compare respitory system of a fish &human
http://www.lung.ca/children/grades4_6/respiratory/fish.html
http://kidshealth.org/kid/htbw/lungs.html
To compare the respiratory system of a fish and a human, we need to understand how each system works. Let's break it down:
1. Fish Respiratory System:
Fish have gills, which are specialized organs for obtaining oxygen from water. When a fish opens its mouth, water flows in and passes over the gills. Inside the gills, there are thin-walled structures called gill filaments. The filaments have numerous tiny blood vessels that allow oxygen to transfer from the water into the fish's bloodstream, while carbon dioxide is expelled back into the water. This process is known as countercurrent exchange.
2. Human Respiratory System:
Humans have lungs for their respiratory system. When we inhale, air enters through the nose or mouth, passes through the throat, and enters the windpipe or trachea. The trachea then branches into two bronchi, which lead to each lung. Inside the lungs, there are millions of tiny air sacs called alveoli. Oxygen from the inhaled air diffuses across the thin walls of the alveoli into the bloodstream, while carbon dioxide from the bloodstream is released into the alveoli and exhaled out of the body.
Comparison between Fish and Human Respiratory Systems:
1. Medium for Oxygen Exchange:
- Fish: Gills extract oxygen from water.
- Humans: Lungs extract oxygen from the air.
2. Structural Differences:
- Fish gills are located on the sides of their bodies, protected by gill covers.
- Humans have lungs protected by the ribcage, located in the chest cavity.
3. Method of Oxygen Extraction:
- Fish gills extract oxygen using countercurrent exchange, where water passes over the gill filaments and oxygen diffuses into the bloodstream.
- Humans have alveoli in their lungs, where oxygen diffuses from inhaled air into the bloodstream.
4. Respiratory Surface Area:
- Fish gills have a large surface area due to the numerous gill filaments, allowing for efficient gas exchange in water.
- Human lungs have a large surface area due to the vast number of alveoli, facilitating efficient gas exchange in air.
In summary, fish and humans have different respiratory systems adapted to their respective environments (water vs. air). Fish use gills to extract oxygen from water, while humans use lungs to extract oxygen from the air we breathe.