Chap 21 Checkpoint A&P II

Which type of blood vessel has (a) the largest lumen and (b) the thickest tunica media?

(a) Veins have larger lumens than arteries. (b) Arteries, specifically muscular arteries, have the thickest tunica media.

Why does blood pressure increase during exercise?

Blood pressure increases during exercise because (1) cardiac output increases and (2) resistance in visceral tissues increases.

Which type of vessel is characterized by thin walls with very little smooth muscle tissue in the tunica media?

Blood vessels with thin walls and very little smooth muscle tissue in the tunica media are veins. Arteries and arterioles have a large amount of smooth muscle tissue in a thick, well-developed tunica media.

Explain the role of aldosterone and ADH in long-term restoration of blood volume.

Both aldosterone and ADH promote fluid retention and reabsorption at the kidneys, preventing further reductions in blood volume.

Define aneurysm.

An aneurysm is the ballooning out of a weakened arterial wall resulting from sudden pressure increases.

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

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

A thrombus that blocks the popliteal 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 veins (which form the popliteal vein) and the small saphenous vein (which joins the popliteal vein).

Define thrombus.

A thrombus is a stationary blood clot within the lumen of a blood vessel.

Identify components of the cardiovascular system that are affected by age.

Components of the cardiovascular system affected by age include the blood, heart, and blood vessels.

Why would compression of the common carotid arteries cause a person to lose consciousness?

Compression of the common carotid arteries would decrease blood pressure at the carotid sinus and cause a rapid reduction in blood flow to the brain, resulting in a loss of consciousness. An immediate reflexive increase in heart rate and blood pressure would follow.

Which of the following would increase vascular resistance? increased vessel length, increased vessel luminal diameter, turbulence.

Factors that would increase vascular resistance would be increased vessel length and turbulence. Increased vessel luminal diameter would decrease vascular resistance.

Where in the body would you find fenestrated capillaries?

Fenestrated capillaries are located where fluids and small solutes 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.

For blood flow to be autoregulated, what types of stimuli signal inadequate local blood flow and blood pressure?

For blood flow to be autoregulated, physical stress (such as trauma or high temperature), chemical changes, or increased tissue activity are stimuli that signal inadequate local blood pressure and blood flow.

In a healthy person, where is blood pressure greater: at the aorta or at the inferior vena cava? Explain.

In a healthy person, blood pressure is greater at the aorta than at the inferior vena cava. Blood, like other fluids, moves along a pressure gradient from areas of high pressure to areas of low pressure. If the pressure were higher in the inferior vena cava than in the aorta, the blood would flow backward.

Why are valves located in veins but not in arteries?

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

Mike's blood pressure is 125/70. What is his mean arterial pressure (MAP)?

Mike's mean arterial pressure (MAP) is approximately 88.3 mm Hg; 70 + (125 − 70)/3 = 70 + 18.3 = 88.3.

How would applying slight pressure to the common carotid artery affect your heart rate?

Pressure on the common carotid artery would decrease blood pressure at the baroreceptors in the carotid sinus. This decrease would lower the frequency of action potentials along the glossopharyngeal nerve (IX) to the medulla oblongata, and more sympathetic impulses would be sent to the heart. The net result would be an increase in the heart rate.

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

Rupture of the celiac trunk would most directly affect the stomach, spleen, liver, and pancreas.

Name the structures in the fetal circulation that stop functioning at birth. What becomes of these structures?

Structures specific to the fetal circulation include two umbilical arteries, an umbilical vein, the ductus venosus, the foramen ovale, and the ductus arteriosus. In the newborn, 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 what the cardiovascular system provides for all other body systems.

The cardiovascular system provides other body systems with oxygen, hormones, nutrients, and white blood cells in blood, while removing carbon dioxide and metabolic wastes; it also transfers heat to body tissues.

Identify the factors that contribute to total peripheral resistance.

The factors that contribute to total peripheral resistance are vascular resistance, vessel length, vessel luminal diameter, blood viscosity, and turbulence.

List the five general classes of blood vessels.

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

Name the immediate and long-term problems related to the cardiovascular response to hemorrhaging.

The immediate problem during hemorrhaging is maintaining adequate blood pressure and peripheral blood flow; the long-term problem is restoring normal blood volume.

Identify the major patterns of blood vessel organization seen in the pulmonary and systemic circuits of the cardiovascular system.

The major patterns are as follows: (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; and (3) tissues and organs are usually serviced by several arteries and veins.

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

The path of blood through the lungs is right ventricle → pulmonary trunk → left and right pulmonary arteries → pulmonary arterioles → alveolar capillary network → pulmonary venules → pulmonary veins → left atrium.

Name the blood vessels that enter and exit the lungs, and whether they contain primarily oxygenated or deoxygenated blood.

The pulmonary arteries enter the lungs carrying deoxygenated blood, and the pulmonary veins leave the lungs carrying oxygenated blood.

What veins are shown draining directly into the superior vena cava?

The right and left brachiocephalic veins, the mediastinal veins, and the azygos vein directly drain into the superior vena cava.

What is the relationship between the skeletal system and the cardiovascular system?

The skeletal system provides calcium needed for normal cardiac muscle contraction, and it protects developing blood cells in the red bone marrow. The cardiovascular system provides calcium and phosphate for bone deposition, delivers erythropoietin to red bone marrow, and transports parathyroid hormone and calcitonin to osteoblasts and osteoclasts.

The superficial temporal, maxillary, occipital, facial, and lingual arteries are all branches of what carotid artery?

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

Identify the two circuits of the cardiovascular system.

The two circuits of the cardiovascular system are the pulmonary circuit and the systemic circuit.

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

The vein that is bulging in Noah's neck is the external jugular vein.

A blood sample taken from an umbilical cord contains high levels of oxygen and nutrients, and low levels of carbon dioxide and waste products. Is this sample from an umbilical artery or the umbilical vein? Explain.

This blood sample was taken from the umbilical vein, which carries oxygenated, nutrient-rich blood from the placenta to the fetus.

Name the three vessels that carry blood to and from the placenta.

Two umbilical arteries supply blood to the placenta, and one umbilical vein returns blood from the placenta. The umbilical vein then drains into the ductus venosus within the fetal liver. (Remember, arteries carry blood away from the heart, and veins carry blood to the heart.)

What effect would vasoconstriction of the renal artery have on blood pressure and blood volume?

Vasoconstriction of the renal artery would decrease both blood flow and blood pressure at the kidney. In response, the kidney would increase the amount of renin it releases, which in turn would lead to an increase in the level of angiotensin II. The angiotensin II would bring about increased blood pressure and increased blood volume.

Describe the actions of vasodilators and local vasodilators.

Vasodialators promote the dilation of pre capillary sphincters. Local vasodialators, such as decreased O2 level or increased CO2 level, act on tissues to accelerate blood flow.

While standing in the hot sun, Lailah begins to feel lightheaded and faints. Explain what happened.

While Lailah was standing for a period of time, blood pooled in her lower limbs, which decreased venous return to her heart. In turn, cardiac output decreased, so less blood reached her brain, causing light-headedness and fainting. A hot day adds to this effect, because the loss of body water through sweating reduces blood volume.