Ch 14

__________ is a polypeptide vasodilator produced by the sweat glands. A) Bradykinin B) Histamine C) Seratonin D) Endorphin

A) Bradykinin Feedback: Histamine is secreted by tissue mast cells that cause vasodilation during an allergic response of the immune system. Seratonin functions as a monoamine neurotransmitter in the nervous system. Endorphin is an endogenous opioid that acts as an analgesic in the nervous system.

Cardiac control centers in the medulla oblongata receive input from baroreceptors located in some of the arteries. A) True B) False

A) True

Stroke volume is directly proportional to end-diastolic volume. A) True B) False

A) True Feedback: Stroke volume is the volume of blood ejected per heart beat and is directly proportional to the end-diastolic volume, which is the amount of blood in the ventricles immediately before they begin to contract.

Low blood pressure stimulates the secretion of the mineralcorticoid ______________. A) aldosterone B) angiotensin II C) vasopressin (ADH) D) atrial natriuretic peptide (ANP)

A) aldosterone Feedback: The secretion of aldosterone is stimulated during salt depravation, when blood volume and pressure are reduced. The adrenal cortex is not directly stimulated to secrete aldosterone by these conditions. Instead, a decrease in blood volume and pressure activates an intermediate mechanism; the renin-angiotensin-aldosterone system.

Veins are said to have a higher ____ than arteries because they expand more easily and a higher ___________ because they contain more blood. A) compliance; capacitance B) elasticity; capacitance C) elasticity; compliance

A) compliance; capacitance Feedback: Veins have thinner, less muscular walls than do arteries therefore at a given amount of pressure will cause more expansion in veins than arteries (compliance) so the veins can hold more blood (capacitance).

The SA node depolarizes more frequently under the influence of ____________. A) norepinephrine B) acetylcholine C) the vagus nerve D) the medulla oblongata

A) norepinephrine

The enzyme that converts angiotensinogen into angiotensin II is _____________. A) renin B) angiotensin-converting enzyme (ACE) C) atrial natriuretic peptide (ANP D) vasopressin (ADH)

A) renin Feedback: Angiotensin II indirectly raises blood volume by stimulating thirst centers and stimulating secretion of aldosterone causing more salt and water to be retained by the kidneys.

Since the veins contain most of the body's blood at any one time, they have a higher blood pressure than any other type of vessel. A) True B) False

B) False Feedback: Although veins contain almost 70% of the total blood volume, the mean venous pressure is only 2mmHg therefore they have the lowest pressure than any type of vessel.

All parasympathetic nerve fibers to the heart innervate the SA node. A) True B) False

B) False Feedback: Parasympathetic nerve fibers innervate the AV node as well as the SA node. See Table 14.1 Effects of Autonomic Nerve Activity on the Heart.

In spite of the fact that the systemic vessels cover substantially more total length than the pulmonary vessels, the same amount of blood must flow through both of these systems at a given time. A) True B) False

B) False Feedback: The difference is the pressure. The pressure put on the blood due to right ventricular systole is much less than the pressure put on the blood due to left ventricular systole.

According to the classic view of the Starling forces, capillaries usually tend to absorb fluid ________________. A) at the arteriolar end B) at the venular end C) only when the precapillary sphincters are open D) at neither end; they filter fluid and it is up to the lymphatic vessels to absorb it

B) at the venular end Feedback: The distribution of fluid across the walls of a capillary. The positive value at the arteriole end indicates that the Starling forces favor the extrusion of fluid from the capillary predominates. The negative value at the venular end indicates that the net Starling forces favor the return of fluid to the capillary.

Stroke volume is regulated by all of the following except ____________. A) end-diastolic volume B) cardiac output C) contraction strength D) mean arterial pressure

B) cardiac output

Any mechanism that increases heart rate is said to have a positive ______ effect. A) feedback B) chronotropic C) inotropic D) cholinergic

B) chronotropic Feedback: Mechanisms that affect cardiac rate are said to have a chronotropic effect (chrono = time). Those that increase cardiac rate have a positive chronotropic effect while those that decrease cardiac rate have a negative chronotropic effect.

The contractility of heart muscle is its _______________. A) contraction strength at any length B) contraction strength at any given fiber length C) contraction frequency, which determines heart rate D) ability to contract, which is restored after the refractory period

B) contraction strength at any given fiber length Feedback: When the heart muscle is subjected to an increasing degree of stretch, it contracts more forcefully.

