Name___________________________________________________



Name___________________________________________________

|Cat Dissection Instructions |

This packet is going to be your instructions and guide to dissecting the cat. The packet is going to be worth 100 points. As you go through the packet and dissection, there will be questions that you need to answer. Instead of doing a cat practical or test, you will be completing a cat project that will be worth 90 points (due March 1, 2012). The rubric and guidelines are included in this packet. Some general rules about dissecting the cat:

• Any “horseplay” during the dissection will result in an immediate dismissal of the cat project. You will not be allowed to participate in the cat dissection from then on and will get a referral.

• You are welcome to check out other groups cats, however please do not wonder around as people are cutting.

• In general, leave the specimen intact as much as possible. All parts of the cat should be kept in your bag. DO NOT THROW AWAY PARTS OF THE CAT IN THE NORMAL TRASH CAN. Leave it in your bag and all cat parts will be thrown away together (in an ethical manner).

• You must clean up your desks after dissection. If class is left messy you will be getting extra work.

|DAY ONE 2/7/2012 |

|Materials: This packet, pen/pencil, your brain |

|INTRODUCTION TO THE CAT: You will have a quiz on this section on 2/9/2012. You must get an 80% on the quiz to start the dissection.|

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|Why dissect a cat? Charts cannot give a complete idea of what an organ or organ system is like. The concentration and involvement |

|in searching out structures aids learning and develops skills that may be of later use. A cat is large enough for its internal |

|organs (which are much like our own) to be found easily and for its blood vessels to be traced, but not so large as to present |

|special difficulty in storage and handling. |

|While dissecting, observe these safety precautions. Wear safety glasses or regular glasses to protect the eyes if you have |

|allergies or sensitive eyes. Contact lenses are not encouraged to be worn on dissection days. Gloves will be provided to you to |

|protect your hands. You must wear the gloves. If you would like, please bring in an old sweatshirt/t-shirt to wear during the |

|dissection so your clothes don’t get nasty! Sharp instruments must be used with caution. |

|It will often be necessary to refer to certain directions or positions relative to the cat’s body or its organs. The terms listed |

|are the ones you are responsible for: lateral (toward the side), medial (toward the midline), proximal (near or toward the point of|

|reference), distal (away from the point of reference), dorsal (toward the back), ventral (toward the belly), anterior (toward the |

|head), and posterior (toward the tail). In observing the positions and relationships of internal structures, it’s useful to imagine|

|the body as being sectioned along certain fixed planes of reference. There are three major planes: sagittal (divides the body or |

|organ into left and right positions, will produce a longitudinal section), transverse plane (perpendicular to the long axis, cross |

|section), and frontal plane (divides the body into dorsal and ventral portions). |

|DAY TWO 2/9/2012 |

|Materials: This packet, pen/pencil, your brain, computer |

|ANIMAL ETHICS: |

|You are going to be conducting a trial on if animals should be dissected. You are going to get into groups of four. Two people will|

|argue for animal dissection and two people will argue for banning animal dissection. You will have 45 minutes in the computer lab |

|to find facts and make your case. You need at least a page of information from the internet with the sources listed. After the Dell|

|lab you will have 5 minutes to compile your thoughts with your partner. For the last 40 minutes you will go back and forth and |

|argue your cases. There will be no yelling, major arguments, threatening statements, etc. If I see this going on you’ll be asked to|

|stop and be given a worksheet to complete. One group will state one point and the opposing side will come up with a rebuttal. You |

|will go back and forth with these points. Keep track of the points and comments being made below. This will count for 30 points (15|

|points for the Dell lab information and 15 points for the sheet below). |

|Website suggestions: |

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|DAY THREE 2/13/2012 |

|Materials: Dissecting pan, paper towels, dissecting kit, gloves, this packet, pen/pencil, your brain |

|You will have a quiz on this section on 2/13/2012. You must get an 80% on the quiz to start the dissection. |

|EXTERNAL ANATOMY AND SKINNING THE CAT: |

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|Spend a few minutes examining the external anatomy of your cat. Like most mammals, the cat is almost completely covered with a |

|dense coat of hair. The primary function of mammalian hair is insulation, but there are interesting secondary functions as well. |

|The cat has around its mouth, cheeks, and eyes, long hairs called vibrissae. These have a sensory function, allowing the cat to |

|“feel” its way in darkness. |

|Other important sense organs located on or opening onto the head include the eyes, ears, and nose. The external nares (nostrils) |

|are separated by a groove, the philtrum, which forms a cleft in the upper lip. In man the philtrum is normally closed and flat. The|

