tissues, biology unit 5 Flashcards
revision
what is Epithelial tissues?
Epithelial tissue is found lining tubes, ducts and other structures which connect with the outside of the body.
e.g trachea, bronchi, bronchioles
what is Endothelial tissue?
Endothelial lines inner surfaces of the body – where the surfaces are
totally enclosed within the body.
e.g lining of all blood vessels
what are Types of Epithelial Cell and Where they Are found?
Squamous epithelial cells Make up the walls of the alveoli in the lungs.
They can also be found in the skin They make up the walls of nephrons in the kidney.
what are Types of Epithelial Cell and Where they Are found?
Cuboidal epithelial
These make up the walls of tubules e.g. the sweat ducts
what’s the Function of good blood supply?
A good blood supply is needed around each alveolus so that the
maximum amount of oxygen can be absorbed by the blood and carried
away to where it is needed in the rest of the body.
whats Diffusion of carbon dioxide?
From blood to alveolus to be breathed out. The squamous cells of the alveoli and capillary walls allows a short diffusion pathway to make
diffusion as efficient as possible.
whats the Diffusion of oxygen:
Diffusion occurs across the thin walls of the alveolus which are made of
squamous epithelium and across the thin walls of the capillaries which
are also made of squamous cells.
what is Chronic bronchitis?
The epithelial cells in the walls of the bronchi
become inflamed.
Excess mucus is produced.
These two things together greatly reduce the size of the lumen of the airways.
This blocks movement of air making it much harder to breathe.
The repeated inflammation damages the cilia which are then unable to remove the mucus which builds up.
This is an ideal environment for bacteria to grow so people with chronic bronchitis are
more prone to chest infections.
what is Emphysema?
The alveoli walls are made of squamous epithelial tissue just one cell thick.
This makes them easy to damage.
When the alveoli get damaged, the walls break down making much larger air sacs.
This greatly reduces the overall surface of the lungs making it hard to absorb enough oxygen.
Elastic fibres within the alveoli also get damaged meaning the air sacs cannot spring back to shape as easily.
Consequently, air gets trapped in the air sacs making it hard to breathe in more oxygen-rich air
whats the Structure and function of capillary walls?
Capillary walls are one cell thick and are composed of squamous cells.
This ensures the shortest possible diffusion pathway.
Enabling substances such as oxygen and nutrients to diffuse out of
the blood as quickly as possible is vital otherwise the tissues that are
supplied by the blood capillaries will not get enough oxygen and nutrients for their needs.
