Epithelium

Epithelium:-Broad sheet-like tissue that covers (lines) surfaces-Divides body into compartments and forms barriers that control and modify substances traversing it- Protection, Secretion, Excretion, Absorption, Transport

Sites of Occurrence:1. Skin2. Body Cavities3. Serous Sacs4. Blood Vessels5. Glands6. Many Other Organs

Embryology:Ectoderm- SkinEndoderm- GITMesoderm- Endothelium & Mesothelium

Characteristics in General:1. Hypercellularity2. Avascularity3. Polarity4. Cell Cohesion/ Adhesion5. Cell Renewal6. Metaplasia7. Surface Modifications8. Basement Membrane9. Lamina Propia10. Nuclei Tend to Conform with Shape of Cell

Polarity Metaplasia

Apical Surface Specialization #1: Microvilli

Actin Filaments

Apical Specialization #2: Cilia

Microtubules: Core of Cilia, Flagella, Centriole, & Basal Body

Cilium &Flagellum

(9 2 + 2)“axoneme”

Centriole &Basal Body

(9 3)

Apical Specialization #3: Stereocilia

Lateral Surface Modifications: Junctional Complex

“Zonula” – circumferential band, a “belt”

“Macula” – a spot, or a patch

1. Zonula Occludens – Tight Junction

Zonula Occludens – crests fit into grooves, seals off intercellular space

2. Zonula Adherens – attachment of actin filaments

Zonula Adherens – cell to cell adhesion

3. Macula Adherens (Desmosome) – two dense plaques on opposing membranes

Desmosome – keratin (intermediate) filaments anchor to plaques; cell to cell attachment

4. Gap Junction (Nexus) : - cell to cell transfer of ions and other small molecules - thus, for intercellular communications

Basement Membrane (Basal Lamina)

Chemical Composition of Basal Lamina

Types of Epithelial Tissue

Simple Squamous, Surface View, Silver Stain

Types of Epithelium (cont.)

Simple Squamous # 1: Parietal Layer of Bowman’s Capsule (of Kidney) (Diag.)

Simple Squamous # 2: Endothelium

Simple Squamous # 3: Mesothelium

myo

card

ium

epica

rdium

endo

card

ium

Simple Cuboidal Epithelium # 1: Kidney Tubules

CELLS OF PROXIMAL TUBULE

Simple Cuboidal # 2: Follicular Cells of Thyroid Gland

Simple Cuboidal # 3: Pigment Epithelium of Retina (diag.)

Simple Columnar Epithelium # 1: Mucosa of Small Intestine

Simple Columnar Epithelium w/ Striated Border

Simple Columnar Epithelium #2 (w/ Cilia) : Mucosa of Oviduct (Fallopian Tube)

Pseudo-Stratified Columnarw/ Cilia and Goblet =“Respiratory Epithelium”

Pseudo-Stratified Columnar w/ Stereocilia : Ductus Epididymis , Ductus Deferens

Stereocilia = Long Microvilli

Stratified Squamous Epithelium, Keratinized (Dry): Epidermis of Skin

Stratified Squamous, Non-Keratinized (Wet): Esophagus, Vagina

Transitional Epithelium : Urinary Bladder, Ureter

Transitional Epithelium = “Stretchable Epithelium”

Stratified Cuboidal Epithelium: (rare) , Larger Ducts of Sweat and Salivary Glands

Stratified Columnar Epithelium: (rare), Larger Ducts Sweat and Salivary Glands , and in…….

