In sequential order, the components of the intrinsic conduction system, beginning at the SA node, are ________.
AV node, AV bundle, bundle branches, Purkinje fibers
The function of the intrinsic conduction system is to ________.
insure that the heart beats in a sequential and coordinated manner
If the AV node is damaged so that it can no longer transmit the signal from the SA node (total heart block), will the ventricles continue to contract? Why or why not?
Yes: however, ventricular contractions will no longer follow atrial contractions, and the rate of ventricular contractions will be significantly slowed.
The cerebral arterial circle (circle of Willis) ________.
is an example of an anastomosis, lies at the base of the brain, and may provide an alternative set of pathways for blood to reach brain tissue
The subclavian artery that arises directly from the aorta supplies the ________.
left upper extremity and neck
Bronchial arteries that supply oxygenated blood to the lungs and bronchi arise from the ________.
In a microscopic field showing an artery and its corresponding vein, you can easily distinguish the two because ________.
veins have thinner walls and are irregular in shape
In correct sequence from superior to inferior, the three single arteries that arise from the abdominal aorta are ________.
celiac trunk, superior mesenteric, inferior mesenteric
This artery of the foot is often palpated to assess the circulatory efficiency of the limb as a whole.
dorsalis pedis artery
Arteries that supply the intestines arise from the aorta. Veins that drain the intestines ________.
ultimately drain into the hepatic portal vein
In the fetus, which blood vessel(s) carries carbon dioxide and metabolic wastes from the fetus to the placenta?
A woman in her early 50s appeared at a walk-in clinic, complaining of aching pain in her right leg following a fall. Visual examination revealed that the medial aspect of that leg was red and swollen. A diagnosis of phlebitis was made. What is phlebitis, and what more serious condition may result if proper healing does not occur?
Phlebitis is an inflammation of a vein accompanied by painful throbbing and redness of the skin over the inflamed vessel. Thrombophlebitis can result if proper healing does not occur.
Which tunic of an artery is most responsible for maintaining blood pressure and continuous blood circulation?
Histologically, the ________ is squamous epithelium supported by a sparse connective tissue layer.
Which of the choices below explains why the arterioles are known as resistance vessels?
The contraction and relaxation of the smooth muscle in their walls can change their diameter.
What type of tissue is found in the walls of the arteries that leave the heart but not in the walls of the large veins that enter the heart?
Atherosclerosis is a progressive disease of blood vessels that is responsible for millions of deaths each year. Which of the following answers is correct for the disease process?
Damage occurs to the tunica intima, resulting in release of chemicals and accumulation of fats, LDLs, and cholesterol. These cells are transformed into foam cells, which become fatty streaks that form atherosclerotic plaques, resulting in a narrowing of the blood vessels.
T OR F: A precapillary sphincter is a cuff of smooth muscle that regulates the flow of blood into the capillaries.
Permitting the exchange of nutrients and gases between the blood and tissue cells is the primary function of ________.
Which of the following is true about veins?
Veins are called capacitance vessels or blood reservoirs.
Mrs. Gray, a 50-year-old mother of seven children, is complaining of dull, aching pains in her legs. She reports that the pain has been getting progressively worse since the birth of her last child. During her physical examination, numerous varicosities are seen in both legs. What pathologic changes have occurred in these veins?
The veins have become tortuous and dilated because of incompetent valves that allow the blood to pool, stretching the vein walls.
A pregnant patient comes into a clinic and asks about a small dark bulge that is becoming more apparent on her leg. What is it and what caused it?
A varicose vein. The growing fetus puts downward pressure on the vessels of the groin and restricts the return of blood to the heart, causing the valves in the peripheral veins to begin to fail.
T OR F: Arteries supplying the same territory are often merged with one another, forming arterial anastomoses
The influence of blood vessel diameter on peripheral resistance is ________.
significant because resistance is inversely proportional to the fourth power of the vessel radius
Select the correct statement about blood flow.
Blood flow through the entire vascular system is equivalent to cardiac output.
Which of the following is NOT an important source of resistance to blood flow?
TOTAL BLOOD VOLUME
Which of the choices below does not explain why low capillary pressures are desirable?
Most capillaries are extremely permeable and thus even low pressures force solute-containing fluid out of the bloodstream.
LOW BLOOD PRESSURE IS MORE DESIRABLE THAN HIGH BLOOD PRESSURE.
