Structure of the Human Gas-Exchange System Flashcards
What do all aerobic organisms require in order to release energy in the form of ATP?
A constant supply of oxygen
Why does the carbon dioxide produced as a result of respiration have to be removed?
Build up can be harmful to the body
Why is the volume of oxygen that has to be absorbed and the volume of carbon dioxide that has to be removed large in mammals?
- they are relatively large organisms with a large volume of living cells
- they maintain a high body temperature which is related to them having high metabolic and respiratory rates
What do mammals use to ensure efficient gas exchange between the air and their blood?
Lungs
What is the site of gas exchange in mammals?
The lungs
Why are the lungs located inside the body?
- air is not dense enough to support and protect the delicate structures
- the body as a whole would otherwise lose a great deal of water and dry out
How are the lungs supported and protected?
By the rib cage
How are the ribs moved to allow for breathing?
By the internal intercostal muscles and the external intercostal muscles
What does ventilation within the lungs allow for?
The air within them to be constantly replenished
What are the lungs and what do they consist of?
A pair of lobed structures made up of a series of highly branched tubules, called bronchioles, which end in tiny air sacs called alveoli
What is the trachea and what does it consist of?
It is a flexible airway that is supported by rings of cartilage, the cartilage prevent the trachea from collapsing as air pressure falls when breathing in. The tracheal walls are made up of muscle, lined with ciliated epithelial and globlet cells
What are the the bronchi and what do they consist of?
The bronchi are two divisions of the trachea, each leading to one lung. They are similar in structure to the trachea and they produce mucus like the trachea to trap dirt particles, which the cilia move upwards towards the throat. Larger bronchi are supported by cartilage but cartilage is reduced as bronchi get smaller
What are the bronchioles and what do they consist of?
A series of branching subdivisions of the bronchi. Their walls are made of muscle lined with epithelial cells. This muscle allows them to constrict so that they can control the flow of air in and out of the alveoli
What are the alveoli and what do they consist of?
Minute air-sacs with a diameter of between 100um and 300um, at the end of the bronchioles. Between the alveoli there are elastic and collagen fibres which allow the alveoli to stretch as they fill with air when breathing in. They can then spring back during breathing out in order to expel the carbon dioxide-rich air. The alveolar membrane is the gas-exchange Surface Arbilla gets
What supports the trachea?what does cartilage prevent?
The trachea from collapsing when pressure drops during breathing in
What are the muscular walls of the trachea lined with?
Ciliated epithelium and goblet cells
What is the role of ciliated epithelium in the trachea and bronchi?
They waft the mucus they produce (which contains trapped dust and dirt) out of the lungs towards the throat
What are the two divisions of the trachea?
The bronchi
What are larger bronchi supported by?
Cartilage
What does the muscle within the bronchioles allow?
It allows them to control the air flow in and out of the alveoli
Where are the alveoli?
At the end of the bronchioles
What are found between the alveoli?
Collagen and elastic fibres
What are the alveoli lined with?
Epithelium
What do elastic fibres allow the alveoli to do?
Stretch as they will with air and as they spring back during breathing out they expel carbon dioxide-rich air
What is the gas exchange in the lungs?
The alveolar membrane
State two reasons why humans need to absorb large volumes of oxygen from the lungs
- humans are large
- humans have a large volume of cells
- humans have a high metabolic rate
- humans have a high body temperature
List in the correct sequence all the structures that air passes through on its journey from the gas-exchange surface of the lungs to the nose
Alveoli - bronchioles - bronchus - trachea - nose
Explain how the cells lining the trachea and bronchus protect the alveoli from damage
- The cells produce mucus that traps particles of dirt and bacteria in the air breathed in. The cilia on these cells move this debris up the trachea and into the stomach
- the dirt can damage and cause infection in the alveoli
