Action potentials generated by the autorhythmic cells spread to the contractile cells through what structures in the membrane?
gap junctions
One of the changes that occurs in the pacemaker potential (unstable resting membrane potential) in the SA node (an autorhythmic cell) is a decreased efflux of what ion?
potassium
When threshold is reached at the SA node (an autorhythmic cell), what channels open causing further depolarization of the membrane?
fast calcium
Repolarization of an autorhythmic cell is due to the opening of which channels?
voltage-gated potassium channels
In order to cause cardiac muscle contraction, the contractile cells must also depolarize. What causes the depolarization of the contractile cells?
the flow of postive ions from adjacent cells
Isovolumetric relaxation and ventricular filling (two phases of the cardiac cycle) take place during __________.
ventricular diastole
Which of the following is correct about the filling of the ventricles?
Most blood flows passively into the ventricles through open AV valves.
Describe the pressures in the atria and ventricles that would cause the opening of the AV valves.
Pressure in the atria would be greater than the pressure in the ventricles.
What causes the aortic semilunar valve to close?
greater pressure in the aorta than in the left ventricle
Put the phases of the cardiac cycle in the correct order, starting after ventricular filling.
isovolumetric contraction, ventricular ejection, isovolumetric relaxation
Increased pressure in the ventricles would close what valve(s)?
Av valves only
Which part of the conduction system initiates the depolarizing impulse, which spreads throughout the heart?
SA node
What does the ECG wave tracing represent?
electrical activity in the heart
What does the QRS complex represent in the ECG wave tracing?
ventricular depolarization
Contraction of the atria results from which wave of depolarization on the ECG tracing?
P wave
Which part of the intrinsic conduction system delays the impulse briefly before it moves on to the ventricles?
AV node
The heart is actually (one, two, or three) pumps?
two pumps
Which chamber receives blood from the superior and inferior vena cavae?
right atrium
Which heart chamber receives blood from the pulmonary veins?
left atrium
Which heart chamber pumps unoxygenated blood out the pulmonary trunk?
right ventricle
Which chamber pumps oxygenated blood out the aorta to the systemic circuit?
left ventricle
Which of the following would increase cardiac output to the greatest extent?
increased heart rate and increased stroke volume
Which of the following would increase heart rate?
epinephrine and norepinephrine
How would an increase in the sympathetic nervous system increase stroke volume?
increased contractility
By what mechanism would an increase in venous return increase stroke volume?
increased end diastolic volume
How would a decrease in blood volume affect both stroke volume and cardiac output?
decreased stroke volume and no change in cardiac output
Choose the correct order of structures that a drop of blood would contact as it traveled from the left atrium through the blood vessels and back to the right atrium.
Left ventricle, Abdominal aorta, Hepatic artery, Ascending veins, Inferior vena cava
What is an advantage to the longer duration of cardiac action potential compared to the skeletal muscle action potential?
The longer duration prevents tetanic contraction, which ensures that the heart chambers will relax and refill with blood before the next contraction.
Which blood vessels have the lowest blood pressure?
veins
As a result of the long refractory period, cardiac muscle cannot exhibit
tetany
Sympathetic stimulation to the pacemaker cells ________ heart rate by ________ ion flow through ________ and ________ channels.
increases, increasing, If, calcium
Which of the following does NOT directly influence cardiac stroke volume?
Rate of pacemaker potentials
Which event happens at the start of a cardiac cycle?
SA node fires
During the cardiac cycle,
the QRS complex of the ECG precedes the increase in ventricular pressure.
The volume of blood ejected from each ventricle during a contraction is called the
stroke volume
According to Starling's law of the heart, the cardiac output is directly related to the
venous return
Which of these will increase the heart rate?
both sympathetic stimulation and application of epinephrine to the SA node
The cells responsible for establishing the rate of a cardiac contraction are the
nodal cells
Listening to the heart through the chest wall is called
auscultation
The ________ is the amount of blood in a ventricle at the beginning of systole.
end-diastolic volume
The ________ is the amount of blood in a ventricle after it has contracted and before it begins to refill.
end-systolic volume
In which of the following situations would the end-systolic volume (ESV) be the greatest?
when parasympathetic stimulation of the heart is increased
Acetylcholine slows the heart rate by
increasing the permeability to K+ and decreasing the permeability to Ca2+.
In which situation would the stroke volume be the greatest?
when venous return is increased
Drugs known as calcium channel blockers can be used to
decrease the force of cardiac contraction.
The net pressure gradient in the cardiovascular system is created by _____.
heart contraction
Heart valves open and close in response to __________.
pressure changes in heart chambers
Changes in the radius of _____ has the most impact on resistance to blood flow, because radius can be changed quickly and precisely.
arterioles
The driving force for blood flow is a(n) ________ gradient.
pressure
Each of the following changes will result in increased blood flow to a tissue except one. Identify the exception.
decreased vessel diameter
Which parameters are associated with increased resistance?
reduced flow
As blood vessel length increases,
resistance increases and flow decreases.
The only blood vessels whose walls permit exchange between the blood and the surrounding interstitial fluids are the
venules and capillaries
The force behind blood flow is __________.
the pressure gradient
Vasodilation in skeletal and cardiac muscle tissue results from the signal molecule _____ binding to _____ receptors.
epinephrine; beta 2
Parasympathetic stimulation results in vasodilation in _________.
the genitals
What is the role of the kidney in blood pressure regulation?
The kidney can eliminate water to decrease blood volume or it can conserve water to maintain blood volume.
Which is the correct relationship between pressure, flow, and resistance?
Pressure ? Flow � Resistance
What compensatory mechanisms are available to help maintain blood pressure when a large volume of blood is lost, such as during a hemorrhage?
