Exercise 5: Blood Vessels: Superior and InferiorExercise 5 Learning Goals After completing this lab, you should be able to:

• Know and identify the difference in histology of arteries, veins, and capillaries
• Identify and describe the location of major arteries and veins of the human upper and lower body
• Identification of arteries and veins from a dissection specimen, lab models or images

Pre-Lab Activities for Exercise 5

Pre-Lab Activity 5.1: Superior Arteries

Use your textbook to complete the information for selected superior arteries in the table below.

Pre-Lab Activity 5.2: Superior Veins

Use your textbook to complete the information for selected superior veins in the table below.

Pre-Lab Activity 5.3: Inferior Arteries

Use your textbook to complete the information for selected inferior arteries in the table below.

Pre-Lab Activity 5.4: Inferior Veins

Use your textbook to complete the information for selected inferior veins in the table below.

Blood Vessels

Blood is carried through the body to the tissues through a conduit system known as blood vessels. An artery is a vessel that carries blood away from the heart, is thick walled, under high pressure, and branches into increasingly smaller diameter vessels known as arterioles. Arterioles further branch into tiny single-layered capillaries, where nutrients and wastes are exchanged, and then capillaries converge to form venules. Venules are small blood vessels that carry blood to veins and veins are larger thin-walled vessels that return blood to the heart.

Arteries and veins transport blood in two circuits: the systemic circuit and the pulmonary circuit. Systemic arteries provide oxygen rich blood to the body’s tissues. The blood returned to the heart through systemic veins is depleted of oxygen, since much of the oxygen carried by the arteries has been delivered to the cells in tissues. In contrast, the pulmonary circuit arteries carry blood low in oxygen directly to the lungs for oxygen loading. Pulmonary veins then return freshly oxygenated blood from the lungs to the heart to be pumped back out into systemic circulation. Although arteries and veins differ structurally and functionally, they share certain common features such as both having three distinct tissue layers.

Figure 5.2 Pulmonary and systemic circulation highlighting major blood vessels.

Pre-Lab Activity 5.5: Critical Thinking

Identify the structures in the body where capillary beds are found. What physiological processes occur in capillaries? Why do some single organs have such high concentrations of capillaries within their tissues?

Exercise 5 Activities: Blood VesselsThe Difference Between Blood Vessel Types

Blood vessels vary slightly in their structures and function; however, they share the same general features. Arteries and arterioles have thicker walls than veins and venules because they are closer to the heart and receive blood that is surging at great pressures. Each vessel type has a lumen, a hollow passageway through which blood flows. Arteries have smaller lumens compared to veins, a characteristic that helps to maintain the high pressure of blood moving through the system. Together, their thicker walls and smaller diameters give arterial lumens a rounded appearance in cross section than the lumens of veins.

By the time blood has passed through the capillaries and entered venules, the pressure initially exerted upon by the heart has diminished. In comparison to arteries, venules and veins are under much lower pressure from the blood that flows through them. Their walls are thinner, and the lumens are correspondingly larger in diameter, allowing more blood to flow with less resistance. In addition, many veins of the body, particularly those of the limbs, have valves that assist the unidirectional flow of blood back toward the heart. This is critical because blood flow becomes sluggish in the extremities, due to the lower pressure and the effects of gravity.

Figure 5.3 Histological section of an artery and vein. The artery has a thicker wall and holds the round shape, whereas the the vein does not.

The walls of arteries and veins are composed of cells and their products (including collagen and elastic fibers); the cells require nourishment and produce wastes. Since blood passes through the larger vessels quickly, there is limited opportunity for blood in the lumen of the vessel to provide nourishment to or remove waste from the vessel’s cells. Furthermore, the walls of the larger vessels are too thick for nutrients to diffuse through to all the cells. Larger arteries and veins have small blood vessels within their walls known as the vasa vasorum, literally “vessels of the vessel,” to provide them with this critical exchange ability. Since the pressure within arteries is high, the vasa vasorum must function in the outer layers of the vessel or the pressure exerted by the blood passing through the vessel would collapse them, preventing any exchange from occurring. The lower pressure within veins allows the vasa vasorum to be closer to the vessel lumen. Both arteries and veins have the same three distinct tissue layers, called tunics, which vary in thickness.