|eyes face forward, giving the cat stereoscopic vision. Spread apart the upper and lower eyelids and locate, in the medial corner of|

|the eye, the third eyelid or nictitating membrane. In life this is a transparent layer that helps protect and cleanse the eye. |

|Mammanls are the only animals that have pinnae, external ear structures. These pinnae protect the ear openings and reflect sound |

|into the middle ear. |

|Mammalian digits (toes) are usually tipped with claws, hooves, or nails. Carnivores have claws, and the cat’s claws are highly |

|specialized so that they can be retracted. This protects them from being dulled by contact with the ground, yet they can be brought|

|into play when needed. Notice that one claw on each foot is raised above the level of the rest. On the undersurface of each foot |

|are epidermal thickenings called friction pads or tori. These cushion the step and give traction. There are seven tori on each |

|forefoot and five on each hindfoot. |

|Mammals are animals with mammary glands. Cats have two rows of about five mammary glands each. Look for the nipples to the left and|

|right of the ventral midline. |

|The cat’s tail is well developed and often expresses the cat’s mood. The anus, the posterior opening of the digestive system, is |

|located just ventral to the base of the tail. |

|The external genitalia are the external sexual structures. Examine specimens of both sexes for these. The urogenital aperture, the |

|opening of the female urogenital tract, is just central to the anus. At a similar location on the male is the scrotum, a sac |

|containing testes. Immediately anterior to the scrotum is the prepuce, a slight swelling into which the penis is normally |

|retracted. |

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|Questions and Discussions |

|What is the purpose of the dense hair? |

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|Find the sensory hairs around the mouth and cheeks. What is the purpose of these? |

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|The eyes are bounded by the upper and lower eyelids. What is the name of the third membrane found in the cat eye? What is its |

|purpose? |

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|With gloves on, remove the cat from its bag and lay the cat on a dissecting tray. |

|Place your cat ventral surface up on the dissecting tray, as seen in the picture packet. |

|Identify the gender of the cat. Males have a scrotum and prepuce. Females have a urogenital aperture. Four or five nipples are |

|present on both male and female cats. |

|My cat is a ________________________________________ |

|Prepare a label for your cat with the names of your group members and the gender of the cat. |

|Do not use the scalpel for skinning. You will damage the inside of the cat. |

|Place the cat on its back. There should be a cut on the neck where the blood vessels were injected. Beginning at that point, lift |

|the skin with the forceps, insert the blunt tip of your scissors and cut forward to the “chin”. |

|Notice a white, fibrous tissue, the superficial fascia, connects the skin to the underlying tan-colored muscles. |

|Now extend the cut posteriorly along the ventral midline to the external genitalia. |

|Cut around the genatalia, the anus, and the base of the tail. |

|Extend the cut down each limb and around each “wrist” just before the paw. |

|Also cut around the mouth to the eyes and around the eyes and ears. |

|As you cut the skin, lift it up and use the blunt probe or fingers to separate the skin from muscle. |

|In some places you may have to use the scissors to get the skin to separate properly. Work with the tip of the probe or scissors |

|against the skin rather than against the muscle. This will prevent damage to the muscles. |

|Remove the skin as a whole piece rather than cutting into bits. |

|As you skin the thorax, you will find the cutaneous maximus, the cutaneous muscle that twitches in the skin. In the neck area is a |

|second cutaneous muscle, the platysma. It is almost impossible to remove skin without damaging these muscles, and they must be |

|removed before the skeletal muscles can be studied. LEAVE THE CUTANEOUS MUSCLES IN TACT FOR NOW. |

|Carefully remove as much fat and superficial fascia as possible with your fingers or forceps. |

|Wrap the skin around the cat and place the cart back into the bag. Wrap the bag with rubber bands. The skin will prevent the |

|tissues from drying out and prevent the growth of bacteria and mold. |

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|Questions and Discussions |

|Thus far you have observed at least two features that are unique to mammals. List these. |

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|List the body surface areas that are not covered by hair. Give possible reasons for the lack of hair in these areas. |

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|List some external features of your specimen that are specializations for a predatory life. |

