Dissection of the Rat

An Exploration of the Various Organs Systems

Day 1: Guiding Questions #11. Make a list of instruments you’ll be using and the number of each.2. After reading the objectives of the lab, how many organs for each system

are you required to know and identify.3. Name the two major regions of the integumentary system. Name three

functions of this system.4. Name the four key parts to the skeletal system. What does Hemopoiesis

mean?5. What is the only function of the muscular system? Name the three parts

of the body mentioned that the muscular system plays a role.6. Name the three parts of the nervous system. Which parts make up the

central nervous system?7. Name two functions of the endocrine system. What chemical is

produced by the glands that make up this system? How is this system different from the nervous system? Name the eight types of organs that make up this system.

Guiding Questions #21. What purpose does the circulatory system serve? What is it

primarily composed of?2. Name the six key structures that make up the respiratory

system. What purpose does this system serve? Name the minute little sacs in the lungs that help with gas exchange.

3. Name the six parts of the digestive system. Where does digestion begin? Which part of the system is used to remove water from the food?

4. What roles do the pancreas and liver play in the digestive process?

5. Name one of the key waste products excreted by the Urinary system. Name the four main organs of this system.

6. Name the key structures of the male and female.

Initial Procedures to Begin the Dissection

• Dissection Guide: turned to the appropriate pg.• Instruments: see list• Paper towels• Water cup (half-filled) & dropper• Lab coat (optional)• String tied to each limb to immobilize the rat.• Freezer Bag: Names of lab partners (2-3)

-Preliminary (male & female) names for your rat

Guiding Questions #31. From your dissection guide which chapter discusses the

muscular system?2. Before identifying the muscles the rat must be skinned. The

first incision to be made begins on the - surface of the _____ and continues down to the point just anterior to the ______.

3. Circumvent cuts are made to the (right,left) by the genetials and mouth. How does the guide suggest that you separate the skin from the body?

4. Before separating the muscles and identifying them you first need to remove the tough white connective tissue that surrounds the muscles. Name this tissue.

5. Using Figure 14 (lateral view) list all of the muscles labeled in the diagram. You will ID these in your rat first.

General Rules• No Food or Drink at your Station at all times• Remain at your station at all times unless

instructed• Keep track of all instruments (do a count

everyday)• No open toed shoes• Do not cut anything unless instructed• Always follow your Dissection guide

Instruments • 1 dissecting pan• 1 Lg. Freezer Bag• 4 pieces of string (25 in each)• 2 forceps (fine & blunt)• 1 scapel• 2 blunt probes• 4 sharp probes• 12 pins• 2 scissors (tissue & paper)• Water dropper & cup• Ruler • Index card (labels)

Basic Procedure1. Ventral Incision & Extension to the limbs2. Separating skin from the underlying muscles3. Separate the fascia off the muscle4. Identify the indicated muscles

-Make labels for structures listed on overhead

Separate & ID these Muscles (10 muscles)

-Masseter -Sternomastoideus-Spinodeltoideus -Latissimus dorsi-Triceps -Brachialis-Biceps femoris -Gluteus Maximus-Tensor fascia Latae -Semitendinosus

Please use the following in your guide:

Lateral View (Pg. 16, Fig 14)

Lateral View of the Muscles

Muscles to locate & ID from Ventral view (14 muscles)

-Pectoralis major -Biceps brachii-Pronator teres -Flexor carpi radialis-Palmaris longus -Triceps-Pectoralis minor -Rectus abdominus-External oblique -Sartorius-Gracilis -Gastrocnemius-Vastus medialis -Semimembranosus

Ventral View of the Muscles

Guiding Questions #4(Ch. 4 Digestive system)

1. Name the three pairs of salivary glands commonly found in the rat.2. Within the mouth cavity if you were to look inside you would

observe a hard and soft palate. Where are they specifically located? 3. After opening the abdominal cavity you should be able to locate the

esophagus and follow it to the stomach. Name two structures that would be located next to the stomach.

4. On page 28 of your guide sheet the diaphragm separates two cavities. Name them.

5. How many lobes is the liver is divided into? Name them. 6. Name the three regions of the stomach. How is the great omentum

different from the lesser omentum?7. Where is the spleen located with reference to the stomach?8. Name all of the structures discussed from #11 to #19.

Guiding Questions #4(Ch. 4 Digestive system cont’d)

Tasks to still complete:Finish separating the intestinal tract from the mesenteryTransect the intestine from STOMACH end off the esophagus-Measure the length of the intestines (____ cm.)-Make a cross section of the stomach and make observations -Label all key structures

Be sure you have the following labels and pin these on your rat

Set #1 Set #2-Liver (left lateral lobe) -Ureter -Heart (atrium & ventricle) -Jugular (left)-Small intestine -Trachea-Spleen -Vena Cava-Kidney (right)-Aorta (abdominal)-Lung -Iliac artery-Diaphragm -Renal artery & vein-Thymus gland-Carotid (right)-Mesentery *(2) male or two female struct.-Large intestine (caecum)

Contents of the Abdominal & Thoracic Cavities

Digestive System

Guiding Questions #5(Ch. 5 Circulatory system-Pgs 31-36)

1. What was injected into the veins and arteries of your rat? Why was this done?

2. The pericardial membranes surround the . Name the two types of membranes present. How are these two membranes different from each other?

3. Which area (chamber) does blood enter the heart? Name the vein that drains blood from the lungs to the left atrium.

4. Name the structure that divides the two ventricles of the heart.5. How many branches come off the aortic arch? Name them. 6. Where are the following arteries found?

-coronary, carotid, subclavian, hepatic, gastric, femoral, caudal and intercostal? 7. Is the jugular a vein or artery?8. What is the difference between an artery and a vein? Which one moves

blood away from the heart?

Tasks to complete for the Circ. System

• Find the FIVE major vessels off the aorta• Cross section of the heart• Trace major blood vessels in the arms and

legs

Internal Chambers of the Heart

Thoracic Cavity

Arterial System

Guiding Questions #61. Name the five branches that come off the aortic arch.2. How many chambers does the heart have? (After

splitting the heart in two).3. Find the following blood vessels in your rat and label

them: Carotid artery, Pulmonary artery, Vena Cava, Aorta, Renal, and iliac arteries (left & right).

5. Name the gland that sits on top of the kidney. (see Chapter IV.

6. The kidney are said to be “retroperitoneal” what does this mean?

7. Name the small tubular structure that comes out of the kidney and into the urinary bladder

Tasks to Complete for Urinary System

• Trace the three main structures that come to and from the kidney

• Trace the ureters from the kidney to the bladder

• Locate adrenal glands• Cross section of the kidney

Male Reproductive System

Female Reproductive System

Tasks to Complete for Reproductive System

• Determine sex • Find major structures to verify the sex