RESPIRATORY SYSTEM Flashcards
Where is mucus lining located?
The nasal cavity and upper airways
What is the function of mucus lining?
The epithelial lining contains globlet cells which secrete a clear, sticky mucus.
What is oxygen used for in the body?
All cells in the body need oxygen for cellular respiration as well as a way to remove the carbon dioxide that they produce
What is the relationship between the circulatory and respiratory system?
They work together to ensure that all cells have a constant supply of oxygen and that carbon dioxide is continually removed from the cells.
What are the organs of the respiratory system?
The nose, through which air is taken in; the trachea, which branches into two tubes; the bronchi; and the two lungs.
Where does air enter through first?
Air enters the body through the mouth and nasal cavity.
What happens to air when it enters the nose?
As air passes over the mucus membranes it is warmed and humidified. The hair and mucus lining the nose trap debris, preventing it from reaching the lungs.
What is the pharynx?
The region from the nasal cavity to the top of the trachea and oesophagus.
What happens after air passes through the nasal cavity?
Air travels through the pharynx before being diverted into the trachea by the epgilottis, a flap of cartilage.
What is the role of the epiglottis during inhalation?
It covers the oesophagus, guiding the air into the trachea; when swallowing and covering the larynx, preventing food from entering it.
What is the larynx?
A cartilage and trachea. It contains the vocal cords, which are mucus membranes that vibrates as air passes over them.
What is the trachea?
It takes air to/from the lungs. It contains C-shaped cartilage rings that hold the structure open.
What happens when air gets to the trachea?
The air goes down the trachea where it divides, forming the primary, secondary, and tertiary bronchi. As the bronchi get smaller there are fewer cartilage rings and more smooth muscle and elastin.
What happens to air in the trachea and bronchi?
As air moves through the trachea and bronchi, mucus and cilia work together to trap and remove foreign particles.
What are the bronchioles?
Finer than bronchi and do not contain cartilage
What does the bronchioles’ structure allow them to do?
Allows them to control the flow of air in the lungs, expanding when the body needs more oxygen.
- Cilia/mucus protect lungs from contiminants
What happens when air arrives at the bronchioles?
The bronchioles end in air sacs called alveoli, which are the site of gas exchange.
How do alveoli allow efficient gas exchange to occur?
- Very large surface area
- Rich blood supply
- Thin
- Covered by thin layer of moisture
- Constant movement of air
What is the surface area of alveoli? Why is it that way?
- 50 to 80m2
- So that large amounts of gases can be exchanged in a relatively short time.
Why does the alveolus supplied have a rich blood supply?
- So that as much blood as possible is close to the air in the alveolus.
What does the continuous flow of blood help with?
As blood flowing through the capillaries around each alveolus picks up oxygen and loses carbon dioxide, it is replaced by more blood being pumping into the capillaries.
This helps to maintain a difference in concentrations of oxygen and carbon dioxide between the blood in the capillaries and the air in the alveolus.
Why is the alveolus so thin? How thin is it?
- So that gas molecules don’t have far to travel when moving into or out of the blood.
- One cell thick (1 micrometre)
What is the importance of the thin layer of air in the alveolus?
Gases can diffuse into/out of lungs only when they are dissolved in the fluid.
Why is the constant movement of air important?
Ensures that their is always a concentration gradient of oxygen and carbon dioxide between the air and the blood.
