Respiratory System Flashcards
Exchange Surfaces
Multicellular organisms will have specialised structures to assist them in exchanging materials with their environment, as not all of their cells are in direct contact with the external environment.
Examples of exchange surfaces include:
Alveoli – found in the lungs, part of respiratory system
Villi – found in small intestine, part of digestive system
Nephron – found in kidney, part of exceretory system
Why do exchange surfaces work?
Membrane thickness – reducing the distance that materials need to move during exchange.
Moist – assisting the transport of materials across the exchange surface.
Surface area - providing more space for exchange to take place.
The concentration gradient is the difference in concentration of a substance between two areas. The greater the concentration gradient, the faster the rate of diffusion.
Diffusion
Diffusion is the movement of molecules from an area of high concentration to an area of low concentration, until evenly spread out. Diffusion is considered a passive process, as it does not require and energy.
gas exchange in water, plants, animals etc.
In aquatic plants, water passes among the tissues and provides the medium for gas exchange. In terrestrial plants, air enters the tissues, and the gases diffuse into the moisture bathing the internal cells. In animals, gas exchange follows the same general pattern as in plants. Oxygen and carbon dioxide move by diffusion across moist membranes.
Gas exchange - Respiratory system
Diffusion: During gas exchange oxygen moves from the lungs to the bloodstream. At the same time carbon dioxide passes from the blood to the lungs. This happens in the lungs between the alveoli and a network of tiny blood vessels called capillaries, which are located in the walls of the alveoli.
Parts of respiratory system
Inhalation – air is inhaled when your diaphragm lowers, and your intercostal muscles move your ribs upwards and outwards. This increases the volume of your lungs, forcing air in.
Exhalation – air is exhaled when your diaphragm rises, and your intercostal muscles move your ribs downwards and inwards. This decreases the volume of your lungs, forcing air out.
Simple diffusion v active transport (respiration)
The primary difference between active transport and diffusion is that active transport needs cellular energy to transport the molecules against the concentration gradient. In contrast, diffusion refers to the passive transport method where the molecules move across the cell membrane through a concentration gradient.
Respiration and Diffusion in Lungs