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|DAY FOUR 2/15/2012 |

|MUSCLES AND ORAL CAVITY OF THE CAT |

|You will have a quiz on this section on 2/15/2012. You must get an 80% on the quiz to start the dissection. |

|A muscle consists of a fleshy portion or belly, which is attached at both ends to a bone or another muscle by connective tissue. |

|The connective tissue may be a tendon or a flattened band called a aponeurosis. When a muscle contracts, one end usually remains |

|more-or-less fixed while the other end moves. The fixed end is called the origin and the movable end is the insertion. Muscle |

|origins are usually medial or proximal. Insertions are usually lateral or distal. |

|Muscles can be classified according to their actions as follows. |

|Flexor- bends a joint |

|Extensor- straightens a joint |

|Abductor- moves a part away from median plane |

|Adductor- moves part toward the median plane |

|Levator- raises a part |

|Depressor- lowers a part |

|Rotator- twists or rotates a part |

|Sphincter- closes or constricts an opening |

|Dilator- opens an opening |

|As you might guess from the list above, muscles tend to work in opposing pairs. This is because a muscle works only when it |

|contracts; it cannot exert force when it relaxes. |

|The muscles are covered and held tightly together by connective tissue. Therefore, careful, slow work is required to expose them. |

|Dissect the muscle groups in the order in which they are shown below. It may be difficult to find the separation between two |

|adjacent muscles. If so, use caution or you can “create” a muscle. It will be necessary to transect and reflect (fold back) |

|superficial muscles to expose deeper muscles. This is accomplished by cutting through the belly of the superficial muscle and |

|reflecting its cut halves. I recommend that deep muscle dissection only be done on the LEFT side. Then in case of a major error, |

|the right side will be available. This will also leave the right blood vessels and nerves intact for later dissection. |

|Chest muscles: The chest muscles are large and easy to dissect, making the chest a good place to start. In exposing the deep chest |

|muscles, you will find nerves and blood vessels coming out of the lateral chest wall and going into the arm. Try to leave all blood|

|vessels and nerves intact. |

|Transect and reflect the following to expose the deep chest muscles: pectoantibrachialis, pectoralis, pectoralis minor, |

|xiphihumeralis, and clavobrachialis. |

|The levator scapulae ventralis, pectoantibrachialis, transverse costarum, and xiphihumeralis have no human homologues. The |

|clavobrachialis, acrominodeltoid, and spinotrapezius are collectively homologous to the human trapezius. The pectoralis major may |

|seem misnamed in the cat, but in humans the pectoralis major is much larger than the pectoralis minor. |

|Head and neck muscles: Also shown here are three of the salivary glands and thyroid gland. Although there are other salivary |

|glands, they are small in the cat and difficult to find. The salivary glands are easily confused with the large lymph nodes in the |

|area. The lymph nodes are smooth while the salivary glands are bumpy. The thyroid gland is part of the endocrine system. |

|This area of the neck was cut for injection of blood vessels, and the resulting damage determines the exact procedure used to |

|expose the deep muscles. |

|The sternomastoid, stylohyoid, and sternohyoid must be transected and reflected. |

|Forelimb muscles: The dissection of the forelimb muscles require extra care because they are small and tightly packed. A tough |

|sleeve of connective tissue covers the forearm muscles and must be removed. |

|Transect and reflect the following to expose the deep muscles of the medial forelimb: triceps, brachioradialis, extensor difitorum |

|communis, extensor digitorum lateralis, flexor carpi ulnaris. |

|The following must be transected and reflected for the deep muscles of the lateral forelimb to be seen: epitrochlearis, Palmaris |

|longus, flexor carpi ulnaris, flexor carpi radialis. |

|The anconeus and epitrochlearis have no human homologues. The extensor carpi radialis brevis, extensor difitorum lateralis, and |

|Palmaris longus are relatively smaller in humans, and the Palmaris longus is missing in about 10% of the human population. |

|Hind limb muscles: Dissecting the hind limb muscles presents few problems other than identifying some muscles of the lower leg. |

|Transect and reflect the biceps femoris to expose the deep muscles of the lateral hind limb. The delicate tenuissimus will be torn |

|by this procedure. |

|Do not try to trace the origin or insertion. |

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|Questions and Discussions: |

|Choose a muscle and describe the impairment a cat might suffer if that muscle were paralyzed. What other muscles might compensate |

|for the impairment? |

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|DAY FIVE 2/17/2012 |

|INTERNAL ORGANS (DIGESTIVE SYSTEM AND CIRCULATORY SYSTEM) |

|THE DIGESTIVE SYSTEM |

|You will have a quiz on this section on 2/17/2012. You must get an 80% on the quiz to start the dissection. |

|The mammalian body has two major cavities, the abdominal and thoracic, which contain all the internal organs exclusive of the |

|brain. These two cavities are divided by a sheet of muscles, the diaphragm. Mammals are the only vertebrates with a muscular |

|division between thorax and abdomen. We must first open the two body cavities. |

|Begin by opening the abdominal cavity. To do this, locate the posterior end of the sternum. |

