P2 - Outline the structure of the main tssues in the body
Tissues are cells which are similar, and work together to carry out specifc functonss The four main types of
tssues aresss
Epithelial tssues
This tssue is found in the linings of internal and external surfaces and body cavites, also in ducts carrying
secretons from glandss The tssues can be made up of multple layers of cells, known as compound
epithelia, or just one layer, known as simple epithelias The botom layer of cells is connected to a basement
membrane, which supports and connects the epithelias Part of the basement membrane is secreted by the
epithelial cellss There are nerve supplies to epithelia, which are provided with oxygen and nutrients from
deeper tssues through difusions Difusion is when partcles spread, from a high concentraton to a low
concentratons
There are two types of epitheliasss
Simple epithelia; There are diferent kinds of simple epithelial cells; squamous, cuboidal, columnar
or ciliateds Squamous epithelial cells are fat, with each nucleus creatng a lump in the middles They
ft together closely, and do not ofer much protecton as they are so delicates Their main functon is
to allow materials to pass through via difusion and osmosiss Simple squamous epithelium is found
in the walls of lung alveoli, blood capillaries and Bowman's capsule of nephronss Cuboidal epithelial
cells are cube-shaped, with a spherical nucleuss They allow materials to pass through similarly, to
squamous epithelias They usually occur in glandular tssues making secretonss They can be found in
kidney tubules, sweat ducts and glands like the thyroid gland and breast tssues Columnar epithelial
cells are tall, with a rather oval nucleuss They can be compared to microscopic flaments known as
cilia, which are then called ciliated epithelias Cilia move in wave-like movements and are related to
goblet cells, which secrete mucus in the respiratory and alimentary tractss Columnar cells are found
lining the trachea and bronchi, and villi in the small intestnes
Compound epithelia; The main purpose of compound epithelia is to protect deeper structures, and
multple layers of cells which block the passage of materialss The vagina, mouth, tongue and
oesophagus are lined by stratfed epithelia, which are made up of layers of squamous, cuboidal or
columnar cellss These slowly become fatened by pressure from below as they reach the surfaces
The skin has an outer layer of epithelium, which has a similar structure to the stratfed epitheliums
However, it has a layer of fatened dead cells on the outsides This is known as the epidermiss
Connectve tssues
These tssues are most widespread throughout the body and can be found below the epithelial tssues,
they connect diferent parts of the internal structures Diferent kinds of cells lie in a background material
Tissues are cells which are similar, and work together to carry out specifc functonss The four main types of
tssues aresss
Epithelial tssues
This tssue is found in the linings of internal and external surfaces and body cavites, also in ducts carrying
secretons from glandss The tssues can be made up of multple layers of cells, known as compound
epithelia, or just one layer, known as simple epithelias The botom layer of cells is connected to a basement
membrane, which supports and connects the epithelias Part of the basement membrane is secreted by the
epithelial cellss There are nerve supplies to epithelia, which are provided with oxygen and nutrients from
deeper tssues through difusions Difusion is when partcles spread, from a high concentraton to a low
concentratons
There are two types of epitheliasss
Simple epithelia; There are diferent kinds of simple epithelial cells; squamous, cuboidal, columnar
or ciliateds Squamous epithelial cells are fat, with each nucleus creatng a lump in the middles They
ft together closely, and do not ofer much protecton as they are so delicates Their main functon is
to allow materials to pass through via difusion and osmosiss Simple squamous epithelium is found
in the walls of lung alveoli, blood capillaries and Bowman's capsule of nephronss Cuboidal epithelial
cells are cube-shaped, with a spherical nucleuss They allow materials to pass through similarly, to
squamous epithelias They usually occur in glandular tssues making secretonss They can be found in
kidney tubules, sweat ducts and glands like the thyroid gland and breast tssues Columnar epithelial
cells are tall, with a rather oval nucleuss They can be compared to microscopic flaments known as
cilia, which are then called ciliated epithelias Cilia move in wave-like movements and are related to
goblet cells, which secrete mucus in the respiratory and alimentary tractss Columnar cells are found
lining the trachea and bronchi, and villi in the small intestnes
Compound epithelia; The main purpose of compound epithelia is to protect deeper structures, and
multple layers of cells which block the passage of materialss The vagina, mouth, tongue and
oesophagus are lined by stratfed epithelia, which are made up of layers of squamous, cuboidal or
columnar cellss These slowly become fatened by pressure from below as they reach the surfaces
The skin has an outer layer of epithelium, which has a similar structure to the stratfed epitheliums
However, it has a layer of fatened dead cells on the outsides This is known as the epidermiss
Connectve tssues
These tssues are most widespread throughout the body and can be found below the epithelial tssues,
they connect diferent parts of the internal structures Diferent kinds of cells lie in a background material
