Histology Lab Practical: Skin, Bone, and Cartilage Identification

Stratum basale

Deepest layer of the epidermis; crowded nuclei; actively dividing keratinocytes.

Stratum spinosum

Layer of the epidermis with polygonal 'spiny' cells.

Stratum granulosum

Darker layer of the epidermis with granules; nuclei fading.

Stratum lucidum

Clear/light layer of the epidermis; present only in thick skin; no nuclei.

Stratum corneum

Outermost layer of the epidermis; flattened dead cells; no nuclei.

Papillary dermis

Superficial dermis; loose connective tissue; forms dermal papillae.

Reticular dermis

Deeper dermis; dense irregular connective tissue; collagen swirls/marbled look.

Hypodermis

Subcutaneous layer below the skin.

Epidermis

Layer of skin with no blood vessels.

Sweat glands

Coiled tubular glands located in the dermis.

Thick skin

Skin that has stratum lucidum and thick stratum corneum.

Compact bone

Also known as cortical bone.

Osteon

Basic unit of compact bone.

Central canal

Contains blood vessels and nerves in bone.

Lamellae

Concentric rings found in bone.

Lacunae

Pockets in bone that house osteocytes.

Osteocytes

Cells located in lacunae that maintain bone.

Canaliculi

Tiny channels that connect lacunae in bone.

Perforating canals

Connect central canals in bone.

Spongy bone

Also known as trabecular or cancellous bone; has lattice-like trabeculae.

Osteoprogenitor cells

Stem cells that differentiate into osteoblasts.

Osteoblasts

Cells that build bone by secreting osteoid.

Osteoclasts

Cells that break down bone.

Periosteum

Outer covering of bone.

Endosteum

Lines the marrow cavity and canals in bone.

Hyaline cartilage

Contains chondrocytes in lacunae and has a smooth glassy matrix.

Endochondral ossification

Process where cartilage model is replaced by bone.

Diaphysis

Shaft of a long bone.

Metaphysis

Transition zone of a long bone.

Epiphysis

End of a long bone.