Forensic Pig Dissection

What do you do with your pig when he

loses his tail?

Answer:

• Take him to any 're-tail' store.

Safety Procedures• You MUST use safety precautions during this lab!• Goggles and aprons must be worn at all times.• Gloves should be worn when handling the

preserved specimens. • Clean your area and all dissection equipment

Wash your hands when you finish the lab. • Your work station should be cleaner than the way

you found it!!!• Report any broken or missing items to your

teacher!

Objectives • 1. Conduct an investigation of a fetal pig following

an autopsy protocol.• 2. conduct an internal investigation of a fetal pig

following an autopsy protocol. Examine tissues, organs systems and body fluids and note any abnormalities.

• 3. compare and contrast the fetal pig heart and kidney to an adult pig heart and kidney.

• 4. Observe slide sections of a lung, artery and vein, stomach , liver , kidney and reproductive tissues.

• The fetal pigs that we will use in lab were purchased from a Biological supply company. They obtain fetal pigs from processing plants - the unborn pigs are removed from the uteri of slaughtered sows.

• They are NOT produced for this purpose only, they would be used as fertilizer or disposed of if not used for dissection purposes.

• The period of pregnancy (gestation) in pigs is about 17 weeks (compared to 40 weeks in humans).

• The fetal pigs we will use in class are 3-4 weeks from birth. You will work in groups of 4 or 5 on the fetal pigs. Each group of students will be given a fetal pig to be used for the labs on pig dissection.

• Attach a tag with your names (in pencil or sharpie) to one of the hind legs for future identification.

Background

• http://carolinascienceonline.com/page.php/resources/view_all?id=carolinatm_forensic_dissection_student_guide&full=1&w_size=1024&h_size=768

Roles:1. Prosector: (Forensic Pathologist) conducts the

autopsy to determine the cause of death. 2. Diener: helps the prosector with the process.3. Materials Manager: organizes and hands the

dissection instruments to the Prosector and Diener.

4. Recorder: records all of the measurements and observations and includes them in the final report.

5. Assistant: helps any or all members of the team• All members are responsible for clean up!!

Directional and Anatomical Terminology

• Anatomists and morphologists rely on a set of terms to describe structural positions, These may not all be immediately obvious to you, so you should practice using them. The terms are generally presented to you in pairs, as terms are often used to indicate opposing directions.

1. Anterior - near or toward the head 2. Posterior - near or toward the tail 3. Dorsal - referring to the back 4. Ventral - referring to the belly 5. Lateral - referring to the side 6. Median - referring to the midline 7. Cranial - referring to the head 8. Caudal - referring to the tail 9. Proximal - toward the attached end of a structure 10. Distal - toward the free end of a structure 11. Longitudinal - in the axis from head to tail 12. Transverse - across the longitudinal axis 13. Pectoral - chest or shoulder area 14. Pelvic - hip region 15. Inferior- toward or closer to the tail (caudal region) 16. Superior- toward or closer to the head region

Anterior - near or toward the head

Posterior - near or toward the tail or back

Dorsal - referring to the back

Ventral - referring to the belly

Lateral - referring to the side

Median - referring to the midline

Cranial - referring to the head Caudal - referring to the tail

Proximal - toward the attached end of a structure Distal - toward the free end of a structure

Longitudinal - in the axis from head to tail

Transverse - across the longitudinal axis

• is an imaginary plane that divides the body into superior and inferior parts. It is perpendicular to the coronal and sagittal planes.

Pectoral - chest or shoulder area

Pelvic - hip region

Inferior- toward or closer to the tail (caudal region)

Superior- toward or closer to the head region

• As with vertebrate directional terms, superior and inferior can be used in a relative sense in humans, but can not be uniformly applied to other organisms with varying normal anatomical positions. For example, the shoulders are superior to the navel, but inferior to the eyes in humans. In any tetrapod, the shoulders are cranial to the belly, but caudal to the eyes.

sagittal section

• The sagittal section, or plane, divides the subject into left and right portions. Coronal/Frontal - bisects the front and back of the body

Mid-sagittal

• The mid-sagittal section splits the subject exactly into left and right sides.

Transverse/Horizontal/Axial - bisects the upper and lower body

transverse• A transverse plane, also known as an axial

plane or cross-section, divides the body into cranial and caudal (head and tail) portions.

Directional Terms:

• Anatomists rely on a set of directional terms to explain the orientation of subject material. Although some of the terms are unfamiliar, with practice they will become easier to use, and you will see that “proximal to” is lesser cumbersome than “up the extremity and closer to the middle of the body.”

left and right

• stated relative to the subject, not relative to the people viewing it

anterior (cranial)

• towards the front (head) of the animal

posterior (caudal)

• towards the back (tail) of the animal

superior

• higher on the subject- typically used on bipeds such humans

inferior

• lower on subject- also used on subjects such as humans

dorsal

• towards the back

Ventral

• towards the belly

medial

• towards the mid-sagittal section

lateral

• away from the mid-sagittal section

proximal

• towards the mid-sagittal section along a limb

distal

• away from the mid-sagittal section along a limb

External Anatomy

• The body consists of the following regions: head, neck, trunk, and tail. The 2 pairs of appendages present on the trunk are the fore legs and hind legs. The cord projecting from the ventral surface is the umbilical cord. This cord connects the fetal pig to the placenta within the uterus of the mother pig.

