Cells, Tissues, and the Integumentary System

Practice vocabulary flashcards based on lecture notes covering cytology, cellular transport, body tissues, membranes, and the integumentary system.

Cytology

The study of cells.

Nucleus

The control center of the cell containing the genetic material known as DNA.

Nucleolus

The central region within the nucleus where RNA components are stored until needed to copy DNA for protein synthesis.

Chromatin

A thread-like strand of DNA wound around histone proteins that appears spread out and thin when the cell is not dividing.

Histones

Proteins that act like spools of thread around which DNA strands are organized and wound.

Phospholipid bilayer

A two-layered cell membrane arrangement composed of hydrophilic, polar phosphate heads and hydrophobic, nonpolar fatty acid tails.

Tight junctions

Impermeable junctions that bind cells together in leak-proof sheets, such as in the skin.

Desmosomes

Anchoring cell junctions that act like rivets or buttons to prevent cells from being pulled apart by mechanical stress.

Gap junctions

Hollow tube junctions that connect neighboring cells and allow direct chemical and electrical communication.

Mitochondria

Organelles with their own DNA, called the powerhouses of the cell, that break down glucose into ATP through glycolysis.

Rough endoplasmic reticulum

A network of fluid-filled canals studded with ribosomes that manufactures proteins.

Smooth endoplasmic reticulum

A network of fluid-filled canals lacking ribosomes that detoxifies drugs, alcohol, and pesticides.

Golgi apparatus

A set of membrane channels that modifies, puts protective caps on, packages, and ships proteins.

Lysosomes

Membranous vesicles containing digestive enzymes utilized by phagocytes to break down bacteria and cellular debris.

Peroxisomes

Vesicles containing oxidase enzymes that break down free radicals and detoxify harmful substances such as alcohol and formaldehyde.

Microvilli

Tiny, finger-like projections on the cell surface that increase surface area for enhanced absorption, as in the small intestine.

Diffusion

The passive movement of solute particles from an area of higher concentration to an area of lower concentration.

Osmosis

The passive movement of water down its concentration gradient across a semipermeable cell membrane.

Phagocytosis

A non-selective active process of cell eating in which a cell engulfs large particles or bacteria using false feet.

Pinocytosis

A non-selective active process of cell drinking where extracellular fluid is taken into the cell.

Apical surface

The free, unattached surface of an epithelial cell that borders or hangs into the lumen of a tube or body cavity.

Basement membrane

A protein shelf that anchors epithelial tissue to underlying connective tissue structures.

Avascular

Lacking blood vessels, a defining characteristic of epithelial tissue.

Goblet cells

Unicellular glands found intermixed within columnar epithelium that produce and secrete mucus.

Pseudostratified columnar epithelium

An epithelial tissue appearing multi-layered due to varying nuclear positions, possessing cilia and goblet cells to sweep mucus in the respiratory tract.

Transitional epithelium

A specialized stratified epithelium lining the urinary bladder that changes shape from rounded dome cells to flattened cells when stretched.

Exocrine glands

Glands that empty their secretions through ducts onto an epithelial surface.

Endocrine glands

Ductless glands that secrete hormones directly into surrounding blood vessels.

Fibroblast

A cell in connective tissue responsible for making collagen fibers.

Osteocytes

Mature bone cells situated within small cavities called lacunae.

Chondrocytes

Cartilage cells located inside lacunae that secrete and maintain the cartilage matrix.

Tendons

Dense connective tissue structures that attach skeletal muscle to bone.

Ligaments

Dense connective tissue structures that connect bone to bone.

Intercalated discs

Specialized junctional sites containing gap junctions found in cardiac muscle that coordinate synchronized cellular contraction.

Neuroglia

Non-conducting supporting cells of nervous tissue that insulate, protect, and support neurons and are capable of mitosis.

Benign neoplasm

A slow-growing, non-cancerous tumor enclosed in a capsule that does not invade surrounding tissue or metastasize.

Malignant neoplasm

A non-encapsulated cancerous tumor that invades neighboring tissues and metastasizes to other body areas.

Cutaneous membrane

The dry epithelial membrane covering the external body surface, commonly known as the skin.

Serous membranes

Paired epithelial membranes (visceral and parietal layers separated by serous fluid) lining body cavities closed to the exterior environment.

Synovial membranes

Connective tissue membranes that line fibrous joint capsules, bursae, and tendon sheaths, secreting lubricating fluid.

Stratum basale

The deepest layer of the epidermis resting on the dermis, where stem cells constantly undergo mitosis to generate new epidermal cells.

Stratum lucidum

A thin, clear epidermal layer found only in the thick skin of the palms and soles that provides protection from ultraviolet rays.

Stratum corneum

The outermost layer of the epidermis composed of dead, cornified cells whose shedding causes dandruff.

Dermal papillae

Finger-like projections of the papillary dermis that indent the overlying epidermis to create fingerprints.

Erythema

Skin redness caused by embarrassment, fever, inflammation, hypertension, or allergy.

Pallor

Blanching or pale discoloration of the skin resulting from emotional stress, anemia, low blood pressure, or impaired blood flow.

Hematoma

A localized collection of blood beneath the skin resulting from broken vessels, clinically referred to as a bruise or blood tumor.

Sebaceous glands

Cutaneous exocrine glands attached to hair follicles that secrete oily, waxy sebum to lubricate skin and hair.

Vernix caseosa

A white, cheesy biofilm secreted by sebaceous glands that covers a fetus during the last trimester of pregnancy for immunity, temperature control, and water barrier function.

Arrector pili

Smooth muscle bundles connected to hair follicles that contract when cold or frightened to raise hairs, create goosebumps, and generate warmth.

Rule of nines

A diagnostic estimation system dividing the human body into 11 areas, each representing approximately $9\%$ of total body surface area, to estimate fluid loss and burn extent.

Lanugo

Downy hair covering the fetus during the fifth and sixth months of gestation that usually disappears by birth.