Epithelial tissue Flashcards
The basement membrane separates the epithelium from the ____ ____
Underlying tissue
Adjoining epithelial cells form specialised intercellular connections between their cell membranes called a ____ ____
Cell junction
Describe the typical appearance and location of the nucleus of simple columnar epithelium
Elongated, located in the basal end of the cells
Keratinised epithelia are always ____
Stratified
True or false: all cells of pseudostratified epithelium are in contact with the basal lamina
True
What is the most common type of stratified epithelium in the body?
Stratified squamous epithelium
What are the two classifications of gland?
Endocrine and exocrine
All epithelial tissue is highly ____
Cellular
The secretions of endocrine glands are called ____
Hormones
Most glands consist of groups of ____ cells
Epithelial
What is ‘transitional’ epithelium?
A form of specialised stratified epithelium in which the shape of cells can vary
Endocrine hormones are released into the ____ ____
Interstitial fluid
Epithelial tissues can be grouped into how many major types?
Two
The mesothelium forms the surface layer of the serous membrane that lines ____ ____ and ____ ____
Body cavities; internal organs
The endothelium is a single layer of ____ cells
Squamous
Exocrine glands release their contents through what structures?
Ducts that lead to the epithelial surface
Describe the location/appearance of the nuclei of pseudostratified columnar epithelium
The nuclei of neighboring cells appear at different levels rather than clustered at the basal end
Simple and pseudostratified columnar epithelia are both ____
Heterogeneous
What are the possible shapes of epithelial cells?
Squamous (flattened and thin)
Cuboidal (boxy, as wide as it is tall)
Columnar (rectanglar, taller than it is wide)
What is the function of the cilia in the fallopian tubes and respiratory system?
The beating of the cilia helps remove particulate matter
The nucleus of simple cuboidal epithelium appears ____ and is generally located near the ____ of the cell
Round; centre
What type of epithelium lines the oesophagus, vagina, most of the oral cavity, pharynx, and anal canal?
Non-keratinised, stratified squamous epithlium
A stratified squamous epithelium with a top layer covered with dead cells filled with keratin and appearing non-nucleated is known by what name?
Keratinised stratified squamous epithelium
What is a gland?
A structure made up of one or more cells modified to synthesise and secrete chemical substances
The mesothelium forms the surface layer of the ____ ____ that lines body cavities and internal organs
Serous membrane
The mesothelium is what kind of epithelial tissue?
Simple squamous epithelial tissue
What is the purpose of stratified epithelium?
To protect against physical and chemical wear and tear
Name two locations where simple columnar epithelia are found
Lining of of some sections of the digestive system and parts of the female reproductive tract
The endocrine system coordinates the ____ and ____ of body responses
Regulation; integration
The basal region of each epithelium attaches to a non-cellular layer called the ____ ____
Basement membrane
Mesothelial cells are squamous epithelial cells that perform what function?
Secrete a fluid that lubricates the mesothelium
Simple columnar epithelia are active in the ____ and ____ of molecules
Secretion; absorption
What is meant by ‘stratified’ epithelium?
More than one layer, only the basal layer of cells resting on the basal lamina
Describe three characteristics typical of squamous cell nuclei
Flat, horizontal, and elliptical (oval), mirroring the form of the cell
Simple squamous epithelium are generally present where what is occurring?
Rapid passage of chemical compounds
Non-keratinised, stratified squamous epithlium lines which five locations of the body?
Oesophagus, vagina, most of the oral cavity, pharynx, and anal cavity
By what is stratified epithelium named?
The shape of the most apical layer of cells (closest to the free space)
Name four areas/systems of the body that are exposed to the external environment, not including the skin
Airways, digestive tract, urinary system, reproductive system
True or false: all cells of pseudostratified epithelium are in contact with the apical surface of the tissue
False - some do not reach the apical surface
What is the primary function of the mesothelium?
To provide a smooth and protective surface
What is the reasoning behind the name ‘transitional’ epithelium?