|Use forceps to lift the abdominal muscle just posterior to the sternum and cut through the muscles and into the abdominal cavity. |

|Be careful that you do not puncture the internal organs. |

|Insert the blunt tip of the scissors into the cut and make an incision to one side of the midventral line to the posterior end of |

|the abdominal cavity (see picture to right). |

|Beginning at the anterior end of incision, make lateral cuts following the posterior margin of the ribs. |

|Make lateral cuts through the body wall at the posterior end of the abdominal cavity (male cats have cords running from the |

|posterior abdomen along the surface of the thigh muscles to the scrotum. Leave these undamaged). |

|Fold back the lateral body wall and pin it out of the way. |

|If you find a dark brown substance coating the abdominal viscera, blood has leaked into the abdomen and must be flushed out. Rinse |

|the abdomen with the squirt bottles until the viscera is clean. Soak the water out with paper towels. |

|Open the thoracic cavity as follows: |

|Use heavy scissors to cut through the ribs about one cm to either side of the sternum. When all the ribs are cut, lift the sternum,|

|and hold it in place while cutting the underlying membranes until the sternum comes free. Either cut the ribs along the sides of |

|the chest or break them to expose the thoracic cavity (I suggesting breaking them). |

|Use the scissors to cut the bones at the corners of the jaw until a clear view can be had of the interior of the mouth. Digestion |

|begins here with the cutting of food into chunks that can be swallowed. The three major salivary glands, the sublingual, |

|submaxillary, and parotid were exposed when dissecting the neck muscles. There are two other salivary glands, the molar and |

|intraorbital. All the salivary glands empty by ducts into the mouth, where their secretions (saliva) lubricate the food. Saliva |

|also contains enzymes that begin chemical digestion. |

|The rough papillae of the tongue rasp meat off bones. The ridges help grip the food. |

|Just posterior to the incisors are the openings of the two nasopalatine ducts. These communicate with the nasal cavity through the |

|incisive foramens. |

|The palate of the mouth is divided into two parts, the hard palate and soft palate. Near the corners of the mouth are the palatine |

|tonsils, part of the lymphatic system. |

|As food is swallowed, the epiglottis is depressed, closing the glottis, the entrance of the larynx. This prevents food from |

|entering the respiratory tract. |

|The anterior opening of the esophagus can be seen, but most of this tube is covered and will be visible only later in your |

|dissection. |

|Look into the abdominal cavity. Covering the digestive organs is a membrane, the greater omentum. Carefully remove the omentum and |

|locate the organs shown in the picture packet |

|The urinary bladder and spleen are not digestive organs. The spleen is important in the lymphatic system and the bladder is part of|

|the excretory system. |

|The most obvious feature of the digestive system is its marked asymmetry. This results from the fact that the system is coiled to |

|fit into a body that is much shorter than the digestive system. An herbivore has a proportionately longer digestive system than a |

|carnivore. |

|The stomach is a curved muscular sac. The anterior, concave surface is called the lesser curvature while the posterior, convex |

|surface is called the greater curvature. The esophagus connects the mouth and stomach. Food is moved down the esophagus by waves of|

|muscular contraction referred to as peristalsis. The opening from the stomach is closed by the cardiac sphincter. The connection of|

|the esophagus to the stomach is not visible at this time. |

|The larger, anterior portion of the stomach to which the esophagus attaches is the cardiac region. The small intestine attaches to |

|the pyloric end of the stomach and the pyloric sphincter controls the release of food from the stomach into the small intestines. |

|Gastric glands in the stomach wall secrete a highly acidic digestive fluid that contains pepsin, a protein-digesting enzyme. |

|Muscular contractions of the stomach wall mix the food and gastric juices and by the time the good is released from the stomach, it|

|has become a semisolid material called chyme. |

|The liver and pancreas are two large glands. Bile, a digestive juice secreted by the liver, is stored in the gall bladder. The |

|cystic duct, which drains bile from the gall bladder, is joined by the hepatic duct from the liver to form the common bile duct, |

|which enters the small intestine. Trace the pathways of these ducts, removing membranes. |

|Bile contains enzymes that aids digestion of starches, fats, and proteins. Bile, which is alkaline, also helps neutralize the |

|acidic chyme as it enters into the small intestine. The liver has many functions in addition to the production of bile. In fact, it|

|is the site for so many biochemical reactions that it’s sometimes referred to as the body’s “chemical factory”. The liver is |

|incompletely divided into right and left lobes; each lobe is further divided into medial and lateral lobes. The right lateral lobe |

|is again subdivided into cranial and caudal portions. There is also a small division of the liver, the caudate lobe. To find this |

