Tissues and Early Embryology - Vocabulary Flashcards

A set of vocabulary-style flashcards covering epithelial and connective tissues, membranes, organ systems, and embryology basics described in the notes.

Epithelium

A sheet of cells that covers exposed surfaces and lines internal cavities and passageways.

Functions of epithelial tissue

Provides physical protection, controls permeability, provides sensation, and produces secretions.

Microvilli

Small, fingerlike projections that increase the surface area for absorption and secretion.

Stereocilia

Long, immobile microvilli that increase surface area of certain epithelia.

Cilia / Ciliated epithelium

Hairlike, motile processes that move substances across the epithelial surface.

Basal lamina

Basement membrane between epithelium and connective tissue; includes lamina lucida and lamina densa.

Lamina lucida

Part of the basal lamina closest to the epithelium.

Lamina densa

Thicker layer of basal lamina adjacent to connective tissue.

Intercellular connections

Connections between epithelial cells (e.g., tight junctions, desmosomes, gap junctions) that help maintain integrity.

Epithelial maintenance and renewal

Self-perpetuated turnover and renewal of epithelial tissues.

Simple epithelium

Epithelium with a single layer of cells.

Stratified epithelium

Epithelium with several cell layers.

Squamous epithelium

Thin, flat cells forming the outermost layer.

Cuboidal epithelium

Epithelial cells with height approximately equal to width.

Transitional epithelium

Epithelium that can change shape, typically found in the urinary bladder.

Columnar epithelium

Tall, column-like epithelial cells; height usually 3–4 times their width.

Glandular epithelia

Epithelium that forms secretory glands.

Serous glands

Glands that secrete watery fluids rich in enzymes.

Mucous glands

Glands that secrete mucins (glycoproteins) that form mucus when hydrated.

Mixed exocrine glands

Glands containing cells capable of both serous and mucous secretions, secreting both.

Areolar tissue

Loose connective tissue that cushions, supports, and defends; located deep to the dermis and around organs.

Adipose tissue

Fat tissue that cushions, insulates, and stores energy.

Reticular tissue

Connective tissue providing a supporting framework in organs like the liver, spleen, and lymph nodes.

Dense regular connective tissue

Fibrous tissue with tightly packed collagen fibers, forming tendons and ligaments; provides firm attachment and reduces friction.

Elastic tissue

Dense connective tissue rich in elastic fibers; stabilizes and allows stretch in structures like ligaments.

Dense irregular connective tissue

Collagen-rich connective tissue that resists forces from multiple directions; forms the dermis and organ capsules.

Collagen fibers

Strong, long fibers that provide tensile strength in connective tissue.

Reticular fibers

Part of the extracellular matrix composed of collagen proteins forming a supportive network.

Elastic fibers

Fibers made of elastin that allow tissues to resume shape after stretching.

Blood

A fluid connective tissue with a plasma matrix and formed elements (red and white blood cells, platelets).

Lymph

Fluid connective tissue formed when interstitial fluid is collected into lymphatic vessels and returned to the blood.

Hyaline cartilage

Cartilage type with glassy matrix; provides firm but flexible support in joints, the respiratory tract, and nasal region.

Elastic cartilage

Cartilage containing elastic fibers; tolerates distortion and returns to original shape.

Fibrous cartilage

Cartilage with dense collagen fibers; resists compression and limits movement in joints like the intervertebral discs.

Bone

Supporting connective tissue with a mineralized matrix; provides structural support and houses the bone marrow.

Ground substance

The noncellular, gel-like material in the extracellular matrix of connective tissue.

Matrix (extracellular matrix)

All extracellular components of connective tissue, including fibers and ground substance.

Fibroblasts

Fixed cells in connective tissue that synthesize fibers and matrix.

Fibrocytes

Dormant or mature fibroblasts maintaining connective tissue fibers and matrix.

Mesenchyme

Embryonic connective tissue; source of all connective tissues.

Chondroblasts

Cells that produce cartilage matrix; later become chondrocytes.

Chondrocytes

Cartilage cells embedded in lacunae within the matrix.

Osteoblasts

Bone-forming cells that lay down the bone matrix; can become osteocytes.

Osteocytes

Mature bone cells embedded in bone matrix.

Mucous membrane

Wet membranes with a connection to the exterior, lining many tracts.

Serous membrane

Membrane lining the ventral body cavities; produces serous fluid.

Cutaneous membrane

Thick, dry, water-resistant skin (integument).

Synovial membrane

Membrane producing synovial fluid within joint cavities; made of areolar tissue with sparse epithelium.

Superficial fascia

Areolar and adipose tissue between skin and underlying organs; also called the subcutaneous layer or hypodermis.

Deep fascia

Dense connective tissue layer providing a strong internal framework and binding to capsules, tendons, and ligaments.

Skeletal muscle tissue

Muscle tissue composed of long muscle fibers (skeletal muscles) responsible for voluntary movement.

Cardiac muscle tissue

Muscle tissue of the heart; involuntary, striated with intercalated discs.

Smooth muscle tissue

Involuntary muscle tissue with spindle-shaped cells; lines hollow organs and vessels.

Neural tissue

Tissue specialized to conduct electrical signals; includes neurons and neuroglia.

Neuron

Nerve cell that transmits electrical impulses.

Neuroglia

Supporting cells of the nervous system that support, protect, and nourish neurons.

Fertilization

Union of sperm and egg forming a zygote with a full set of chromosomes.

Zygote

A single cell formed by fertilization containing the complete set of chromosomes.

Blastocyst

A hollow ball of cells formed during early embryogenesis; contains an outer trophoblast and inner cell mass.

Inner cell mass

Mass of cells inside the blastocyst that will form the embryo.

Trophoblast

Outer cell layer of the blastocyst that will contribute to the placenta.

Cleavage

Series of rapid cell divisions forming a hollow blastocyst following fertilization.

Germ layers

Three primary cell layers formed in the early embryo: ectoderm, mesoderm, and endoderm.

Ectoderm

Germ layer that forms the epidermis, nervous system, and related structures.

Mesoderm

Germ layer that forms the dermis, muscles, skeleton, circulatory system, and more.

Endoderm

Germ layer that forms the lining of the digestive and respiratory tracts and related glands.

Exocrine gland

Gland that secretes onto an epithelial surface via a duct.

Endocrine gland

Gland that secretes hormones directly into the bloodstream or surrounding tissues without a duct.

Duct

A channel that carries secretions from secretory cells to the epithelial surface in exocrine glands.

Mesenchyme

Embryonic connective tissue from which all connective tissues arise.

Embryonic connective tissue

Early connective tissue in the embryo that differentiates into mature connective tissues.