Figure 5.4 The structure of arteries and veins, with structures labeled.

Lab Activity 5.1: Artery and Vein Histology

Using a light microscope examine the slide with cross sections of arteries and veins and then complete the table listing the features of and structures present/absent in arteries and veins.

Figure 5.5 Arteries of the Thoracic and abdominopelvic regions.

Lab Activity 5.2: Superior Arteries

The aorta is the largest artery carrying oxygenated blood to body tissues and is divided into 4 regions: the ascending aorta, the aortic arch, the thoracic aorta, and the abdominal aorta. The ascending aorta receives blood from the left ventricle and is separated from the heart by the aortic semilunar valve. The aortic arch is the left arching continuation of the ascending aorta which ends between the fourth and fifth thoracic vertebrae. The thoracic aorta is a continuation of the aortic arch which passes through the thoracic cavity and ends at the aortic hiatus of the diaphragm.

Thoracic Aorta and Major Branches

The thoracic aorta begins at the level of thoracic vertebra 5 and continues through to the diaphragm. It travels within the mediastinum to the left of the vertebral column. As it passes through the thoracic region, the thoracic aorta gives rise to several branches, which are referred to as visceral and parietal branches. The branches that supply blood to visceral organs are known as the visceral branches and include the bronchial arteries, pericardial arteries, esophageal arteries, and the mediastinal arteries, each named after the tissues it supplies. The remaining thoracic aorta branches are collectively called parietal or somatic branches and include the intercostal and superior phrenic arteries. Each intercostal artery supplies blood to the muscles of the thoracic cavity and vertebral column. The superior phrenic artery supplies blood to the superior surface of the diaphragm.

Figure 5.6 Major Arteries of the Upper Body, with several descriptions of which part of the body they supply with blood.

• What regions do each of the four divisions of the aorta supply?

Label the following on anatomically correct models in lab.

Arteries:

• Aorta – regions: ascending, arch, descending, thoracic
• Pulmonary trunk
• Pulmonary artery (R&L)
• Ductus arteriosus
• Coronary arteries (surface of heart)
• Brachiocephalic artery
• Subclavian artery (R&L)
• Axillary artery (R&L)
• Internal mammary (thoracic) artery (R&L)
• Intercostal arteries (R-side/L-side)
• Brachial arteries (R&L)

Lab Activity 5.3: Superior Veins

Veins are under low pressure and serve as a reservoir for blood. While arteries are typically deep, veins may be superficial or deep. Superficial veins are clinically important as sites of blood withdrawal or injections. Three systemic veins are responsible for returning deoxygenated blood to the right atrium: the coronary sinus, superior vena cava and inferior vena cava.

Label the following on the anatomical models in lab.

Veins:

• Superior vena cava
• Coronary veins (surface of heart)
• Hemiazygos vein (L side only)
• Internal jugular vein (R&L)
• External jugular vein (R&L)
• Brachiocephalic vein (R&L)
• Subclavian vein (R&L)
• Axillary vein (R&L)
• Cephalic vein (R&L)
• Intercostal veins (R-side/L-side)
• Median cubital (R&L)
• Which three veins drain into the coronary sinus?
• What areas are drained by the internal and external jugular veins?

After crossing through the diaphragm at the aortic hiatus, the thoracic aorta is called the abdominal aorta. This vessel remains to the left of the vertebral column and is embedded in adipose tissue behind the peritoneal cavity. It formally ends at the level of lumbar vertebra 4, where it branches to form the common iliac arteries. Before this division, the abdominal aorta gives rise to several important branches. A single celiac trunk (artery) emerges and divides into the left gastric artery to supply blood to the stomach and esophagus, the splenic artery to supply blood to the spleen, and the common hepatic artery, which in turn gives rise to the hepatic artery to supply blood to the liver, the right gastric artery to supply blood to the stomach, the cystic artery to supply blood to the gall bladder, and several branches, to supply blood to the duodenum and to the pancreas. Two additional single vessels arise from the abdominal aorta. These are the superior and inferior mesenteric arteries. The superior mesenteric artery arises after the celiac trunk and branches into several major vessels that supply blood to the small intestine, the pancreas, and most of the large intestine. The inferior mesenteric artery supplies blood to the distal segment of the large intestine, including the rectum. It arises superior to the common iliac arteries.

