9.3 Trachea, bronchi and bronchioles Flashcards
What is trachea(windpipe)
the tube like structure that extends from the larynx to the bronchi; it allows movement of air into and out of lungs
What airway is found from the throat to the lungs?
trachea
What is found at the base of trachea
two bronchi
What is a bronchus
A major branch of trachea that extends into the lungs
What is a bronchiole
A microscopic branch of a bronchus that lead to the alveoli
The bronchi..
subdivide and branch extensively forming a bronchial ‘tree’ in each lung
Terminal bronchi divide to form
Even narrower respiratory bronchials that supply the alveolar ducts with air
What is cartilage?
A type of skeleton tissue that is strong and flexible
Where is cartilage found?
Supporting the larynx, trachea and bronchi in the gas exchange system
At the joints between bones
In the external ear
What does cartilage do in trachea and bronchi?
Keep these airways open and air resistance low
Prevent them from collapsing or bursting as the air pressure changes during breathing
What does cartilage look like in trachea?
It is a regular arrangement of C- shaped rings
What does cartilage look like in bronchi?
There are irregular blocks of cartilage
How are the delicate surfaces inside the lungs prevented from desiccation(drying out)?
As air flows through the nose and the trachea, it is warmed to the body temperature and moistened by evaporation from the lining.
The lungs also need to be protected from the material carried in the air as they are potential threat to the proper functioning of the lungs. What are the materials?
Dust, sand, pollen, fungal spurs, bacteria, and viruses
How are air particles larger than 5 to 10 µm prevented from entering the lungs
They are caught on the hair inside the nose and the mucus lining the nasal passages and other airways.
What produces the mucus in trachea and bronchi?
The goblet cells of the ciliated epithelium
What are goblet cells?
A cell shaped like a drinking goblet that secretes mucus
Where are goblet cells found?
In the epithelia lining part of the gas exchange system and other organ systems. Example: reproductive and digestive
What is the ciliated epithelium?
An epithelium that consist of many ciliated cells.
The upper part of each gobet cell is swollen with
Mucin droplets which have been secreted by the cell
What is mucin?
Any glycoprotein that forms part of the mucus secreted by goblet cells and mucuos cells
What is mucus?
It is a slimy solution of mucin which is composed of glycoproteins with many carbohydrate chains
What is the role of glycoprotein with many carbohydrate chains in mucus?
They make the mucus sticky and able to trap inhaled particles
Apart from mucin, the rest of the goblet cell contains
Golgi body,some rough endoplasmic reticulum,mitochondria and a nucleus
The lower part of the goblet cell is
Thin so that the cell resembles a drinking vessel known as goblet
Apart from goblet cells, what else produces mucus?
Mucous glands beneath the epithelium
What happens when some chemical pollution such as sulphur dioxide and nitrogen dioxide enter the airway?
They can dissolve in mucus to form an acidic solution that irritates the lining of airway
Between the goblet cells are
Ciliated epithelial cells
What is the function of ciliated epithelial cells?
The continual beating of their cilia carries the layer of mucus upwards towards the larynx at the speed of about 1 cm/m
What happens when the mucus reaches the top of the trachea by the beating of cilia in the ciliated epithelial cells?
Is usually swallowed so that pathogens are destroyed by the acid in the stomach
Bronchioles are surrounded by
Smooth muscles
What is the function of smooth muscle surrounding the bronchioles?
The contract or relax to adjust the diameter of the bronchioles. This means during exercise the muscles relax to allow a greater flow of air to the alveoli.
Which makes the contracting and relaxing of bronchioles by smooth muscles possible
The absence of cartilage
What patrols the surfaces of the airways scavenging small particles such as bacteria and fine dust particles?
Phagocytic white blood cells known as macrophages
What happens during an infection in the airways?
The macrophages are joined by other phagocytic cells which leave the capillaries to help remove pathogens