During systole, the ventricular myocardium gets its oxygen supply mainly from _______. A) hemoglobin B) myoglobin C) its high density of blood capillaries D) its high density of mitochondria

B) myoglobin Feedback: The myocardium contains large amounts of myoglobin that stores oxygen during diastole and releases oxygen during systole.

The Frank-Starling law of the heart describes the relationship between ___________. A) stroke volume and cardiac output B) stroke volume, end-diastolic volume, and contraction strength C) stroke volume and total peripheral resistance D) the left and right ventricles

B) stroke volume, end-diastolic volume, and contraction strength

Cardiac output may drop when one goes from lying to a standing position because of ________________. A) the baroreceptor reflex B) venous pooling C) orthostatic hypertension D) sinus tachycardia

B) venous pooling Feedback: When a person goes from lying to a standing position, there is a shift of 500-700 ml of blood from the veins of the thoracic cavity to veins in the lower extremities. This pooling of blood decreases venous return and cardiac output.

Of all the factors that can affect blood flow to a particular organ, the most effective and easiest to control from moment to moment is _____________. A) blood viscosity B) vessel radius C) vessel length D) pressure differential

B) vessel radius Feedback: Blood flow to an organ is largely determined by the degree of arteriole vasoconstriction, which decreases blood flow, or vasodilation, which increases blood flow.

Edema could be caused by all of the following except ______________. A) high arterial blood pressure (hypertension) B) leakage of plasma proteins into the tissue fluid, as in inflammation and allergy C) an elevated level of albumin in the blood plasma D) an obstruction of the lymphatic drainage

C) an elevated level of albumin in the blood plasma

Intrinsic control of blood flow refers to the ________________. A) way in which blood flow is determined by cardiac output B) blood flow in all places other than the heart itself C) control of blood flow by metabolic products of the tissues D) control of blood flow by the nervous and endocrine systems

C) control of blood flow by metabolic products of the tissues Feedback: Local vasodilation is promoted by a decrease in oxygen concentration from increased metabolic rate, increased carbon dioxide concentration, decrease in tissue pH, and release of adenosine or K+ from tissue cells.

Arteriovenous anastomoses are found mainly in the ___________________. A) renal circulation B) mesenteries of the abdominal cavity C) dermis of the skin D) cerebral circulation

C) dermis of the skin Feedback: These vessels functions as shunts allowing blood to be diverted directly from the arteriole to the venule and thus bypass superficial capillary loops and function in thermoregulation.

The preload acting on a ventricle is equivalent to that chamber's _____________. A) contractility B) stroke volume C) end-diastolic volume D) ejection fraction

C) end-diastolic volume Feedback: The end-diastolic volume is the amount of blood in the ventricles immediately before they begin to contract. This is a workload imposed on the ventricles prior to contraction and is sometimes called the preload.

A positive inotropic agent is something that _______________. A) reduces the heart rate in a positive feedback loop B) increases the heart rate in a positive feedback loop C) increases the contractility of myocardial fibers D) decreases the contractility of myocardial fibers

C) increases the contractility of myocardial fibers Feedback: An increase in the amount of Ca2+ available to the sarcomeres due to an increase in epinephrine increases the strength of myocardial contraction as demonstrated in Figure 14.4 The effect of muscle length and epinephrine on contraction strength.

Myxedema is a disease caused by hypothyroidism, which causes production of excessive amounts of glycoprotein in the interstital spaces. The effect of this on capillary fluid dynamics would be to cause ________________. A) precapillary sphincters to shut off blood flow to affected tissues B) vasodilation of the capillaries C) reduced osmotic return of fluid and thus accumulation of fluid in the tissues resulting in edema D) increased transfer of tissue fluid into the blood stream, resulting in hypertension

C) reduced osmotic return of fluid and thus accumulation of fluid in the tissues resulting in edema Feedback: This would cause the tissue fluid to become hypertonic to blood plasma and therefore water would be drawn into the tissues by osmosis.

