Group #1
Brian Brown and Patrick Egan
Ms. Ong
Biology
23 May 2017
Introduction
The first step to dissecting a fetal pig is gathering the necessary tools and equipment. Tools include scissors, pins, a tray, probes, blades, and needles. To prepare the pig, rinse it to remove excess preservatives and place in a dissecting tray. Make sure its back is down, showing its stomach. Then, to ensure the pig is stable, tie a piece of string around one wrist, pass the string under the tray, then proceed to tie the other wrist. Repeat the process for the legs. The pig should then look as it does in figure 1. Next draw the lines indicated in figure 2. Across the stomach, two lines should be drawn, one over the sternum and another at the bottom of the rib
…show more content…
cage at the diaphragm. 1 2 To determine the sex of the pig, look for the urogenital opening. On females, the opening is located near the anus and a urogenital papilla (a fleshy flap of tissue) is present near the opening. On males, the opening is located near the umbilical cord, but they do not have a urogenital papilla. A male pig will also have a swelling between the upper ends of the hind legs while a female does not. Next, using dissection scissors, cut through the jaw bones at the corner of the pig’s mouth and pull down the lower jaw until it is almost touching the chest. Now, using a scalpel, make a upside down V incision starting at X (in figure 2). Finish the incision with dissection scissors cutting only skin and muscle and avoiding any internal organs. Use forceps to hold the tissue away from the organs while cutting. Cut all the way to the pan. Start the second incision at X and carry it straight down almost to the umbilical cord, but cut a semicircle around the umbilical cord on each side. Make the third incision just above the hind legs and carry it all the way down to the pan. Now, lift up the flaps of skin and peel them back so they lay flat on the pan. If there is connective tissue or membranes attaching the muscles to the underlying organs, cut through it carefully so the flaps can be lifted back. The abdominal cavity should now be exposed. Beginning at X again, make the fourth incision up through the chest. Use the scissors to cut through the rib cage and the sternum. When the midpoint between the forelegs is reached, make another incision down to the pan. Go back to the diaphragm area and use a scalpel to cut the wall of the body cavity away from the diaphragm. The diaphragm should remain intact, but now the rib cage can be pulled back and pinned to the pan, exposing the thoracic cavity. Now that the pig is open, organ dissections may be made. Starting with the stomach in the abdominal cavity, the pig’s stomach is on the viewer’s right side under the liver (large black/brown multi-lobed organ at the top of the abdominal cavity). To easily find the stomach, follow the esophagus (connection from mouth to stomach). With dissection scissors, cut along the outer curve of the stomach and open it to reveal the inside of the stomach. Following the stomach, look for the small intestine, a large mass of coiled tubes that fills the bottom half of the abdominal cavity. On one end it is attached to the stomach and on the other end it is attached to a pouch called the caecum that joins the small and large intestines. It is held in place by the mesentery (lift up a section of the intestine and pull it tight, the mesentery is the thin tissue filled with blood vessels). Carefully cut through the mesentery with dissection scissors, uncoil, and remove the small intestine. Now, to find the kidneys, move the intestines aside to see the large bean-shaped kidneys (one on each side) covered in a shiny membrane. Using a scalpel, make a medial incision on the kidney and open it up to reveal the inside. Now move to the thoracic cavity to begin the dissection of the lungs. The lungs are spongy and surround the heart. Use the scalpel to make a medial incision (similar to the kidney insertion) and observe. Finally is the larynx (voice box) located at the top of the throat at the end of the trachea. Use the scalpel to make a medial incision down the larynx to observe the inside. Structures External Umbilical arteries: Near the bladder. Brings de-oxygenated blood from the fetus. Umbilical Vein: Brings oxygenated blood to the fetus. Oral Cavity Hard palate: Rigid area on the roof of the pig’s mouth that divides the nasal cavity and the mouth. Soft palate: Section below the hard palate that seals off the nasal cavity. Epiglottis: Tissue that seals off the windpipe and prevents food from entering. Opening to the esophagus: Tube that moves food from the pharynx to the stomach Abdominal/Pelvic Cavity Urinary bladder: stores urine until it is ready for the body to get rid of it. Peritoneum: Line wall city to help protect the insides of the abdominal cavity.
Liver: Produces bile, stores glucose as glycogen (largest organ in the pig’s body).
Diaphragm: Muscle forming the bottom of the chest cavity, becomes smaller when inhaling, larger when exhaling (separates thorax from abdomen).
Gallbladder: Stores bile from the liver, then transfers it to the small intestine.
Bile duct: Takes Bile from the gallbladder and empty it into the upper part of the small intestine.
Small intestine: Long, narrow tube where most absorption occurs.
Large intestine: Removes waste from body and removes water from the waste.
Cecum: Between large and small intestines, receives waste products from the small intestine.
Mesentery: Tissues that suspend organs. Holds together parts of the small intestine
Stomach: Sack where digestion takes place, in between the small intestine and the esophagus.
Pyloric Sphincter: Controlling the flow of food from the stomach to the small intestine.
Spleen: Involved in the production of blood cells (included in the immune system).
