To present to you the facts briefly, there it goes…

1. Respiration is the taking in of oxygen to oxidize food and the giving off of carbon dioxide.
2. The respiratory system enables one to take in oxygen, obtain energy from the oxidation of food, and release carbon dioxide.
3. The respiratory system includes the nostrils, nasal chamber, pharynx, larynx, trachea, bronchi, bronchioles, and air sacs or alveoli.
4. A breathing cycle consists of one inhaling and one exhaling. The normal rate is 15 to 18 breathing cycles per minute.
5. An increased chest volume makes the air enter the lungs, while a decreased chest volume makes the air rush out.
6. The nervous system controls all conscious activities, reflex actions, emotions, and the normal functions of all the organs of the body.
7. The nervous system includes five senses, nerves, spinal cord, and the brain.
8. Endocrine glands are ductless glands, and their secretions are called hormones.
9. The endocrine glands are the thyroid, parathyroid, , pituitary, adrenal, thymus, islets of Langerhans, testes, ovary, and pineal gland.
10. The reproductive system enables one to produce offspring.
11. The sperm cell and the egg cell unite during the fertilization, producing a zygote.
12. The human embryo develops into a fetus which stays in the womb for 9 months.
13. The transfer of character traits from parents to offspring is called heredity.
14. The 46 numbers of chromosomes are the bearers of hereditary traits.