Back to School Review Answers September 2020

The 7 systems of the human body are the central nervous system, circulatory system, respiratory system, digestive system, immune system, reproductive system, and skeletal structure and musculature.
The average person’s body is 50-60% water. However, the brain is 70% water.
The human brain weighs between 2.8 to 3 pounds.
A healthy adult heart beats about 60-80 times per minute. Children’s heartbeats are faster, around 100-120 bpm.
An average adult has around five quarts (10 pints) of blood. About one pint is taken during a blood donation.
Signs of a heart attack include difficulty breathing, pain in the left arm, heaviness on the chest, flu-like symptoms, sudden pain in the chest, turning blue.
A pair of lungs weigh about 1kg or 2.2 pounds.
Between 300- 350g or 10 – 12 oz. The size of your heart corresponds with the size of your fist.
Saliva keeps the mouth moist and makes it easier to talk. It allows the tongue to taste food and begins to dissolve food. It helps to keep the mouth clean. The digestive system begins in the mouth
Adults have 206 bones. Babies have 300.
When babies are born their skulls are soft, which helps them pass through the birth canal. It can take up to 18 months before a baby’s skull is fully formed. This allows baby’s skull to expand and keep pace with its rapidly growing brain.
Tooth enamel is the hardest substance in the human body. It is a 96% mineral.
Bones are 4 times stronger than concrete.
The human skeletal system is connected by a network of tendons, ligaments, and cartilage.
The average tongue is about 3 inches
The average stomach comfortably holds about 1.5-2 liter or about half a gallon, although it can stretch to a gallon
Vaccines work by stimulating the immune system to create antibodies for a specific disease. The immune system is able to remember infections and fight them off better through antibodies.
The brain consists of six parts: frontal lobe, temporal lobe, parietal lobe, occipital lobe, cerebellum, and brain stem.
The three kinds of muscles are skeletal, for movement, cardiac, for the heart, and smooth in the digestive system.
The large intestine is about 5 feet. The small intestine is about 20 feet long.