Capillaries are fragile and high pressures would rupture them.
Factors that aid venous return include all except ________.
pressure changes in the thorax
activity of skeletal muscles
Select the correct statement about factors that influence blood pressure.
Excess red cell production would cause a blood pressure increase.
Arteriole blood pressure increases in response to all but which of the following?
increasing stroke volume
FALLING BLOOD VOLUME
increasing heart rate
rising blood volume
all of these
Which of the following is directly involved in long-term blood pressure regulation?
Why is it important that blood pressure drop to lower levels as it reaches the capillary beds?
capillaries are fragile and extremely permeable
T OR F: The carotid sinus reflex protects the blood supply to the brain, whereas the aortic reflex is more concerned with maintaining adequate blood pressure in the systemic circuit as a whole.
Which of the following is not one of the three main factors influencing blood pressure?
Which of the following chemicals does not help regulate blood pressure?
atrial natriuretic peptide
Which of the following processes provides a long-term response to changes in blood pressure?
Which of the following do not influence arterial pulse rate?
THE VESSEL SELECTED TO PALPATE;
Which of the following blood pressure readings would be indicative of hypertension?
170/96 in a 50-year-old man
Mechanisms that do not help regulate blood pressure include ________.
nervous control that operates via reflex arcs involving baroreceptors, chemoreceptors, and higher brain centers;
chemical controls such as atrial natriuretic peptide;
THE DURAL SINUS REFLEX;
renal regulation via the renin-angiotensin system of vasoconstriction
A patient with essential hypertension might have pressures of 200/120 mm Hg. This hypertensive state could result in all of the following changes except ________.
increased damage to blood vessel endothelium;
increased work of the left ventricle;
DECREASED SIZE OF THE HEART MUSCLE;
increased incidence of coronary artery disease
The short-term controls of blood pressure, mediated by the nervous system and bloodborne chemicals, primarily operate via all but which of the following?
reflex arcs associated with vasomotor fibers;
ALTERING BLOOD VOLUME;
reflex arcs involving baroreceptors;
Which of the following would not result in the dilation of the feeder arterioles and opening of the precapillary sphincters in systemic capillary beds?
A LOCAL INCREASE IN PH;
a local increase in histamine;
an increase in local tissue carbon dioxide;
a decrease in local tissue oxygen content
The baroreceptors in the carotid sinus and aortic arch are sensitive to which of the following?
changes in arterial pressure
The ________ in the carotid sinuses and aortic arch detect increases in blood pressure.
Which of the following would not move by diffusion across a capillary into the surrounding tissue?
If blood pressure is increased at the arterial baroreceptors, what would happen with the activity level of the parasympathetic nervous system (PNS) and sympathetic nervous system (SNS)?
increased PNS activity and decreased SNS activity
Which of the following would cause vasodilation of arterioles?
decreased activity of the sympathetic nervous system
Stimulation of the adrenal medulla would result in which of the following?
an increase in heart rate and contractility
A decrease in blood pressure at the arterial baroreceptors would result in which of the following?
an increase in heart contractility
What would be the effect of a high salt diet on blood pressure? What is the physiological basis for your answer?
Increased blood pressure. This is due to increased sodium in the blood, increasing the total extracellular fluid volume.
How would a blow to the head that damages (disables) the vasomotor center affect blood pressure? What is the physiological basis for your answer?
Damage to the vasomotor center will cause a loss of vasomotor tone and a drop in blood pressure, because the vasomotor center is the integrating center for blood pressure control.
How would an attack by a mugger effect blood pressure? What is the physiological basis for your answer?
Blood pressure would increase due to sympathetic nervous system stimulation.
How would a hypothalamic tumor resulting in excess ADH production affect blood pressure? What is the physiological basis for your answer?
Excess ADH production would cause an increase in blood pressure through increased water retention and, therefore, increased blood volume. ADH also stimulates vasoconstriction.
Mr. Wilson is a 45-year-old stockbroker with essential hypertension. He is African American, obese, and he smokes 2-3 packs of cigarettes daily. What risk factors for hypertension are typified by Mr. Wilson? What complications are likely if corrective steps are not taken?
The risk factors are obesity, race, a high-stress job, and smoking. Complications could include atherosclerosis, heart failure, renal failure, and stroke.
