Organ Systems
The human body consists of hundreds of organs that belong to groups known as systems .
The number and naming of systems is open to debate, but for this class you need to learn twelve.
You need to know the function of each system and be able to recognize which organs belong to each, but be careful, some organs belong to multiple systems.
Activity 1: For these activities you must work as part of a team. Your instructor will either assign you to a team or tell you how many people will work in each group. Your first task is to introduce yourself to your team and list your team members' names below.
Your team members: _________________________________________________________________
Activity 2: One way to start learning about organ systems is with a list of them, but just reading or copying what is in the book does not cause learning. Below is a three-step process to make a list of the organ systems, it takes longer to do, but stimulates your brain more.
Step 1: Brainstorm As a group name as many systems as possible in 5 minutes without discussing them. The goal is to make a long list that you will later edit. Do not use your books in this step, just your brains. Take turns so that everyone participates. Record every system named on a separate sheet of paper.
Step 2: Discuss Now work together to edit your list. Take turns making comments on which are wrong, synonymous, or related ideas. Use your book to help make decisions or add missed systems to your list. This process takes a while but is where learning begins. When your group has agreed on 12 systems, list them below then check with another group or your instructor to see if they agree.
Step 3: Mnemonic As a group create a 12-word sentence where each word starts with the same first letter as one of your systems, the order doesn't matter. In astronomy "my very educated mother just served us pizza" helps students recall the planets in order from the sun are: Mercury,
Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Pluto if Pluto is still considered a planet).
Our mnemonic:

Organ Systems
Activity 3: Now that you know what the twelve systems are, it is time to look at which organs belong to each. Your book lists many organs belonging to each system, so compare those lists to models in the lab. List at least 2 organs that we have models of in the lab that belong to each system so that you can recognize the systems.
Major Organs System Represented
1. ________________________
2.
3.
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4.
5.
6.
________________________
________________________
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7.
8.
9.
10.
________________________
________________________
________________________
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11.
12.
________________________
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Activity 4: A final way your team can learn about organs is to see the real thing. Whether viewing a rat, cat or human you will see amazing similarities in the color and shape of organs based on their functions. Choose roles for each team member then follow the procedures listed.
Each team needs 1) an Administrator who reads the directions aloud & records findings; 2) a
Technician to gather equipment, clean-up & put supplies away; a Surgeon who handles scissors and scalpel; and an Assistant to help the surgeon. To begin the Administrator should have a pen to underline key words, the surgeon and assistant must glove up and get specimen, while tech collects: a wax-filled dissection pan, 1 scalpel with blade attached, 1 pair of scissors, 2 pair of forceps, 2 probes (one blunt and one sharp tipped), and about a dozen pins.
1. External anatomy : Place the rat on its dorsal surface in a dissecting tray, & pin its appendages to the tray distally. Begin by observing the rat's integumentary system. Look at the skin, hair & claws. Open the oral cavity to see some accessory organs of the digestive system, the teeth & the tongue. Look in the pubic region to determine their gender.

Organ Systems
2. Superficial layers : make a shallow incision on the ventral surface of your rat, just caudal to the mental region. Carefully extend the incision inferiorly along the median toward the pubic region. After each cut, pull the skin laterally to free it from the superficial fascia (a thin layer of connective tissue) & pin it to the tray. Cut laterally along the ventral surface of an extremity to the carpal or tarsal region. Reflect back & pin down the skin from the appendage as well.
3. Appendages : observe your rat's skinned extremity. Look for dark pink muscles, shiny white tendons, & feel the deeper bones. These organs work together, so they are sometimes referred to as the musculoskeletal system .
4. Cervical region : at the superior end of your main incision, clean away any scraps of connective tissue & the muscles to expose the laterally located salivary glands that secrete into the oral cavity. Along the median see & feel the cartilaginous larynx & trachea, parts of the respiratory system. To find the esophagus, look posterior to the trachea.
5. Thoracic cavity : to open the thorax find the inferior border of the rib cage. Make an incision through the abdominal muscles, then cut laterally in both directions. This should expose the diaphragm that is a muscle, attached to the bones of the rib cage laterally, used in breathing.
Separate the diaphragm from the ribs along its lateral edges. Next cut cranially from the inferior edge of the rib cage along a slightly parasagittal plane to avoid the bony sternum & instead cut through the costal cartilages. Once you have cut through the clavicles at the superior edge of the thorax, spread the halves of the rib cage laterally & pin them to the dissecting tray. Notice the laterally positioned lungs, & the medially located heart still inside the pericardial sac. In the superior, anterior mediastinum you should find a pale colored gland, the thymus that produces hormones to activate lymphocytes in juveniles.
6. Abdominopelvic cavity : cut through the abdominal muscles along the midsagittal plane & pin back the two sides, you may need to make additional laterally incisions in the inguinal region. Near the diaphragm on the rat’s right side you should see the dark red liver, on the left the less colorful stomach. Posterior or lateral to the stomach will be the largest organ in lymphatic system, the dark red spleen. Inferior to all these are the small intestine held to posterior wall by the mesentery & the large intestine (often still containing feces). Uncoil the intestines to determine which is longer.
7. Deep organs : with the intestines out of the way, look for the organs up against the posterior wall belonging to the urinary & reproductive systems. The laterally located kidneys are dark red with nearly transparent ureters leading inferiorly to the urinary bladder. Look superior to the kidneys for the hormone producing adrenal glands. Compare the location & appearance of testes
& ovaries using other teams' rats.
8. Cranial cavity : if time allows, attempt to cut through the cranial bones to see the brain. See if you can separate it from the rest of the nervous system.
9. Clean-up : rats & all tissue from them go into marked container. Gloves & paper towels can be thrown into trash. All equipment must be washed with soapy water and/or bleach, dried & returned to cabinets. Clean desktops with soapy water and/or bleach.