In addition to these single branches, the abdominal aorta gives rise to several significant paired arteries along the way. These include the inferior phrenic arteries, the adrenal arteries, the renal arteries, the gonadal arteries, and the lumbar arteries. Each inferior phrenic artery is a counterpart of a superior phrenic artery and supplies blood to the inferior surface of the diaphragm. The adrenal artery supplies blood to the adrenal (suprarenal) glands and arises near the superior mesenteric artery. Each renal artery branches inferior to the superior mesenteric arteries and supplies each kidney. The right renal artery is longer than the left since the aorta lies to the left of the vertebral column and the vessel must travel a greater distance to reach its target. Renal arteries branch repeatedly to supply blood to the kidneys. Each gonadal artery supplies blood to the gonads, or reproductive organs, and is also described as either an ovarian artery or a testicular artery (internal spermatic), depending upon the sex of the individual. An ovarian artery supplies blood to an ovary, uterine (Fallopian) tube, and the uterus, and is in the suspensory ligament of the uterus. It is shorter than the testicular artery, which travels outside the body cavity to the testes, forming part of the spermatic cord. The gonadal arteries arise inferior to the renal arteries and are retroperitoneal.

Figure 5.7 Major Arteries from the Abdominal Aorta. The figure also lists the areas to which the arteries supply blood.

The four paired lumbar arteries are the counterparts of the intercostal arteries and supply blood to the lumbar region, the abdominal wall, and the spinal cord. In some instances, a fifth pair of lumbar arteries emerges from the median sacral artery.

The aorta divides at the level of lumbar vertebra 4 into a left and a right common iliac artery but continues as a small vessel, the median sacral artery, into the sacrum. The common iliac arteries supply blood to the pelvic region and to the lower limbs. They split into external and internal iliac arteries at the level of the lumbar-sacral articulation. Each internal iliac artery sends branches to the urinary bladder, the walls of the pelvis, the external genitalia, and the medial portion of the femoral region. In females, they also supply blood to the uterus and vagina. The much larger external iliac artery supplies blood to each of the lower limbs.

Arteries Serving the Lower Limbs

The external iliac artery exits the body cavity and enters the femoral region of the lower leg. As it passes through the body wall, it is renamed the femoral artery. It gives off several smaller branches as well as the lateral deep femoral artery that in turn gives rise to a lateral circumflex artery. These arteries supply blood to the deep muscles of the thigh and ventral and lateral regions of the integument. As the femoral artery passes posterior to the knee near the popliteal fossa, it is called the popliteal artery. The popliteal artery branches into the anterior and posterior tibial arteries. The anterior tibial artery is located between the tibia and fibula, and supplies blood to the muscles and integument of the anterior tibial region.

Figure 5.8 Arteries of the Lower Limbs

• What are the paired visceral and parietal branches of the thoracic and abdominal aorta and what body regions do they supply?
• What are the unpaired visceral and parietal branches of the thoracic and abdominal aorta and what body regions do they supply?
• What general regions do the internal and external iliac arteries supply?

Lab Activity 5.4: Inferior ArteriesLabel the following on anatomically correct models in lab.

Arteries

The Inferior Vena Cava

Other than the small amount of blood drained by the azygos and hemiazygos veins, most of the blood inferior to the diaphragm drains into the inferior vena cava before it is returned to the heart. Lying just beneath the parietal peritoneum in the abdominal cavity, the inferior vena cava parallels the abdominal aorta, where it receives blood from abdominal veins. The lumbar portions of the abdominal wall and spinal cord are drained by a series of lumbar veins, usually four on each side. The ascending lumbar veins drain into either the azygos vein on the right or the hemiazygos vein on the left and return to the superior vena cava. The remaining lumbar veins drain directly into the inferior vena cava.

Blood supply from the kidneys flows into each renal vein, normally the largest veins entering the inferior vena cava. Several other, smaller veins empty into the left renal vein. Each adrenal vein drains the adrenal glands located immediately superior to the kidneys. The right adrenal vein enters the inferior vena cava directly, whereas the left adrenal vein enters the left renal vein.

