Video: Tissue Level of Organization - Vocabulary Flashcards

Vocabulary flashcards covering key terms from the video notes on tissue organization, tissue types, junctions, membranes, and glandular/ connective tissues.

Tissue

Group of similar cells with a common embryonic origin and function; histology is the study of tissues.

Histology

The study of tissues.

Epithelial Tissue

Tissue that covers surfaces because its cells are in contact, lines hollow organs and ducts, and forms glands when cells sink beneath the surface.

Connective Tissue

Tissue located between cells that supports and binds structures, stores energy as fat, and provides immunity.

Muscle Tissue

Tissue whose cells shorten in length to produce movement.

Nerve Tissue

Tissue consisting of neurons that conduct electrical signals and detect changes, responding with nerve impulses.

Germ Layer

One of the primary germ layers: endoderm, mesoderm, and ectoderm.

Endoderm

One of the primary germ layers.

Mesoderm

One of the primary germ layers.

Ectoderm

One of the primary germ layers.

Basal Lamina

Layer secreted by epithelial cells, containing collagen fibers; part of the basement membrane.

Reticular Lamina

Layer secreted by connective tissue cells containing reticular fibers; helps attach epithelium to connective tissue and guides development.

Basement Membrane

Composite structure of basal lamina and reticular lamina that anchors epithelium to connective tissue and guides cell migration.

Tight Junctions

Watertight seal between adjacent cells; membranes fused with a strip of proteins; common in GI and bladder epithelium.

Adherens Junctions

Holds epithelial cells together; plaque of proteins inside the membrane connected to microfilaments.

Desmosomes

Resist cellular separation; similar to adherens but with intermediate filaments; provide structural support (especially in cardiac muscle).

Hemidesmosomes

Attach cells to extracellular material and basement membrane; half a desmosome with transmembrane glycoproteins.

Gap Junctions

Tiny gaps bridged by connexon channels that allow ions and small molecules to pass for cell-to-cell communication.

Simple Squamous Epithelium

Single layer of flat cells; lines vessels and body cavities; thin layer facilitates diffusion and filtration.

Simple Cuboidal Epithelium

Single layer of cube-shaped cells; lines kidney tubules; functions in absorption and secretion.

Nonciliated Simple Columnar Epithelium

Single layer of rectangular cells with goblet cells and microvilli for mucus secretion and absorption.

Ciliated Simple Columnar Epithelium

Single layer of rectangular cells with cilia; goblet cells secrete mucus; cilia move mucus; found in respiratory tract and uterine tubes.

Pseudostratified Columnar Epithelium

Single layer of cells with nuclei at varying depths, giving a false multilayered appearance.

Stratified Squamous Epithelium

Multiple cell layers with flat surface cells; keratinized in skin, nonkeratinized in moist surfaces (mouth, vagina, etc.).

Stratified Cuboidal Epithelium

Multilayered epithelium with surface cuboidal cells; rare (e.g., sweat gland ducts and part of male urethra).

Stratified Columnar Epithelium

Multilayered epithelium with surface columnar cells; rare (very large ducts and part of male urethra).

Transitional Epithelium

Multilayered with cells varying in shape; lines hollow organs that stretch (urinary bladder).

Glandular Epithelium

Epithelium derived from cells that sank below the surface during development; forms glands.

Exocrine Glands

Glands that secrete onto free surfaces through ducts; can be unicellular or multicellular.

Endocrine Glands

Glands that secrete hormones directly into the bloodstream.

Merocrine Secretion

Most glands release products by exocytosis.

Apocrine Secretion

Secretions where part of the cell top pinches off (e.g., certain sweat glands and milk).

Holocrine Secretion

Whole cells die to release their products (e.g., sebaceous glands).

Ground Substance

Supports cells and fibers; determines matrix consistency; contains hyaluronic acid, chondroitin sulfate, and fibronectin.

Hyaluronic Acid

Thick, viscous component of ground substance.

Chondroitin Sulfate

Gel-like molecule in ground substance providing support.

Fibronectin

Adhesion protein that binds collagen fibers to ground substance.

