Histology Practical Flashcards
Organ
Structures composed of 2 or more different types of tissue that work together to perform particular functions.
Tissue
Groups of cells that have the same structural characteristics and perform the same functions
Organ system
Composed of various organs
Fixation
Tissue is immersed in the preservative solution to maintain the tissue’s existing structure
Embedding
Water is removed with alcohol, and the tissue is impregnated with paraffin wax
Sectioning
Tissue is cut into extremely thin slices by a microtome. When the section runs the length of the tissue it is called a longitudinal section; when the section runs across the tissue it is called a cross section
Staining
The tissue is immersed in dyes that stain different structures
Simple
Only one layer of cells
Stratified
Cell layers are placed on top of each other
Pseudostratified
They only appear to be layered
Microvilli
Hair-like extensions called cilia
Basement membrane
Consist of glycoproteins and collagen fibers, joins and epithelium to underlying connective tissue
Epithelial tissue
Forms a continuous layer, or sheet, over the entire body surface and most of the body’s inner cavities. It protects the body from infection, injury, and drying out. Some epithelial tissues produce and release secretions. Others absorb nutrients. Epith. Tissues are attached to underlying tissues by a basement membrane composed of extracellular material containing protein fibers. Consist of four types: simple squamous, pseudostratified Ciliated columnar, simple cubital, simple columnar.
Simple squamous Epith.
Single layer of thin, flat, pancake-shaped, many sided cells, each with a central nucleus. Connected to basement membrane.
Lines internal cavities, the heart, walls of capillaries, all blood vessels, parts of the urinary, respiratory (air sacs of lungs), and male reproductive tracts.
Function : filtration, diffusion, osmosis. Protects.
Stratified squamous Epith.
Consists of many layers of cells. Innermost layer produces cells that are first cubital or columnar in shape, but as the cells push toward the surface, the epidermis, they become flattened, accumulating keratin, a protein, and eventually die. Outermost layer of cells surrounding the cavity is simple squamous epith. In these organs, this layer of cells remains soft, moist, and alive.
Composes outer region of the skin, the epidermis, the lining of the mouth, throat, anal canal, vagina.
Function: protection, repel water
Simple cuboidal Epith.
Single layer of cube-shaped cells, each with a central nucleus. Lines the tubules of the kidneys and various glands, where it has a protective function, also occurs in the secretory portions of some glands. Protects, absorbs, secretes.
Location: surface of ovieries, lining of ducts and glands, lining of kidney tubules
Simple columnar Epith.
Single layer of tall, cylindrical cells, each with a nucleus near the base. Lines the digestive tract from the stomach to the anus, including the linings of the small intestine, oviducts, and uterus . Protects, secretes, and allows absorption of nutrients. Goblet cells.
Goblet cells
Mucus secreting cells. In living animals, the mucus is discharged into the gut cavity and protects the lining from digestive and enzymes.
Pseudostratified Ciliated columnar Epith.
Appears to be layered. But actually all cells touch the basement membrane. Many cilia are located on the free end of each cell. In males/females the cilia move sex cells along tubes. Trachea: cilia move mucus, debris, impurities, up toward the throat so that it can’t enter the lungs. Smoking destroys cilia, but they will grow back if smoking is discontinued. Goblet cells.
Lines respiratory passages.
Function: protection, secretion, movement of mucus and sex cells
Connective tissue
Joins different parts of the body together.
4 general classes: connective tissue proper, bone, cartilage, and blood
All consists of cells surrounded by a matrix that usually contains fibers (elastin fibers, collagenous fibers)
Elastic fibers
composed of a protein called elastin