8/14/2019 05 Tissues

1/49

TISSUES

8/14/2019 05 Tissues

2/49

TISSUES

Collection of cells with similar structure andfunction the study of tissues is known as histology four types of tissue

epithelial (covering) connective (support) muscle (movement) nervous (control)

8/14/2019 05 Tissues

3/49

EPITHELIAL TISSUE Covers the surface of the body; lines body

cavities; constitutes the bulk of most glands

Functions: physical protection secretion

sensory reception absorption filtration

8/14/2019 05 Tissues

4/49

EPITHELIAL TISSUE

SHEETS OF CLOSE PACKED CELLS WITH LITTLE EXTRACELULARMATERIAL

AVASCULAR : (GETS NUTRIENTSTHROUGH DIFFUSION FROMUNDERLYING CAPILLARIES)

INNERVATED MAINTAINS THE CAPACITY TO EASILY

REGENERATE (WHY IS THIS

IMPORTANT?)

8/14/2019 05 Tissues

5/49

EPITHELIAL TISSUE

POLARITY : THE NUCLEUS AND ORGANELLES ARE USUALLY

UNEVENLY DISTRIBUTED, SO THERE IS AN UP

AND DOWN SIDE UP SIDE IS ALWAYS A FREE SURFACE, AND IS

CALLED THE APICAL SURFACE THE DOWN SIDE IS THE BASAL SURFACE

ALWAYS SUPPORTED BY A LAYER OFCONNECTIVE TISSUE AT ITS BASALSURFACE ( BASEMENT MEMBRANE )

8/14/2019 05 Tissues

6/49

EPITHELIAL TISSUE May contain microvilli:

(fingerlike extensions ofplasma membrane whichincrease the surface area

for increased absorption/ secretion)

May contain cilia: (largerextensions used forpropelling substances)

8/14/2019 05 Tissues

7/49

EPITHELIAL TISSUECLASSIFICATION

CLASSIFIED BY #OF LAYERS ANDSHAPE

LAYERS: SIMPLE (SINGLE

LAYER) STRATIFIED

(MULTIPLE LAYERS) SHAPE:

SQUAMOUS CUBOIDAL COLUMNAR

8/14/2019 05 Tissues

8/49

SIMPLE EPITHELIUM

Simple squamous: thin, permeable exchange of

substances alveoli in lungs;

lines blood vessels(WHY?)

8/14/2019 05 Tissues

9/49

Simple Epithelium Simple cuboidal:

secretion andabsorption

glands/ ducts; part ofkidney tubules

8/14/2019 05 Tissues

10/49

SIMPLE EPITHELIUM

Simple columnar: secretion and

absorption lines digestive tract

(stomach to rectum):contains microvilli(why?)

lines trachea:contains cilia (why?)

8/14/2019 05 Tissues

11/49

SIMPLE EPITHELIUM Pseudostratified

epithelium: protection and

secretion nuclei position and

cell height arestaggered soappears stratified

all cells in contactwith basementmembrane

contains cilia lines upper

8/14/2019 05 Tissues

12/49

STRATIFIED EPITHELIUM

Stratified squamous: physical protection

against abrasion;pathogens; and

chemicals esophagus, mouth,

vagina, epidermis

Transitional: lines only urinary

bladder, ureters,urethra

able to stretch

8/14/2019 05 Tissues

13/49

GLANDULAR EPITHELIUM

Gland = cell or organ that secretessomething for use inside or outside of thebody

Two types

endocrine: ex. thyroid exocrine: ex. sweat

8/14/2019 05 Tissues

14/49

EXOCRINE GLANDS Secrete into ducts which

lead to the body surface,or a body cavity which iscontinuous with a surface

Unicellular: goblet cell: produces

mucus (intestine,respiratory tract) Multicellular:

merocrine holocrine

8/14/2019 05 Tissues

15/49

EXOCRINE GLANDS Merocrine:

most common secrete products via

exocytosis secretory cells remain in

tact ex. pancreas, sweat

glands, salivary glands Holocrine:

cells rupture releasingtheir products and theirselves

cells are replaced bydivision of underlyingcells

sebaceous (oil) glands

8/14/2019 05 Tissues

16/49

ENDOCRINE GLANDS

Send chemicalmessengershormones directlyinto bloodstream totravel to and affectother cells

Ductless thyroid, testes,

ovaries, pituitary,adrenal, etc.

8/14/2019 05 Tissues

17/49

FOUR TISSUE TYPES

Epithelial tissue

Connectivetissue

Muscle tissue

Nervous tissue

8/14/2019 05 Tissues

18/49

CONNECTIVE TISSUE (CT)

The most abundant, widely distributed,and histologically variable of the 4 tissuetypes

These tissues connect and fill, and theircells are loosely packed

There are few cells, and these aregenerally widely separated by anextracellular material extracellular matrix (ecm)

8/14/2019 05 Tissues

19/49

CONNECTIVE TISSUE Functions:

binding of organs support/ framework

of body physical protection immune protection storage (energy

reserves, minerals) insulation transport

8/14/2019 05 Tissues

20/49

COMPONENTS OF CT

Ground substance : filling material

Fibers: collagen, elastic, or reticular Cells:

fibroblasts, chondroblasts, osteoblasts, andwhite blood cells

8/14/2019 05 Tissues

21/49

Connective tissue

8/14/2019 05 Tissues

22/49

Connective Tissue Massage

8/14/2019 05 Tissues

23/49

Ground Substance Gel-like non-cellular

component of CT

Composed of water,glycosaminoglycans,proteoglycans, andglycoproteins

Varies depending onthe type of CT

8/14/2019 05 Tissues

24/49

FIBER TYPES Collagen :

thick fibers with greattensile strength

interwoven strands ofcollagenous proteins

Reticular : thinner collagen fibers extensive branching to

form frameworks forcertain organs

Elastic: long thin fibers allowing

for stretch and recoil

8/14/2019 05 Tissues

25/49

CELLS

Naming : fibro-; chondro-; osteo- -blast (produce ecm) -clast (destroy ecm) -cyte (maintain ecm)

Other cells in CT adipose (fat) cells white blood cells macrophages, etc.

