Fetal Pig Dissection

I. Fetal Pig Dissection

II. Purpose

Sus scrofa, or the domestic pig is a member of the class Mammalia and the order Artiodactyla. Since we as humans are also a member of class Mammalia, we have a good deal in common biologically with pigs, although we might not like to think so. Since we have a good deal in common, it is very helpful for us to study these animals both anatomically and physiologically. We do this when we test medicines on pigs, perfect surgical procedures on pigs, and even when we used to use pig valves for replacements in human hearts. Thus the pig is a first-rate example of a mammal and the purpose of this lab is to recognize the specific similarities between the pig and ourselves as humans. To accomplish this we will be dissecting and identifying parts in a number of different systems: external features, the skeleton, the muscles, internal organs, the respiratory system, the digestive system, the circulatory system, the urinary system, the reproductive system, and the nervous system.

III. Materials and Procedure

Materials

Fetal Pig

Dissecting tray

Dissecting pad

String

Gloves

Apron

Scalpel

Dissecting scissors

Probe

Forceps

Formaldehyde

Paper towels

Garbage bag

Procedure

External Features

1. Examine the exterior of the pig

2. Measure the pig from the snout to the base of the tail and use the chart in the manual to determine its approximate age.

3. Locate the snout, mouth, eyes, pinnae, teats, umbilical chord, and anus

4. Study legs and feet and examine/explore how the pig walks

5. Determine the sex of your pig (females have genital papilla while males will have a scrotum).

Skeletal System

1. Locate the axial skeleton (vertebal column, ribs, sternum, skull).

2. Examine the vertebral column paying close attention to the inter-vertebral discs, neural arch, neural canal, and transverse processes.

3. Identify 5 types of vertebrae (cervical, lumbar, thoracic, sacral, caudal).

4. Examine the skull and identify the 4 types of teeth

5. Find the sternum and ribs

6. Examine the appendicular skeleton (pectoral and pelvic girdles, forelimbs)

7. Identify the scapula

8. Identify humerus, radius, ulna, carpals, metacarpals, and phalanges

9. Identify the 3 bones of the pelvis

10. Identify femur, patella, tibia, fibula, tarsals, metatarsals, and phalanges

Muscular System

1. Carefully remove the skin of the pig to expose the muscular system by following the cutting sequence designated in the manual

2. Identify: pectoralis major and minor, trapezius, latissimus dorsi, biceps, triceps, brachialis, masseter, brachiocephalicus, splenius, external oblique, internal oblique, transverse abdominis, rectus abdominis, gluteus medius, biceps femoris, rectus femoris, gastrocnemius, soleus, sartorius, gracilus, adductor magnus, peroneus longus, and peroneus brevis.

Internal Anatomy

1. Slice deeper along the midventral line cutting through the muscle

2. Remove and identify thymus and thyroid

3. Cut through the rib cage

Respiratory System

1. Identify the trachea, esophagus, lungs, and diaphragm

2. Open up the lungs and identify bronchi, bronchioles, and alveoli

Digestive System

1. Cut open the mouth and identify teeth, hard plate, soft plate, tongue, and epiglottis

2. Remove and Identify the liver noting the 4 regions

3. Identify: gall bladder, bile duct, stomach (remove), pancreas, spleen, small intestines, large intestine, cecum- be sure to distinguish between the parts of the intestines.

Circulatory System

1. Identify the heart and pericardium noting the 4 chambers and trace the blood flow using the manual as a guide

2. Identify: tricuspid valve, bicuspid valve, pulmonary semilunar valve, aortic semilunar valve, interatrial septum, ductus arteriosus.

3. Examine the network of ateries and veins noting specifically the major ones listed in the handout.

Urinary System

1. Cut open the lower abdomen to expose this system

2. Identify: kidney (noting the 3 regions), adrenal glands (if possible), urinary bladder, ureters, urethra, urogenital orifice

Reproductive System

1. For the male identify: testes, scrotum, epididymis, vas deferens, prostate, seminal vesicle, and bulbourethral glands

2. Also Identify the female parts and vice versa if you have a female

3. For the female identify the ovaries, oviduct, uterus, vagina, and cervix

Nervous System

1. Remove the skin from the skull and back and cut open the bone to expose the central nervous system

2. For the brain identify: cerebrum, medial fissure, cerebellum, medulla oblongata, and corpus callosum

3. For the spinal chord, cut it open and identify gray and white matter.

IV. Data and Observations

Answers