|lobe, lift the left side of the liver and look dorsally. |

|The pancreas is a two-lobed gland. One lobe, the gastrosplenic, lies near the greater curvature of the stomach. The second lobe, |

|the duodenal, lies along the upper section of the duodenum. The pancreas secretes juices containing enzymes that aid in the |

|digestion of starches, fats, and proteins. The pancreas is also an endocrine gland, producing insulin, which is involved in the |

|regulation of blood glucose levels. |

|The first part of the small intestine is the duodenum, which curves to the right and posteriorly. The duodenum then curves to the |

|left and turns posteriorly again. This posterior turn marks the beginning of the jejunum, the second part of the small intestine. |

|The ileum is the third and final part of the small intestine. There is no clear demarcation between the jejunum and ileum. The |

|jejunum is proximal to the duodenum and the ileum is proximal to the large intestine. There is a small blind sac of the large |

|intestine, the cecum, which extends past the junction of the ileum and large intestine. This is a homologue of the human appendix. |

|The small intestine is the chief organ of chemical digestion and the chief organ of nutrient absorption. Water and some vitamins |

|are absorbed in the large intestine. |

|Like the small intestine, the large intestine has three indistinct sections. These are ascending colon, to which the ileum |

|attaches, the transverse colon, and the descending colon. The ascending colon runs anteriorly along the right. The short transverse|

|colon passes to the left, and the descending colon runs posteriorly to the rectum, the terminal portion of the digestive tract. The|

|intestines tend to move about in the living animal. |

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|Questions and Discussions: |

|You have now observed at least one other characteristic unique to mammals. What is it? |

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|Cut open the stomach and describe its internal appearance. |

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|What are the three main salivary glands? |

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|What are the “furry” looking elevations on the tongue? |

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|Locate the epiglottis and push it back. Describe your observations. |

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|What is the function of the gallbladder? |

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|Describe the following parts of the stomach: Cardiac end, pyloric end, greater curvature, lesser curvature. |

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|What do you think causes a burp? |

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|THE CIRCULATORY SYSTEM |

|You will have a quiz on this section on 2/17/2012. You must get an 80% on the quiz to start the dissection. |

|For this system the directions are included in the paragraph below. |

|Anterior Blood Vessels |

|The heart occupies the center of the thoracic cavity and is covered by a tough membrane, the pericardium. In the pericardium is the|

|pericardial vein. Remove the pericardium and locate the anterior vena cava, the large vein attached to the anterior side of the |

|heart. Follow this vein and its branches, locating the veins in the figure to the right. |

|Take careful note of the areas drained by each vein. The internal jugular veins drain the brain and spinal cord. |

|The anterior arteries are generally parallel and dorsal to the veins. Once the veins have been clearly observed, remove them, |

|beginning at the heart (as you do so, try not to damage the nearby nerves). Then locate the arteries shown in the figure to the |

|right. Note which areas are supplied by blood by which arteries. The internal carotid arteries supply the brain. The linguals, as |

|their name implies, go to the tongue and also to the pharyngeal muscles. |

|Heart |

|Lift the heart and cut the vessels and connective tissue attaching the heart dorsally (be very careful!). Identify the parts shown |

|in the figure below. The right ventricle of the heart pumps blood to the pulmonary (respiratory) circulation and the left ventricle|

|to the general or systemic circulation. The arterial ligament is the remnant of the ductus arteriosus which, during fetal life, |

|shunts blood from the pulmonary to systemic circulation. The auricles are sac-like flaps of the atria. The atria receive blood |

|returning to the heart. The ventricles are the main pumping chambers. The dorsal view shows the posterior vena cava, which returns |

|blood from regions posterior to the heart. Also visible are the pulmonary veins and arteries. Trace the connections to the lungs. |

|Open the right side of the heart by making the cuts shown by the dashed lines on the figure below. Locate the structures shown on |

|the figure. The papillary muscles are attached to the flaps of the tricuspid valve by the chordae tendinae and prevent the valve |

|from being pushed into the atrium when the ventricle contracts. Blood from the coronary veins returns to the right atrium through |

|the opening of the coronary sinus. Open the left side of the heart as shown by the dashed lines and arrows of the figure below. |

|Locate the structures shown in that figure. |

|Abdominal Blood Vessels |

|Make an incision near the base of each thigh just lateral to the rectum. Remove the rectum in tact and push the digestive tract to |

|one side, cutting the membranes as necessary to achieve a good view of the dorsal wall of the abdomen. Remove fat and tissue to |

