Fetal Pig Dissection

CC BY Lynette Hauser, Tidewater Community College

1. Fetal Pig Dissection Blood vessels in pigs were injected with a latex dye Arteries: Thicker, lead away from the heart Veins : Thinner with valves, lead to the heart. Pigs are mammals Mammary glands Hair Two distinct sexes Similarities to humans Placental Tetrapods

2. Dissection Directional Terms Anterior : towards the head end Posterior : towards the hind end Ventral : towards the belly Dorsal : towards the back

3. External Anatomy Compare forelimb to upper arm Compare hindlimb to legs Find umbilical cord Both males and females have nipples Look for hair

4. Identify as male or female

5. Oral Cavity and Pharynx Oral cavity: tongue, teeth, and hard and soft palate Pharynx: epiglottis , glottis , esophagus The jaw is opened wide enough so that the glottis and epiglottis are exposed. The epiglottis projects up through the soft palate into a region called nasopharynx . The hard palate and soft palate separate the nasal and oral cavities. When breathing, air passes through the nasal passages to the pharynx. The pharynx is the space in the posterior portion of the mouth that both food and air pass through. From the pharynx, it passes through the glottis to the trachea.

6. Neck region Thymus, larynx, trachea, thyroid gland A blunt probe is used to separate the two lobes of the thymus gland and to further separate the musculature over the trachea. The thyroid gland is darker and lies between the posterior ends of the two lobes of the thymus gland.

7. Thoracic Cavity Identify heart in pleural cavity Lungs and bronchi Diaphragm separates from abdominal cavity

8. Abdominal Cavity Identify heart, liver, lungs, small intestine , large intestine , diaphragm, urinary bladder, spleen, stomach Food passes through the esophagus to the stomach, small intestine, and large intestine. The first part of the small intestine is the duodenum. Secretions released from the pancreas and gall bladder empty into the duodenum.

9. Excretory System Identify bladder and kidney The ureter carries urine from the kidney to the urinary bladder.

10. Male Pig Reproductive System

11. Female Pig Reproductive System The urethra (carries urine from the bladder) merges with the vagina to form a common duct called the urogenital sinus.

12. Observe human model and compare to pig Cardiovascular Respiratory Digestive Reproductive Excretory

13. Respiratory System Trachea : tube that brings air from mouth and nose Bronchi : airways that branch going to each lung Branch into bronchioles Lungs : elastic breathing organs Alveoli : thin, cup shaped membrane surrounded by capillaries Location of gas exchange with the blood

14. Digestive System Esophagus: transports food to stomach Stomach : muscular sac Mechanical and chemical diges ti on Two sphincters control food entry and exit Small intes ti ne : diges ti on Three sec ti ons : duodenum, jejunum, and ileum Large intestine : absorbs water, concentrates undigested materials

15. Liver: produces bile with digestive enzymes Gallbladder : stores bile and releases into small intestines Pancreas : secretes digestive enzymes Digestive System