Thoracic Cavity
Diaphragm: Muscle forming the bottom of the chest cavity, becomes smaller when inhaling, larger when exhaling (separates thorax from
…show more content…
abdomen). Pericardium: Thin membrane around the heart (supports the heart). Lungs: organs closed by the diaphragm and the rib cage. Blood picks up oxygen and loses carbon dioxide. Larynx: Noise production. Area for air moving from pharynx to trachea, has vocal chords. Alveoli: Movement of gases.
Exchanges of oxygen and carbon dioxide takes place.
Atriums:
Right: Receives de-oxygenated blood from the vena cavas and pumps it through the valve to the right ventricle
Left: Receives oxygenated blood from the pulmonary veins.
Coronary artery: Brings blood and nutrients to the heart, also helps to remove waste products.
Ventricles:
Right: Receives deoxygenated blood and pumps it through the pulmonary valve.
Left: Receives oxygenated blood (more muscular than the right ventricle).
Pulmonary Artery: Between the two atria that carries de-oxygenated blood from the right ventricle to the lungs.
Aorta: The largest artery in the body. Brings oxygenated blood from the left ventricle to the tissues.
Vena Cava(s):
Inferior: brings de-oxygenated blood from the LOWER part of the body to the right atrium
Superior: Carriers de-oxygenated blood from the UPPER part of the body to the right atrium
Thyroid gland: Located below the larynx, produces hormones to control the pig’s metabolism.
Trachea: Windpipe. Leads down the larynx to the lungs. Moves air in the respiratory system
Esophagus: Tube that moves food from the pharynx down into the stomach.
Salivary gland: Located in the mouth. Releases
saliva. Pancreas: Produces hormones that regulate blood sugar. In between stomach and large intestine. Kidneys: Removes urea and other waste products from the blood and passes them to the ureter. Adrenal gland: Produces hormones, located at the top of the kidney. Ureter: Tubes that carry urine from the kidney to the bladder. Renal artery: Artery carrying blood to the kidneys from the aorta. Renal vein: Carries blood away from the kidney to the inferior vena cava. Villi: Near both intestines and plays a large role in the process of absorption. Renal cortex: The renal cortex is the part of the kidney where similar functions such as filtering waste occur. Renal medulla: Innermost part of the kidney. In a number of sections. Filters waste, and eliminating excess water. Testes: Male reproductive organ, holds sperm for reproduction. Vagina: Female reproductive organ, canal that leads from the uterus to the outside of the body. Pictures outlying internal anatomy
Once the external anatomy was observed the pig was then laid down on the dissection pan and held down by rubber bands exposing the ventral side of the pig. Then the cardiovascular and digestive systems were analyzed. The fetal pig did in fact have small teeth which were fairly sharp. Before the lab I wasn’t aware of the intricate details of the mouth cavity or that the kidneys were underneath the intestines. The hardest part was locating the trachea and the gall bladder. Additionally actually feeling the heart and various parts of the fetal pigs internal anatomy made learning the parts of the body
In Labs 22 through 26, my lab partner and I were assigned a fetal pig to perform a dissection on in order to understand anatomy, the study of an organism’s structure1, and physiology, the study of the functions and activities of a living organism2. Throughout these labs, we studied the structure of the fetal pig and performed experiments to understand four system processes: digestion, cardiovascular, respiratory, and excretory. Dissecting an organism, physically moving and seeing the different portions of the organism, especially of a fetal pig, is very important. This helps in the understanding of the skeletal structure and what series of physical and chemical processes the mammalian species body performs in order to survive.
25-4 Describe how the diaphragm and rib cage function in moving air into and out
So, it will alternately send blood to the lungs and then to the body, instead of both at the same time as a natural heart does. The AbioCor is able to pump more than 10 liters per minute, which is enough for everyday activities.
Healthy lung tissue is predominately soft, elastic connective tissue, designed to slide easily over the thorax with each breath. The lungs are covered with visceral pleura which glide fluidly over the parietal pleura of the thoracic cavity thanks to the serous secretion of pleural fluid (Marieb, 2006, p. 430). During inhalation, the lungs expand with air, similar to filling a balloon. The pliable latex of the balloon allows it to expand, just as the pliability of lungs and their components allows for expansion. During exhalation, the volume of air decrease causing a deflation, similar to letting air out of the balloon. However, unlike a balloon, the paired lungs are not filled with empty spaces; the bronchi enter the lungs and subdivide progressively smaller into bronchioles, a network of conducting passageways leading to the alveoli (Marieb, 2006, p. 433). Alveoli are small air sacs in the respiratory zone. The respiratory zone also consists of bronchioles and alveolar ducts, and is responsible for the exchange of oxygen and carbon dioxide (Marieb, 2006, p. 433).