|locate the abdominal vessels shown in the figure below. The adrenal gland shown in this figure is an important endocrine gland. |

|Notice that the aorta, which at first is dorsal to the posterior vena cava, comes to lie ventral to it. Usually a capillary bed |

|gives rise to a vein that joins with other veins, eventually to terminate at the heart; however a capillary bed may also give rise |

|to a vein that terminates in another capillary bed. These are called hepatic portal system, which carries blood from the capillary |

|beds in the intestines to capillary beds to the liver. If yours is a triple-injected cat, the hepatic portal system has been |

|injected with yellow. The intestines and blood vessels are held in place by mesenteries. Also held in the mesenteries are lymph |

|nodes, which may have to be removed before a clear view of the blood vessels can be obtained. |

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|Question and Discussion |

|Which features of the cat’s circulatory system are unique to mammals? |

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|Trace the path of circulation in the adult mammalian heart. How would this differ in the fetus? |

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|Describe the abnormalities of the circulatory system found by yourself or other students. |

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|What is the pericardium? What is its purpose? |

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|DAY SIX 2/21/2012 |

|INTERNAL ORGANS (UROGENTITAL/REPRODUCTIVE SYSTEMS AND RESPIRATORY SYSTEM) |

|You will have a quiz on this section on 2/21/2012. You must get an 80% on the quiz to start the dissection. |

|For this system the directions are included in the paragraph below. |

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|Urogentital System and Reproductive System |

|Push the intestines to one side until the kidneys are located. The kidneys are dorsal to the peritoneum, the membrane that lines |

|the inner body wall and coats the viscera. The kidneys are usually surrounded by a cushioning layer of fat. Both fat and peritoneum|

|must be removed to obtain a clear view of the kidneys. The medial surface of each kidney has an indentation called the hilus, to |

|which are attached the renal blood vessels and the ureter. Follow the ureters to their attachment to the urinary bladder. To locate|

|the attachment site, use forceps to cut through and remove the pubic bones. Once the ureters’ attachments are located, remove more |

|tissue to locate the urethra. |

|Blood brought to the kidneys is filtered to remove waste products, especially urea. Also removed from the blood are substances |

|(such as salt) that have been ingested in excessive amounts. Thus, the kidneys help regulate the osmotic pressure of the blood. |

|Urine excreted by the kidneys goes through the ureters to the urinary bladder for temporary storage. Contractions of the bladder |

|wall force urine out through the urethra. These parts, kidneys to urethra, compromise the urinary system, and they are the same for|

|male and female. |

|The genital system (which is closely associated with and attached to the urinary system) is, different for the two sexes. The male |

|and female cat figures are in the picture packet and labeled. |

|DISSECTION FOR A MALE CAT |

|To dissect the genital system, remove the connective tissue around the urethra and genital parts. There are blood vessels located |

|dorsal and lateral to the rectum and you should be careful not to damage them. |

|Remove the tissue ventral to the urethra to find the junction of the urethra and the vas deferens. At this junction there should be|

|a swelling, the prostate gland. The vas deferens carries sperm from the testes. The prostate gland adds fluid secretions to the |

|sperm, producing the semen. During copulation, muscular contractions of the prostate gland force semen down the urethra through the|

|penis. Along the way, more fluid secretions are added by the bulbourethral glands. The bulbourethral and prostate glands may be |

|small and difficult to locate in young, sexually immature specimen. Near the bulbourethral glands are the ischiocavernosus muscles,|

|which help restrict blood flow from the penis. When these muscles contract, sinuses within the penis fill with blood, erecting the |

|penis in preparation for copulation. Slip the prepuce (foreskin) to locate the glans penis. The glans penis contains nerve endings |

|that are stimulated during copulation, leading to ejaculation of semen. Find the urogenital opening at the tip of the penis. |

|Trace the vas deferens from the prostate gland to the abdominal wall. The vas deferens passes through the wall by way of the |

|inguinal canal. In the inguinal canal, the vas deferens is covered by a sheath and is joined by spermatic blood vessels to form the|

|spermatic cord. Trace this cord to the scrotum. There the outer sheath of the spermatic cord, the tunica vaginalos, encloses the |

|testes. Carefully slit the tunica to reveal the testis and epididymis. |

|DISSECTION FOR FEMALE CAT |

|The ovaries are located just posterior to each kidney. The suspensory, broad, and round ligaments hold the ovary and uterine horns |

|in place. The ovary is held to the uterine horn by the proper ligament of the ovary. A mature follicle is shown in the drawing of |

|the left ovary. Follicles can also be seen by cutting open the ovary. Each follicle contains a developing ovum. The ovum is |

