Tissues and Cells Flashcards
What is histology?
The study of tissues and their function; cells, tissues and organs
What is the study of cells?
Cytology
What is the study of tissues?
Histology
What is the study of organs?
Organology
Which are the four basic types of tissues?
Epithelia, connective tissue, muscle and nervous tissue
What is a tissue?
Connections of similar cells and the intercellular substances around them
What is epithelia?
Continuous layers of cells with little intercellular space which line surfaces and form glands
Types of simple epithelium;
Squamous
Cuboidal
Columnar
Simple Squamous Epithelium
Very thin and flat. It forms the peritoneal lining and the inner lining of all vascular elements
Examples of simple squamous epithelium?
Mesothelium (small intestine)
Endothelium (artery, vein and nerve)
Lung alveoli
Bowman’s capsule (kidney)
Simple Cuboidal Epithelium
Lines small tubules and follicles. The cells are about equal in hight and width with a visible central nucleus.
Where can simple cuboidal epithelium found?
Lining the collecting tubules of kidneys and in some of the ducts in some exocrine glands.
Simple Columnar Epithelium
These cells are taller than they are wide and the height varies
Where are simple columnar cells found?
In organs adapted for absorption and secretion. Throughout the lining of the gut, uterine tubes, large ducts of the exocrine glands, small intestine and colon.
Cells in the duodenum
Simple columnar cells which are covering the villi
Striated cells
Simple columnar. They possess microvilli on their surface, found in the duodenum
Goblet cells
Simple columnar. They are adapted for mucous secretion, found in the duodenum and respiratory tract
Pseudo Stratified Columnar Epithelium
Contains columnar and basal cells and give the appearance that it is layered. All cells are attached to the basement membrane, but not all extend to the lumen.
Where are pseudo stratified columnar epithelia found?
Lining the upper respiratory tract (ciliated and with goblet cells), trachea, epididymis, testis, ductus deferens and portions of the urethra.
Stratified Squamous Epithelium
Thick epithelium found where protection is needed. In the skin, it is rounded with progressive flattening of the cells toward the free surface. There is also non keratinized stratified squamous epithelia.
Where are stratified squamous epithelia found
In the skin, linings of the oral cavity, esophagus, anal canal and vagina.
Stratified Cuboidal and Columnar Epithelium
Rare types, found lining large ducts
Where are stratified cuboidal and columnar epithelia found?
Pharynx (sublingual gland), palpebral conjunctiva and the urinary passages (urethra)
Transitional Epithelium
Unusual type of epithelium found in organs which undergo distention and therefore become thicker and thinner.
Where are transitional epithelia found?
Lining the urinary tract from the renal calyces through to a portion of the urethra and the urinary bladder (best example)
Microvilli
Increase the surface area and re for absorption, found in the duodenum
Cilia
Are whip like structures that beat and move substances along the surfaces of their cells, found the trachea.