Life Cycle - Human Biology (3A)
Pre Lab 

  • Comparing human organ systems.
  • Discussing human body systems. 
  •  circulatory
  •  digestive
  •  endocrine
  •  muscle
  •  nervous
  •  renal
  •  respiratory
  •  sensory
  •  skeleton

Students review the human body systems.



The human body is composed of different systems that have specific tasks to complete.  The Respiratory System contains organs, that working together will allow us to breathe.  The respiratory system has lungs, diaphragm, and trachea.  However, the heart is also part of the respiratory as it pumps blood into the lungs to get oxygenated.  It is important to emphasize that we operate as a well-tuned machine, with most of our parts having more than one function.  When one part of the body fails, it sometimes triggers other  organs to fail also.  Below are descriptions that may be useful when the students do their activity.

The lungs are found in the chest and abdomen region.  The main function is to transport oxygen to all parts of the body.  The lungs contain air tubes, tissues, and blood vessels.  There are two lungs that are in an airtight compartment of the chest.  This compartment is surrounded by tissue, thin sheets of muscles and the ribs.  When you inhale, a large, dome shaped muscle under the lungs, the diaphragm, lowers and the chest expands.  This changes the air pressure in the pleura and causes the lungs to draw in air.  Reversing the process causes you to exhale.  

The two kidneys of humans are located behind the abdomen.  The kidneys regulate how much water, sodium, potassium, calcium, and phosphate are in the blood.  The kidneys also remove waste products from the body such as uric acid.  Each kidney is filled with capillaries wrapped around very tiny nephrons which filter the blood.  

The liver is about 3.5 pounds and is located in the abdomen.  The main function is to produce digestive juices and enzymes for our body.  The pancreas is about 2.5 ounces and produces a mixture which helps to neutralize the strong acid from the stomach (a natural “Tums”).  It also contains enzymes that help break down food mixtures so it can easily be absorbed.  The liver produces a salty fluid known as bile which is stored in the gall bladder.  This fluid also enters the small intestine and is used to digest fats. 

The stomach fits under the diaphragm and can hold 1.2 liters (2.5 pints) of food.  Food usually remains for about 2-4 hours in the stomach on its way through the body.  Digestive glands in the stomach wall release acid that aids in digestion and kills off most harmful bacteria.

The small intestines extend from the stomach to the large intestines.  In an average adult the small intestine is about 6.4 meters (21 feet) long.  It is coiled and folded to fit into the abdomen.  The small intestines receives digestive juices from the pancreas and liver.

The large intestines help remove food that cannot be digested.  Indigestible parts of the food move from the small to the large intestines.  Some water is recycled back into the blood stream and the remaining waste travels on to the rectum and out the body through the anus.

The heart is only about 12 ounces and is located on the left side of the chest.  The main function is to pump blood to all parts of the body.  The heart pumps more than five quarts of blood through the body every minute.  The organ is divided into four chambers, two sending blood to the body and lungs, and two receiving it.  The heart beats about seventy two times each minutes.  Each beat has two parts.  During the first, blood from the body and lungs enters the upper chambers of the heart, then passes through one way valves to the lower chambers.  The next stage allows the blood to go to the body and lungs.  The lub-dub sound of your heart is the sound of the valves opening and closing.

The cerebrum and cerebellum are part of the brain, which is part of the nervous system.  It is located in the head and weighs about 2-3 pounds.  The brain interprets and reacts to nerve signals.  The cerebellum controls certain movements and keeps the body balanced.  The cerebrum is divided into two halves covered by a thin layer of millions of nerve cell bodies. It is responsible for learning, judgment, creativity, and some parts of your emotions.  

  1. Review the different body systems by using the human torso.  Show students where each organ is located.  The torso should be placed where students can look at it during class.
  2. Cut the worksheet into pieces.  Copy enough copies so there is enough for your classroom.  Put them in a bowl and have students select one
  3. Each child is to take the card home  or go to the library and read information on that organ or system.  If they have Internet access have them do a search on their browser. Parent involvement should be encouraged. 
  4. Instruct students to  develop a series of questions for their particular organ.  They should have at least five questions.  The first one should be hard and the last one should be easy.  For example:  

 1.  I am 30 feet long.
 2.  I help absorb food into the blood.
 3.  I help absorb water into the blood.
 4.  I am curled up into the lower part of the stomach.
 5.  I digest food. 

   The answer is the INTESTINES.  

  1.  Each students should try their questions with the rest of the class.  The other students should try to identify the organ or system.
  2. Read the story My Belly Hurts.  Point out that doctors have to know all the parts of the body and have to ask questions in order to find the problem. 

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