Re: What is the heart made of? What are lungs made of?

To Mrs. Atchley's 3rd grade class ----- 11/11/99

Hello from Massachusetts!

I love to receive questions from students who are interested in how the human body works. Maybe some day, one of you will study medicine - become a doctor or nurse. That would be wonderful - we need bright, young people who will be the next leaders in healthcare

The heart is hollow and shaped like a cone. It is made of specialized muscle tissue which allows it to beat your entire lifetime. It is relatively small and is about the same size as your closed fist. Your teacher's heart weighs about 10 oz, and is about 5 inches long and 3 1/2 inches wide at its broadest point. It pumps 30 times it's own weight each minute. Here's a good arithmetic question for you - how much does it actually pump in a minute? If you did your math right - you came up with an answer of 5.3 quarts. How much would it pump in a day (24 hours)? (answer 1800 gal) and how much would it pump in a year? (answer 1.3 million gal) WOW! that sure is a lot of blood! Once that blood leaves the heart it travels about 60,000 miles of blood vessels before it returns back to the heart. If the average heart beats 60 times a minute how many miles does the blood travel in an entire 60 seconds?? Anything that can work that hard with with only a little rest between beats has to be something very strong. It's a muscle.

Your lungs are paired (meaning that you have two of them) The word "lung" actually means "light" so that they float.(the only place of attachment in the body is the trachea - so they literally "float" in the chest). The lung tissue is very porous and made of many small units called alveoli. If stretched out, their area would cover a tennis court! The large area helps the exchange of oxygen gas into the red cells of the blood which will carry the oxygen to other parts of your body.

The funny shapes of the lungs are caused by the lungs molding themselves to the surrounding organs in the body. The base is concave to fit over the convex area of the diaphragm. The surface of the lungs lying against the ribs is rounded to match the curve of the ribs. The right lung is thicker and broader than the left. It's shorter than the left because the diaphragm is higher on the right side to accomodate the liver which lies below it Each lung is divided into lobes. Each lobe has its own bronchus. The right side has 3 sections and the left side has 2 sections (lobes). The entire function of the respiratory system is to exhange oxygen with carbon dioxide (waste from the body).

I hope this answers your questions.

Have a wonderful Thanksgiving holiday.

If you have any more questions - just let me know. Now you all have some arithmetic and spelling words to look up. :):):)

Fondly, Florrie Surrette