Figure 5.9 Veins of the Thoracic and Abdominopelvic Regions

From the male reproductive organs, each testicular vein flows from the scrotum, forming a portion of the spermatic cord. Each ovarian vein drains an ovary in females. Each of these veins is generically called a gonadal vein. The right gonadal vein empties directly into the inferior vena cava, and the left gonadal vein empties into the left renal vein.

Each side of the diaphragm drains into a phrenic vein; the right phrenic vein empties directly into the inferior vena cava, whereas the left phrenic vein empties into the left renal vein. Blood supply from the liver drains into each hepatic vein and directly into the inferior vena cava. Since the inferior vena cava lies primarily to the right of the vertebral column and aorta, the left renal vein is longer, as are the left phrenic, adrenal, and gonadal veins. The longer length of the left renal vein makes the left kidney the primary target of surgeons removing this organ for donation.

Figure 5.10 Veins Returning Blood via the Inferior Vena Cava. The figure also lists which areas are drained by the veins.

What structure do the lumbar, gonadal, renal, and adrenal, inferior phrenic and hepatic veins drain?

Veins Draining the Lower Limbs

Close to the body wall, the great saphenous vein, the deep femoral vein, and the femoral circumflex vein drain into the femoral vein. The great saphenous vein is a prominent surface vessel found on the medial surface of the leg and thigh that collects blood from the superficial portions of these areas. The deep femoral vein, as the name suggests, drains blood from the deeper portions of the thigh. The femoral circumflex vein forms a loop around the femur just inferior to the trochanters and drains blood from the areas in proximity to the head and neck of the femur.

As the femoral vein penetrates the body wall from the femoral part of the upper limb, it becomes the external iliac vein, a large vein that drains blood from the leg to the common iliac vein. The pelvic organs and integument drain into the internal iliac vein, which forms from several smaller veins in the region, including the umbilical veins that run on either side of the bladder. The external and internal iliac veins combine near the inferior part of the sacroiliac joint to form the common iliac vein. In addition to blood supply from the external and internal iliac veins, the middle sacral vein drains the sacral region into the common iliac vein. Like the common iliac arteries, the common iliac veins come together at the level of lumbar vertebra 5 to form the inferior vena cava.

Figure 5.11 Veins of the Lower Limbs

Hepatic Portal System

The liver is a complex biochemical processing organ. It packages nutrients absorbed by the digestive system; produces plasma proteins, clotting factors, and bile, while disposing of worn-out cell components and waste products. Instead of entering the circulation directly, absorbed nutrients and certain wastes travel to the liver for processing. They do so via the hepatic portal system. Portal systems begin and end in capillaries. In this case, the initial capillaries from the stomach, small intestine, large intestine, and spleen lead to the hepatic portal vein and end in specialized capillaries within the liver.

The hepatic portal system consists of the hepatic portal vein and the veins that drain into it. The hepatic portal vein itself is short, beginning at the level of lumbar vertebra 2 with the convergence of the superior mesenteric and splenic veins. It also receives branches from the inferior mesenteric vein, plus the splenic veins and all their tributaries. The superior mesenteric vein receives blood from the small intestine, two-thirds of the large intestine, and the stomach. The inferior mesenteric vein drains the distal third of the large intestine, including the descending colon, the sigmoid colon, and the rectum. The splenic vein is formed from branches from the spleen, pancreas, and portions of the stomach, and the inferior mesenteric vein. After its formation, the hepatic portal vein also receives branches from the gastric veins of the stomach and cystic veins from the gall bladder. The hepatic portal vein delivers materials from these digestive and circulatory organs directly to the liver for processing.

Because of the hepatic portal system, the liver receives its blood supply from two diverse sources: from normal systemic circulation via the hepatic artery and from the hepatic portal vein. The liver processes the blood from the portal system to remove certain wastes and excess nutrients, which are stored for later use. This processed blood, as well as the systemic blood that came from the hepatic artery, exits the liver via the right, left, and middle hepatic veins, and flows into the inferior vena cava. Overall systemic blood composition stays stable since the liver can metabolize the absorbed digestive components.

Figure 5.12 The Hepatic Portal System

Describe the importance of the hepatic portal system?Lab Activity 5.5: Inferior VeinsLabel the following on anatomically correct models in lab.

Veins:

Lab Activity 5.6 Superior Vessels Fetal Pig Dissection (Optional)

Supplies needed: Gloves, scalpel, blunt probe, and tweezers.