Conjunctiva

Formation of Glands

Types of Gland as to Morphology

Types of Gland as to Nature of Secretion

Serous Acinus Mucous Acinus

Mixed Muco-Serous Gland

Serous Demilune (of Gianuzzi)

Types of Gland as to Manner of Cell Participation During Secretion

Release of Sperm Cell or Ovum :“Cytogenic Secretion”

FUNCTIONS: 1. Structural Support 3. Repair 2. Defense 4. Storage a) Physical b) Immunological

SITES OF OCCURRENCE: ALL OVER THE BODY, IN ALL ORGANS: 1. Supports epithelium 2. Surrounds blood vessels, nerves, hollow viscera, solid organs 3. Fills in spaces and interstices forming compartments 4. Connects organ to organ

GENERAL PROPERTIES: 1. Less cells, more matrix 2. Highly vascular 3. Rapid rate of metabolism

BASIC STRUCTURE: 1. CELLS 2. MATRIX (EXTRA- / INTER-CELLULAR SUBSTANCE) - Fibers - Amorphous Ground substance

CELLS:I. FIXED ( NATIVE ) 1. MESENCHYMAL CELL 2. FIBROBLAST 3. RETICULAR CELL 4. ADIPOCYTE (FAT CELL)

II. WANDERING 1. MACROPHAGE 2. MAST CELL 3. PLASMA CELL 4. LEUCOCYTES (WBC’ s)

MATRIXI. FIBERS 1. COLLAGENOUS 2. ELASTIC 3. RETICULAR

II. AMORPHOUS GROUND SUBSTANCE 1. PROTEOGLYCAN

CLASSIFICATION:

A. CONNECTIVE TISSUE PROPER 1. LOOSE (AREOLAR) 2. DENSE a. REGULAR b. IRREGULAR

C. SPECIAL TYPES 1. ADIPOSE 2. MUCOUS 3. ELASTIC 4. RETICULAR 5. CARTILAGE 6. BONE 7. BLOOD 8. MYELOID 9. LYMPHOID

Fibroblast, Mesenchymal Cell,and Reticular Cell have commonmorphology:1. Stellate cell2. Long cytoplasmic processes3. Central pale, ovoid nucleus with prominent nucleolus4. Features of protein-secreting cell: a) Abundant ribosomes (basophilia) b) Numerous RER c) Prominent Golgi complex d) Numerous mitochondria

FIXED CELLS

1. FIBROBLAST = the “Matrix Maker”

FIBROBLAST (CONT.)

2. MESENCHYMAL CELL = the “Mother Cell”

MESENCHYMAL CELL (CONT.)Adventitial Cells – Mesenchymal cells that remain undifferentiated in adult connective tissue

3. RETICULAR CELL = “ Fiber Maker”, Stem cell, Immune Cell

Reticular Cells in Stroma of Lymph Node

4. ADIPOCYTE (FAT CELL) = the “Energy Keeper”

UNILOCULAR ADIPOCYTES

( At Times Yellow,due to Carotenoid Pigment)

, Unilocular

THE MORE ABUNDANT TYPE

( Reddish- Brown color dueto mitochondrial cytochromes)

Limited in occurrence to the axillary region, posterior cervical triangles,and renal hilus of newborn and elderly.More intense metabolic activity.

WANDERING CELLS

1. PLASMA CELL = the “ Antibody Producer”

PLASMA CELL (LM)

PLASMA CELL (EM)

2. MAST CELL = the “ Allergy Agent”

MAST CELL (EM)

3. MACROPHAGE = the “ Intruder Swallower”

MACROPHAGE (EM)

MACROPHAGES COALESCE TO FORM – MULTINUCLEAR GIANT CELL

4. LEUCOCYTES = the “ Precursors”

1. COLLAGEN FIBERS = the “strength” (Collagen type I)

FIBERS

COLLAGEN FIBERS (CONT.)

2. ELASTIC FIBERS = the “Flexibility”

ELASTIC FIBERS (CONT.)

3. RETICULAR FIBERS = the “ Motile Cells’ Support” (Collagen Type III)

TYPES OF CONNECTIVE TISSUE

1. LOOSE (AREOLAR) CONNECTIVE TISSUE

LOOSE CONNECTIVE TISSUE (CONT.)

