Tissues & Integumentary System – Vocabulary Review

A comprehensive set of vocabulary flashcards covering key terms related to tissues, glands, connective tissue, muscle, nervous tissue, and the integumentary system for exam review.

Tissue

Group of similar cells working together to perform specialized functions.

Intracellular

Environment located inside the cell membrane.

Extracellular

Environment outside the cell membrane surrounding cells.

Extracellular Matrix (ECM)

Cells secrete substances to help regulate their extracellular material and fluids. Network of proteins, molecules, and fluid that surrounds and supports them.

Histology

Microscopic study of tissues and their extracellular matrix.

Epithelial Tissue

Covers surfaces, lines cavities, forms glands; avascular with one free (apical) surface. EX: skin surface (epidermis)

Connective Tissue

Supports, binds, protects, insulates, transports; characterized by abundant ECM and variable vascularity. EX: cartilage, bones, tendons, fat, soft padding

Muscle Tissue

Tissue specialized to contract and produce movement; irritable and contractile. EX: attached to bones, heart wall, walls of hollow organs

Nervous Tissue

Carries electrical impulses and translates to control body activities; irritable and conductive. EX: brain, spinal cords, nerves

• Highly unique cellular structure and function 

• Allows for the propagation of electrical impulses 

• Variety of sizes and shapes 

Apical Surface

Free surface of an epithelial cell facing a lumen or external environment. Allows the cells to secrete or absorb materials from the lumen

Basal Surface

Surface of an epithelia attached to the basement membrane.

Basement Membrane (Basal Lamina)

Non-cellular protein-rich layer—allowing cells to anchor to it for support. Separates epithelium from other tissue

Polarity (Epithelium)

cells have unique surfaces, each with specialized features

Avascular (Epithelium)

No direct blood supply/lacks blood vessels; nutrients/wastes diffuse from underlying tissues. Innervated.

Regeneration (Epithelium)

High mitotic rate; stem cells near basal surface replace lost cells quickly.

Hyaluronan (hyaluronic acid)

Type of polysaccharides derivative that helps lock epithelial cells together called intercellular cement 

Cell Junction

Lateral surfaces are connected between adjoining cells with specialized intercellular connections with unique proteins 

Gap Junction

Unique cellular structures that permit the free diffusion of ions and small molecules between cells 

Tight Junction (occluding junctions)

Serve as an impermeable barrier; don’t allow solutes and fluid to diffuse between the cells in these locations. Located at the most apical point between adjoining cells; formed when plasma membrane of 2 outer layers of the cells fuses together.

Adhesion Belt

Forms deep tight junctions, forming a continuous bandlike structure between cells. Belt is then tied into the microfilaments that make up the terminal web 

Terminal Web

Found in the apical zone of epithelial cells, at the base of the microvilli, running across the entire width of the cell 

Spot Desmosome

Found throughout the lateral surfaces of epithelial cells; Help tie adjacent cells together; Allow for an anchoring port for intermediate filaments, allowing for direct cel-to-cell contact; Provide a very strong attachment between the cells, like welding, using cell adhesion molecules (CAMs)

Hemidesmosome

Anchor the intermediate filaments of a cell to the extracellular matrix. EX: this can anchor the cell to the protein fibers found in the basement membrane. 

Simple Epithelium

Single layer of cells

Stratified Epithelium

Multiple cell layers

Squamous Cell

when the cells are wider than the height

Cuboidal Cell

Cube-shaped cell with equal height, width, depth.

Columnar Cell

when the height of the cells is greater than width

Simple Squamous Epithelium

One layer of flat cells; enables diffusion/filtration; Allows for materials to be exchanged via diffusion through cells. Can act as a thin barrier or allow for lubrication to help reduce friction between two structures  EX: alveoli in lung, blood vessels, found in places like the vascular system, respiratory spaces in lungs, and lining body cavities.

Endothelium

lining of the blood and lymphatic vessels

Endocardium

lining of the ventricles and atria of the heart

Mesothelium

the walls and closed cavities of the body; Abdominal, pericardial, and pleural cavities  

Stratified Squamous Epithelium

Multilayered flat cells; keratinized and non-keratinized; protects against abrasion, pathogens, and external chemicals; EX: skin, mouth, esophagus.

Keratinized Epithelium

Stratified squamous cells with keratin; tough, water-resistant; skin surface.

Nonkeratinized Epithelium

Stratified squamous without keratin; moist surfaces like oral cavity, vagina.

Simple Cuboidal Epithelium

Single layer; absorption/secretion; EX: kidney tubules, glands.

Exocrine Glands

Secrete a substance through a duct onto an epithelium rather than into the bloodstream 

Stratified Cuboidal Epithelium

Multiple layers; absorption and secretion: EX: sweat & mammary gland ducts.

Simple Columnar Epithelium

One layer of tall cells; absorption/secretion; EX: stomach, intestines, uterine tubes.