For the ANTERIOR part of the fetal pig circulatory system:

These are analogous to the SUPERIOR vessels of the human circulatory system. Use human terminology wherever terms for the pig may differ.

• Open the body cavity. You can often “begin” a cut using your scalpel then switch to scissors.

To begin, make two incisions through the skin of the abdomen so that each one goes around one side of the umbilical cord, and each extends down to the beginning of the legs. Be careful that you are only cutting through the abdominal wall- if you cut too deeply the underlying organs will be destroyed. We may need them for future dissections!

Figure 5.13 Fetal Pig Dissection Diagram. The figure depicts the incisions that should be made to perform a dissection. (Diagram by Gina Profetto)

1. Make a lateral incision at the base of the rib cage. This should be as close as possible to where the diaphragm separates the thoracic and abdominal cavities. Extend this cut to both the right and left sides by using the inferior edge of the ribcage as a guide.
2. Finally, make an incision beginning at the papilla on the underside of the chin and extending down to the base of the sternum.
   • • In the first step, cut through the skin of the thoracic cavity, but DO NOT cut into the sternum. Peel the skin back away from the rib cage. This will allow you to see more clearly where the sternum is before you cut it open.
     • Ideally, you will cut the sternum directly down the middle to open the thoracic cavity. Be careful that you do not cut too deeply and damage the heart or the blood vessels coming out of the heart. To avoid this, take your blunt probe and run it up underneath the sternum. You can then use your scalpel to cut down on the probe without damaging any important structures. If the mid-line cut does not seem to be working well, cut through the costal cartilages immediately to the right or left of the sternum. Cutting too far away from the sternum will destroy vessels you need to see.
3. Once the thoracic cavity is opened, put away your scalpel. Everything else can be accomplished with the blunt probe, tweezers, and your gloved hands. The first thing you will need to do is clean out the connective tissue on each side of the throat. The blood vessels you are looking for are deep in the body cavity here and so the overlying tissue must be removed. Most of this tissue is the thymus, an important endocrine gland, which sits on each side of the throat and over the front of the heart. You will need to remove all the pebble-looking thymus tissue.

• Remove only connective tissues on both sides of the throat. DO NOT remove the structures in the middle of the throat- these are parts of the respiratory system (larynx and trachea) and the thyroid gland. The thyroid is superficial to the trachea, just superior to the heart.

1. After you have removed the thymus and outer masses of connective tissue, there may still be considerable connective tissue around the blood vessels. Use your probes or the tweezers to clean off the vessels so that you can trace them from the heart out into the body.
2. Identify the arteries that supply the anterior portion of the fetal pig (superior in humans):
   1. Pulmonary trunk - connects with the right ventricle.
   2. Aorta - lies immediately behind the pulmonary artery. The aorta is divided into different sections: the ascending aorta is the small section where it leaves the heart, the aortic arch is where it arches over the heart, and the descending aorta is that portion that goes down along the spinal column from the heart. Once it clears the heart it becomes the thoracic aorta and then after passing through the diaphragm, it is the abdominal aorta.
   3. Ductus arteriosus- follow the pulmonary artery from where it leaves the heart until you see a small branch connecting to the aorta. Notice that one branch of the pulmonary artery connects it with the aorta- this is the ductus arteriosus. The other branch of the pulmonary trunk splits to become the right and left pulmonary arteries.
   4. Coronary arteries – oxygenated vessels on the surface of the heart. If you look closely, you should be able to see where the left and right coronary arteries branch off the ascending aorta.
   5. Brachiocephalic artery – first major branch that comes off the aortic arch. The brachiocephalic artery travels underneath the superior vena cava and branches into the 1) right subclavian artery - which goes into the right front leg, and the 2) right & left common carotid arteries - which supply the head.
   6. Left subclavian artery – second major branch off the aortic arch; supplies the left front leg.
   7. Internal mammary arteries (R&L) – branch immediately off the subclavian; run parallel down the internal surface of the ribcage, following the nipple line.
   8. Axillary arteries (R&L) – continuation of the subclavian as the move into the front limbs; will become the brachial arteries as they continue down the humerus.
   9. Intercostal arteries – run parallel to and supply the tissue along each rib.

