[Intro Music]
[Instructor] Hi there I'm Hugo
an instructor here at Auxerio Education
Today we will be covering human gas exchange
these are the course specifications of the IGCSE that we will be going over today.
Gas exchange is just the swapping of different types of gases.
In humans, this would be swapping oxygen for carbon dioxide.
This is very important as a lot of carbon dioxide can make blood acidic
and oxygen is needed for cell respiration which produces energy.
When they say thorax they are referring to this area of your body.
It contains your lungs, upper back bone, heart, muscles and everything inside this highlighted area
This is your rib cage
it is a set of bones that protects your internal organs
Behind it are your lungs and heart.
The pleural membranes are very thin and moist.
These membranes make an airtight seal around your lungs which can help you breathe.
Intercostal muscles are just a group of muscles that sit between the ribcage.
There are 2 types of intercostal muscles, internal and external.
Internal is on the inside and external is on the outside.
The diaphragm is a large sheet of muscle that sits at the bottom of your lungs
and it separates the lung from your abdomen.
This is a key muscle that helps you breathe which we will talk more about in part 2 of this video.
The trachea sometimes referred to as the windpipe
is a tube in your respiratory system connecting your mouth and nose to the rest of your lungs
Going further down, the trachea splits into 2 bronchi (1 bronchi is called a bronchus)
Cartilage is soft connective tissue and the bronchi
and trachea have rings of cartilage in it which allows the 2 pipes to maintain its tube-like structure
The bronchi will split into many bronchioles
which split into roughly 600 million microscopic air sacs called alveoli
This is where gas exchange occurs.
Oxygen will go through the trachea to a bronchus, to a bronchiole, and then into an alveolus
It is important that you know how these alveoli are designed specifically to be good at gas exchange.
Alveoli have 1 cell thick walls which allows for a low diffusion distance.
This means that gases don’t have to diffuse or move very far to enter or exit the bloodstream.
Alveoli also have a large surface area, so there are many contact points for gases to come in or out.
In addition, alveoli have many blood capillaries.
Capillaries are blood vessels that are about 1 cell wide
this means that red blood cells will slow down allowing gas exchange to occur
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Thank you for watching!
[Outro music]