A patient lost a lot of blood during surgery and his blood pressure dropped from 120/80 to 90/50. How did the kidneys respond to this change in blood pressure?
Aldosterone and ADH release is triggered. Aldosterone causes increased sodium absorption and ADH causes increased water absorption, increasing blood volume and blood pressure.
T OR F: The adjustment of blood flow to each tissue in proportion to its requirements at any point in time is termed autoregulation.
T OR F: Osmotic pressure is created by the presence in a fluid of small diffusible molecules that easily move through the capillary membrane.
T OR F: Whereas diffusion is more important for solute exchange between plasma and interstitial fluid, bulk flow is more important for regulation of the relative volumes of blood and interstitial fluid.
Which of the following signs of hypovolemic shock is a relatively late sign?
rapidly falling blood pressure
Which of the following is likely during vigorous exercise?
Capillaries of the active muscles will be engorged with blood.
Which of the choices below reflects the balance (or imbalance) between the direction and amount of fluid that flows across the capillary walls?
hydrostatic and osmotic pressure
Which of the following is a type of circulatory shock?
vascular, due to extreme vasodilation as a result of loss of vasomotor tone
The form of circulatory shock known as hypovolemic shock is ________.
shock that results from large-scale loss of blood volume, or after severe vomiting or diarrhea
In the dynamics of blood flow through capillaries, hydrostatic pressure ________.
is the same as capillary blood pressure
Which of the choices below does not involve tissue perfusion?
gas exchange in the lungs;
absorption of nutrients from the digestive tract;
delivery of oxygen and nutrients to, and removal of wastes from, tissue cells;
The velocity of blood flow is ________.
slowest in the capillaries because the total cross-sectional area is the greatest
Where in the body would you find low oxygen levels causing vasoconstriction and high levels causing vasodilation?
If blood pressure is almost normal in a person who has lost blood, does that mean the tissues are receiving adequate blood flow?
A family of peptides called ________ are released by the endothelium and are among the most potent vasoconstrictors known.
________ shock is due to abnormal expansion of blood vessels and a rapid drop in blood pressure.
Which of the following would be a result of anaphylaxis (a systemic allergic reaction)?
Substances absorbed in the intestines would be routed to the liver via the__________.
hepatic portal system
Which organ blood-flow pattern results in low oxygen levels causing vasoconstriction and high oxygen levels causing vasodilation?
Which of the following is NOT a capillary transport mechanism?
movement through intracellular clefts or fenestrations;
diffusion through the membrane;
transport via vesicles or caveolae
The net hydrostatic pressure (HP) is the hydrostatic pressure in the __________ minus hydrostatic pressure in the __________.
capillary; interstitial fluid
What is the effect of hypovolemic shock on the blood vessels and the heart?
Blood vessels constrict to increase venous return and maintain pressure. Heart rate increases to compensate for loss of blood pressure and to maintain cardiac output.
Bulk fluid movement across capillary walls is typically through what structures?
Net (positive) hydrostatic pressure tends to move fluid out of capillaries. The resulting bulk fluid movement is known as __________.
Net (positive) osmotic pressure tends to move fluid into capillaries. The resulting bulk fluid movement is known as __________.
Near the arteriole end of a capillary, what is the relationship between net hydrostatic pressure and net osmotic pressure?
Net hydrostatic pressure is greater than net osmotic pressure.
How do net hydrostatic pressure and net osmotic pressure each change along the length of a capillary (from arteriole to venule)?
Net osmotic pressure stays about the same and net hydrostatic pressure decreases.
Which of the following most accurately describes how net filtration pressure (NFP) affects bulk fluid flow across capillary walls?
positive NFP causes filtration
At a given point along a capillary, the net hydrostatic pressure (Net HP) is 20 mm Hg and the net osmotic pressure (Net OP) is 25 mm Hg. What is the Net Filtration Pressure (NFP) at that point?
Overall, fluid moves out of capillaries and into the interstitial space. Which of the following best describes why this occurs?
Capillary filtration is greater than capillary reabsorption
Which of the following most correctly describes the need for a functional lymphatic system?
Lymphatic vessels return interstitial fluid to the blood.
T OR F: Arterial pressure in the pulmonary circulation is much higher than in the systemic circulation because of its proximity to the heart.
The circulatory route that runs from the digestive tract to the liver is called ________.