A severe infection could decrease blood pressure by causing _____________. A) cardiogenic shock B) anaphylactic shock C) septic shock D) hypovolemic shock

C) septic shock Feedback: Septic shock is caused by an endotoxin produced by bacteria that decreases blood pressure and affects of ability of the heart to pump. Cardiogenic shock is due to cardiac failure. Anaphylactic shock is due to a severe allergy in which histamine is released causing systemic vasodilation. Hypovolemic shock is due to blood loss.

Baroreceptors are specialized pressure receptors found in the ____________. A) vena cava B) descending aorta C) medulla oblongata D) aortic arch

D) aortic arch

The amount of blood pumped by one ventricle in one minute is called _____________. A) stroke volume B) end-diastolic volume C) ejection fraction D) cardiac output

D) cardiac output Feedback: Stroke volume is the volume of blood ejected per beat. End-diastolic volume is the volume of blood in the ventricles at the end of diastole. Ejection fraction is the proportion of the end-diastolic volume that is ejected against a given afterload.

Atrial natriuretic peptide (ANP) helps to lower blood pressure and is secreted by the _____________. A) hypothalamus B) kidneys C) adrenal cortex D) heart

D) heart Feedback: ANP promotes the increase excretion of salt and water in the urine thereby helping to lower the blood volume.

During exercise, the cardiac output may rise to five times the resting value. In most people this is due mainly to an increase in ______________. A) stroke volume B) ejection fraction C) end-diastolic volume D) heart rate

D) heart rate

Osmoreceptors regulating the release of ADH are found in the _______________. A) kidneys B) right atrium of the heart C) aortic arch and carotid sinuses D) hypothalamus

D) hypothalamus Feedback: The hypothalamus functions as the thirst center and when osmoreceptors are stimulated, a person becomes thirsty and there is an increase in the amount of ADH released by the posterior pituitary. See Figuren14.11 The negative feedback control of blood volume and blood osmolality.

Pulmonary edema, shortness of breath, and fatigue are most likely to result from _________________. A) cardiogenic shock B) anaphylactic shock C) right-sided congestive heart failure D) left-sided congestive heart failure

D) left-sided congestive heart failure Feedback: Failure of the left ventricle raises the left arterial pressure and produces pulmonary congestion causing shortness of breath and fatigue.

Production of angiotensin II indirectly ____________. A) causes vasodilation of arterioles and muscular arteries B) inhibits the sense of thirst C) stimulates excretion of excess sodium by the kidneys D) raises the blood volume

D) raises the blood volume Feedback: Angiotensin II indirectly raises blood volume by stimulating thirst centers and stimulating secretion of aldosterone causing more salt and water to be retained by the kidneys.

During fight or flight reaction, the sympathetic nervous system causes vasodilation in skeletal muscle but vasoconstriction in the skin. It is able to achieve these opposite effects because ___________________. A) sympathetic fibers secrete epinephrine in the muscle and acetylcholine in the skin B) bradykinin stimulates constriction of arterioles in the dermis C) the muscles have cholinergic sympathetic fibers and the skin has adrenergic fibers D) the muscle arterioles have α-adrenergic receptors and the skin arterioles have β-adrenergic receptors

D) the muscle arterioles have α-adrenergic receptors and the skin arterioles have β-adrenergic receptors Feedback: Binding of norepinephrine to the β-adrenergic receptors in skeletal muscle arterioles causes vasodilation whereas binding of norepinephrine to α-adrenergic receptors in the skin arterioles causes vasoconstriction.

All of the fluid filtered by the capillaries of the kidneys is ultimately excreted as urine. A) True B) False

False Feedback: The percent of the glomerular filtrate reabsorbed and thus the urine volume and blood volume is adjusted according to the needs of the body.

Cerebral blood flow remains fairly constant at about 750 ml/min, in spite of changes in brain activity, blood pressure, and blood flow to other organs. A) True B) False

False Feedback: Only when mean arterial pressure rises to about 200 mmHg, sympathetic nerves cause vasoconstriction in cerebral circulation. This helps protect the arterioles from bursting and causing a stroke.

The arteries that supply blood to the organs are generally in a series with each other than in parallel with each other. A) True B) False

False Feedback: The arteries that supply blood to the organs are generally in parallel, that is, arterial blood passes through only one set of arterioles before returning to the heart.

Decreased osmolality of the blood leads to decreased secretion of ADH. A) True B) False

True Feedback: Dilution of the blood (as in drinking excessive amounts of water) decreases the plasma osmolality and inhibits the release of ADH.