Mammalian Gaseous Exchange System Flashcards
Describe the trachea
•It’s a wide tube supported by c-shaped cartilage
•Lined by ciliated epithelium cells and contain goblet cells
•Smooth muscle is within the walls
•Elastic fibres allow for the walls to expand and relax
Describe the function of the trachea
•The c-shaped cartilage keeps the air passage open during pressure changes
•Goblet cells produced mucus which is moved by the epithelium cells
•Smooth muscle contracts if there are harmful substances in the air ->results in the lumen constricting air flow
•Carries air to the bronchi
Describe the bronchi
•Also supported by rings of cartilage
•Lined by ciliated epithelium cells and goblet cells
•More narrow than the trachea
•Two of them (one for each lung)
What is the function of the bronchi’s
•Carries air to and from the lungs
•Warms, moistens and cleans inspired air and distributes it to the gas exchanging zone of the lungs
Describe the bronchioles
•Narrower than the bronchi’s
•Don’t need to be kept open by cartilage
•Mainly only have smooth muscle and elastic fibres
What’s the function of the bronchioles?
•Allows for the air flow into the alveoli
Describe the alveoli’s
•Mini air sacs
•Lined with epithelium cells
•Walls only one cell thick
•300 million in each lung
•Walls are covered in a network of capillaries
What is the function of alveoli?
Site of gas exchange
How are alveoli adapted for gas exchange?
Large surface area -> many alveoli
Short diffusion distance -> thin walls
Maintains a concentration gradient -> all are surrounded by a network of capillaries
What do the surrounding network of capillaries do for the alveoli?
Remove exchanged gases
What is the job of the goblet cells?
Secretes mucus which collects dust and bacteria
(Produced by the Golgi apparatus in the goblet cells)
What does ciliated epithelium do?
The cilia move the mucus along the airway to be coughed back out
What is the job of the smooth muscle?
Controls involuntary movement
Help regulate airflow
Responsible for contractions
What’s the job of the elastic fibres?
to provide elasticity and recoiling to tissues and organs and to maintain the structural integrity against mechanical strain over a lifetime
What neurotransmitter is secreted by the neurones that are found int he sympathetic nervous system?
Noradrenaline
What can allergens cause airways to do?
They can cause the smooth muscle in the walls of the airways to contract
What effect can allergens have on ventilation?
•Means less oxygen can be consumed
•Less carbon dioxide can be released
•Increased breathing rate
•Reduces the diameter of the lumen in the bronchi/broncheoles
