Chapter 21 Blood Vessels and Circulation Checkpoint Questions

Describe the actions of vasodilators and local vasodilators.

Vasodilators promote the dilation of precapillary sphincters; local vasodiators act at the tissue level to accelerate blood flow through their tissue origin.

Name the blood vessels that enter and exit the lungs, and indicate the relative oxygen content of the blood in each.

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

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 cone marrow. The cardiovascular system provides calcium and phosphate for bone desposition delivers erythropoietin to bone marrow, and transports parathyroid hormone and calcitonin to osteoblasts and osteoclasts.

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).

Why does blood pressure increase during exercise?

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

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 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 the blood vessels.

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

Compression of the common carotid arteries would reduce blood pressure at he 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.

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.

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

In a healthy individual, 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 values 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. Values in veins prevent blood from flowing backward whenever the venous pressure drops.

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

Mike's mean arterial pressure 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 cause a decreased frequency of action potentials along the glossopharyngeal cranial 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.

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

Right ventricle ----> pulmonary trunk ---> left and right pulmonary arteries ---> pulmonary arterioles ---> alveoli ---> pulmonary venules ---> pulmonary veins ---> left atrium

Grace 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 cease to function 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 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.

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

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

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 while removing carbon dioxide and metabolic wastes, it also transfer heat.

List the five general classes of blood vessels.

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

Identify the two circuits of the cardiovascular system.

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

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

The vein that is bulging is the external jugular vein.

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

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

Identify the factors that contribute to total peripheral resistance.

Total peripheral resistance reflects a combination of vascular resistance, vessel length, vessel, diameter blood viscosity; and tubulence.

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.

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

Vascoconstriction 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 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.

While standing in the hot sun, Sally begins to feel light-headed and faints. Explain what happened.

While a person stands for periods of time, blood pools in the lower limbs, which decreases venous return to the heart. In turn, cardiac output decreases,, so less blood reaches the brain, causing light-headedness and fainting. A hot day adds to this effect, because the loss of body water through sweating reduces blood volume.