Vasoconstriction, increased thirst, and decreased renal fluid output in the urine
What effect would an increase in blood volume have on the resistance to blood flow?
Nothing, they are not directly linked.
All of the following would cause an increase in blood pressure EXCEPT
a decrease in cardiac output.
Which organ is NOT part of the cardiovascular system and plays an important role in regulating blood pressure?
kidney
Blood pressure is highest in the ________ and decreases continuously as blood flows through the circulatory system, due to ________.
arteries, resistance from vessel walls
Venous return to the heart is aided by the
skeletal muscle pump and the respiratory pump.
If cardiac output increases and resistance in arterioles does NOT change, what happens to arterial blood pressure?
increases
The integrating center for neural control of blood pressure resides in the
medulla oblongata
When the baroreceptor reflex is triggered by a decline in blood pressure,
sympathetic activity increases and cardiac output increases.
Which of the following conditions would have the greatest effect on peripheral resistance?
doubling the diameter of vessel
Increased levels of carbon dioxide in the blood will result in
decreased parasympathetic stimulation of the heart
During the fight-or-flight reaction, epinephrine is released from the adrenal medulla and binds to ________ receptors on the vascular smooth muscle of heart, liver, and skeletal muscle arterioles and results in ________ blood flow to these organs; epineph
?2, increased, ?, decreased
Blood velocity is lowest in the ________.
capillaries
What is the mechanism by which bulk flow occurs at the capillaries?
Relatively higher hydrostatic pressure on the arterial end of the capillary and relatively higher colloid oncotic pressure on the venous end results in net flow out of the capillary.
Due to the differences in opposing forces, there is net ________ occurring at the arteriolar end of most capillaries, coupled with net ________ at the venous end.
filtration, absorption
Bulk flow refers to the mass movement of fluid between the blood and the interstitial fluid. Which of the following statements is not correct concerning bulk flow?
In a typical capillary, overall bulk flow transitions from net absorption on the arterial end to net filtration on the venous end.
In the capillaries, hydrostatic pressure (HP) is exerted by __________.
blood pressure
The net hydrostatic pressure (HP) is the hydrostatic pressure in the __________ minus hydrostatic pressure in the __________.
capillary, interstitial fluid
Which of the following would reflect the typical net hydrostatic pressure (HP) at the arterial end of the capillary?
34 mm Hg
The colloid osmotic pressure in the capillary is caused by __________.
proteins in the blood
Which net pressure draws fluid into the capillary?
net osmotic pressure
Reabsorption of fluid into the capillary takes place at the arterial end or venous end of the capillary?
venous
________ are a group of diseases characterized by the abnormal growth and development of white blood cells, and ________ are diseases where patients have too few white blood cells.
Leukemias, neutropenias
Red blood cell production is regulated by the hormone
Erythropoetin
These are fragments of a megakaryocyte.
platelets
Which of the following structures are found on 97.5% of adult hemoglobin?
porphyrin ring, ?-chain, ?-chain, iron
When oxygen binds to a hemoglobin molecule, which of the following structures does it bind to directly?
iron on the porphyrin ring
A protein carrier needed for the transport of iron throughout the plasma
transferrin
The site of excess iron storage and metabolism of bilirubin from red blood cell breakdown
liver
The primary site for the destruction of old red blood cells
spleen
Must be insgested from our diet in order to produce new red blood cells
iron
A byproduct of the breakdown of old red blood cells thatis removed from the body eitherthrough therenal system or as bile
bilirubin
Red blood cell synthesis (sequential order)
Iron is absorbed across the digestive tract via active transport, transferrin transports iron throughout the blood plasma, bone marrow uses iron to produce hemoglobin, new red blood cells are synthesized
Red blood cells are broken down (sequential order)
Red blood cells produced by the bone marrow have aged approximately 120 days, Red blood cells are delivered to the spleen, Hemoglobin is converted to bilirubin, Bilirubin and other metabolites are excreted through the urine and feces.
Which of the following losses of function would occur if a person were not able to absorb iron through the digestive tract?
An individual would no longer be able to produce red blood cells.
Which of the following is NOT thought to be a cause of anemia?
decreased metabolic function in the spleen
A deep cut to the skin damages blood vessels. What is the first step in preventing excessive blood loss through the wound?
vasoconstriction
Which component of bile is
produced from the metabolism of old erythrocytes?
bilirubin
Which organ is most responsible for the breakdown of old erythrocytes?
spleen
A hematocrit is used to indicate
the ratio of red blood cells to the total blood volume and the packed cell volume.
The condition where the skin and the whites of the eyes appear slightly yellow is due to high blood levels of the substance
bilirubin
In hemostasis, vasoconstriction is rapidly followed by mechanical blockage of the hole by a
platelet plug.
The purpose of having valves in the cardiovascular system is to
ensure that blood flows in one direction.
Place these structures in the order that blood returning to the heart from the body would pass through them.
1. right ventricle
2. left atrium
3. right atrium
4. pulmonary artery
5. left ventricle
6. pulmonary vein
3, 1, 4, 6, 2, 5
If the radius of a tube decreases by half, what would happen to the resistance to fluid flow?
Resistance would increase 16 times
Which of these would cause an increase in blood flow through a vessel?
Vasodilation
In skeletal muscle cells, action potentials cause the release of calcium from the SR by directly opening SR voltage-gated calcium channels. What causes the release of calcium from the SR in cardiac muscle cells?
Influx of extracellular calcium ions opens ryanodine receptors allowing Ca2+ to flow out of the SR.
What are If channels responsible for in cardiac autorhythmic cells?
the pacemaker potential
The term used to describe the amount of blood in the ventricle available to be pumped out of the heart during the next contraction is
end-diastolic volume (EDV).
Edema is likely to occur when
The heart becomes an insufficient pump