Respiratory - The lung 2/2 Flashcards
How do the epithelial cells change as the cells get deeper into the reparatory tract?
They become shorter (i.e. go from columnar to cuboidal to squamous in the alveoli)
What is the purpose of the smooth muscle surrounding the bronchiole?
Can constrict or relax to control flow of air
What does the control of smooth muscle in the bronchiole make it?
The main controller of air flow
What happens in an asthma attack related to the bronchioles?
Asthma is when the smooth muscle in the bronchioles constrict
How can an asthma attack be alleviated?
With a bronchodilator (relaxes the smooth muscle)
What is a common bronchodilator?
Salbutamol
Label the diagram
What are alveolar sacs?
A group of alveoli
In the terminal bronchiole, is there gas exchange? Why?
No because the wall of the bronchiole is too thick to allow the diffusion of gases (i.e. gas exchange)
What are alveoli?
A group of alveolus
What are alveolus?
An individual air sac in the lung
Label the diagram
What is the function of the surfactant cells?
It secretes a surfactant that decreases the surface tension inside the alveolus
What is the advantage of secreting a surfactant inside the alveolus?
It prevents it from collapsing therefore reducing the work of breathing as it means the alveolus doesn’t have to re-inflate the cells every time you breathe
What is the function of the alveolar macrophage?
It is a last line of immune defence against any foreign bodies that get into the lungs
What is the location of the alveolar macrophage?
They move around so don’t have a specific position
Label the diagram
What is the diffusion barrier trying to do?
Trying to minimise its distance between the blood and air
How close are the basement membranes of the alveoli and capillaries? Why?
They are touching to minimise the distance between air and blood
What is the trend of the epithelial lining in the lungs?
Starts off columnar (i.e. thick) and trends into the lower respiratory tract getting thinner into squamous cells
What is the trend of the smooth muscle in the lungs?
Less smooth muscle in the upper tract with the most in the bronchiole but NONE in the alveoli
What does the trend of smooth muscle indicate about the control of air flow?
The lower respiratory tract has greater control over air flow than the upper respiratory tract
What is the trend of the mucous glands in the lungs? Why?
Found only in the upper respiratory tract (trachea and bronchus) where there is more space for the glands in the thicker layers
What is the trend of the cartilage in the lungs?
Found only in the upper respiratory tract (trachea and bronchus)
What are the subdivision of the lungs?
Primary, secondary and tertiary bronchi
What are the primary bronchi?
The left and main stem supplying each lung
What are the secondary bronchi?
The bronchi supplying each of the lobes of the lungs (2 on the left, 3 on the right)
Wha are the tertiary bronchi?
The segmental bronchi supplying segments of the lung (8 on the left 10 on the right)
What does each segment of the lung have? What does it make this?
Each segment has its own air and blood supply making it a seperate functional unit
How does the segment aid a patient with lung disease?
If there is the disease isolated to a single segment it can be removed without affect the rest of the lung adversely
What membrane covers the lungs?
The pleurae
What is the structure of the pleurae?
A double layered membrane that is continuous at the root of the lung (hilum) with a thin film of fluid separation the layers
Label the diagram
What is the purpose of the pleural fluid?
Allows sliding between the pleurae layers and also prevents them from separating (liquid layer creates suction between layers FYI)
What are the muscles on the rib cage that are used for breathing called?
Internal and external intercostal muscles
What are the external intercostal muscles used for?
They help to move the ribs up which result in the expansion of the lungs causing ~25% of the air movement of the lungs
What are the internal intercostal muscles used for?
They are used during exercise to increase the rate of expiration by pulling the rib cages down forcing air out of the lungs faster
What is quiet breathing?
Breathing when you are not exerting yourself
Why you are doing quiet breathing, what is the energy usage?
Inspiration is active (external intercostal muscles and diaphragm contract), expiration is passive (both relax)
When you are breathing during exercise, what is the energy usage?
Inspiration is active (external intercostal muscles and diaphragm contract), and expiration is active (internal intercostal muscles contract)
How does the diaphragm control air flow into the lungs?
The diaphragm is connected onto bones via the vertebrae and the sternum and is connected to the floor of the thorax (i.e. bottom of the lungs) by the pleurae fluid. When it contracts it pulls the lungs downwards lowering air pressure therefore brining air into the lungs, when it relaxes it makes the lungs smaller therefore pressure increases expelling air
Label the diagram
What part of the diaphragm contracts?
The muscular portion
What kind of muscle is the muscular portion? What is it innervated by?
Fast action skeletal muscle
Phrenic nerve
What portion of the bulk flow of air during quiet breathing is caused by the diaphragm?
75%