Stratified Columnar Epithelium

more than one layer with columnar apical cells; protection; EX: secretion of mucus and movement of fluids and debris

Pseudostratified Epithelium

Single layer with staggered nuclei—appears stratified but is not; Secretion of mucus and movement of fluids and debris—often ciliated; EX: trachea nasal cavities.

Transitional Epithelium

Stratified epithelium that stretches; round apical cells; EX: urinary tract only.

Glandular Epithelium

Epithelial cells specialized to secrete substances.

Endocrine Gland

Ductless gland releasing products (hormones) into bloodstream and connective tissue.

Paracrine Secretion

Secrete their products that do not reach the bloodstream. Only affects other cells nearby 

Merocrine Secretion

Products released by exocytosis; salivary & eccrine sweat glands.

• When a product is delivered via membrane bound vesicles to the apical surface 

• Vesicle fuses with the plasma membrane 

• Release of contents via exocytosis 

• Pancreas, sweat, and salivary glands 

Apocrine Secretion

Apical surface and cytoplasm of cell is secreted and then cell regenerates lost component 

When a product is released from the apical side of the cell 

• Apical portion of the cell is lost, including the cytoplasm, within an envelope of plasma membrane 

• Gland must regrow and repair itself 

• Mammary glands—releasing large amounts of lipids into the mild  

  —Milk production 

Holocrine Secretion

Whole cell ruptures to release product; sebaceous glands.

• When a product accumulated within the maturing cell 

• Entire cell is lost at programmed time—apoptosis  

• The superficial cells will undergo apoptosis as the underlying cells are maturing  

• Entire cellular contents along with secretions are released into the lumen 

• Sebaceous glands (sweat glands) 

Unicellular Gland

Simplest structure; Single secretory cell among other non-secretory, e.g., goblet cell producing mucus.

Goblet Cell

Found in ciliated columnar epithelium cells; Disperse throughout to provide mucous layer of protection, trapping bacteria; Provides a protective layer in the digestive tract  

Multicellular

• Typically form a tube-like formation from the surface 

• Ends in the secretory portion, other portion serves as the duct 

• Classification on duct structure 

• Simple = if duct is unbranched 

• Compound = if duct is branched  

Simple Tubular Gland

Unbranched duct with tube-shaped secretory portion. EX: intestinal glands

Simple Coiled Tubular Gland

Unbranched duct with coiled tube secretory region. EX: merocrine sweat glands

Simple Branched Tubular Gland

One duct with multiple tubular secretory branches. EX: gastric glands, mucous glands of esophagus, tongue, duodenum

Simple Alveolar (Acinar) Gland

Unbranched duct with outpouching secretory region. EX: not found in adult

Simple branched alveolar

branches of multiple acinar-shaped secretory portions

Compound Tubular Gland

more than one branch with tube-like secretory portions

Compound Alveolar (acinar) Gland

more than one branch with outpouching of secretory portions

Compound Tubulo-Alveolar Gland

more than one branch with a combination of tubelike and alveolar-type secretory portions.

Ground Substance

Fills space between connective tissue cells; contains fibers

• Clear and colorless 

• Viscous (syrupy) due to presence of proteoglycans and glycoproteins 

• Liquid (plasma) 

• Rubbery, semi-stiff (cartilage) 

• Solid, mineral-like substance (bone) 

Collagen Fiber

• White, Straight, no branching 

• Strongest and most abundant type 

• Provides high tensile strength 

Elastic Fiber

• Networks of long, thin, elastin fibers 

• Allows for stretch 

Reticular Fiber

• Short, fine, highly branched collagenous fibers 

• Provides support with strength to hold structures in place 

blasts

mitotically active and secretory cells

Fibroblast

• Mitotically active 

• Always present 

• Function to secrete hyaluronan (hyaluronic acid) and proteins 

• Helps to lock cells together 

• Secrete protein components that come together in the matrix to form extracellular fibers 

Macrophage

• Large cells throughout the matrix 

• Phagocytize (ingest)/ destroy pathogens or damaged cells 

• Release chemical messengers to help activate the immune system 

Adipocyte

• Adipose cells (fat cells) 

• Ring-shaped due to a large lipid droplet in the center 

• Pushes nucleus and other organelles off to the side 

• Number of fat cells dependent upon region of the body and differs per person  

Mesenchymal Cell

• First type of connective tissue to develop in the embryo 

• Adults do not have this connective tissue 

• Mesenchymal stem cells remain present  

• Assist with tissue repair after injury 

• Can divide; daughter cells turn into fibroblast, macrophages or other types of connective tissues 

Mast Cell

• Small cells 

• Move around, tend to reside near blood vessels 

• Release histamine and heparin after an injury 

• Chemicals help stimulate local inflammatory response 

• Brings other cells to the area 

Neutrophil and Eosinphils

• Phagocytic cells 

• Move through connective tissue 

• Attracted by histamine and heparin  

• Respond to help fight infection, ingest pathogens, and damaged cells

Lymphocyte

• Travel though connective tissues and entire body 

• Migrate to an area when there is an injury o tissue damage 

• Cell count increases as needed 

• Plasma cells - (effector B cells) 

