Human Physiology Practice Questions

Edema may be caused by

- High blood pressure - Decreased plasma protein concentration - Leakage of plasma protein into the interstitial fluid - Blockage of lymphatic vessels

At rest, each complete cardiac cycle lasts about 0.8 secs. of which diastole lasts _____ seconds and systole lasts ________ seconds.

0.5; 0.3

At rest the heart of an average human will pump ___ liters of blood per minute

5

If someone's heart has a stroke volume of 70 ml and a heart rate of 90 beats/min, the cardiac output equals _____________.

6.3 L/min

Contraction of the left ventricle of the heart at rest normally expels about ____ of the blood contained in the chamber

60 - 70%

What do platelets release?

A chemical called serotonin that constricts blood vessels - Platelets have a life span of 5 - 9 days, are formed from teh fragmentation of megakaryotes in the bone marrow, and ar ecapable of ameboid movement

An ischemic injury to the heart that destroys myocardial cells is

A myocardial infraction

Pacemakers may be useful in treating

A third degree AV node block

Low blood pressure stimulates the secretion of the Mineralocortoid

Aldosteron

Which of these statements is true?

All of the myocardial cells in the ventricles are normally in a refractory period at the same time

Edema could be cuased by all of the following except

An elevated level of albumin in the blood plasma

Baroreceptors are specialized pressure receptors found in the

Aortic arch

In the absence of compensations, the stroke volume will decrease when

Arterial blood pressure increases

The greatest resistance to blood flow occurs in

Arterioles

According to the classic view of the Starling forces, capillaries usually tend to absorb fluid

At the venular end

The first heart sound is produced at

Atrioventricular valves

Which of the following leukocytes usually accounts for less than 1% of white blood cells present?

Basophils

The "lub" or first heart sound is produced by closing of

Both AV valves

The activation of the factor X occurs in

Both the intrinsic and extrinsic pathway

_____ is a polypepride vasodilator produced by the sweat glands

Bradykininin

The most important ion involved in the blood clotting sequence is

Ca2+

The exchange of gases and nutrients between the blood and the tissues occur in blood vessels called

Capillaries

Theamount of blood pumped by eaach ventricle in one minute is called

Cardiac Output

Stroke volume is regulated by all of the following except

Cardiac output

A mechanism that increases heart rate is said to have a positive _____ effect

Chronotropic

The second heart sound results from vibrations generated by

Closing of the semilunar valves at the start of diastole

Veins are said to have a higher ____ than arteries because they expand more easily and a higher ___________ because they contain more blood.

Compliance; capitance

The terms "systeole" and "diastole" refer, respectively to the

Contraction phase and relaxation phase of the ventricles

The contractlity of heart muscle is its

Contraction strength at any given fiber length

Intrinsic control of blood flow refers to the

Control of blood flow by metabolic products of the tissues

The QRS wave of ECG (Electrocardiograph) is produced by

Depolarization of ventricular cardiac muscles

The SA node is the n ormal pacemaker of the heart becuase the SA node

Depolarizes to its threshold potential before other pacemakers in the heart

Arteriovenous anastomoses are found mainly in the

Dermis of the skin

Changes in the cardiac rate primarily reflect changes in the duration of

Diastole

Accroding to Frank Starling law of the heart, the strength of ventricular contraction is

Direcrly proportional to the end-diastolic volume

The preload acting on a ventricle is equivalent to that chamber's _____________.

End-diastolic volume

Which of these is a paracrine regulator that stimulate vasoconstriction?

Endothelin-1

Production of which of the following cells is stimulated by a hormone secreted by the kidnyes

Erythrocytes

Which of these statements is false regarding exchanges betweeen blood and tissue fluid?

Exchanges between blood and tissue fluid occur accross the walls of venules

During the phase of isovolumetric relaxation of the ventricles, the pressure in the ventricle is

Falling

Blood clotting would not occur if the plasma was deficient in

Fibrinogen

Platelets

Form a plug by sticking to each other, release chemicals that stimulate vasocontraction, provide phospholipids needed for the intrinsic pathway

Artial netriuretic peptide (ANP) helps lower blood pressure and is secreted by the

Heart

During excerxise, the cardiac output may rise to five times the resting value. In most people this is due to an increase in

Heart rate

Osmoreceptors regulating the release of ADH are found in the

Hypothalamus

Both ADH and aldosterone act to

Increase blood volume

If a vessel were to dilate to twice its prevoius radius, and if pressure remained constant, blood flow through this vessle would

Increase by a factor of 16

Blood flow in coronary circulation

Increase during diastole

A positive inotropic agent is something that

Increases the contractility of myocardial fibers

The atrioventricular (AV) valve

Is called the mitral valve, separates the left atrium and left ventricles, and is also called bicupsid

Total blood flow in the cerebral circulation

Is maintained constant within physiological limits

Which of these statements about plasmin true?

It functions in fibrinolysis

Which of these statements about interstitial fluid is false?

