Blood vessels and circulation

Describe the pattern of fetal blood flow to and from the placenta.

Deoxygenated blood flows from the fetus to the placenta through a pair of umbilical arteries, and oxygenated blood returns from the placenta in a single umbilical vein. The umbilical vein then drains into the ductus venosus within the fetal liver.

Trace a drop of blood through the lungs, beginning at the right ventricle and ending at the left atrium.

Right ventricle--->right and left pulmonary arteries---> pulmonary arterioles---> alveolar capillaries---> pulmonary venules---> pulmonary veins---> left atrium.

Identify the major branches of the inferior vena cava.

The major branches of the inferior vena cava are the lumbar, gonadal, hepatic, renal, adrenal, and phrenic veins.

The plantar venous arch carries blood to which three veins?

The plantar venous arch delivers blood to the anterior tibial, posterior tibial, and fibular (peroneal) veins.

Describe the pulmonary circuit

The pulmonary circuit carries blood through the arteries, capillaries, and veins of the lungs from the right ventricle to the left ventricle.

Which chamber of the heart receives blood from the systemic circuit?

The right atrium receives blood from the systemic circuit.

Define varicose veins.

Varicose veins are sagging, swollen veins distorted by the pooling of blood resulting from gravity and hte failure of venous valves.

A blockage of which branch of the aortic arch would interfere with blood flow to the left arm?

A blockage of the left subclavian artery would interfere with the blood flow to the left arm.

A blood clot that blocks the politeal vein would interfere with blood flow in which other veins?

A blockage of the popliteal vein would interfere with blood flow in the tibial and fibular (peroneal) veins (which form the popliteal vein) and the small saphenous vein (which joins the popliteal vein).

Describe a capillary

A capillary is a small blood vessel, located between an arteriole and a venule, whose thin wall permits the diffusion of gases, nutrients, and wastes between blood and interstitial fluids.

Besides containing valves, cite another major difference between the arterial and venous systems.

A major anatomical difference between the arterial and venous systems is the existence of dual venous drainage in the neck and limbs.

What is the function of angioblasts?

Angioblasts remodel blood islands first into capillary networks, and then into larger arterial and venous networks.

How is blood pressure maintained in veins to counter the force of gravity?

Assisted by the presence of valves in the veins, which prevent backflow of the blood, the contraction of the surrounding skeletal muscles squeezes venous blood toward the heart.

What are blood islands, and from which cells do they form?

Blood islands are aggregated groups of cells scattered in the yolk sac. They are formed from early precursor cells called angioblasts.

Why do capillaries permit the diffusion of materials, whereas arteries and veins do not?

Capillary walls are thin, so distances for diffusion are short. Continuous capillaries have small gaps between adjacent endothelial cells that permit the diffusion of water and small solutes into the surrounding interstitial fluid but prevent the loss of blood cells and plasma proteins. Fenestrated capillaries contain pores that permit very rapid exchange of fluids and solutes between interstitial fluid and blood. The walls of arteries and veins are several cell layers thick and are not specialized for diffusion.

At what sites in the body are fenestrated capillaries located?

Fenestrated capillaries are located where solutes as large as small peptides move freely into and out of the blood, including endocrine glands, the choroid plexus of the brain, absorptive areas of the intestine, and filtration areas of the kidneys.

Why are valves located in veins, but not in arteries?

In the arterial system, pressures are high enough to keep the blood moving away from the heart. In the venous system, blood pressure is to low to keep the blood moving back toward the heart. Valves in veins prevent blood from flowing backward whenever the venous pressure drops.

Grace is in an automobile accident, and her celiac trunk is ruptured. Which organs will be affected most directly by this injury?

Rupturing the celiac trunk would most directly affect the stomach, inferior portion of hte esophagus, spleen, liver, gallbladder, and proximal portion of the small intestine.

Name the arterial structure in the neck region that contains baroreceptors.

The arterial structure in the neck region that contains baroreceptors is carotid sinus.

Identify the branches of the external carotid artery.

The branches of the external carotid artery are the superficial temporal, maxillary, occipital, facial, and lingual.

Describe the structure and function of the cerebral arterial circle.

The cerebral arterial circle (also known as the circle of Willis) is a ring-shaped anastomosis that encircles the infundibulum of hte pituitary gland. Its anatomical arrangement creates alternate pathways in the cerebral circulation, s that if blood flow is interrupted in one area, there blood vessels can continue to perfuse the entire brain with blood.

