Fetal Pig-Observations of the Circulatory System PDF

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Name: Gleyanne Alicos Anatomy and Physiology 12

Dissection of the Fetal Pig with a focus on the Cardiovascular System External anatomy of the pig Like humans, pigs are mammals, which are characterized by the presence of hair and mammary glands. Since both pigs and humans are placental animals, they develop in the uterus of their mother. Humans and pigs both have four limbs, however pigs walk on all four of their limbs. Observe and examine the body regions and limbs of the pig following the guide. Observe and examine the umbilical cord and its vessels. What is the function of the umbilical cord? The function of an umbilical cord is to send nutrients and oxygenated blood to the fetus Observe the nipples and hair. Where is the hair? The hair can be found around the body Observe the anus and external genitals. What sex is your pig? Female

Internal anatomy Observe the oral cavity and the pharynx. How could you prove that food and air passages join in the pharynx? Food and air passages join in the larynx but the epiglottis blocks the pathway Open the thoracic cavity. List the organs you find in the thoracic cavity: thyroid glands, lungs, heart & esophagus Which two cavities does the diaphragm separate? The thoracic/abdominal cavities Open the abdominal cavity. List the organs you find in the abdominal cavity: spleen, liver, stomach, small & large intestine, umbilical cord, bladder Observe the Liver. Name some functions of the liver: it secretes bile, filters blood, detoxifies toxins Observe the stomach. What is its function? it breaks down & stores food Observe the spleen. What system is the spleen part of? What is its function? It’s part of the lymphatic system and it filters blood Observe the small intestine. What is its function? It digests nutrients Observe the gallbladder and pancreas. What are their functions? They secrete enzymes for digestion Observe the large intestine. What is its function? absorbs water Trace the path of food from mouth to anus: mouth -> esophagus -> stomach -> small/large intestine -> anus

Observe the kidneys and trace the path of urine to the outside. Observe the gonads (sex organs), which does your pig have? Genital papilla

From Laboratory 12, Mader Biology 9th Ed Laboratory Manual

Cardiovascular System Blood must circulate to bring nutrients to the body and remove wastes. The heart pumps the blood which moves away from the heart though arteries and arterioles and it moves back towards the heart through venules and veins. Capillaries connect arterioles to venules, and are the location where exchange of wastes and nutrients with tissues occurs. Pulmonary Circuit 1. Trace the path of blood in the pulmonary circuit starting with the heart. Follow the arrows provided in Figure 13.1 and use the label names provided in the figure. Right ventricle Pulmonary artery Lungs Pulmonary vein and left atrium Notice that in the adult there is no connection between the right and left side of the heart except via the lungs.

Systemic Circuit 2. Trace the path of blood in the systemic circuit to and from the kidneys. Left ventricle Aorta -> renal artery Kidneys Renal vein -> inferior vena cava -> right atrium

Names of Blood Vessels 3. Use figure 13.1 to complete table 13.1 Table 13.1 Major Blood Vessels in the Systemic Circuit Body Part Artery Head carotid Arms subclavian Kidney Renal Legs Iliac Intestines mesentric Path of Blood in Fetal Humans

From Laboratory 13, Mader Biology 9th Ed Laboratory Manual

Vein Jugular Subclavian Renal Iliac Hepatic portal

Human fetal circulation has five features absent in adults. These features are listed in Table 13.2 and shown in Figure 13.2. Notice that the blood passes through the heart to the aorta without going to the lungs and that the umbilical vessels take blood to and from the placenta, the organ that develops on the inner wall of the uterus where exchange takes place between fetal blood and mother’s blood. The respiratory and digestive systems are not operative in the fetus; oxygen and nutrients are acquired at the placenta.

Table 13.2 Unique Features of Human Fetal Circulation 1. Oval opening (foramen ovale): an opening between the atria 2. Arterial duct (ductus arteriosus): a short, stout vessel leading directly from the pulmonary trunk to the aorta 3. Umbilical arteries: take blood from the iliac arteries to the placenta 4. Umbilical veins: returns blood from the placenta into the liver 5. Venous duct (ductus venosus): a continuation of the umbilical vein that takes blood to the inferior vena cava Through the Heart 1. Trace two possible pathways of the blood through the heart to the aorta. First pathway:

Second pathway:

Right atrium

Right atrium

rv

Oval opening

pt

LA

arterial duct

LV

Aorta

Aorta

Through the Placenta 2. Trace the path of blood from the aorta to the placenta and from the placenta to the inferior vena cava. To the placenta: Aorta communiliac umbilical arteries Placenta

From Laboratory 13, Mader Biology 9th Ed Laboratory Manual

From the placenta: Placenta Umbilical vein Venus duct Inferior vena cava

Comparison 1. Complete Table 13.3 to compare human fetal circulation with human adult circulation. Table 13.3 Comparison of Human Fetal and Adult Circulation Fetus Vessel with the highest oxygen Umbilical vein

Adult Pulmonary vein

concentration Passage from right to left side of heart

Oval opening

Through lumas

Entrance of blood into aorta

Arterial duct

LV

Area of gas exchange

placenta

lungs

13.2 Pulmonary Circuit It is possible to locate the pulmonary arteries and veins in your pig even though they are not operative in fetuses. In the pulmonary circuit of adults, pulmonary arteries take blood from the heart to the lungs and pulmonary veins take blood from the lungs to the heart. Remember that in your pig all arteries have been injected with red latex and all veins have been injected with blue latex. What do you suppose the red and blue represent? Is this true of all veins and arteries? The red represents oxygenated blood while blue is deoxygenated. This is not rue of all veins and arteries because they carry different types. Observe the Pulmonary Trunk and Pulmonary Arteries carefully. Find the arterial duct that connects the pulmonary trunk with the aorta. What might happen if the arterial duct did not degenerate in a newborn? The deoxygenated & oxygenated blood will mix together 13.3 Systemic Circuit The systemic circuit serves all parts of the body. In this circuit, arteries bring oxygenated blood to all parts of the body from the heart, and veins bring deoxygenated blood from all parts of the body back to the heart. The aorta is the major artery, and the vena cavae (anterior and posterior) are the major veins. Identify on your pig all of the major arteries and veins shown in Figure 13.4.

From Laboratory 13, Mader Biology 9th Ed Laboratory Manual

Cardiovascular System Recap: 13.1 Path of blood in adult vs fetus 1. What fetal structure connects the pulmonary artery to the aorta? Arterial duct 2. What fetal blood vessel contains the most oxygen? Umbilical cord 13.2 Pulmonary Circuit 3. Does the pulmonary artery in adults carry oxygenated or deoxygenated blood? deoxygenated 13.3 Systemic Circuit 4. 5. 6. 7. 8. 9.

Identify the blood vessel that conducts blood to the head. Carotid artery Name the arteries and veins that serve the kidney. renal Identify the large artery that runs dorsally along the wall of the abdominal cavity. Dorsal aorta What are the arteries that take blood from the aorta to the legs? Iliac What part of the human body is served by the subclavian vessels? Arm Identify the large vein that runs between the diaphragm and the heart. Posterior vena cava

13.4 Blood vessel comparison 10. Which type of blood vessel artery or vein has thicker walls? Artery 11. Do arteries always carry oxygenated blood? Explain. Pulmonary arteries carry deoxygenated blood 12. Trace the path of blood from the left ventricle to the kidneys and back to the right atrium. LV -> aorta -> renal artery -> arterioles -> renal capillaries -> venules -> vein -> inferior vena cava

From Laboratory 13, Mader Biology 9th Ed Laboratory Manual...