2. A) DENSE REGULAR CONNECTIVE TISSUE

DENSE REGULAR CONNECTIVE TISSUE – “Rope-like”

2. B) DENSE IRREGULAR CONNECTIVE TISSUE

DENSE IRREGULAR CONNECTIVE TISSUE – “Fabric-like”

3. MUCOUS / MESENCHYMAL / EMBRYONIC CONNECTIVE TISSUE

4. ADIPOSE CONNECTIVE TISSUE

5. ELASTIC CONNECTIVE TISSUE

6. RETICULAR CONNECTIVE TISSUE

Matrix

Chondrocyte

Perichondrium

(Colloidal)

Cartilage Matrix

1. Hyaline Cartilage

2. Elastic Cartilage

3. Fibrous Cartilage

CalcifiedMatrix

Compact and Cancellous Bone

Compact Bone

Haversian and Volkmann’s Canals

Cancellous or Spongy Bone

Red Marrow

Endochondral Ossification

Intramembranous Ossification

Skeletal Muscle

Cardiac Muscle

Intercalated Disc

Smooth Muscle

T-System of Skeletal Muscle

T-System of Cardiac Muscle

FORMED ELEMENTS OF BLOOD:

I. RBC (ERYTHROCYTES)II. WBC (LEUCOCYTES) A. GRANULOCYTES 1. NEUTROPHILS 2. EOSINOPHILS 3. BASOPHILS B. AGRANULOCYTES 1. LYMPHOCYTES 2. MONOCYTESIII. PLATELETS (THROMBOCYTES)

7.5 u

1.9 u

R B C

1. SIZE AND SHAPEPHYSICAL PROPERTIES:

RBC’s , WRIGHT’s STAIN

CentralPallor

PLATELETS

PHYSICAL PROPERTIES, WRIGHT’s STAIN

MEGAKARYOCYTE

PLATELET’s 2 ZONES: HYALOMERE & GRANULOMERE

W B C’s

2 GROUPS: GRANULOCYTES & AGRANULOCYTESSOME PHYSICAL PROPERTIES

2 TYPES OF GRANULES IN LEUCOCYTES

NEUTROPHILS (PMN=POLYMORPHONUCLEARS)

EOSINOPHIL

BASOPHIL

LYMPHOCYTES (MN=MONONUCLEARS)

MONOCYTE

2 TYPES OF BONE MARROW: RED & YELLOWRED MARROW- CHIEF HEMOPOIETIC TISSUE IN MAN

BONE MARROW

BONE MARROW SECTION

BONE MARROW SMEAR

STRUCTURAL COMPONENTS

1. RETICULAR CONNECTIVE TISSUE FRAMEWORK

2. CELLS: A) BLOOD CELLS AT VARIOUS MATURATIONAL STAGES B) CONN. TISSUE CELLS: FAT CELLS, MACROPHAGES, MAST CELLS, PLASMA CELLS, RETICULAR CELLS

3. VASCULAR TREE: SINUSOIDS

MONOPHYLETIC THEORY OF HEMOPOIESIS

ERYTHROPOIESIS: BASIC CHANGES

STAGES OF ERYTHROPOIESIS

PROERYTHROBLAST

BASOPHILIC , POLYCHROMATOPHILIC ERYTHROBLASTS

POLYCHROMATOPHILIC, ORTHOCHROMATIC ERYTHROBLASTS

ORTHOCHROMATIC ERYTHROBLASTS ( NORMOBLASTS )

BASOPHILIC ERYTHROCYTE

RETICULOCYTES ( BASOPHILIC ERYTHROCYTES )

GRANULOPOIESIS: BASIC CHANGES (nucleus)

GRANULOPOIESIS: BASIC CHANGES (cytoplasm)

STAGES OF GRANULOPOIESIS

PROMYELOCYTE

BASOPHILIC MYELOCYTE

EOSINOPHILIC MYELOCYTE

NEUTROPHILIC METAMYELOCYTE

THROMBOPOIESIS

MEGAKARYOCYTE

LYMPHOPOIESIS, MONOPOIESIS

DEVELOPMENT OF B & T LYMPHOCYTES