Histology and Tissue Types Flashcards

Flashcards covering key vocabulary and concepts from the histology lecture notes.

Histology

The study of tissues, requiring microscopic examination of multiple cells.

Four Tissue Classes

Epithelium, Connective, Muscular, and Nervous tissue.

Organ

Composed of two or more tissues functioning together.

Epithelium Tissue Function

Covers body surfaces, lines internal organs/passageways; forms barriers, glands (secrete), surfaces for absorption.

Connective Tissue Function

Support, connect, protect organs; matrix is more abundant than cells; examples include cartilage, bone, tendons, ligaments, blood.

Nervous Tissue Function

Excitable cells that carry signals to and from the central nervous system (brain and spinal cord).

Muscle Tissue Function

Allows for movement; excitable cells responding to stimuli; types: skeletal, cardiac, smooth.

Tissue

Group of similar cells and their cell products.

Matrix

Extracellular space consisting of fibrous proteins and ground substance (goo).

Embryonic Tissue Layers

Ectoderm, endoderm, and mesoderm.

Ectoderm

Outermost layer that develops into epidermis and nervous system.

Endoderm

Inner lining that forms mucous membranes lining the gastrointestinal and respiratory tracts, and digestive glands.

Mesoderm

Middle layer that forms mesenchyme, including muscle, bone, and blood.

Apical Surface

The top of the cells, exposed to the outside or lining an internal passageway/organ.

Basement Membrane

Layer of collagen and adhesive proteins to which epithelial cells adhere.

Simple Epithelium

Single layer of cells named by cell shape (squamous, cuboidal, columnar).

Stratified Epithelium

More than one layer of cells, named by the shape of the cells at the top layer.

Simple Squamous Epithelium

Single layer of flattened cells allowing for easy diffusion (e.g., alveoli of lungs, kidney filters).

Simple Cuboidal Epithelium

Single layer of cube-shaped cells for absorption and secretion (e.g., glands, kidney tubules).

Simple Columnar Epithelium

Single row of tall cells, often with goblet cells (mucus) and microvilli, for absorption and mucus secretion (e.g., lining of stomach and intestines).

Pseudostratified Columnar Epithelium

Looks stratified but all cells contact the basement membrane; contains goblet cells and cilia; traps particles (e.g., respiratory epithelium).

Stratified Squamous Epithelium

Multiple cell layers, named for squamous surface cells; can be keratinized (dead cell layer) or nonkeratinized (live cells all the way up); abrasion resistant (e.g., epidermis, oral mucosa).

Transitional Epithelium

Stratified epithelium named for its function to stretch/expand and recoil (e.g., lining of the bladder).

Fibroblast

Connective tissue cell that produces collagen.

Collagen

Essential component of connective tissues, providing strength and resilience.

Adipocytes

Fat cells that store triglycerides.

Loose Connective Tissue

More ground substance and cells than fibers.

Dense Connective Tissue

More fibers than cells and ground substance.

Areolar Tissue

Loose connective tissue with all three fiber types (collagen, elastic, reticular) and various cell types; acts as packing material everywhere.

Reticular Tissue

Loose connective tissue with heavy reticular fibers; acts as a scaffold for blood-filled organs (e.g., spleen, lymph nodes).

Adipose Tissue

Loose connective tissue for fat storage, cushion, and heat production; filled with adipocytes.

Dense Regular Connective Tissue

Collagen fibers aligned in parallel bundles (tendons, ligaments).

Dense Irregular Connective Tissue

Collagen fibers orientated in random directions (underlying layers of skin).

Chondroblasts

Cartilage cells that produce the rubbery matrix.

Chondrocytes

Mature cartilage cells trapped in the matrix.

Hyaline Cartilage

Basic form of cartilage; in movable joints and fetal skeleton.

Elastic Cartilage

Hyaline cartilage with elastic fibers; highly flexible (external ear, epiglottis).

Fibrocartilage

Hyaline cartilage with abundant collagen fibers; strong (pubic symphysis, intervertebral discs).

Osteon

Structural unit of bone with a central canal for blood vessels and nerves.

Erythrocytes

Red blood cells that carry gases.

Leukocytes

White blood cells that protect the immune system.

Thrombocytes

Platelets that function in blood clotting

Neuron

Nervous tissue cells that transmit information throughout the body.

Glial cells

Nervous tissue cells that Support the function of the neuron.

Skeletal Muscle

Striated, voluntary muscle fibers with multiple nuclei.

Cardiac Muscle

Striated, involuntary muscle fibers with one nucleus and intercalated discs.

Smooth Muscle

Nonstriated, involuntary muscle fibers with one nucleus; found in internal organs.

Tight Junctions

Zipper-like junctions preventing passage between cells (GI and urinary tracts).

Desmosomes

Snap-like junctions holding cells physically together (cervix, heart, skin).

Gap Junctions

Pores allowing transport of signaling molecules and ions between cells (embryonic development, cardiac and smooth muscle).

Exocrine Glands

Connect to the surface with a duct (sweat, oil, mammary, digestive glands).

Endocrine Glands

Secrete hormones directly into the blood; doesn't connect to the surface with a duct.

Hyperplasia

Tissue growth due to increase in cell number (childhood growth).

Hypertrophy

Tissue growth due to enlargement of preexisting cells (body building).

Neoplasia

Abnormal tissue growth forming a mass or tumor.

Atrophy

Shrinkage due to loss of cell size or number.

Necrosis

Pathological cell death due to toxins, trauma, or infection.

Apoptosis

Programmed (healthy) cell death.