Learning from teaching
Last week in Biology class, matters of the heart were the main topic of discussion. The structure and function of the human heart, I mean! I teach Biology rarely, once in 2-3 years. Every experience gives me food for thought.
During our discussion, I made an erroneous comment that humans may be unique in having a sophisticated circulatory system with a four-chambered heart. My student was quick to correct me and told me that other animals have them too.
Slightly disappointed with myself, I came back and studied a bit to refresh my brain. Here is what I learned.
Chambered hearts, in general, are not unique to humans. All vertebrates and even some higher form invertebrates have chambered hearts.
- Four-chambered hearts are definitely present in all mammals and birds
- Three-chambered hearts are common in reptiles and amphibians
- Two-chambered hearts are common in fish
- Single-chambered hearts are present in other lower forms
Many vertebrates also have double circulatory system, like humans. This involves two loops of circulation to complete one cardiac cycle. One loop from the heart to the lungs and another from the heart to the rest of the body. Lungs convert de-oxygenated blood to oxygenated blood, which in turn is circulated to all the cells in the body. The double circulatory system is crucial in keeping oxygenated and de-oxygenated blood separate.
Curiosity feeds the brain
Here are some more interesting facts about the heart to ignite your curiosity.
- The heart of snakes can move around, to be protected from movement of large animals via the oesophagus
- Blue baby syndrome can be caused by a pin sized opening between the left and right ventricles, which allows mixing of oxygenated and de-oxygenated blood
- Human blood vessels span a distance of 60,000 miles
- Octopuses and squids have 3 hearts
- Provided with enough Oxygen, human heart can beat outside the body for short periods of time
The internet can throw up some unexpected titbits while searching for any kind of information. While I was looking for articles about the heart, I came across this interesting article about dinosaurs.
Did reading this short article ignite your curiosity to explore more? Share your thoughts in the comments.
Until next time, continue to stay curious!
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