3.1 Human Respiratory System Flashcards
Why can small organisms diffuse gases straight into their environment?
Large surface area to volume ratio
Low metabolic rate
Give an example of a small organism:
Amoeba
What do large organisms needs specialised exchange system?
Small surface area to volume ration
Higher metabolic rate
What 4 thing do
Lungs have to increase the efficiency of gas exchange?
Large surface area
Thin permeable walls
Good blood supply
Efficient ventilation
How do lungs have large surface area?
Alveoli sounded shape meaning oxygen and carbon dioxide can diffuse quickly
What are alveoli encapsulated by?
Capillaries which allow for quick gas exchange
Why do the lungs have thin permeable walls and how does this affect the rate of diffusion?
Alveoli is made up of squamous tissue and their walls are one cells thick this decreased the area over which diffusion takes place increasing the rate of diffusion
Why do the lungs need a good blood supply?
They need as much blood per minute as the rest of the body
How is a concentration gradient maintained in the lungs?
CO2 is always entering and O2 is always leaving maintaining a high conc of CO2 in the capillaries which maintains the concentration gradient
What is efficient ventilation?
The physical pumping mechanism called breathing that continually brings fresh air to the Alveoli, keeping the concentration gradient large
What is the nasal cavity and what does it do?
- Where air enters the body
- nc has a large s/a to v ratio and good blood supply
- warms air to body temperature
- hairy lining secretes mucus trapping dust and bacteria
What does the trachea and what does it do?
Carries air from the nose to the lungs
Wide tubes supported by incomplete rings of cartilage
Lined with goblet cells and ciliated epithelium
What is cartilage and what does it do?
Rings of cartilage support the trachea and bronchi
They are strong and flexible and are incomplete in the trachea to allow food to pass down the oesophagus
What does ciliated epithelium do?
Lines the airways
Beats and moved mucus away from the lungs to the throat where they are digested
What do goblet cells do?
They line other airways and secrete mucus to trap bacteria