8/14/2019 05 Tissues

26/49

CATEGORIES OF CT

1: Fibrous CT AKA connective tissue proper Loose (3) and Dense (2)

2: Supporting ct Cartilage (3) and bone

3: Fluid ct blood and lymph

8/14/2019 05 Tissues

27/49

FIBROUS CT Loose CT

lots of ground substanceand cells, few fibers

areolar, reticular, adipose Dense CT

many fibers, few cells, and

little ground substance dense regular, and dense

irregular

8/14/2019 05 Tissues

28/49

LOOSE AREOLAR TISSUE

Loosely arranged Contains all three

fiber types,fibroblasts,macrophages, wbcs

Surrounds bloodvessels and smallnerves

8/14/2019 05 Tissues

29/49

LOOSE AREOLAR TISSUE

Underlies almost all epithelial tissue Serves as packing material between

tissues; allows for some movement, butkeeps things in place

Site of edema Reservoir of nutrient, water, salts , for

surrounding tissues

8/14/2019 05 Tissues

30/49

8/14/2019 05 Tissues

31/49

LOOSE RETICULAR TISSUE

Supports bloodcells in lymphoidorgans

(reticular fibers actas scaffolding.)

found in spleen,

liver, lymph nodes

8/14/2019 05 Tissues

32/49

LOOSE ADIPOSE TISSUE Filled with adipocytes

adipocytes are filled with inclusion body (oil droplet)

Not much ecm

Energy storage, thermal insulation, shockabsorption

Richly vascularized (why?)

Found under skin; around highly active organs(heart, kidney)

8/14/2019 05 Tissues

33/49

8/14/2019 05 Tissues

34/49

DENSE REGULAR

Fibers: mainly collagen Cells: mainly fibroblasts Not much ground substance Poorly vascularized Collagen fibers run in parallel

densely packed gives much tensile strength in one direction

very strong

8/14/2019 05 Tissues

35/49

DENSE REGULAR

Tendons : muscle to bone

Aponeuroses : sheetlike muscle to muscle; or muscle to bone

Ligaments : bone to bone

8/14/2019 05 Tissues

36/49

8/14/2019 05 Tissues

37/49

DENSE IRREGULAR

Densly packed collagen running in manydirections

durable, can withstand stresses in many/

unpredictable directions Poorly vascularized Locations:

deep dermis of skin; organ capsules;surrounding cartilage and bone

8/14/2019 05 Tissues

38/49

8/14/2019 05 Tissues

39/49

Supportive/Structural CT

Cartilage hyaline cartilage fibrocartilage elastic cartilage

Bone

8/14/2019 05 Tissues

40/49

CARTILAGE

Dense tissue of cells (chondrocytes) andcollagen

High viscosity/ firmness 80% water

allows it to withstand compression Good for tension and compression

8/14/2019 05 Tissues

41/49

CARTILAGE

No nerve or blood supply nutrients are obtained through diffusion from

the surrounding ct Chondroblasts slow down in their

production of new matrix after theskeleton stops growing

Injuries to cartilage are very difficult toheal Osteoarthritis

8/14/2019 05 Tissues

42/49

CARTILAGE (3 TYPES)

Hyaline cartilage: glassy

appearance chondrocytes

randomlyoriented

embryonicskeleton, articularcartilage, tip ofnose, ribs tosternum

8/14/2019 05 Tissues

43/49

CARTILAGE TYPES

Fibrocartilage: chondrocytes in

groups betweencollagenous fibers

strong andcompressable

pubic symphysis;

intervertebral discs

8/14/2019 05 Tissues

44/49

CARTILAGE TYPES

Elastic cartilage similar to hyaline with

more elastic fibers

has strength andflexibility ear; epiglottis

8/14/2019 05 Tissues

45/49

BONE

Hard calcified matrixwith many collagenfibers

Well vascularized Cells:

osteoblasts, -cytes,-clasts

8/14/2019 05 Tissues

46/49

FLUID CT: BLOOD

Matrix: blood plasma Cells: rbc, wbc

Fibers: in clotting Functions:

carry nutrients, wastes, respiratory gases,

etc.

8/14/2019 05 Tissues

47/49

FOUR TISSUE TYPES

EPITHELIAL

CONNECTIVE

NERVOUS

MUSCLE

8/14/2019 05 Tissues

48/49

NERVOUS TISSUE

Excitable Cells: neurons; glia

Functions: communication,

control

8/14/2019 05 Tissues

49/49

MUSCLE TISSUE Excitable Cells: muscle cells Function: movement Types:

Skeletal Voluntary movements

Cardiac In heart, involuntary

Smooth important in digestive system found mainly in walls of hollow organs (except heart)