CHAPTER 5 - HISTOLOGY

Tissues

TISSUE IS COMPOSED OF SIMILAR CELLS TO PERFORM

A PARTICULAR FUNCTION

CELLS ARE SURROUNDED BY NON-LIVING MATERIAL

CALLED THE MATRIX

THE DENSITY OF THE MATRIX DETERMINES THE

RIGIDITY OF THE TISSUE

TYPES OF TISSUES

Epithelial – surface, lining body cavities

Connective – hard and soft

Muscle – movement

Nervous - communication

EMBRYONIC DEVELOPMENT

After two wks. three germ layers produced – endoderm, mesoderm, ectoderm

Histogenesis determines the tissue type.

Epitheial – all Connective/muscle – mesoderm Nervous - ectoderm

EPITHELIAL TISSUE – TWO CATEGORIES

Membranous – Body coveringVesselsResp., digestive, GU systems

Glandular - Endocrine and exocrine glands

EPITHELIAL FUNCTIONS Protection Sensory – skin, nose, eye, ear

Secretion – hormones, sweat, mucus, digestive enzymes

Absorption – gut – resp. gases

Excretion – renal tubules

EPITHELIAL GENERALIZATIONS Limited matrix material Under scope appears as tightly packed

sheets Epithelium attached to basal membrane

(layer of connective tissue by a thin noncellular layer)

Glycoproteins (basal lamina) secreted by epithelial cells and a mesh of fibers (reticular lamina) produced by the connective tissue

Adhesive molecules (integrins) help bind cytoskeleton of epithelial cells to basement membrane

Avascular Diffusion allows for O2 and nutrients Can reproduce themselves

CLASSIFICATION Based on cell shape

Based on layers of cells

SIMPLE SQUAMOUS Give criteria Flat One layer Scale-like Diffusion easy through this tissue Alveoli, pleura, pericardium, lymph

vessels

SHAPE - SQUAMOUS

SIMPLE CUBOIDAL

One layerCube shapedGlandskidneys

SHAPE - CUBOIDAL

SIMPLE COLUMNAR Mucus membrane Stomach lining Uterus Intestine Goblet cells – secretory vesicles – mucus Microvilli present Surface structure expands – fan demo

SHAPE - COLUMNAR

PEUDOSTRATIFIED COLUMNAR Air passages Urethra Cells differ in height and gives false

impression of stratification Resp.system lining = cilia moves one

direction for protection = in or out?

SHAPE - PSEUDOSTRATIFIED

LAYERS – SIMPLE – ONE CELL THICKNESS

STRATIFIED EPITHELIUM – MORE THAT ONE CELL THICKNESS

STRATIFIED SQUAMOUS Keratinized

Protective factor on outer surface -keratohyaline

Resistance to friction and tractionDry Typically impermeable

Non-keratinizedLining the vagina, mouth, esophagusFree surface is moistAllows diffusion of materials

STRATIFIED CUBOIDAL Two or more rows arranged randomly

over basement membrane Sweat gland ducts Pharynx Part of epiglottis

STRATIFIED COLUMNAR Multiple layers Rare locations

Male urethraMucus layer near anus

STRATIFIED TRANSITION Find in areas of stress and tension

change

Wall of bladder Shape changes from cuboidal to

columnar

DURING THE VOIDING PROCESSS, THIS TISSUE GOES THROUGH GREAT TRANSITION!

LEGO LAB

GLANDULAR Secretory in nature

Exocrine glands – discharge secretion into ductssaliva

Endocrine glands – discharge secretion into the bloodhormones

CLASSIFICATION OF EXOCRINE GLANDS Apocrine

Holocrine

Merocrine

APOCRINE - MAMMARY

HOLOCRINE - SEBACEOUS

MEROCRINE - SALIVARY

POINTS TO PONDER……….

? What is the most widespread

abundant tissue? Nerve tissue is derived from

what germ layer? Define tissue Blood is a member of what

tissue type?

PONDER….

What tissue lines body cavities? Function of epithelial tissue Where is keratinized squamous

epithelium found? Know glandular differences Function of connective tissue Where is collagenous tissue

found?

CONNECTIVE TISSUE

One of the Most widespread tissues in the body

VARIED FORMS Delicate tissue paper webs

Tough resilient cords

Rigid bones

Blood

FUNCTIONS Connects – muscle to muscle

Supports - framework Transports - nutrients, hormones, waste

Defends - skin

CHARACTERISTICS Matrix – intracellular material Ground substance – embedded in matrix

along with fibers and fluid Qualities of matrix and fibers determine

structure of tissue Blood – matrix is plasma – no fibers,

many cells (except during coagulation) Number of fibers determine

consistency/strength

CONNECTIVE TISSUE MATRIX:ONE OR MORE FIBERS Collagenous – white – tough and strong –

occur in bundles (provides strength) Possibly accounting for more than one-fourth of

protein in body Typically reflects aging process

Reticular – elastic and delicate – occur in networks (supports nerves, capillaries)

These are produced by fibroblasts and some other cells

ELASTIC FIBERS

Made of elastin Found in tissues that can stretch – nose, etc.

What do you know about elastic products?

