Histology and Tissue Types: Cell Junctions, Membranes, and Body Cavities

Histology

the study of tissues.

Intracellular

All fluid within the cells.

Interstitial fluid

All fluid between the cells.

Extracellular fluid

All fluid outside of cells.

Cell junctions

Hold cells together to form tissue + point of contact between plasma membranes of cells.

Epithelial tissue

Covers body surfaces, lines hollow organs, body cavities + ducts, forms glands, allows the body to interact with internal + external environments.

Connective tissue

Protects + supports the body + organs, vascular tissue that distributes all blood vessels.

Muscular tissue

Composed of fibers (cells) specialized for contraction of force, generates heat that warms the body.

Nervous tissue

Detects changes in a variety of conditions, generates electrical signals that activate muscular contractions.

Mucous membranes

Forms mucous, little or no interstitial fluid or matrix, no blood vessels.

Serous membranes

Divided into visceral and parietal membranes.

Synovial membranes

Line synovial joint capsules, connective tissue membranes.

Peritoneum

Serous, located in the abdominopelvic cavity.

Pleura

Serous membranes that surround the lungs.

Pneumothorax

Air in the pleural cavity.

Pleural effusion

Fluid in the pleural cavity.

Pleurisy

Inflammation of the serous membranes that line the chest cavity.

Peritonitis

Inflammation of the serous membranes in the abdominal cavity.

Quadrants and Regions of Abdominopelvic Cavity

Anatomical divisions used to describe locations within the abdominopelvic cavity.

Tight junctions

Prevent leakage of organ contents into extracellular fluid or blood and prevents the passage of substances between cells.

Adhering junctions

Fasten cells to each other and help epithelial surfaces resist separation.

Desmosomes

Prevents epidermal cells from separating under tension and cardiac muscle cells from pulling apart during contraction.

Hemidesmosomes

Strongly anchor cells to an underlying basement membrane and help anchor epithelial cells to the basement membrane.

Gap junctions

Facilitate rapid signal communications between adjacent cells.

Thoracic cavity

Contains pericardial cavities, pleural cavities, and the mediastinum.

Abdominopelvic cavity

Subdivided into abdominal and pelvic cavities.

Simple squamous epithelium

One cell thick, allows for easy transport of nutrients and waste.

Mediastinum

Mid portion of thoracic cavity; contains heart and trachea.

Simple cuboidal epithelium

Found in glands and ducts, involved in secretion and absorption.

Simple columnar epithelium

Has more surface area for absorption of nutrients; can be nonciliated.

Loose fibrous tissue (Areolar)

Fibers arranged randomly in a web-like, airy structure to hold organs in place and attach epithelial tissue to underlying tissue. Provides strength, elasticity and support

Adipose tissue

A type of connective tissue that stores fat.

Dense fibrous tissue

A type of connective tissue that provides strength and support.

Muscle Tissue

Enables movement.

Skeletal muscle

Attaches to bones and is under voluntary control. Striated

Smooth muscle

Involuntary muscle found in walls of hollow organs. Non-striated.

Liquid connective tissue

Includes blood and lymph.

Visceral

Closely packed cells with no blood vessels and involuntary movement.

Cardiac muscle

Striated muscle found in the heart. Involuntary

Ciliated simple columnar epithelium

Creates motion to move substances across the surface.

Stratified transitional epithelium

Stretchy tissue that can change shape.

Neurons

Cells that carry nerve impulses; consists of a cell body, axon, and dendrites.

Axon

Carries impulse away from the cell body.

Dendrites

Carry impulse toward the cell body.

Tissue repair

Begins regeneration that varies by tissue type.

Free-radical theory of aging

Suggests that aging results from damage caused by free radicals.

Epithelial tissues

Regenerate easily.

Smooth and cardiac muscle

Have limited regeneration capabilities.

Neoplasm

New growth, which can be benign or malignant.

Benign tumors

Localized growths that do not spread.

Malignant tumors

Growths that spread to other parts of the body.

Radiographic tissue appearances

Tissue density and thickness affect visualization.

Dense regular connective tissue

Includes tendons and ligaments.

Dense irregular connective tissue

Includes pericardium and heart valves.

Elastic connective tissue

Found in arteries, lung tissue, and trachea.

Hyaline cartilage

Found in the trachea and nose.

Fibrous cartilage

Found in intervertebral discs.

Compact bone

Forms the dense outer layer of bones.

Smooth muscle tissue

Found in tube-shaped organs and is non-striated.

Cardiac muscle tissue

Striated muscle found in the heart.