*Remember: Immediately below each rib is a V-A-N

V- intercostal vein, A- intercostal artery, N- intercostal nerve

1. Find the veins that drain the anterior part of the fetal pig (superior in humans):

Note: we are tracing the veins in the opposite direction of how blood flows through them. Arteries branch (bifurcate) while veins join.

Thoracic/Upper Limbs:

• 1. Superior vena cava - large vessel entering the heart from above; just above the right auricle.
  2. Inferior vena cava - large blue vessel entering the heart from below; just above the coronary sulcus where the posterior interventricular sulcus ends.
  3. Brachiocephalic veins (R&L) – To locate follow the superior vena cava out from the heart and find the two short branches which join to form it.
  4. Subclavian veins (R&L) – the large vessels which continue to form the brachiocephalic veins; come from the direction of each upper limb.
  5. Axillary veins (R&L) – formed by the joining of many veins in the shoulder; continues as the subclavian at the lateral margin of the 1^st rib.
  6. Subscapular veins (R&L) –contributing vessel to the axillary vein; typically, small and runs from humeral head.
  7. Cephalic veins (R&L) – large contributing vessel to the axillary vein; comes superficially out of the limbs from the ventral (anterior) surface headed deep.
  8. Internal mammary veins (R&L) – drain into the superior vena cava; run along the internal surface of the sternum.
  9. Coronary veins – deoxygenated vessels on the surface of the heart; drain into the coronary sinus.
  10. Intercostal veins (R&L) – run parallel to and drain the tissue along each rib. Remember: V-A-N
  11. Hemiazygos vein (L only) - receives blood from the left intercostal veins and lies underneath the descending aorta next to the spinal column. This vessel is left-sided only. There is no right-side version.

Head/Neck:

• 1. Internal jugular veins (R&L) - closest to the midline on either side of the trachea; typically, “bundled” with the carotid arteries and vagus nerves.
  2. External jugular veins (R&L) – lateral to the internal jugulars; imagine the midline as 12 on a clock face- the externals run down from 2 (left) and 10 (right). Typically, the right external jugular is used as the site of latex injection, so it is typically cut and tied with string.

Lab Exercise 5.7: Inferior Fetal Pig Dissection (optional)

Supplies needed: Gloves, scalpel, blunt probe, and tweezers

For the POSTERIOR portion of the fetal pig circulatory system:

These are analogous to the INFERIOR vessels of the human circulatory system. Use human terminology wherever terms for the pig may differ.

