The Circulatory System

December 17, 2009 by · Leave a Comment 

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The circulatory system is an organ system that passes nutrients (such as amino acids and electrolytes), gases, hormones, bloodcells, , etc. to and from cells in the body to help fight diseases and help stabilize body temperature and pH to maintain homeostasis. This system may be seen strictly as a blood distribution network, but some consider the circulatory system as composed of thecardiovascular system, which distributes blood, and thelymphatic system, which distributes lymph. While humans, as well as other vertebrates, have a closed cardiovascular system (meaning that the blood never leaves the network of arteries, veins and capillaries), some invertebrate groups have an open cardiovascular system. The most primitive animal phyla lack a circulatory system. The lymphatic system, on the other hand, is an open system.

The main components of the human circulatory system are the heart, the blood, and the blood vessels. The circulatory system includes: the pulmonary circulation, a “loop” through the lungswhere blood is oxygenated; and the systemic circulation, a “loop” through the rest of the body to provide oxygenated blood. An average adult contains about a gallon and a half of blood, which consists of plasma, red blood cells, white blood cells, and platelets.

Also, the digestive system works with the circulatory system to provide nutrients the system needs to keep the heart pumping.

Two types of fluids move through the circulatory system: blood and lymph. The blood, heart, and blood vessels form the cardiovascular system. The lymph, lymph nodes, and lymph vessels form the lymphatic system. The cardiovascular system and the lymphatic system collectively make up the circulatory system.

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Bumps on the Head

July 23, 2009 by · Leave a Comment 

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Bumps that go away when you bump your head and others don’t has to do with the severity of the damage to the underlying tissue. When you bump your head, you get a bruise because you break small blood vessels under the skin and the blood pools causing discoloration and swelling in the surrounding tissue. As the blood clot (hematoma) breaks down it gets reabsorbed and disappears. If you whack your head hard enough you could damge the skull, the bone may be injured but not broken.  You can hurt your skull without causing a fracture. As the bone heals, it could get thicker in the damaged area. The same way your skin might form a scar. You could wind up with a knot that doesn’t go away.

Bumps on the head, even large ones, don’t always warrant a trip to the ER or even a call to your doctor. However a hard hit may shake up the brain – called a concussion, also blood can slowly leak out from a damaged blood vessel beneath the skull, called a hematoma–that push into the brain tissue. Larger hematomas can push into the brain tissue. This can either happen very quickly within an hour, or it can take two or three days. This is an emergency and requires a CAT scan of the head to diagnose. Remember, considering the many times children hit their head, injury to the brain is unusual. Most bumps on the head, even large ones, are not serious.

Loss of consciousness. If your child blacks out, even for a few seconds, this can mean that the force of the bump was strong enough to cause a hematoma. A reassuring sign is that you either hear or see your child start to cry immediately after the bump. This means he did not lose consciousness. If your child is unconscious, but breathing and pink (no blue lips), lay her on a flat surface and call emergency medical services. If you have cause to suspect a neck injury, don’t move the child but let the trained experts in neck injuries transport her.

Be very careful if your child has a head injury.

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