EXAM 2 A/P Lecture

Histology

Study of Tissue

Tissue

Bassed on structure of cells and extracellular matrix, and function

Biopsy

removal of tissue for diagnostic purpose

Autopsy

Examination of organs of dead body to detirmine cause of death

Extracellular matrix

a complex network of proteins, glycoproteins, and polysaccharides outside of cells that provides structural and biochemical support to surrounding tissue

Epithelial Tissue composition

Mostly cells, little extracellular matrix

Epithelial Tissue purpose

covers/lines body surface

Epithelial positioning

Apical surface and basement membrane

The Epithelial tissue is …

Avascular - gasses/nutiants must diffuse across basement membrane

Classification

Based of # of cell layers and cell shape

Simple

Monolayer

Stratified

Multilayer

Pseudostratified

False appearence of being multilayered; each cell is in contact with basement membrane

Squamous

Flat

Cuboidal

Boxlike

Columnar

Tall, Narrow

Stratified Squamos

may be moist or keratinized protein

keratinized

outer cells dead & contain tough, moisture- resistant protein

Transitional Epithelium

Stratified, stretches without tearing, cell layers slide past one another

Where can Transitional Epithelium be found

Uninary Bladder

Funtion Simple Epithelial tissue

Diffusion(lungs), secretion(glands), filtration(glomerulus), absorption(intestines)

Function Stratified Epi. Tissue

Protection/barrier function, found in areas where abrasion occurs

Funtion Squamous Epi. Tissue

Thin/Flat, secretion or absorption

Funtion Cudoidal/Columnar Epi. Tissue

Secretion and Absorption

Goblet Cells

Produce Mucus

Microvilli

Increase Surface area (brush border or small intestine)

Cilia

Directed movment across cell membrane (trachea, nasal cavity)

Cell Connections

Bind cells together

Cell Connections form

a permeability barrier

Cell Connections permit

intercellular communication

Cell Connections are made of

Epi. cells that produce glycoprotein that connects cells to each other and to basement membrance

Desmosomes

Disk shaped structures with sticky glycoproteins

Desmosomes function

reinforce cell to cell connections at stress points

Hemidesmosomes

attach epi. cells to basement membrane

Hemidesmosomes are

half a desmosome

tight junctions function

material can’t pass between cells but must pass through cells instead

tight junctions

form a permeability barrier

Zona Adherens

Girdle of glycoproteins, binds cells together

Zona occludens

rings around cells

Adhesion belts

found just below tight juntions

Gap Junctions

small protein channel, allows small polar materials to pass between cells

Gap Junction are for

important coordinating function (ex. intercalated disks-cardiac muscles)

Glands

Secretory function, composed primarily of epithelia

exocrine

ducts that go to surface

endocrine

ductless, produce hormones, go to blood vessels

unicellular

goblet cells → mucus

Multicellular

classification based on duct structure and secretion

Simple multicell

duct with few branches

Compound multicell

duct with many branches

Tubuar multicell

duct ends in straight/coiled tubes

Acinar

duct ends in cluster of small sacs

Alveolar

duct ends in hallow sacs

Merocrine

secretion with no loss of cytoplasm(ex. eccrine sweat gland)

Aprocrine

Secretion with some loss of cytoplasm(ex. mammary glands)

Holocrine

Cell becomes part of the secretion(ex.sebaceous glands)

Connective tissue

Abundent nonliving, extracellular matrix

Matrix components

protein fibers,ground substance, fluid, well vascularized

Osteo-

bone

Chondro-

cartilage

Fibro-

connective tissue

-blasts

cells that build matrix

-cytes

cells that maintain matrix

clasts

cells that breakdown the matrix

Collagen

strong & flexible, dosen’t stretch, primary protein in the body

Reticular

Fine collagen fiber network

Elastin

stretch and recoil

Ground Substance is made up of

Hyaluronic acid, proteoglycan

Fluid

All extracellular fluid associated with a tissue

Difference between loose vs dence CT

based on protein fibers

Difference between regular vs irregular CT

based on fiber arrangment

Areolar/Loose CT

lacy network of protein fibers

Dense CT

fibers fill nearly all of extracellular space

Regular Dense CT

Run in a single direction

collagenous tissue

seen in tendons & ligaments

Elastic tissue

seen in ligaments of vertebrae

Irregular Dense CT

Fibers run in many directions

Collagenous Irregular

Reticular layer of dermis

elastic irregular

walls of large arteries

Adipose

Fat Cells,surround lipid droplet

Reticular Tissue

network of collagen fibers forms fromework of lymphoid tissue, bone marrow & liver

Yellow Bone Marrow

Fat storage

Red Bone Marrow

Blood Cell production

Cartilage

regid matrix, lacunae surround chrondocytes, avascular

Hyaline Cart.

Rigid with some flexibility

Fibrocartilage

Withstands great pressure ( intervertebral disks, meniscus of knee)

Elastic Cart.

most flexible (ex.pinna, epiglottis)

Bone

solid matrix with organic& mineralized inorganic material

Inorganic matrix

give rigidity

organic matrix

give flexible strength

Spongy Bone

bone spicules arranged in trabecular network

Compact bone

dense bone with regular repeating structure units

Blood

Liquid Marix=Plasma

Muscle tissue

excitable tissue and contracts

Skeletal muscle

Striated, voluntary, multinucleated, movment

Cardiac

Striated, involuntary, branched fibers, intercalated

Smooth

Nonstriated, involuntary, walls of hallow organs, spindle shaped

Nervous Tissue

Irritable, conducts electrical impulses

Neurons

Conducting Cells

Neuroglia

Supportive, protective cell, insulate neurons

Axon

carries signal away from soma