• Produce antibodies = proteins that help the body fight pathogens 

Melanocyte

• Present in the epithelium in the skin 

• Store pigment melanin 

• Determines skin color pigmentation 

Areolar Tissue

• Most common connective tissue proper 

• Function: Packing material of the body (wraps and cushions) 

• Location: Deep to the dermis of the skin, between muscles, around joints 

• Separates- allows for independent movement  

Adipose Tissue

• Functions as energy reserve, padding, cushions, and insulates  

• Location: Deep to skin in various areas of body 

• Mostly cells (adipocytes) 

Reticular Tissue

• Many reticular fibers forming network (stroma) 

• Function: Provides support and resists distortion 

• Location: “soft organs” 

• Liver kidney, spleen, lymph nodes, and bone marrow 

Dense Regular Connective Tissue

Parallel collagen fibers; tensile strength in one direction;

• Tendons—connect muscle to bone 

• Ligaments—connect bone to bone (or stabilize internal organs) 

• Aponeuroses—flat sheet (like a tendon) attach a larger flat muscle to another muscle  

Dense Irregular Connective Tissue

withstand tensile stress in any direction; no consistant pattern of fiber arrangement

• forms a capsule

  • Thick, fibrous layer surrounding organs like the kidneys and liver 

  • Also formed from dense irregular tissue around the joint cavities 

• Location

  • Covering visceral organs 

  • Superficial layers of bones 

  • Cartilage 

  • Peripheral nerves  

  • Dermis  

Elastic Connective Tissue

Recoil after stretch; more elastic fibers than collagen, making it springy and resiliant

location: Between vertebrae, walls of large blood vessels, erectile tissues of penis 

Blood

Fluid connective tissue of plasma; contained within the vessels of the cardiovascular system, circulated by the heart; contains plasma and formed elements (RBCs, WBCs, Platelets)

Erythrocyte

Red blood cell transporting oxygen and carbon dioxide.

Leukocyte

White blood cell defending against infection and disease.

Found in smaller numbers, many different types: 

• Monocytes 

• Neutrophils 

• Basophils 

• Lymphocytes  

Macrophages

• Large phagocytic cells called monocytes in the blood 

• Important parts of the immune system that help the body fight off infection and disease and engulf pathogens or damaged cells  

Microphages

• Small phagocytic cells (eosinophils and neutrophils) that are attracted by signals from macrophages and mast cells.  

• Help to phagocytize pathogens in the blood.  

Platelet (Thrombocyte)

Cell fragment aiding blood clotting cascade. “tiny packets”—membrane bound cytoplasm

Lymph

Fluid CT formed from interstitial fluid entering lymphatic vessels.

Interstitial Fluid

• Fluid that surrounds the cells, released in the capillaries of the cardiovascular system 

• Fluid that is not returned to the heart by the veins of the cardiovascular system enters lymphatic vessels and is then called lymph 

Cartilage

made of chondrocytes; contains lacunae; ECM= firm gel; avascular; antiangiogenesis factor:

• blood vessels cannot grow because chondrocytes produce a chemical antiangiogenesis factor

Perichondrium

surrounds the cartilage, separating it from other tissues

Chondrocyte

Mature cartilage cell occupying a lacuna.

Perichondrium

CT membrane surrounding cartilage providing nutrients and support.

Hyaline Cartilage

• Most common type 

• Matrix—collagen fibers close together, surrounded by dense pericardium 

• Stiff and somewhat flexible 

• Major function: articular cartilage  

• Covers ends of bones articulating at a joint 

• Reduces friction 

• Knee, elbow, shoulder 

Elastic Cartilage

• High number of elastic fibers 

• Highly flexible  

• provides support, easily returns to original shape 

• Location: 

• Outer ear, epiglottis 

Fibrocartilage

• More durable  

• Matrix: interwoven collagen fibers 

• Resists and absorbs shock 

• Prevents bone-to-bone contact 

• Location: 

• Between spinal vertebrae 

• In between pubic bones 

Antiangiogenesis Factor

Chemical from chondrocytes preventing blood vessel growth in cartilage.

Regenerative Capacity: Cartilage

• Cartilage growth occurs during development 

• Does not undergo regular growth in adult 

• Minor damage  

• May be repaired in the surface 

• Major damage 

• Tissue will be replaced with a thick fibrous patch rather than cartilage  

• Leaves cartilage permanently damaged  

Bone (Osseous Tissue)

Matrix: mostly calcium phosphate, calcium carbonate with some collagen fibers

• calcium

  • brittle by itself, flexible with collagen

Osteocyte

Mature bone cell in a lacuna maintaining bone matrix.

Lacuna

Organized to surround blood vessels, branch through the matrix 

Canaliculi

• Small passageways in the bone matrix 

• Allow osteocytes to communicate with each other and blood vessels  

Periosteum

• Covers bone surfaces 

• Tough fibrous outer layer, inner cellular layer 

• Helps anchor the bone to the surrounding tissues