Epithelia Flashcards
Where is simple squamous epithelium located?
Lining the blood and lymph vessels (endothelium) and lining the body cavities including the pericardium, pleura and peritoneum (mesothelioma)
What is epithelia?
Sheets of cells that over external surfaces of the body and line the internal surfaces.
What is simple epithelia?
One cell thick layer attached to the basement membrane.
What is the basement membrane?
Thin, flexible layer between the epithelial cells and the connective tissue.
What is stratified epithelia?
More than one cell thick layer attached to the basement membrane.
What are the 4 layers of the Epidermis?
Horny Layer (stratum cornermen), granular layer, prickle cell layer and the basal layer.
What are keratinocytes and where are they found?
Synthesise keratin which gives the cells strength. They are produced in the basal layer but migrate up through the prickle layer.
What type of epithelia is the epidermis made up of?
Stratified squamous
What types of cells are in the epidermis?
Keratinocytes, melanocytes and langerhan cells
What are melanocytes and where are they found?
They are dendritic cells that produce melanin. They are found in the basal layer of the epidermis
What are Langerhan cells and where are they found?
They are dendritic cells which present antigens to T Lymphocytes and mediate immune reactions. They are found in the prickle layer of the epidermis.
What are the functions of the epidermis
Protect from abrasion, trauma and water loss. Shield from UV damage.
What is transitional epithelium?
Epithelium which can stretch to give a cuboidal shape and relax to have a columnar shape.
Where are transitional epithelia located?
Urethra, bladder and ureter
What is Pseudostratified epithelia?
Where all the cells are attached to the basement membrane despite it looking as if there are several layers of cells. Therefore, some cells reach the lumen but others don’t.
What are squamous cells?
Thin, flat cells
What is the name of the simple squamous epithelium linking the cardiovascular system to the blood?
Endothelium
What is the name of the simple squamous epithelium lining the pleural membrane, pericardial sac and the peritoneum?
Mesothelium
Where is simple columnar epithelium located? (5)
Stomach lining, gastric glands, small intestine, colon and gall bladder.
Where is Pseudostratified epithelium located?
Lining he nasal cavity, trachea and bronchi
What are the 2 layers of the epidermis?
Dead, keratinised layer and a layer of living epidermal cells
What is the dermis made of?
Connective tissue
Where are mucous membranes found?
Lining internal tubes that open to the exterior (Alimentary tract, Respiratory tract and urinary tract)
What do mucus membranes consist of?
A lining of epithelium cells over a layer of loose connective tissue called the lamina propria. (In the alimentary tract there is also a layer of smooth muscle)
What are often present in the lamina propria?
Aggregations of lymphocytes (Peyer’s Patches)
What are serous membranes?
Thin, two part membranes which line closed body cavities.
What does a serous membrane consist of?
The inner layer that covers organs (viscera) in body cavities is called the visceral membrane; this inner layer of epithelial cells is followed by a connective tissue; after the connective tissue is the second layer of epithelial cells of the serous membrane called the parietal layer.
What do the serous membranes do?
They secrete a lubricating fluid which allows for a friction free movement of the organs and structures they surround
What is the serous membrane surrounding many abdominal organs called?
The peritoneum
What is the serous membrane surround the heart called?
The pericardial sac
What is the serous membrane surrounding the lungs called?
Pleural sacs
What type of epithelium are the layers of serous membrane?
Simple squamous epithelium (mesothelium)