|eventually expelled from the follicle and passes into the oviduct. Notice that there is no direct connection between the ovary and |

|oviduct; rather, the oviduct has an opening that is pressed close against the ovary. If your specimen is pregnant, the uterine |

|horns will be enlarged over the condition. In this case, there will be enlargements along the uterine horns and each enlargement |

|marks the position of the fetus. Cut open the uterus and examine it. One female cat can produce three to four litters of up to six |

|kittens per year. |

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|Questions and Discussions |

|The male and female genital systems originate from the same embryonic tissues. List the parts of the male genital system and give |

|the female homologues. |

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|RESPIRATORY SYSTEM |

|You will have a quiz on this section on 2/21/2012. You must get an 80% on the quiz to start the dissection. |

|For this system the directions are included in the paragraph below. |

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|By this time the respiratory system should be well exposed. Clear away any remaining muscle that obscures the trachea, larynx, and |

|hyoid bone. Locate the structures shown in the figure below. As the lungs inflate and deflate during breathing, they rub against |

|the inner thoracic walls. To prevent damage from this friction, both the lungs and inner thoracic wall are lined with smooth |

|lubricating membranes, the pleura. |

|When the respiratory system has been thoroughly studied, expose the esophagus from the pharynx to the stomach. |

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|Questions and Discussions |

|Describe the actions that take place in breathing. |

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|DAY SEVEN 2/23/2012 |

|You will have a quiz on this section on 2/23/2012. You must get an 80% on the quiz to start the dissection. |

|INTERNAL ORGANS (NERVOUS SYSTEM) |

|Part ONE |

|The cat has twelve pairs of cranial nerves (nerves that originate from the brain) and 38 pairs of spinal nerves. Of these spinal |

|nerves, eight pairs originate in the neck region and are referred to as cervical nerves, and 13 pairs originate in the thorax and |

|are called thoracic nerves. Three cranial nerves (hypoglossal, vagus, and spinal accessory) can be found around the neck. |

|Additionally, several cervical nerves and the first thoracic nerves can be found in the neck and upper thoracic regions. |

|The nerves are the same color as the fat and connective tissue around them, and many of them are delicate, so the dissection must |

|be made carefully. |

|Use a forceps with fine points and a probe. |

|A network of nerves going to the arm (brachium) should be visible. This is the brachial plexus and it is formed by the four |

|posterior cervical nerves and the first thoracic nerve. These nerves are large and fairly sturdy. |

|Begin your dissection by exposing the brachial plexus and its branches. Once this is done, the other nerves can be exposed with |

|more confidence. |

|Follow the vagus nerve forward to locate the superior cervical and nodose ganglia and the nearby cranial nerves. |

|Extend the dissection to the backbone. |

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|Questions and Discussions |

|Trace the brachial nerves into the forearm. |

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|Part TWO EXTRA CREDIT |

|For this dissection, place the cat on its ventral side and use a scalpel to remove the ears and all muscle from the head down to |

|the level of the eyes and zygomatic arch. |

|Remove the neck muscles to expose the cervical vertebrate and the occipital area of the skull. |

|Clean the bone of all muscle |

|Using forceps, break the vertebrae and pick them up to expose the spinal cord |

|Break a hole at the back of the skull |

|Carefully break away the bone from the top and side of the cranium to expose the brain |

|Once the brain is well exposed, cut the spinal cord about 3 cm posterior to the brain and raise the brain from the floor of the |

|cranium. |

|Cut away the spinal nerves and reach under the brain with dissection scissors or a probe |

|Cut the cranial nerves but leave as much of the main cranial nerves to the brain as possible. Remember that there is a partial bony|

|partition between the cerebellum and cerebrum. This may require some extra cutting before the brain will come out. |

|Once the brain is out, examine it, locate the features shown in the figures below. Most of the cranial nerves will probably be |

|lost. The olfactory nerves always break because they pass through the cribrifom plate. |

|The hypophysis (pituitary gland) will also break off. Its point of attachment is the infundibulum. |

|Place the brain dorsal side up. Use your fingers to gently widen the medial longitudinal fissure. |

|Insert a thin scalpel into the fissure, and with a single, smooth cut divide the brain into two longitudinal halves. See the figure|

|below for identification of parts. |

|Cerebrum |

|The cerebrum is the largest brain part and the seat of higher functions such as memory, learning, etc. There are left and right |

|cerebral hemispheres divided by the medial longitudinal fissure. The two hemispheres are connected by a broad band of nerve fibers,|

|the corpus callosum. The pyriform lobes are separated from the rest of the cerebrum by the rhinal fissure. The pyriform lobes, |

