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