium Edothelium The type of simple suamous that lies the heart, blood vessels, ad lymphatic vessels Mesothelium The type of epithelial layer of serous membraes such as the pericardium, pleura, or peritoeum Ulike other epithelial tissue, Both are derived from embryoic mesoderm

23 Simple cuboidal epithelium Cuboidal shaped cells Cell uclei roud ad cetrally located Foud i thyroid glad ad kideys Fuctios i secretio ad absorptio

24 Simple columar epithelium Colum shaped cells Oval uclei at ear base Nociliated ad ciliated

25 Nociliated simple columar epithelium Cotais columar cells with microvilli at their apical surface ad goblet cells Secreted mucus serves as lubricat for the liig of digestive, respiratory, reproductive ad uriary tracts Also prevets the destructio of the stomach liig by acidic gastric juices

26 Ciliated simple columar epithelium Columar epithelial cells with cilia at the apical surface I respiratory tract, goblet cells are iterspersed amog ciliated columar epithelia Secreted mucus o the surface traps ihaled foreig particles. Beatig cilia moves particles to the throat for removal by coughig, swallowig, or seezig Cilia also moves oocytes to the uterie tubes

27 Coverig ad Liig Epithelium Pseudostratified columar epithelium Appears to have several layers due to uclei are various depths All cells are attached to the basemet membrae i a sigle layer but some do ot exted to the apical surface Ciliated cells secrete mucus ad bear cilia Nociliated cells lack cilia ad goblet cells

28 Coverig ad Liig Epithelium

29 Stratified Epithelium Two or more layers of cells Specific kid of stratified epithelium depeds o the shape of cells i the apical layer Stratified suamous epithelium Stratified cuboidal epithelium Stratified columuar epithelium Trasitioal epithelium

30 Stratified Suamous Epithelium Several layers of cells that are flat i the apical layer New cells are pushed up toward apical layer As cells move further from the blood supply they dehydrate, harde, ad die Keratiized form cotai the fibrous protei kerati Foud i superficial layers of the ski Nokeratiized form does ot cotai kerati Foud i mouth ad esophagus

31 Stratified Cuboidal Epithelium Fairly rare type of epithelium Apical layers are cuboidal Fuctios i protectio

32 Stratified columar epithelium Also very ucommo Columar cells i apical layer oly Basal layers has shorte, irregular shaped cells Fuctios i protectio ad secretio

33 Trasitioal Epithelium Foud oly i the uriary system Variable appearace I relaxed state, cells appear cuboidal Upo stretchig, cells become flatteed ad appear suamous Ideal for hollow structure subjected to expasio

34 Gladular Epithelium: Edocrie Glads Secretios, called hormoes, diffuse directly ito the bloodstream Fuctio i maitaiig homeostasis

35 Gladular Epithelium: Exocrie Glads Secrete products ito ducts that empty oto the surfaces of epithelium Ski surface or lume of a hollow orga Secretios of the exocrie glad iclude mucus, sweat, oil, earwax, saliva, ad digestive ezymes Examples of glads iclude sudoriferous (sweat) glads

36 Structural Classificatio of Exocrie Glads Multicellular glads are categorized accordig to two criteria: Ducts are brached or ubrached Shape of the secretory portio of the glad Simple glad duct does ot brach Compoud glad duct braches Tubular glads have tubular secretory parts Aciar glads have rouded secretory parts Tubuloaciar glads have both tubular ad rouded secretory parts

37 Structural Classificatio of Exocrie Glads

38 Fuctioal Classificatio of Exocrie Glads

39 Coective Tissue Most abudat ad widely distributed tissues i the body Numerous fuctios Bids tissues together Supports ad stregthe tissue Protects ad isulates iteral orgas Compartmetalize ad trasport Eergy reserves ad immue resposes

40 Extracellular matrix of Coective Tissue Extracellular matrix is the material located betwee the cells Cosist of protei fibers ad groud substace Coective tissue is highly vascular Supplied with erves Exceptio is cartilage ad tedo. Both have little or o blood supply ad o erves

41 Cells ad Fibers i Coective Tissue

42 Coective Tissue Cells Fibroblasts Secrete fibers ad compoets of groud substace Adipocytes (fat cells) Store triglycerides (fat) Mast cells Produce histamie White blood cells Immue respose Neutrophil ad Eosiophils Macrophages Egulf bacteria ad cellular debris by phagocytosis Plasma cells Secrete atibodies

43 Coective Tissue Extracellular Matrix Groud substace Fibers Betwee cells ad fibers Fluid, semifluid, gelatious, or calcified Fuctios to support ad bid cells, store water, ad allow exchage betwee blood ad cells Complex combiatio of proteis ad polysaccharides Collage fibers Elastic fibers Reticular fibers

44 Classificatio of Coective Tissues Embryoic coective tissue Mesechyme ad mucous coective tissue Mature coective tissue Loose coective tissue Areolar, adipose, ad reticular Dese coective tissue Dese regular, dese irregular, ad elastic Cartilage Hyalie, fibrocartilage, ad elastic cartilage Boe tissue Liuid coective tissue Blood ad lymph

45 Embryoic Coective Tissue Mesechyme Gives rise to all other coective tissues Mucous (Wharto s Jelly) Foud i umbilical cord of the fetus

