On an EKG a PR interval that is abnormally long represents a delay in:
AV conduction
The Frank-Starling Law of the Heart can be defined as:
The heart will contract more forcefully as more blood is returned to it.
Left atrial pressure is:
Approximately 12 mmHg as the Mitral Valve opens.
The organ that receives about 25% of the total cardiac output and is a big time conditioner is the...
Kidneys
Cardiac output is defined as...
The stroke volume times the heart rate.
Which of these is a mechanical property of cardiac cells?
contractility
When describing a positive dromotrophic effect, we are saying that...
There is a increase in conduction velocity.
During the action potential, which phase is most of the repolarization occurring?
3
Excitation-Contraction coupling describes...
the process by which the contractile cell contracts once it has been stimulated.
Isometric contraction means:
The muscle will not shorten but will develop tension.
The contraction that actually allows the muscle to shorten:
Is the isotonic contraction.
End diastolic pressure in the LV is approximately...
10 mmHg
The semilunar valves are open during...
Ventricular systole
If cardiac output is decreased due to heart failure what is the response of the CVP?
Increase in CVP
What will renal failure do to the CVP?
Increase
Venous constriction increases central venous pressure by...
Reducing venous compliance
What is the formula for compliance?
C = change in volume / change in pressure
What is the thoracic venous compartment?
All the veins above the diaphragm.
When a person with poor LV function and RVVO lies down flat, they have trouble breathing. What is the cause of this?
The fluid shit to the thoracic cavity due to gravitational forces and the resulting congestion.
Define central venous pool.
It is the volume enclosed by the right atrium and the great veins in the thorax.
Define venous return.
It is the rate at which blood returns to the thorax from the peripheral vascular beds. It is the rate at which blood enters the central venous pool.
What are some examples of increasing peripheral venous tone? (5)
1.) Sympathetic vasoconstriction
2.) Endothelin-1
3.) Exercise
4.) Vasopressin
5.) Wearing elastic stockings
Define Preload
Preload represents the volume in the right or left ventricle at end diastole. (Passive filling and atrial contraction).
What is the formula for determining pulse pressure?
Pp = Ps - Pd
What is the average pulse pressure in a healthy adult?
40 mmHg
What is the formula for pulse pressure if you don't have the blood pressures available?
Pp = SV / CA
What is the formula for MAP?
MAP = CO x TPR
Define MAP
It is the average effective pressure that drives blood through the systemic organs.
What is the formula for MAP if only the blood pressure is known?
MAP = Pd + 1/3(Ps-Pd)
Solve MAP with a blood pressure of 120/70.
86.66 mmHg or 87 mmHg
What is TPR when MAP is 100 mmHg and CO is 6 L/min?
16.7 mmHg
What is a normal stroke volume?
70- 120 mL
Afterload increases ESV which ___________.
Decreases Sv
Inotrophy decreases ESV which ______________.
Increases SV
Name several factors that increase ventricular preload. (5)
1.) Ventricular compliance
2.) Atrial contractility
3.) Ventricular failure
4.) Increased venous pressure
5.) Increased outflow resistance
What does the law of Laplace state? (2)
1.) The wall tension is increased with increasing vessel radius.
2.) In a normal heart it facilitates ejection, but in an unhealthy heart it only impairs an already poor pump.
Define myocardial oxygen consumption.
The amount of oxygen used by the heart.
Which is more costly for oxygen consumption for the heart...an increase volume or an increase in pressure?
An increase in pressure.
So reduce afterload first before preload.
What is the abdominothoracic pump? (2)
1.) It is basically the difference in pressure form between the abdominal vena cava and the right atrium.
2.) It is enhanced by inspiration.
Venous return is ___________below the diaphragm during inspiration.
Decreased
During respiration ( inspiration) intrathoracic pressure __________.
Decrease
Deep rapid breathing __________venous return.
Increased
Venous return is ___________ by couphing.
Decreased
During the Valsalva maneuver there is a large increase in intrapleural pressure which ___________ resistance to venous return.
Increases
What is the skeletal muscle pump?
The muscles surrounding the deeper veins contract and aid the return to blood to the right atrium and promote venous return.
Define orthostatic or postural hypotension.
It is when arterial pressure falls by more than 20 mmHg upon standing.
An older patient may experience difficultly going from a supine position to a standing position. Why?
Lightheadedness or syncope may occur due to pooling of the blood in the lower extremities. Because there is a decrease in venous return and CO when standing up.
Describe your appearance in a zero gravity environment.
VERY UNATTRACTIVE
Skinny legs and puffy swollen face and upper body.