Hepatic portal circulation
Which of the following are involved directly in pulmonary circulation?
right ventricle, pulmonary artery, and left atrium
A thrombus (blood clot) in the first branch of the arch of the aorta would affect the flow of blood to the ________.
right side of the head and neck and right upper arm
T OR F: When albumin levels in the blood are below normal, fluid absorption from the tissues into the bloodstream increase.
At the battle of Shiloh in the American Civil War, Confederate General A. S. Johnston was killed when he was shot in the thigh. Witnesses reported that he bled to death almost before he realized that he was wounded. Which blood vessel was most likely to have been injured? Would a tourniquet be recommended for this wound?
Femoral artery. A tourniquet may be ineffective because it is a high-pressure, deep artery with a large diameter.
A patient has an 80% blockage of his left anterior descending coronary artery. What would occur in terms of myocardial oxygen supply and demand if his sympathetic nervous system is stimulated?
Increased myocardial contractility increases the oxygen demand for the myocardial cells. If the demand of oxygen exceeds the supply, death of myocardial tissue can occur.
T OR F: In infants and young people, congenital vascular problems are less common than congenital heart disease.
The term ductus venosus refers to ________.
a special fetal vessel that allows umbilical blood to bypass the liver
What do the ductus arteriosus and the foramen ovale become at birth?
ligamentum arteriosum; fossa ovalis
The embryonic mesodermal cells that will eventually form the endothelial lining of blood vessels are called ________.
Of the following vessel types, which are responsible for the exchange of gases and nutrients with tissues?
Of the following vessel types, which conduct blood toward the heart, regardless of oxygen content?
Of the following blood vessel components, which is the most critical in regulating systemic blood pressure?
Of the following cardiovascular components, which contains the majority of the body's blood volume at any one time?
Systemic veins and venules
Some of the least permeable capillaries are found in the ____, while some of the most permeable capillaries are found in the _____.
brain; bone marrow
Predict the change in peripheral resistance as blood vessel diameter increases.
Peripheral resistance decreases
WHy has pulse pressure disappeared by the time blood reaches capillary beds? Because_____.
the muscular arterioles do not exhibit elastic rebound
WHat effect does a long period of skeletal muscle inactivity have on blood flow?
It causes blood pooling and a slowing of blood flow.
What is the major factor controlling stroke volume during resting periods?
Venous return to the heart
Of the following factors affecting blood pressure, which is (are) the most easily regulated?
Vessel diameter and cardiac output
Predict what might happen to peripheral resistance in arterioles supplying skeletal muscle when pH levels drop.
Vasodilation in vessels supplying skeletal muscle
If baroreceptors are primed to detect blood pressure changes and compensate for them, how is it that some patients suffer from chronic hypertension?
The baroreceptors in these patients have a new higher set point.
When blood levels of sodium are increased which of the following hormones would you expect to increase?
Atrial natriuretic peptide
Which of the following changes would effect the longest lasting changes in blood pressure?
Release of antidiuretic hormone
Why are ACE-inhibitor drugs effective blood pressure-lowering medications?
By inhibiting angiotensin 2, peripheral resistance stays low and the kidneys continue to excrete sodium.
Why does blood velocity decrease as it flows into a capillary bed?
The cross-sectional area of the capillary beds is approximately 2000x than that of the aorta.
A decrease in 02 level in skeletal muscle would initiate an autoregulatory mechanism that would stimulate _____ in the arterioles supplying the muscle.
Why is vasodilation prominent in the skin when a person increases physical activity?
Heat is dissipated across the skin from the blood to help cool the body.
In what way is pulmonary circulation different from circulation in other body tissues?
As opposed to other tissues, low O2 levels in the lungs induces vasoconstriction.
The primary mechanism driving filtration in capillary beds is _____.
hydrostatic pressure within the capillaries
Capillary colloid osmotic pressure created by ____ tends to ______.
nondiffusable plasma proteins; draw fluids into the capillary
What role do the lymphatic vessels have when it comes to fluid movements across the capillary beds?
Lymphatic vessels reclaim any fluid from the tissue spaces that doesn't get returned to the blood.
Blood is returned to the heart via the ___.
superior vena cava, inferior vena cava, and coronary sinus.
Blood drained from digestive organs empties into the ____ before going through the liver.
Hepatic portal vein
THe superior vena cava receives systemic blood draining from all areas superior to the diaphragm except the ______.