BARRIERS AND GLUE Protein fibers + proteoglycans

(polysacharide chains – glucosamine) = matrix fluid

This fluid is thick

Barrier for microbes

Also, transparent lubricant to hold tissue together

CLASSIFICATION Structural characteristics of the

intracellular materialFibrous – extracellular fibers are

predominant featureBone – fibers and hard mineral

ground substanceCartilage – ground substance traps

water to form a firm gelBlood - lack of fibers in matrix

FIBROUS Loose/ordinary/areolar Stretchable Most widely distributed of all tissues Connects adjacent structures – acts like glue

that permits movement Term areolar refers to bubbly effect when

pulled apart on dissection Matrix is soft, thick gel but hyaluronic acid

can turn it watery IM absorption increases with watery state Strep bacterium release this acid to allow

for ease of permeability

Macrophages carry on phagocytosis

Type of WBC – mast cell

ADIPOSE Predominately fat cells and few

fibroblasts, macrophages and mast cells

Provides padding

Storage

insulation

RETICULAR Three dimensional web (reticular

network) Framework of the spleen, lymph, bone

marrow

Defense mechanism that acts as a filter, traps and eats invaders

DENSE FIBROUS TISSUE Fibers packed densely in matrix Few fibroblasts Regular/irregular – depends on

arrangement of fibers Dense – bundles of fibers of collagen –

tendons (flexible and great strength) ligament – mostly elastic fibers Irregular – bundles not in parallel rows,

but thick mat - dermis

BONE Osseous Most specialized of connective tissue Collagen and mineral salts (65%) which

creates density and strength

Support/protection/mineral reserve Basic unit of the bone is the osteon

(Haversian system) Osteocytes located in lacunae – arranged in

concentric manner called lamellae Canaliculi connect each lacuna and

osteocyte with bl vessels in Haversian canal

Osteoblast

Osteocyte

osteoclast

CARTILAGE Only has one cell type – chondrocyte Chondrocytes produce fibers and tough

gristle ground substance Also found in lacunae Avascular – diffusion Cartilage injury heals slowly

CARTILAGE TYPES Fibrocartilage – strongest/most durable

Strong densly packed collagen Intervertebral disks,meniscus

Elastic cartilage – little collagen/great amt of elastic fibersGreat flexibility

External ear, voice box, larynx

Hyaline (glass) - low amount of collagen – shiny/transparentEsophageal rings, end of bones

BLOOD Most unusual Liquid state No ground substance or fibers Plasma (55%) and formed elements

(cells) Body transport Maintains body temp. Regulates ph of body fluids Phagocytosis/defense Hematopoiesis – red marrow

MUSCLE 3 types Skeletal – striated - voluntary Smooth - involuntary Cardiac - cross striations and bands

NERVOUS More developed excitability and

conductivity than other tissue types Organs – brain, spinal cord, nerves

Neurons – basic unit Neuroglia – supporting/connecting cells

Cell body – soma Axon – away Dendrite - down

TISSUE REPAIR Damage = scars = keloid Phagocytic cells remove debris Regeneration

Fibrous tissueGranulation tissue

Greatest regeneration capacity – epithelial and connectiveMuscle – limited regeneration – decreased

strengthNerves – limited regeneration

brain and spinal cord do not regenerate Nerve growth factor may prove successful

BODY MEMBRANES Epithelial

Cutaneous Serous

Parietal – lines wall of cavity like wallpaper Visceral – covers organs Peritoneum – covers abd. viscera

Mucus Produce mucus Defense Moistens food Lubricant for digestion

Connective Line spaces btwn bones Synovial fluid

DISEASE Neoplasm – new matter Benign Malignant Tumor Metastasis Papilloma – fingerlike projections Adenoma – tumor of gland Nevus – mole Hyperplasia – too many cells Anaplasia - undifferentiated cells

CAGenetic Environmental Ingestion InhalationRadiation

Detection of CAMRICAT scanX-RaySerumSelf-examBx.

Grading staging

TMTHerbal Psychotherapy Chemotherapy Radiation PO medLaser Immunotherapy –Nuclear medsGene therapy

PONDER……

How are salivary glands classified?

What is known as loose ordinary connective tissue?

What is the purpose of adipose tissue?

What kind of tissue is red bone marrow?

Another name for skeletal muscle

PONDER…..

What tissue is composed of neurons?

Most prevalent cartilage? Cilia are found on what types of

cells? Most complex tissue Mature bone cells are called – Characteristics of skeletal

muscles

PONDER….. Define matrix Phagocytosis Keloid Inflammation process

WARNING!GROSS WILL

FOLLOW…

DECUBITUS ULCER

DECUBITUS ULCER

PRESSURE ULCER

STASIS ULCER OF THE FOOT

KELOID SCAR

NEVUS

NEVUS

NEOPLASM - AMELOBLASTOMA BENIGN TUMOR OF ODONTOGENIC

FIBROADENOMA - CANCEROUS

MALIGNANT MELANOMA

PAPILLOMA - MILD

PAPILLOMA - SEVERE

STASIS ULCER

BEAUTY……………………

CANNOT BE TAKEN FOR GRANTED

RICHARD NORRIS – GUNSHOT WOUND – FACIAL TRANSPLANT

ALLOGRAFT

IMAGINE………

HAND TRANSPLANTATION

WELCOME TO THE WORLD OF REGENERATION