The shape of the apical cells gradually changes as the urinary bladder fills with urine
Name two locations where simple cuboidal epithelia are found
Lining of the kidney tubules and in the ducts of glands
Mucous, sweat, saliva, and breast milk are all secreted through ____ ducts
Tubular
Muous, sweat, saliva, and breast milk are all secreted through tubular ____
Ducts
Simple cuboidal epithelia are active in the ____ and ____ of molecules
Secretion; absorption
What is ‘pseudostratified’ epithelium?
One layer of irregularly shaped cells that give the false appearance of more than one layer
Hollow organs and cavities that do not connect to the exterior of the body are lined by ____
Endothelium
Name two locations where keratinised stratified squamous epithelium can be found
The skin and the hard palate
The endotheium is the epithelial tissue that lines vessels of the ____ and ____ systems
Lymphatic; cardiovascular
What are the two major types of epithelial tissues?
Surface epithelia and glandular epithelia
What is a cell junction?
The connection between the membranes of adjacent epithelial cells
What is an exocrine gland?
A gland whose secretions leave through a duct that opens directly or indirectly to the external environment
What happens to endocrine hormones after they are released into the interstitial fluid?
They diffuse into the bloodstream and are delivered to target cells that have receptors to bind the hormones
How does the transitional epithelium appear when the urinary bladder is empty compared to when it is full?
Thicker and more multi-layered when empty; stretched and less stratified when full and distended
The segments of kidney tubules are made of what kind of epithelial tissue?
Simple squamous epithelial tissue
Cilia are found on the ____ surface of epithelial cells
Apical
The alveoli of lungs are made of what kind of epithelial tissue?
Simple squamous epithelial tissue
True or false: epithelial tissues are almost entirely avascular
True
Surface epithelial tissues are classified according to what two factors?
The shape of the cells and the number of cell layers formed
Give four examples of endocrine glands
Anterior pituitary, thymus, adrenal cortex, and gonads
Describe the form of the transitional epithelium when the urinary bladder is empty
The epithelium is convoluted and has cuboidal apical cells with convex, umbrella-shaped aprical surfaces
What is meant by ‘simple’ epithelium?
One layer, every cell resting on the basal lamina
Give an example of a type of cell that might be interspersed among simple or pseudostratified epithelia
Goblet cell
What are ciliated columnar epithelium?
Simple columnar epithelial cells with cilia on their apical surfaces
Name a location where pseudostratified epithelia can be found
In the respiratory tract (some of these cells have cilia)
What makes simple and pseudostratified columnar epithelia heterogeneous?
They include additional types of cells interspersed among the epithelial cells
The lining of capillaries are made of what kind of epithelial tissue?
Simple squamous epithelial tissue
Epithelium forms most of the ____ tissue of the body
Glandular
There are differences in structure and function between the exposed/____ surface of the cell and the ____ surface closest to the underlying body structures
Apical; basal
Give four examples of secretions from exocrine glands
Mucous, sweat, saliva, and breast milk
Epithelial cells are typically characterised by the polarised distribution of ____ and ____-____ ____ between their basal and apical surfaces
Organelles; membrane-bound proteins
Where is transitional epithelium found?
In the ureters and urinary bladder
What is a goblet cell?
A mucous-secreting unicellular ‘gland’
The shape of the cells in simple epithelium reflects their ____
Function
Epithelial cells are typically characterised by the polarised distribution of organelles and membrane-bound proteins between heir ____ and ____ surfaces
Basal; apical
Why are keratinised epithelia always stratified?
They are located in areas of high physical trauma and are localised only in areas exposed to the external environment
What type of epithelium is found excusively in the ureters and urinary bladder?
Transitional epithelium
What is keratin?
A protein produced to provide protection against abrasion and drying out
A stratified epithelium with squamous apical cells and either columnar or cuboidal basal layer cells is what kind of stratified epithelium?
Stratified squamous epithelium
Name two locations where ciliated columnar epithelium can be found
Lining of the fallopian tubes and parts of the respiratory system
What is an endocrine gland?
A ductless gland that releases secretions directly into surrounding tissues and fluids
Are secretions into the lumen of the GIT endocrine or exocrine?
Exocrine
What happens to the transitional epithelium as the urinary bladder fills with urine?
The epithelium loses its convolutions and the apical cells transition from cuboidal to squamous