Name the first two branches of the common iliac artery.

The first two branches of the common iliac artery are the internal iliac artery and the external iliac artery.

List the five general classes of blood vessels.

The five general classes of blood vessels are arteries, arterioles, capillaries, venules, and veins.

Which vessel collects most of the venous blood inferior to the diaphragm?

The inferior vena cava collects most of the venous blood inferior to the diaphragm.

Name the veins that drain the dural sinuses of the brain.

The internal jugular veins drain the dural sinuses of the brian.

Identify the largest artery in the body.

The largest artery in the body is the aorta.

Identify two veins that carry blood away from the stomach.

The left and right gastroepiploic veins carry blood away from the stomach.

Identify the six structures that are necessary in the fetal circulation but cease to function at birth, and describe what becomes of these structures.

The six necessary structures in the fetal circulation are two umbilical arteries, one umbilical vein, the ductus venosus, the foramen ovale, and the ductus arteriosus. After birth, the foramen ovale closes and persists as the fossa ovalis, a shallow depression; the ductus arteriosus persists as the ligamentum arteriosum, a fibrous cord; and the umbilical vessels and ductus venosus persist throughout life as fibrous cords.

Describe the systemic circuit

The systemic circuit transports blood through the arteries, capillaries, and veins of the body from the left ventricle to the right atrium. Blood returning to the heart from the systemic circuit must complete the pulmonary circuit before it re-enters the systemic circuit.

Name the three branches of the internal carotid artery.

The three branches of hte internal carotid artery are the ophthalmic, anterior cerebral, and middle cerebral arteries.

Briefly describe the three general patterns of blood vessel organization.

The three general patterns of blood vessel organization are the following: 1. The peripheral distributions of arteries and veins on the body's left and right sides are generally identical, except near the heart where the largest vessels connect to the atria or ventricles. 2. A single vessel may have several names as it crosses specific anatomical boundaries, making accurate anatomical descriptions possible 3. tissues and organs are usually serviced by several arteries and veins.

Identify the three veins that merge to form the hepatic portal vein.

The three veins that merge to form the hepatic portal vein are the superior mesenteric, inferior mesenteric, and sphlenic veins.

Name the two arteries formed by the division of the brachiocephalic trunk.

The two arteries formed by the division of the brachiocephalic trunk are the right common carotid artery and right subclavian artery.

Compare the oxygen content in the two circulatory circuits.

The two circulatory circuits of the cardiovascular system are the pulmonary circuit and the systemic circuit. The pulmonary circuit carries deoxygenated blood from the right ventricle to the lungs and returns oxygenated blood to the left atrium. The systemic circuit carries oxygenated blood to the organs and tissues of the body and returns deoxygenated blood to the right atrium.

Name the two large veins that collect blood from the systemic circuit.

The two large veins that collect blood from the systemic circuit are the superior vena cava and the inferior vena cava.

Identify the two types of capillaries.

The two types of capillaries are continuous capillaries and fenestrated capillaries.

List the unpaired branches of the abdominal aorta that supply blood to the visceral organs.

The unpaired branches of the abdominal aorta that supply blood to the visceral organs ar ethe celiac trunk, superior mesenteric artery, and inferior mesenteric artery.

Identify the veins that combine to form the brachiocephalic vein.

The veins that combine to form the brachiocephalic vein are the external jugular, internal jugular, vertebral, and subclavian veins.

A cross section of tissue shows several small, thin-walled vessels with very little smooth muscle tissue in the tunica media. Which type of vessels are these?

These blood vessels are veins. Arteries and arterioles have a large amount of smooth muscle tissue in a thick, well-developed tunica media.

Whenever Thor gets angry, a large vein bulges in the lateral region of his neck. Which vein is this?

Thor's bulging vein is his external jugular vein.

Distinguish between vasculogenesis and angiogenesis.

Vasculogenesis refers to the formation of the first blood vessels, Angiogenesis is the growth of new blood vessels from pre-existing vessels

Compare a ventricular septal defect with tetralogy of Fallot.

Ventricular septal defects are abnormal openings between the left and right ventricles. Tetralogy of Fallot includes a ventricular septal defect plus three other heart defects; a narrowing of the pulmonary trunk, a displaced aorta, and an enlarged right ventricle with corresponding thickened right and left ventricles.