The Structure and Functions of the Arteries Arteries are blood vessels that convey blood from the heart to the tissues of the body. The arteries expand and then constrict with each beat of the heart, a rhythmic movement that may be felt as the pulse. Arteries are usually named from the part of the body that they are found, for example; brachial artery found in the arms, metacarpal artery found in the wrist; or from the organ which they supply as the hepatic artery supplies the liver, pulmonary artery brings deoxygenated blood the lungs. The facial artery is the branch of the external carotid artery that passes up over the lower jaw and supplies the superficial portion of the face; the haemorrhoidal arteries are three vessels that supply the lower end of the rectum; the intercostal arteries are the arteries that supply the space between the ribs; the lingual artery is the branch of the external carotid artery that supplies the tongue. The structure of the artery enables it to perform its function more efficiently.
The pattern of blood flow starts in the left atrium to right atrium, then into the left ventricle and right ventricle. During its course, blood flows through the mitral and tricuspid valves. Simultaneously, the right atrium is granted blood from the veins through the superior and inferior vena cava. The job of the superior vena cava is to transport de-oxygenated blood to the right atrium. When your heart beats, the first beat represents the AV valves closing to prevent the backflow of blood into the atrium.
The heart serves as a powerful function in the human body through two main jobs. It pumps oxygen-rich blood throughout the body and “blood vessels called coronary arteries that carry oxygenated blood straight into the heart muscle” (Katzenstein and Pinã, 2). There are four chambers and valves inside the heart that “help regulate the flow of blood as it travels through the heart’s chambers and out to the lungs and body” (Katzenstein Pinã, 2). Within the heart there is the upper chamber known as the atrium (atria) and the lower chamber known as the ventricles. “The atrium receive blood from the lu...
The larynx provides a passageway for air between the pharynx and the trachea. The trachea is made up of mainly cartilage which helps to keep the trachea permanently open. The trachea passes down into the thorax and connects the larynx with the bronchi, which passes to the lungs. 3. Describe the mechanisms of external respiration including the interchange of gases within the lungs.
Dissections of a fetal pig are used to educate students around the world about the significance of the internal and external structures found within many organisms, thus contributing to a more profound understanding. These dissections provide visual education to students thereby providing them with knowledge that can be potentially be accessed in the future. The systems that are examined specifically are the respiratory, digestive, reproductive and the circulatory systems. The fetal pig are particularly useful due to the similar structures to that of a human. Furthermore, fetal pigs are used for dissection due to their relative size which can be managed in the classroom. The major organs examined during the dissection will be the heart, lungs,
the aortic valve, between the left ventricle and the aorta. heart_chambers.jpg Each valve has a set of "flaps" (also called leaflets or cusps). The mitral valve normally has two flaps; the others have three flaps. Dark bluish blood, low in oxygen, flows back to the heart after circulating through the body. It returns to the heart through veins and enters the right atrium.
Through the examination, it was evident that the tissues within the heart varied significantly in thickness and size. We were able to insert our fingers through the blood vessels. By doing so, we were able to identify whether the vessel was an artery or vein. The artery of the heart was much thicker and bigger than the veins, this was because the arteries were responsible for transferring oxygenated blood from the heart to the rest of the body, which requires great strength. The heart itself created pressure differences that helped blood to flow from high to low pressure. The artery pumped blood at high pressure so that it could travel to all the body parts. The thick walls of the arteries were needed to withstand the high pressure coming from the heart. The blood returned to the heart through veins, and because of the lower pressure, the walls of the veins were
It begins at the right atrium. Blood enters the right atrium from the superior and inferior vena cava and the coronary sinus, then it moves through the tricuspid valve. After the tricuspid valve, blood enters the right ventricle which then leads to another valve called the pulmonary semilunar valve. From the pulmonary semilunar valve, blood enters the pulmonary trunk which branches off into the right and left pulmonary arteries. From the pulmonary arteries, the blood enters the lungs and undergoes a gas exchange in the alveoli. After gas exchange has occurred, oxygenated blood flows through the pulmonary veins into the left atrium. From the left atrium, blood runs through the bicuspid valve. From the bicuspid valve, the blood enters the left ventricle and is pumped through a fourth valve, the aortic semilunar valve, and courses through the aortic arch. From the aortic arch, the blood rushes down the descending aorta and runs through the celiac trunk. Said trunk branches off into 3 arteries, one being the common hepatic artery. From the common hepatic artery, blood branches off to the right hepatic and cystic arteries. It is the latter that ultimately supplies the
The trachea filters the air we breathe. At the end of the Trachea it splits into two which is called Bronchus. Bronchus are two air tubes that branch off to the Trachea and carry air directly into the lungs. The lungs are the main organ in the respiratory system. In the lungs, oxygen is taken into the body and carbon dioxide is breathed out. The red blood cells collect oxygen from the lungs and deliver it to other cells in our body and they also pick up the waste from the other cells (Carbon Dioxide) and bring it back to the lungs to get exhaled. The diaphragm is not part of where the air travels, but it is used to air in and out of the lungs. The diaphragm is a muscle that moves, causing a change in air pressure. When you breathe out, the diaphragm moves upward, which decreases the volume of the lungs, causing high pressure. When you breathe in, the diaphragm moves downwards in it can increase the volume of the lungs which causes negating pressure. These organs are equally useful as they all play a role to keep your respiratory system working. You need to