46 Loose Coective Tissue: Areolar Coective Tissue Most widely distributed i the body Cotais several types of cells ad all three fibers

47 Loose Coective Tissue: Adipose Tissue Cotais adipocytes Good for isulatio ad eergy reserves White (commo) ad brow adipose tissue

48 Loose Coective Tissue: Reticular Coective Tissue Fie iterlacig reticular fibers ad cells Forms the stroma of liver, splee, ad lymph odes

49 Dese Coective Tissue Dese coective tissue Cotais umerous, thicker, ad deser fibers Packed closely with fewer cells tha loose coective tissue Dese regular coective tissue Budles of collage fibers are regularly arraged i parallel patters for stregth Tedos ad most ligamets

50 Types of Mature Coective Tissue: Dese Irregular Coective Tissue Collage fibers are usually irregularly arraged Foud where pullig forces are exerted i may directios Dermis of ski ad heart

51 Dese Coective Tissue: Elastic Coective Tissue Cotai brachig elastic fibers Strog ad ca recoil to origial shape after stretchig Lug tissue ad arteries

52 Types of Mature Coective Tissue: Cartilage Cartilage is a dese etwork of collage fibers ad elastic fibers firmly embedded i chodroiti sulfate Chrodrocytes Cartilage cells foud i the spaces called lucuae Pericodrium Coverig of dese irregular coective tissue that surrouds the cartilage Two layers: outer fibrous layer ad ier cellular layer No blood vessels or erves, except pericodrium

53 Hyalie cartilage Most abudat cartilage i the body Surroudig by perichodrium (some exceptios like articular cartilage) Provide flexibility ad support. Reduces frictio

54 Fibrocartilage Chodrocytes are scattered amog budles of collage fibers withi the extracellular matrix Lack a perchodrium Strogest type of cartilage Foud i itervertebral disc (betwee vertebrae)

55 Elastic Cartilage Chrodrocytes are located withi a threadlike etwork of elastic fibers Pericodrium is preset Provides stregth ad elasticity

56 Repair ad Growth of Cartilage Cartilage grows slowly Whe ijured or iflamed, repairs is slow due to its avascular ature. Two patters of cartilage growth: Iterstitial growth Growth from withi the tissue Appositioal growth Growth at the outer surface of the tissue

57 Boe tissue Boes are orgas composed of several differet coective tissues: boe (osseous) tissue, periosteum, ad edosteum. Compact or spogy Osteo or haversia system Spogy boe lacks osteos. They have colums called trabeculae

58 Liuid Coective Tissue Blood tissue Coective tissue with liuid extracellular matrix called blood plasma Lymph

59 Membraes

60 Epithelial Membraes Mucous membraes Lies a body cavity that opes directly to the exterior Epithelial layer is importat for the body s defese agaist pathoges Coective tissue layer is areolar coective tissue ad is called lamia propria

61 Epithelial Membraes Serous membraes or serosa Lies a body cavity that does ot ope directly to the exterior. Also covers the orgas that lie withi the cavity Cosist of areolar coective tissue covered by mesothelium (simple suamous epithelium) that secrete a serous fluid for lubricatio

62 Epithelial membraes: Mucous Membraes Membraes are flat sheets of pliable tissue that cover or lie a part of the body Epithelial membraes are a combiatio of a epithelial layer ad a uderlyig coective tissue layer Mucous, Serous, ad Cutaeous membraes Syovial membraes Lies joits ad cotais coective tissue but ot epithelium

63 Muscular Tissue Cosists of elogated cells called muscle fibers or myocytes Cells use ATP to geerate force Several fuctios of muscle tissue Classified ito 3 types: skeletal, cardiac, ad smooth muscular tissue

64 Skeletal Muscle Tissue Attached to boes of the skeleto Have striatios Volutary movemet or cotractios by coscious cotrol Vary i legth (up to 40 cm) ad are roughly cylidrical i shape

65 Muscular Tissue Cardiac muscle tissue Have striatios Ivolutary movemet or cotractio is ot cosciously cotrolled Itercalated disc uiue to cardiac muscle tissue

66 Smooth Muscle Tissue Walls of hollow iteral structures Blood vessels, airways of lugs, stomach, ad itesties Nostriated Usually ivolutary cotrol

67 Nervous Tissue Cosists of two priciple types of cells Neuros or erve cells Neuroglia

68 Excitable Cells Neuros ad muscle fibers Exhibit electrical excitability The ability to respod to certai stimuli by producig electrical sigals such as actio potetials Actios potetials propagate alog a erve or muscle plasma membrae to cause a respose Release of eurotrasmitters Muscle cotractio

69 Tissue Repair: Restorig Homeostasis Whe tissue damage is extesive both stroma ad parechymal cells are active i repair Fibroblast divide rapidly New collage fibers are maufactured New blood capillaries supply materials for healig All of these process create a actively growig coective tissue called graulatio tissue

70 Agig ad Tissues Tissue heal faster i youg adults Surgery of a fetus ormally leaves o scars Youg tissues have a better utritioal state, blood supply, ad higher metabolic rate Extracellular compoets also chages with age Chages i the body s use of glucose, collage, ad elastic fibers cotribute to the agig process