HISTOLOGY/INTEGUMENTARY SYSTEM LAB PRACTICAL

Squamous Epithelium

Flat, "fried egg"

Smear, you can't determine from the appearance if it is simple or stratified.

This is a smear of stratified squamous epithelium.

FOUND IN LUNGS, KIDNEYS, SEROUS MEMBRANES

FUNCTIONS IN OSMOSIS AND SECRETION

Simple Squamous Epithelium (lung)

Edge view, alveoli

Stratified Squamous Epithelium

Edge view, layers

Focusing on the upper deep pink band

Non-keratinized

FOUND IN ESOPHAGUS AND SKIN

Simple Cuboidal Epithelium (1)

Cube-shaped with centrally located nucleus

FOUND IN KIDNEY TUBULES (LINES DUCTS)

Simple Cuboidal Epithelium (2)

Cube-shaped with centrally located nucleus

Simple Columnar Epithelium

Longer than wide, nucleus close to the basement membrane

FOUND IN LINING OF KIDNEY COLLECTING TUBULES

Pseuostratified Ciliated Columnar Epithelium (1)

Cells have surface modification of cilia

Cells not equal in size

All cells in contact with basement membrane, but not all reach surface

FOUND LINING TRACHEA AND BRONCHI

Pseuostratified Ciliated Columnar Epithelium (2)

Cells have surface modification of cilia

Cells not equal in size

All cells in contact with basement membrane, but not all reach surface

Stratified Ciliated Columnar Epithelium

"Leaves on a tree"

FOUND IN MALE URETHRA AND LARGE EXCRETORY DUCTS OF SOME GLANDS

Transitional Epithelium

Stratified epithelium with some cells appearing squamous and stratified cuboidal, and basal cells being cuboidal or columnar.

Cells are flattened while others are flattened side to side, allowing elasticity

LINES THE URETERS, BLADDER, AND PART OF THE URETHRA

Areolar (Loose) Fibrous Connective Tissue

Matrix of elastic and collagenous fibers

Small amounts of reticular fibers in hyaluronic acid

Elastic fibers thin and dark (thread)

Collagen fibers thick and pink

Fibroblasts large and flat (black dots)

FOUND IN PAPILLARY REGION OF THE DERMIS

Dense Irregular Fibrous Connective Tissue

Lower region of the dermis

FASCIA, RETICULAR REGION OF THE DERMIS

PERIOSTEUM OF BONE

PERIOCHONDRIUM OF CARTILAGE

FIBROUS CAPSULES AROUND KIDNEYS, LIVER, TESTES, LYMPH NODES

Dense Regular Fibrous Connective Tissue

Collagen fibers densely packed in regular parallel rows with fibroblasts between the fibers

TENDONS, MUSCLE TO BONE AND MUSCLE TO MUSCLE

LIGAMENTS, BONE TO BONE

APONEUROSES, MUSCLE TO MUSCLE OR BONE

Adipose Tissue (1)

Adipose Tissue (2)

Cytoplasmic membrane (stained purple) between the adipose cells (white)

Nuclei (black dots)

Hyaline Cartilage

Dense matrix

Fibers not visible

Chondrocytes in lacunae

Bare

FOUND IN JOINTS, NOSE, LARYNX, TRACHEA, BRONCHI

Osseous (Bone)

Matrix found in concentric layers (lamellae) around a central canal (haversian canal)

Osteocytes interconnected with haversian canal by tiny cracks (canaliculi)

Blood (1)

Purple: Leucocyte

Blood (2)

Smooth Muscle (1)

Oriented around (circular) or lengthwise (longitudinal)

Long spindly fibers

Elongated nuclei

INTESTINE AND BLOOD VESSELS

Smooth Muscle (2)

Smooth Muscle (3)

Skeletal Muscle (1)

Striated

Multinucleated

Non-branching

Lack cell boundaries

*Parallel, multinucleated

Skeletal Muscle (2)

Striated (lines)

Multinucleated

Non-branching

Lack cell boundaries

*Horizontal, striations

Cardiac Muscle (1)

Striated

Branched

Intercalated discs (heavy bands)

Cardiac Muscle (2)

Intercalated discs stained pink,red

Nucleus is dark dot

Neuron (1)

Axon, thick pink appendage

Dendrite, thin pink appendage

Glial cells, black scattered dots

Neuron (2)

Dermal Papillae

Finger-like projections of the papillary layer

-Made up of areolar connective tissue

Arrector Pili Muscle

Associated with hair follicles and sebacious oil glands

Smooth muscle tissue

Makes your hair stand up on end

Hair papilla

Invagination

Sudoriferous (Sweat) Glands

Seen as numerous cross sections of tubules

Stratum corneum

Uppermost layer of the epidermis

Dead keratin-filled cell "horny layer"

25-30 layers of dead cells filled with keratin

"Stratified squamous epithelium"

Stratum lucidium

Thin translucent zone

FINGERTIPS, PALMS, AND SOLES (THICK SKIN)

Filled with eleiden (precursor to keratin)

Stratum granulosum

Middle of epidermis

Distinctive feature: dark stained granules of protein keratohyalin

Stratum spinosum

8-10 rows of keratinocytes

Produce spine like cytoplasmic processes that interlock with adjacent cells by desmosomes

Strength and flexibility

Stratum basale

Single layer AT BOTTOM

Youngest layer of epidermis

Columnar or cuboidal cells

High mitotic rate

Reticular Layer