Collagen Fibers

Tough, strong fibers; provide structural strength.

Elastin Fibers

Flexible fibers that stretch and return to shape; found in tissues like lungs and arteries.

Reticular Fibers

Thin, branched fibers forming supportive networks in organs.

Areolar Connective Tissue

Loose connective tissue with all three fiber types in a gelatinous ground substance.

Adipose Tissue

Fat storage tissue with peripheral nuclei; cushions and insulates; brown fat in infants generates heat.

Reticular Connective Tissue

Supportive framework of organs formed by reticular fibers.

Dense Regular Connective Tissue

Collagen fibers in parallel bundles with fibroblasts; forms tendons; white fibrous tissue.

Dense Irregular Connective Tissue

Dense collagen fibers arranged irregularly to resist tension from multiple directions; found in dermis and sclera.

Elastic Connective Tissue

Dense tissue with abundant elastic fibers; stretches and recoils (lungs, vocal cords, ligaments).

Hyaline Cartilage

Bluish, glassy cartilage; chondrocytes in lacunae; avascular; reduces friction in joints.

Fibrocartilage

Strongest type of cartilage; intervertebral discs; dense collagen fibers with chondrocytes in lacunae.

Elastic Cartilage

Cartilage with elastic fibers; maintains shape; found in ear, nose, and larynx.

Spongy Bone

Bone with trabeculae and red bone marrow; no osteons.

Compact Bone

Dense bone whose basic unit is the osteon (Haversian system); provides strength.

Osteon

Basic structural unit of compact bone, consisting of concentric lamellae around a central canal.

Lacuna

Small spaces housing osteocytes (bone) or chondrocytes (cartilage).

Canaliculi

Tiny channels connecting lacunae for cell-to-cell communication in bone.

Blood

Connective tissue with a liquid matrix (plasma) containing erythrocytes, leukocytes, and platelets; functions include clotting and transport.

Erythrocytes

Red blood cells that carry O2 and CO2.

Leukocytes

White blood cells involved in immune defense.

Platelets

Cell fragments essential for blood clotting.

Skeletal Muscle

Long cylindrical cells, multiple peripheral nuclei; striated; under voluntary control.

Cardiac Muscle

Branched cells with one nucleus; involuntary and striated; intercalated discs and desmosomes connect cells.

Smooth Muscle

Spindle-shaped cells with a single nucleus; lines hollow organs; involuntary and nonstriated.

Nerve Cell (Neuron)

Nerve cell that conducts impulses; has dendrites and an axon.

Dendrite

Branch of a neuron that receives signals toward the cell body.

Axon

Long neuron process that transmits signals away from the cell body.

Membranes

Epithelial layer on a connective tissue base; include mucous, serous, synovial, and cutaneous membranes.

Mucous Membranes

Membranes lining cavities that open to the outside; protect against microbes and secrete mucus to keep surfaces moist.

Serous Membranes

Simple squamous epithelium over loose connective tissue; secrete slippery fluid; line closed body cavities (parietal vs visceral layers in pleura, peritoneum, and pericardium).

Synovial Membranes

Membranes lining joint cavities; lack epithelial cells and secrete synovial fluid.

Cutaneous Membrane

Skin; consists of epidermis and dermis; protective barrier.

Pleura

Serous membrane lining the thoracic cavity and covering the lungs.

Peritoneum

Serous membrane lining the abdominal cavity and covering abdominal organs.

Pericardium

Serous membrane enclosing the heart.

Goblet Cells

Unicellular gland that secretes mucus to lubricate and protect mucous membranes.

What forms the Basement Membrane?

The basal lamina (secreted by epithelial cells) and the reticular lamina (secreted by connective tissue cells).

What are the main functions of Connective Tissue?

Supports and binds other tissues, stores energy as fat, and provides immunity.

How do Serous Membranes aid organ movement?

They secrete a slippery fluid between their parietal (lining cavity) and visceral (covering organ) layers, reducing friction as organs move.

What are the components of Blood tissue?

A liquid matrix called plasma, containing erythrocytes (red blood cells), leukocytes (white blood cells), and platelets.