1. The blood vessels of the abdominal organs lie deep within the abdominal cavity, underneath the parietal peritoneum (layer of serous membrane which lines the abdominal cavity). Hence, the blood vessels are said to be retroperitoneal (behind the peritoneum). To see the blood vessels, you will need to use your probe/tweezers to peel off the peritoneum. BE CAREFUL as you do this. The vessels, especially the arteries that you are looking for here, are much smaller than the anterior vessels. Be sure you do not tear these out as you are removing the peritoneum. Aside from peeling back the peritoneum, there is no other tissue that should be removed from the abdominal cavity.
2. To fully open the abdominal flaps you originally cut, you will have to cut the umbilical vein leading from the internal aspect of the umbilicus to the liver. Cut it midway along its length so you can “reconnect” the two halves during identification.
3. Identify the arteries that supply the posterior portion of the fetal pig (inferior in humans):
   1. Abdominal aorta – begins where the aorta passes through the diaphragm; is the source which all the posterior (inferior) arteries branch from; runs parallel with the spinal column – usually appears undyed because of its thick, muscular walls.
   2. Celiac trunk - first branch off the abdominal aorta; supplies the stomach, liver, and spleen with blood.
   3. Superior mesenteric artery –found immediately after the celiac artery; supplies the small intestine.
   4. Adrenolumbar arteries (R&L) - branch off just below the superior mesenteric and can best be seen by lifting a kidney; supply the tissue of the abdominal wall underneath the kidney.
   5. Renal arteries (R&L) - branch off the aorta immediately after the adrenolumbar; can be seen entering the hilum of each kidney.
4. Near the base of the aorta, three small, thread-like arteries branch off.
   1. Inferior mesenteric artery - runs medially along the underside of the descending colon; supplies the lower small intestines and large intestines.
   2. Gonadal arteries (R&L) – branch laterally; supply the gonads (ovaries in a female; testes in a male).
5. The aorta ends in the lower abdominal cavity where it branches into 4 main vessels.
   • Internal iliac arteries (R&L) - inner-most medial branches from the aorta; become the umbilical arteries
     • Umbilical arteries (R&L) – continuation of the internal iliac arteries as they change course at the pelvis to run along each side of the bladder.
     • Median sacral artery – thread-like vessel coming off the underside of the aorta between the internal iliac arteries; runs deep toward the sacral region of the spine.
   • External iliac arteries (R&L) - outer lateral branches; branching off these vessels are the left and right iliolumbar- which supply blood to the lower part of the abdominal wall.
6. Trace the external iliac into the legs. From here each branch is divided into 2 vessels.
7. Femoral artery- external branch that continues down into the leg (femur)
8. Deep femoral artery- internal branch that goes toward the buttocks and inner thigh.
9. Identify the veins that drain the posterior portion of the fetal pig (inferior in humans): Note: we are tracing the veins in the opposite direction of how blood flows through them. Arteries branch (bifurcate) while veins join.
   1. Inferior vena cava - large blue vessel running to the right, parallel with the spinal column; drains blood of all structures posterior (inferior) to the heart.
   2. Hepatic veins – drain the sinusoids of the liver; To find scrape away some of the liver tissue at the junction of the liver and inferior vena cava.
   3. Umbilical vein – cut previously to allow access to abdomen; reconnect the two halves to see how it brings freshly oxygenated blood through the umbilicus.
   4. Hepatic portal vein – blood “bypass” route from the small intestine into the inferior aspect of the liver.
   5. Renal vein (R&L) – exit from the hilum of each kidney.
10. Follow the inferior vena cava down to the base of the abdominal cavity where two major branches join to form the inferior vena cava.
11. Common iliac veins (R&L) –the joining of the common iliac veins occurs underneath the aorta- you may have to lift the aorta to see this junction. The left and right common iliac veins run immediately beneath the external iliac arteries.
12. Internal iliac vein (R&L) – medial branch joining into the common iliac vein; come from deep in the back of the pelvic cavity
13. External iliac vein (R&L) – lateral branch; comes from the leg where it arises from the femoral & deep femoral veins

Clean up procedure:

Dispose of all organic debris in the proper biohazard containers and clean the dissecting instruments and tray with soap and water before leaving the laboratory. Do not forget to wash your hands with water and soap, and to disinfect the lab bench.

Post-Lab 5 Review

Post-Lab Activity 5.1: Identify Superior Arteries

Fill in the table below using the lettered diagram provided.

Figure 5.14 The Aorta and Major Branches

Post-Lab Activity 5.2: Identify Superior Arteries

Fill in the table for the numbered vessels.

Figure 5.15 Major Arteries of the Upper Limb

Post-Lab Activity 5.3: Identify Superior and Inferior Arteries

Fill in the table below with the corresponding lettered vessels from the diagram.

Figure 5.16 Major arteries of the thoracic and abdominopelvic region.

Post-Lab Activity 5.4: Identify Superior Veins

Fill in the table below with the letter of the corresponding vessel:

Figure 5.17 Major Veins of the Upper Limbs

Post-Lab Activity 5.5: Identify Superior and Inferior Veins

Fill in the table with letter of the corresponding vessel:

Figure 5.18 Major Veins of the Upper Limbs

Post-Lab Activity 5.6: Matching

Match the vessel with the correct description.

Post-Lab Activity 5.7: Identify Inferior Veins

Label the diagram with the letter of the corresponding vessel: (Letters may be used more than once.)

Locate these Veins:

A: Common iliac vein

B: Internal iliac vein

C: External iliac vein

D: Great saphenous

E: Femoral vein

Figure 5.19 Major Veins of the lower limbs

Post-Lab Activity 5.8: Identify Inferior Arteries

Label the diagram with the number of the corresponding vessel: (Numbers may be used more than once.)

Figure 5.20 Major arteries of the lower limbs.

Locate these Arteries:

1) Femoral artery

2) Deep femoral artery

3) Common iliac artery

4) Internal iliac artery

5) External iliac artery