External Anatomy

Sacral

Abdominal ThoraxHead

Head =yellow. Neck = Purple. Trunk = red. Tail = green

External Anatomy

Draw a pig’ external anatomy and include labels for the following:

1. Anterior - near or toward the head 2. Posterior - near or toward the tail 3. Dorsal - referring to the back 4. Ventral - referring to the belly 5. Cranial - referring to the head 6. Caudal - referring to the tail 7. Proximal - toward the attached end of a structure 8. Distal - toward the free end of a structure 9. Pectoral - chest or shoulder area 10. Pelvic - hip region 11. Inferior- toward or closer to the tail (caudal region) 12. Superior- toward or closer to the head region

• 2 Basic Anatomical terms Diagram showing 16 terms from the lab 37 pts 2pts each 5pts color

1. Anterior - near or toward the head 2. Posterior - near or toward the tail 3. Dorsal - referring to the back 4. Ventral - referring to the belly 5. Lateral - referring to the side 6. Median - referring to the midline 7. Cranial - referring to the head 8. Caudal - referring to the tail 9. Proximal - toward the attached end of a structure 10. Distal - toward the free end of a structure 11. Longitudinal - in the axis from head to tail 12. Transverse - across the longitudinal axis 13. Pectoral - chest or shoulder area 14. Pelvic - hip region 15. Inferior- toward or closer to the tail (caudal region) 16. Superior- toward or closer to the head region • • 3 External anatomy: Diagram of head, neck, trunk, tail. color 5pts Label=Thorax, Abdomen,

Sacral. What is inside and out of these sections? How can you tell male from female? Thorax (what is inside?) Abdomen (what is inside?) Sacral (what is here?)

•

External Anatomy• draw a diagram of the main parts

• Place the pig on its side in the pan and note that the body consists of the following regions:

• head, neck, trunk, and tail. • The 2 pairs of appendages present on the trunk are the

fore legs and hind legs. The cord projecting from the ventral surface is the umbilical cord.

• This cord connects the fetal pig to the placenta within the uterus of the mother pig.

External Anatomy

Sacral

Abdominal ThoraxHead

Head =yellow. Neck = Purple. Trunk = red. Tail = green

• The head bears the mouth and jaws, the snout (nose), the external nostrils (nares), the eyes, and the external ears. Feel the relatively thick neck in the fetal pig. This thickness is due to the presence of well-developed neck muscles that will eventually be used for rooting.

• The cranial portion of the trunk is called the thorax (chest) and is encased by the ribs. Feel the ribs under the skin and determine the posterior border of the thorax. The thorax contains the lungs, heart, and major blood vessels.

• The fore legs are found in the thoracic region. The parts of each of these appendages as well as those of the hind legs (in the sacral region) are the upper leg, lower leg, wrist, foot, and toes (digits).

• Examine the digits present on the legs and note that only 2 of the 5 digits found in most terrestrial vertebrates are present. The first toe (corresponding to our thumb) has been lost; the second and fifth toes are reduced, with only the third and fourth toes being fully developed.

• The caudal portion of the trunk is called the abdomen.

• In contrast to the thorax, the ventral portion of the abdomen is soft. The umbilical cord is located near the posterior end of the abdomen. There are 2 rows of teats (mammary papillae), one on either side of the umbilical cord. The stomach, intestine, kidneys, and other viscera (soft internal organs) are found within the abdominal cavity.

• The sacral region includes the hind legs, pelvic bones, and their attachment to that area of the vertebral column.

• The anus (posterior opening of the digestive tract) is located under the tail.

• In female pigs, the vulva (openings of the reproductive and urinary tracts) is found just below the anus.

• In male pigs, the external opening of the penis is located posterior to the umbilical cord. The scrotum (scrotal sacs) are found on either side of the midline of the anus.

External Anatomy

Sacral

Abdominal ThoraxHead

Materials

• Prepare all materials1. Pig/ plastic bag/rubber band 2. Sponge/ absorbent blue pad3. 2 dissection pans4. 5 weigh boats5. String/rubber bands to tie the legs of the pig 6. 1 Suture needle/ nylon string for sutures7. Set of microscope slides ( 6 slides) some groups will share these!8. Microscope9. Dissection scope10. Dissection kit scalpel, forceps, scissors, probes11. lab Apron 1 for each person12. Gloves 1 for each person13. Goggles 1 for each person 14. Metric rulers one large one small 15. Straw16. Cleaning materials17. Triple beam balance 18. access to an electronic balance to weigh organs and pig check all materials and replace what you use at the end of class for the next group!

Procedure• Use excellent observational skills~!!!!• 1. gather and check your materials. Put on your

apron, protective goggles and gloves.• 2. Place the absorbent pad under the dissecting

pan.• 3. Rinse your pig in water and dry it before

weighing it. Use a dissecting pan to weigh the pig. DO NOT use the electronic balance to weigh the pigs!!!! Remember to subtract the weight of the pan from the total before recording the mass of the pig.

• 4. Measure the length of the pig using string. From the tip of the nose to the base of the tail.

• 5. Examine the external structures of the pig and help the recorder with details for the report on each of the areas of the external features. Pictures may be taken to help with the report.

• 6. Examine the DORSAL side of the legs and describe the feet in detail.

• 7. Examine the VENTRAL side of the pig. Describe the mammary papillae and umbilical cord, the artery and vein and allantoic duct.

•

8. Is your pig a male or female?

• Incisions Read your dissection directions very carefully for instructions for male and female pigs!

Female reproductive organs