The hard palate makes up the anterior part of the roof of the mouth. Made of bone and covered with folds of mucus membrane, the hard palate separates the oral cavity from the nasal cavities.
The surface of the soft palate is a posterior continuation of the mucous membrane, but it contains no bone. The pharynx is the region encompassing the base of the tongue and the junction of the passageways for food esophagus and air trachea. Note the epiglottis small flap of tissue at rear of pharynx visible in this picture. As an endocrine gland,the pancreas secretes the hormones insulin and glucagon.
These hormones are secreted into the blood stream. Locate the spleen. It is a long, flat reddish organ attached to the stomach by mesentery. The spleen is a lymphoid organ in the immune system. It stores both red and white blood cells. Open one side of the stomach and note the appearance of the interior surface.
Is it smooth or rough? Why does the pig have such a long intestine? Slit open the intestine. Is the lining of the intestine smooth or rough? Look at the inside of the intestine using a dissecting scope.
What do you see? What are the structures you saw above called? What is the function of the villi? The Cardiovascular System of the Fetal Pig. The heart pumps blood, circulating it to all parts of the body. What blood vessel carries blood away from the heart? What blood vessel carries blood to the heart? What structure joins the arterioles to the venules? Blood is pumped from the heart under pressure.
Arteries have thick walls that expand when thepressurized blood enters them. Blood moves away from the heart through the larger arteries and the smaller arterioles. Veins have thinner wallsand valves that prevent blood from flowing backwards in the veins. Blood returns to the heart from the tissues via the larger veins and smaller venules. Blood is pumped away from the heart by the contraction of thebeating heart.
Blood is returned to the heart when skeletal musclescontract and press against the veins and venules; this forces blood to move through the veins back toward the heart. Capillaries have exceptionally thin walls; this allows the exchange of materials from the blood with the tissue fluid, which surrounds the capillaries. Circulation is different in adults and in fetuses. In the adult, blood is oxygenated in the lungs and nutrient molecules enter the blood in the digestive tract.
In the fetus, the lungs and digestive system do not function. Fetal blood obtains oxygen and nutrients when diffusion exchange occurs with the mother's blood in the placenta. Where does the systemic circuit move blood? Where doesthe pulmonary circuit move blood? What is the main artery that leaves the heart? What is the main vein that returns blood to the heart?
How many chambers are found in the mammalian heart? What is the function of the ventricles? What is the function of the atria? Where does the right side of the heart pump blood?
Where does the left side of the heart pump blood? Trace the path of blood as it moves from the right ventricle to the lungs. Trace thepath of blood as it moves from the left ventricle to the kidneys. Observation of the Blood Vessels of the Fetal Pig. In the fetal pig the pulmonary arteries and veins are not functional. In your pig thearteries have been injected with red latex and the veins have been injected with blue latex. Refer to Fetal Pig Heart as you observe the following structures.
Pulmonary Circuit. What isthe function of the pulmonary circuit? Locate the pulmonary trunk. What color is it in your pig? Observe the pulmonary trunk and notice that it seems to connect directly with the aorta. This connection is the arterial duct. In the fetus, blood passes through to the aorta without going to the lungs.
This duct is closed in adults. Locate thepulmonary arteries that leave the pulmonary trunk and go to the lungs. What color are they? Locate the pulmonary veins as they leave the lungs; trace them back to the heart. Systemic Circuit. The systemic circuit carries blood to the entire body. Arteries take oxygenated blood from the heart to the organs; veins take deoxygenated blood from the organs to the heart.
The aorta is the major artery, and the venae cavae are the major veins. Using the diagram , locate the following arteries and veins.
Thoracic Cavity. The coronary arteries and the cardiac veins can be seen on the surface of the heart. The carotid arteries and the jugular veins serve the neck and head regions ofthe body. Locate these vessels. The subclavian arteries and veins transport blood to and from the forelimbs.
Abdominal Cavity. Examine the aorta. It may be necessary to life the left lung to observe the aorta. The aorta may appear white in color due to its thick wall.
Trace the aorta as it passes through the diaphragm and into the abdominal cavity. Lift the liverand the stomach and move it to the side. Observe the renal arteries as they branch from the aorta. Trace them to the kidneys. Locate the renal veins that leave the kidneys. Trace the path of the renal veins to the vena cava. Locate the vena cava; it is a large blue vessel dorsal to the aorta.
Trace the path of the vena cava back to the heart. Comparison of Blood Vessels. Blood pressure from the pumping heart keeps blood moving in the arteries away from the heart.
