1. Spleen
   Pancreas
2. Small intestine

The pancreas releases insulin into the bloodstream, helping regulate blood sugar levels.

1. Liver
   Skin
2. Lungs

Skin is classified as an organ and is the largest organ of the human body. For an adult, skin can weigh eight pounds and measure 22 square feet.

1. Two
   Four
2. Six

The human heart uses four chambers to circulate blood through the body: the left atrium, right atrium, left ventricle and right ventricle.

1. True
2. False

While the spleen does function to filter blood and manage the immune system, humans can live without it. Other organs (e.g., the liver) take on the functions of a spleen when it is removed.

1. Fallopian tube
   Uterus
2. Ovary

Ovaries are almond-size organs in the female pelvic cavity that produce eggs.

1. Liver
   Gall bladder
2. Appendix

The gall bladder is located under the right lobe of the liver and stores bile for digestion. Bile is a yellow-green fluid that is excreted into the small intestine to break down fatty foods.

1. Lungs
   Liver
2. Pancreas

In addition to filtering blood, the liver produces important proteins like albumin.

1. Ears
   Eyes
2. Nose

The semicircular canals are located in the inner ear and contain hair cells that are activated by movement of fluid within each canal.

1. Endocrine
   Respiratory
2. Nervous

The nervous system includes ganglia and neurons and responds to internal as well as external stimuli.

1. Thyroid
   Gall bladder
2. Adrenal gland

The adrenal glands produce hormones that trigger the "fight or flight" response. These hormones (adrenaline and noradrenaline) increase blood pressure, heart rate and oxygen intake and prepare the body for action.

1. Brain
   Stomach
2. Heart

The human brain weighs an average of three pounds and is approximately 73 percent water. Attention, memory and other cognitive skills are affected by as little as a 2 percent drop in hydration.

1. Uterus
   Stomach
2. Bladder

The uterus is a muscular female organ located in the pelvis. It has a pre-pregnancy size of a pear, but during pregnancy can stretch to the size of a watermelon.

1. Integumentary
   Respiratory
2. Nervous

The trachea, bronchi and alveoli are all parts of the respiratory system.

1. Adrenal gland
   Thyroid gland
2. Prostate gland

The thyroid gland regulates metabolism and maturation of the human body.

1. One
   Three
2. Five

The integumentary system, commonly known as skin, is made up of three main layers: the epidermis, dermis and the hypodermis.

1. Reproductive
   Biliary
2. Urinary

As part of the urinary system, kidneys filter blood and produce urine.

1. Ear
   Eye
2. Nose

The cochlea is an organ that translates sound into nerve impulses which are sent to the brain. Humans have two cochlea. They are snail-shaped caverns in the mastoid bones behind each ear.

1. Large intestine
   Small intestine
2. Stomach

The large intestine extracts moisture from food particles and excretes the unusable waste. The portion of the large intestine between the cecum and the rectum is called the colon.

1. True
2. False

At a length of approximately 20 feet, the small intestine is indeed the longest part of the digestive system.

1. Bladder
   Kidneys
2. Gall bladder

The bladder is a muscular organ that stores urine before expelling it through the urethra.

1. Kidneys
   Pancreas
2. Spleen

The spleen filters out old as well as damaged red blood cells. The spleen can recycle useful components, such as iron, when the old cells are broken down.

1. Ears
   Nose
2. Eyes

Rod and cone cells are the two photoreceptors of the human eye. Rods are most sensitive to light and dark transitions as well as movement. Cones are sensitive to color.

1. Spleen
   Appendix
2. Pineal gland

The pineal gland is the smallest human organ, and it is located near the center of the brain. The pineal gland produces a hormone called melatonin, which affects how humans sleep.

1. Pyelonephritis
   Kidney dysplasia
2. Unilateral renal agenesis

Unilateral renal agenesis is a condition in which a person is missing a kidney at birth. Most people experience no symptoms or complications.

1. Endocrine
   Integumentary
2. Circulatory

The endocrine system is made up of glands and secretes hormones to regulate a number of body functions.

1. Left
   Right
2. Neither

The right lung is larger and heavier than the left. The left lung is smaller because of the position of the heart.

1. Liver
   Pancreas
2. Stomach

The stomach is a bean-shaped organ about the size of a fist. Food is swallowed through the esophagus and churned by the stomach before passing on to the small intestine.

1. Organ
   Skeleton
2. System

An organ is defined as a group of tissues that perform a specific function or group of functions.

1. Small intestine
   Stomach
2. Large intestine

The small intestine contains the duodenum, jejunum and ileum. The primary functions of the small intestine are to digest food and absorb nutrients.

1. True
2. False

Carbon dioxide (not monoxide) and oxygen are exchanged in the lungs. Oxygen is inhaled into the lungs and carbon dioxide is exhaled.