|olfactory bulbs, olfactory tracts and other deeper parts form the rhinencephalon, the part of the brain concerned with smell. |

|The surface of the cerebrum is folded into a series of ridges or gyri. The furrows between gyri are sulci. These ridges and furrows|

|increase the surface area of the cerebrum and therefore it is grey matter. |

|Cerebellum |

|The cerebellum is in many ways similar to the cerebrum. It also has an outer cortex of grey matter, is folded, and is divided into |

|two hemispheres. The division is produced by a dorsal, central ridge, the vermis. The cerebellum is an important center for |

|muscular coordination. |

|Medulla |

|The medulla is the most posterior portion of the brain. All nerve tracts between the spinal cord an higher parts of the brain pass |

|through the medulla. The medulla also contains centers that regulate autonomic functions such as heart rate, blood pressure, and |

|respiration. The pons is an important center for nerve tracts that connect the cerebellum with other parts of the brain and spinal |

|cord. |

|Tectum |

|The tectum is a part of the midbrain. It is a center for responses to visual and auditory stimuli. |

|Thalamus |

|All sensory nerves other than the olfactory nerves enter the thalamus. There, their impulses are sent to the appropriate higher |

|centers for interpretation. The hypothalamus is directly ventral to the thalamus and regulates homeostatic processes such as body |

|temperature. It also controls the secretion of hormones by the pituitary gland. |

|Ventricles |

|The ventricles are four spaces within the brain. They communicate with the central canal of the spinal cord. In the life they and |

|the central canal contain the cerebrospinal fluid. The fourth ventricle is connected to the third ventricle by the cerebral |

|aqueduct. The first and second ventricles can be seen by removing the septum pellucidum in the transected brain. |

CAT PROJECT OUTLINE AND RUBRIC

This packet and project will be used as a test (instead of taking one or doing a practical). During your lab, you will be taking pictures of the dissection (use your phone if you can transfer the pictures from it to a computer) or bring in a camera on dissection days. Each day you will take pictures of each part that you are dissecting. For example, during the muscle dissection, you will take pictures of the muscles you are dissecting.

When you get home, you are going to create a project. You can either create a powerpoint, movie, or scrapbook of the pictures. You will be graded on the amount of pictures per body system (listed below) and labeling the parts of that system correctly.

|Description |Points Worth |

|Pictures of the external cat before dissection. Two pictures must|10 points |

|be present (2 different views). Label the following: hair, | |

|pinnae, mammary glands, gender of cat, and tail. | |

|Vibrissae (1 picture). Label the vibrissae. |3 points |

|Foot (1 picture). Label the foot, pads, and claws. |3 points |

|Pictures during the beginning, middle, and end of skinning (5-10 |5 points |

|pictures). | |

|Chest muscles (5-10 pictures). Label each muscle that you |10 points |

|identified in the chest. | |

|Forelimb muscles (2-3 pictures). Label each muscle that you |3 points |

|identified in the forelimb. | |

|Head and neck muscles (1-2 pictures). Label each muscle that you |3 points |

|identified in the head/neck. | |

|Hindlimb muscles (1-2 pictures). Label each muscle that you |3 points |

|identified in the hindlimb. | |

|Interior of the mouth (3-6 pictures). Label the papillae, |10points |

|salivary glands, teeth, palates, and epiglottis. | |

|Abdomen (5-10 pictures). Label parts of the stomach, parts of the|10 points |

|small intestine, parts of the large intestine, liver, pancreas, | |

|and gall bladder. | |

|Heart (4-8 pictures). Label parts of the heart including major |10 points |

|arteries and veins. | |

|Kidney (4-6 pictures). Label the parts of the kidney that you |2 points |

|identified. Also label the urethra, and bladder. | |

|Reproductive organs (4-10 pictures). Depending on your cat’s sex,|10 points |

|include and label the appropriate parts (see the description on | |

|the reproductive system for details on parts). | |

|Respiratory (3-5 pictures). Label the trachea, larynx, and lungs.|5 points |

|Nervous system (1-3 pictures). Label the spinal cord. |3 points |

PAGE OF INFORMATION ON ANIMAL ETHICS FROM DELL LAB

Remember to include websites/sources for full credit!!!!!

MY PARTNER IS_________________________________

WE ARE DEBATING AGAINST ___________________________________________________

Remember to include detailed information such as the point made and the rebuttal of that point. Use this as an outline for writing your thoughts in the debate:

|AGAINST ANIMAL DISSECTIONS |FOR ANIMAL DISSECTIONS |

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