Download Organ Systems Overview Rat Dissection and Observation

Name _____________________________________ Period __________
Organ Systems Overview
Rat Dissection and Observation
Objective 1: Identify several organs of the various organ systems on a dissected rat.
Now you will have a chance to observe the size, shape, location, and distribution of some organs and their organ systems.
Many of the external and internal structures of the rat are quite similar in structure and function to those of the human.
Note that four of the organ systems will not be studied at this time (integumentary, skeletal, muscular, and nervous), as
they require microscopic study or a more detailed dissection.
Safety Precautions: gloves, lab coat, goggles
Check off as you locate and observe the following structures:
Oral cavity (teeth, tongue)
Pin rat to wax tray dorsal side down. Cut through skin layer as shown in diagram. Carefully cut through muscles of
abdominal wall in the pubic region to avoid underlying organs. Make a cut from the pubic region to the rib cage and
lateral cuts at the base of the rib cage. Cut the diaphragm to loosen the rib cage.
Heart
Lungs (left and right)
Observe throat region
Trachea
Bronchi
Push trachea to one side
Esophagus
Diaphragm
Stomach
Small intestine
Large intestine
Large intestine begins at cecum and ends at rectum
Cecum
Rectum
Anus
Lift intestines to view mesentery.
Mesentery (delicate membrane that suspends small intestines)
Pancreas (lift stomach to view)
Spleen (dark red organ curves around stomach)
Liver (large and brownish red)
Gently move stomach and intestines to one side
Kidneys (bean-shaped organs secured to posterior wall of body)
Adrenal glands (sit on superior margin of each kidney)
Strip away part of the membrane covering one kidney
Ureters
Urinary bladder
Urethral opening
Look along midline of body between kidneys
Inferior vena cava (large vein that returns blood to heart from lower body)
Abdominal aorta (deep to inferior vena cava; largest artery in abdominal cavity)
Determine if animal is male or female (saclike scrotum and single body opening=male; three body
openings=female) _________________
If male,
Scrotum
Testis (oval-shaped)
Epididymis (coiled tube connecting testis to ductus deferens)
Ductus deferens or vas deferens(sperm duct that joins urethra)
Penis
If female,
Uterus (Y-shaped)
Ovary
Vaginal orifice (external vaginal opening)
Please clean tools and lab table! Specimens will be saved and used for lab practicum.
Objective 2: Identify several organs on a dissectible human torso model, and, given a list of organs, assign each to the
correct organ system.
Dorsal body cavity: brain, spinal cord
Thoracic cavity: heart, lungs, bronchi, trachea, esophagus, diaphragm, thyroid gland
Abdominopelvic cavity: liver, gall bladder, stomach, pancreas, spleen, small intestine, large intestine, rectum, kidneys,
ureters, bladder, adrenal gland, uterus, abdominal aorta, inferior vena cava
Assign each of the organs identified on the human torso model to one of the following organ system categories.
Digestive
Urinary
Cardiovascular
Endocrine
Reproductive
Respiratory
Lymphatic
Nervous