The thick walls of the arteries expand when blood is pumped into them. The contraction of skeletal muscle causes the blood to flow back tothe heart. Do you expect that arteries or veins will be more superficial? Which type of blood vessel has thicker walls? Observation of the Fetal Pig Heart. With a blunt probe find the oval opening between the two-atrial chambers.
This is the shunt that allows the blood to bypass lung circulation prior to birth. Would you expect to find this shunt in an adult pig? The Urogenital System of the Fetal Pig. The urinary and reproductive systems are very closely associated in mammals. The organs of each system are particulary associated in males. What structure is part of both the male reproductive system and the male urinary system? What are the major organs of the urinary system?
The kidneys are located on the dorsal body wall wher they are held in place by connective tissue. The renal artery and vein supply blood to the kidneys. What is the function of the ureters? What isthe function of the urinary bladder? What is the function of the urethra? In males, sperm are produced in the seminiferous tubules of the testes.
The sperm arestored in the epididymis and carried through the vas deferens to theurethra. The seminal vesicles, the prostate gland and the bulbourethralgland Cowper's gland add fluid to the semen after sperm reach theurethra. In females, the eggs are produced in follicles of the ovaries. The egg moves from the ovarytot he oviduct where fertilization occurs. The fetus develops in theuterus.
The cervix, the opening to the uterus, connects to thevagina. The vagina serves both as the organ of copulation and as the birth canal. Observation of the Urinary System of the Fetal Pig. This cone-shaped flap of cartilage is located at the top of the larynx voice box near the base of the tongue. It protects the glottis, the slit-like opening to the trachea. During swallowing and eating the epiglottis prevents food from entering the trachea. Thin elastic cartilaginous structure located at the root of the tongue that folds over the glottis to prevent food and liquid from entering the trachea during act of swallowing.
This tube is commonly called the windpipe. It is topped by the epiglottis and larynx. It is kept open by rings of cartilage which extend around the trachea at intervals. They are incomplete dorsally.
The trachea branches to form two bronchi which enter the lungs. A thin-walled tube of cartilaginous and membrane tissue descending from the larynx to the bronchi and carrying air to the lungs. The overall external texture of the trachea is rough and bumpy due to the tracheal cartilaginous rings. Slightly raised cartilaginous rings in a tube.
Cartilaginous rings : Prevent the trachea from collapsing when you breath out; no air in trachea. This muscular tube, located dorsal to the trachea is also known as the gullet. Unlike the trachea, however, it is collapsed. Food is pushed forward in the esophagus by the rhythmic contractions of its walls, a process knows as peristalsis.
The esophagus extends posteriorly and dorsally within the thorax, then passes through the diaphragm into the abdominal cavity where it ends at the stomach In order to find the trachea and esophagus use two wooden probes. With one, penetrate the glottis and pass into the trachea. Move the probe up and down and observe the movement of the trachea.
With the second probe enter the esophagus dorsal to the glottis. Move it up and down and observe the corresponding movement of the esophagus. The muscular, membrane tube for passage of food from pharynx to stomach. Esophagus is attached to the stomach. Controls the passage from the esophagus into the stomach; sphincter muscles normally limit passage to one direction.
Stops food from going back up the esophagus. Controls the passage from the stomach to the duodenum. Stops bile and digested food from entering the stomach, and acid from entering the intestines. A membrane that surrounds the heart and lines the pericardial cavity Contains a lubricating fluid and isolates the heart from body movements such as the expansion and contraction of the nearby pleural lung cavity.
This dome-shaped muscular wall separates the thoracic from the abdominal cavity. It is also the most important muscle for? Three major vessels pass through the diaphragm between the thorax and the abdomen. These are the? This dark brown organ dominates the upper abdomen.
The falciform ligament lies in a cleft of the liver which divides it into right and left halves. Five lobes can be differentiated. The four principal lobes may be seen from the ventral aspect, they are the? A very small lobe, the? It is attached to the posterior surface of the right lateral lobe.
Liver : A large organ located above and in front of the stomach. It filters toxins from the blood, and makes bile which breaks down fats and some blood proteins. This sac-like structure stores bile secreted by the liver and releases it into the duodenum. Bile is transported by the? It is joined by the? A small, muscular, sac-like organ located near the duodenum.
It stores and releases bile a digestive chemical which produced in the liver into the small intestine. This muscular pouch lies on the left side in the upper abdomen.
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