Tissues - Histology Study Guide

Comprehensive practice flashcards reviewing epithelial, connective, muscle, and nervous tissues based on lecture material.

What are the four primary types of tissue in the human body?

Epithelial, Connective, Muscle, and Nervous tissue.

What are the primary functions of each of the four main tissue types?

1. Epithelial: covers, lines, and facilitates absorption or secretion.
2. Connective: supports epithelium and binds it to underlying tissues.
3. Muscle: facilitates movements.
4. Nervous: facilitates response to stimuli.

What are the key characteristics of epithelial tissues?

They cover body surfaces and line internal organs; cells are tightly packed together with no space for blood vessels (avascular); they readily divide; and they exhibit polarity.

How is cellular polarity defined in epithelial tissues?

The apical surface is closest to the lumen or cavity, whereas the basal surface is near the basement membrane.

What is the basement membrane and what is its role?

It is a thin, fibrous, noncellular region that anchors epithelium to underlying connective tissue and serves as a mechanical barrier.

How are epithelial tissues classified based on cell shape (morphology)?

1. Squamous: flat, spindle-like cells.
2. Cuboidal: as tall as they are wide.
3. Columnar: taller than they are wide.

How are epithelial tissues classified based on layer arrangement?

1. Simple: single layer of cells.
2. Stratified: multiple layers of cells.
3. Pseudostratified: single layer attached to the basement membrane, but not all cells reach the surface.
4. Transitional: layers of cuboidal cells capable of stretching to become squamous in shape.

What are the characteristics, functions, and example locations of simple squamous epithelium?

Characteristics: Single layer of flattened cells (simplest form). Functions: Allows passage of materials by diffusion, filtration, and produces lubricating fluid in serosae. Examples: Air sacs of lungs, kidney glomeruli, lining of heart and blood vessels (endothelium), lymphatic vessels, and lining of ventral body cavity (serosae).

What are the characteristics, functions, and example locations of simple cuboidal epithelium?

Characteristics: Single layer of cube-like cells. Functions: Secretion and absorption. Examples: Typically found in glandular tissues, kidney tubules, ducts and secretory portions of small glands, and ovary surface.

What are the characteristics, functions, and example locations of simple columnar epithelium?

Characteristics: Single layer of tall cells; some cells bear cilia; layer may contain mucus-secreting goblet cells. Functions: Absorption, secretion of mucus and enzymes; cilia propel mucus (or reproductive cells) by ciliary action. Examples: Non-ciliated types line most of the digestive tract (stomach to rectum) and gallbladder; ciliated types line small bronchi, uterine tubes, and uterus.

What are the characteristics, functions, and example locations of pseudostratified columnar epithelium?

Characteristics: Single layer of cells of differing heights seen at different levels; may contain goblet cells and bear cilia. Functions: Secretion of mucus; propulsion of mucus by ciliary action. Examples: Non-ciliated types in male's spermatic ducts and ducts of large glands; ciliated types line the trachea and most of the upper respiratory tract.

What are the characteristics, functions, and example locations of stratified squamous epithelium?

Characteristics: Thick, composed of several cell layers; basal cells are cuboidal/mitotically active and surface cells are flattened. Functions: Protects underlying tissues in areas subjected to abrasion. Examples: Non-keratinized type forms moist linings of esophagus, mouth, and vagina; keratinized type forms the epidermis of the skin.

What are the characteristics, functions, and example locations of stratified cuboidal epithelium?

Characteristics: Generally composed of two layers of cube-like cells. Functions: Protection. Examples: Forms large excretory ducts of sweat glands, mammary glands, and salivary glands.

What are the characteristics, functions, and example locations of stratified columnar epithelium?

Characteristics: Several cell layers; basal cells are usually cuboidal; superficial cells are elongated and columnar. Functions: Protection and secretion. Examples: Relatively rare; small amounts in male urethra and in large ducts of some glands like salivary glands.

What are the characteristics, functions, and example locations of transitional epithelium?

Characteristics: Resembles both stratified squamous and stratified cuboidal; basal cells are more cuboidal while surface cells change shape depending on organ stretch. Functions: Stretches readily and permits distension of urinary organ by contained urine. Examples: Lining the ureters, bladder, and part of the urethra.

What are cilia, and where are they located?

Cilia are motile, hair-like cylindrical projections located in the respiratory tract and reproductive tract. In respiratory epithelium, they function to expel mucus with trapped microorganisms.

What is the function of goblet cells, and where are they found?

Goblet cells produce mucus and are found in the respiratory epithelium and gastrointestinal tract (GIT).

What are microvilli, and what is their functional importance?

Microvilli are non-motile, thin, short folds of the cell membrane at the apical surface. They increase surface area for absorption of substances and are found at sites of absorption and secretion, such as the GIT.

What are stereocilia, and where are they found in the body?

Stereocilia are non-motile, long, tapering projections bundled like hair. They are found in the male reproductive tract (epididymis and vas deferens), where they reabsorb fluid needed for sperm movement, as well as in the inner ear.

What are the key structural features and control mechanism of skeletal muscle tissue?

Skeletal muscle consists of long, cylindrical, multinucleate, striated cells (muscle fibers) packaged by connective tissue. It is under voluntary control and attached to the skeleton.

What are intercalated discs, and which muscle tissue contains them?

Intercalated discs are junctional structures in cardiac muscle tissue containing gap junctions that allow rapid conduction of electrical impulses for a functional syncytium.

What are the characteristics and functions of smooth muscle tissue?

Smooth muscle cells are spindle-shaped, single-nucleus, and non-striated under involuntary control. Found in walls of hollow organs (stomach, uterus, blood vessels), they contract slowly to change cavity size and propel substances (e.g., peristalsis).

What are the main functions and functional features of neurons?

Neurons receive and conduct electrochemical impulses over long distances. Their key functional properties are irritability and conductivity, enabled by long cytoplasmic extensions.

What are neuroglia, and what are their primary functions?

Neuroglia are specialized supporting cells in the nervous system (brain, spinal cord, and nerves) that insulate, support, and protect neurons.