Major Organs
This organ filters blood and produces urine.
What is the kidney
Unlike humans, rats lack this small organ that stores bile.
What is the gallbladder
This structure separates the thoracic and abdominal cavities and helps with breathing.
What is the diaphragm
This organ begins digestion by mechanically breaking down food.
What is the mouth
These bean‑shaped structures are found on either side of the spine in the abdominal cavity.
What are the kidneys
This muscular organ pumps blood throughout the rat’s body.
What is the heart
Rats have this inferior external structure, while humans have none.
What is the tail
This organ pumps blood throughout the body.
What is the heart
This long tube connects the mouth to the stomach.
What is the esophagus
This organ sits just under the liver and is J‑shaped.
What is the stomach
This organ stores glycogen and detoxifies chemicals; it’s large and dark in rats (because they have a terrible diet).
What is the liver
Humans have 5 lung lobes total; rats have this number.
What is 4 (one left, three right)
These organs are responsible for gas exchange.
What are the lungs
This organ absorbs most nutrients after digestion.
What is the small intestine
This thin membrane holds the intestines together and contains blood vessels.
What is the mesentery
This organ is responsible for gas exchange and has fewer lobes on the left side.
What are the lungs
Rats’ ____ grow continuously throughout life, unlike humans’ ____.
What are their incisors / teeth
This major blood vessel carries blood away from the heart.
What is the aorta
This organ reabsorbs water and forms feces.
What is the large intestine
This gland sits on top of the heart in young rats and is involved in immune development; this structure is most prominent in extremely young or old people.
What is the thymus
This organ lies under the stomach and produces digestive enzymes and hormones.
What is the pancreas
Rats rely heavily on this digestive structure for breaking down plant material, while humans have only a small version of it.
What is the cecum (appendix)
This system transports oxygen, nutrients, and waste throughout the body.
What is the circulatory system
Rats have a more prominent version of this organ than humans because they digest more plant material (in humans it’s called the appendix).
What is the cecum
This hollow muscular organ stores urine before it leaves the body.
What is the bladder