Its colloid osmotic pressure is greater than that of plasma

The presence of __________ in the circulatory system would be considered abnormal.

Kreb's Cycle Enzymes

Erythrocytes (Red Blood Cells)

Lack both a nucleus and mitochondria organelles

Pulmonary edema, shortness of breath, and fatigue are most likely to result from

Left-sided congestive heart failure

Peristaltic waves of contraction move fluid within which of these vessels

Lymphatic Vessels

Whic of the following does not belong to the class of granular leukocytes?

Lymphocyte

A sphygmomanometer is used for

Measuring blood pressure

During systole, the ventricular myocardium gets its oxygen supply mainly form

Myoglobin

Which of the following is not a broad area of function within the circulatory system?

Neurochemical Release

The SA node depolarizes more frequently under the influence of

Norepinephrine

Vasodilation in the heart and skeletal muscles during excercise is primarily due to the effects of

Products released by exercising muscle cells

Within the pulmonary circulation, the

Pulmonary arteries carry oxygen - poor blood

Production of anglotensisn II indirectly

Raises the blood volume

Lymph contains all of the following substances except ____________.

Red blood cells and platelets

A normal hematocrit value of 45 means that

Red blood cells make up 45% of the total blood volume

Myxedema is a disease caused by hypothyroidism, which causes production of excessive amounts of glycoprotein in the Interstitial spaces. The effect of this on capillary fluid dynamics would be to cause ________________.

Reduced osmotic return of fluid and thus accumulation of fluid in tissue resulting in edema

The semilunar valves

Regualte the passage of blood from teh ventricles into the pulmonary artery and the aorta

During one cardiac cycle, the major difference between the left and right halves of the ehart is that the

Right heart pumps blood with less force (at lower pressure) than the left heart

An increase in blood volume will cause

Secretion of ADH

A severe infection could decrease blood pressure by causing

Septic shock

Stretch receptors in the aortic arch and cartoid sinus

Serve as osmoreceptors that stimulate the release of ADH

Which of these organis is able to tolerate the greatest reduction in blood flow?

Skin

Action potentials in myocardial cells have a characteristic plateau phase which is caused primarily by the

Slow inward diffusion of Ca2+

Normal venous return rellies up on all of the folllowing except

Standing upright, perfectly still

Angiotensin II

Stimulates vasoconstricution, stimulates the adrenal cortex to secrete aldosterone, inhibits the actin of bradykinin

The Frank-Starling law of the heart describes the relationship between

Stroke volume, end-diastolic volume, and contraction strength

The second heart sound immediately follows the occurence of the

T wave

The hydrostatic pressure of blood in a capillary is 19 mmHg and that of the tissue fluid is 1 mmHg, while the colloid osmotic pressure of the blood is 23 mmHg and that of the tissue fluid is 0 mm Hg, at this particular portion of the capillary, fluid is being _____ with a neet force of ______

Taken up; -5 mmHg

The cells that normally have the fastest rate of spontaneous diastolic depolarization are located in

The SA nodes

The sound of korotkoff are produced by

The artery blood flow through an artery as pressure is released from a cuff

Which statement about erythroblastosis fetalis (hemolytic disease of the newborn) is false?

The baby is born with abnormally high number of red blood cells (anemia)

Cardiac output may drop when one goes from lying to a standing position because of

The barorecptor reflex

Aplastic anemia results in an abnormally low red blood cell count due to

The destruction of the bone marrow, perhaps by chemicals in environment or chemotherapy

The pulse pressure is a measure of

The differenc between systolic pressures

Which of the following events is the first to occur during the process of hemostasis after a blood vessel becomes injured?

The endothelial lining is damaged, exposing collagen proteins to the blood

Congenital septal defects are holes that form in the septum during the embryonic development of the heart - resulting in the abnormal flow of blood from

The left side of the heart to the right

All arteries in the blood contain oxygen-rich blood with the exception of

The pulmonary artery

In a normal ECG tracing

The repolarization of the artia is hidden by the QRS wave

The volume of blood pumped per minute by the left ventricle is

The same as the volume pumped by the right ventricle

Which of these statements about ateriovenous shunts in teh skin is true?

They are closed when the ambient temperature is very low

Antibodies against both A and type B antigens are foiund in the plasma of a person who is

Type O

Blood pressure is lowest in

Veins

The lymph eventually enters the circualtion by draining into two specific

Veins - The right and left subclavian veins

Which of the following statements about arteries and veins is false?

Veins can collapse, serving as the blood vessels with the greatest resistance to blood flow in the circulatory system

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

Vessel Radius

The endothelial cells of the blood vessel produces two important chemicals involved in hemostasis; prostacyclin and

Von Willebrand factor

The "buffy coat" that forms when whole blood is centrifguged is a test tube composed of

White blood cells and platelets

In the ABO system of red blood cell typing, which of the following genotypes would produce type O blood?

ii

A person whose blood genotype is IAi has red blood cells with _________ antigens bound to the outer membrane surface and anti-_____ antibodies floating in the plasma.

- A - B