What does squatting due for venous return?
Increases venous return
What does anyl-nitrate do the cardiovascular system? (3)
1.) It is a potent vasodilator and it decrease TPR.
2.) Increases HR, SV and CO.
3.) Used to diagnose certain pathologies.
Give an example of dynamic exercise.
Running
Give an example of static exercise.
Isometric as in weight training
Between dynamic and static exercise which one promotes more venous return.
Dynamic
What are the benefits of a conditioned cardiovascular system? (6)
1.) Increases cardiac output
2.) Decreases resting HR
3.) Promotes a larger stroke volume
4.) Decreases arterial blood pressure during resting and exercising states.
5.) Can recover from exercise more rapidly.
6.) Decreases myocardial oxygen demand.
Define Cardiac reserve
It is the measure of how many times more than average cardiac output the heart can produce.
High altitudes does what to stroke volume and cardiac output?
Decreases SV and CO
Most parameters increase during exercise. What is one parameter that decreases?
Systemic vascular resistance decreases
What is the "central command"?
It is the higher brain center that sends information to the hypothalamus.
What purpose does the skin play when a person exercises?
It enhances heat loss through the skin by sweating. However the vessels to the skin can vasoconstrict to maintain MAP.
If sympathetic nerves restore tone to the skin during exercise, there will be a higher risk for...
Heat stroke
As we age there are many parameters that decrease...as in HR, SV, etc. What is one parameter that increases? (2)
1.) There is an increase in contraction and relaxation time of the heart muscle.
2.) There is an increase in myocardial stiffness during diastole.
During pregnancy outputs can increase as much as __________during the third trimester.
30-50% more
Name at least three symptoms of shock. (4)
1.) skin is pale, cold and sweating
2.) pulse is rapid and weak
3.) Breathing is rapid and shallow.
4.) MAP and PP is reduced.
How would you define circulatory shock? Give two examples.
A generalized severe reduction in blood supply to the body.
1.) cardiogenic
2.) hypovolemic shock
Define septic shock.
It is caused by the release of bacterial endotoxins that activate the inflammatory cascade. These endotoxins cause excessive amounts of nitric oxide and other vasodilation substances.
If arterial pressure falls below __________, brain blood flow begins to fall.
60 mmHg
Define hypotension.
Low blood pressure
Systolic arterial pressure less than 90 mmHg.
and a Diastolic pressure less than 60 mmHg.
Since hypotension is caused by a decrease in HR or SV. What are some of the more common causes of decreased SV. (6)
1.) Decreased atrial kick with atrial fibrillation
2.) Mitral stenosis
3.) Dehydration
4.) Severe blood loss
5.) Anything that reduces preload
6.) Decrease in venous return
If a condition of hypotension exists and the mean arterial pressure is dropping, what is the first compensatory response?
Baroreceptors decrease firing so parasympathetic responses decrease and sympathetic responses increase.
Define Decompensatory mechanisms
Any mechanism that is more of a positive feedback. It leads to further reduction of MAP.
Name some of the decompensatory mechanism. (6)
1.) Cardiac depression
2.) Sympathetic escape
3.) Metabolic acidosis
4.) Cerebral ischemia
5.) Theological factors
6.) Systemic inflammatory responses
What moves fluid along a tube?
An energy gradient
Gravitational energy is also known as ________.
Hydrostatic pressure
What are the two types or characteristics of blood flow?
1.) Laminar
2.) Turbulent
What is the basic flow equation?
Q = change in pressure / resistance
What is Poiseuille's Law?
The formula that addresses resistance.
List the variables of Poiseuille's Law. (5)
1.) Resistance
2.) Radius
3.) Length of tube
4.) viscosity
5.) (Pie)
Define vessels that are "in-series".
The same volume of blood through each.
Define what is meant by an "in-parallel" system?
Organs or vessels are receiving the same composition but different volumes of blood.
What is the formula for calculating resistance in an "in-parallel" system?
1/Rp = 1/R1 + 1/R2 + 1/R3
There are two methods for calculating the percent of stenosis of a vessel. Name them.
1.) % of stenosis using the diameter
2.) % of stenosis using the cross sectional area.
What is the formula for calculating systemic vascular resistance?
SVR = (MAP-CVP) / CO
What are the units of measurement for systemic vascular resistance?
mmHg/ L/min.
Define tone
Tone is the balance of vasodilation and vasoconstriction.
Define compliance.
The ability of a blood vessel or cardiac chamber to change its volume in response to changes in pressure.
High pressures result in ____________compliance.
(More or less)
Less
The vascular system has two main functions, what are they?
1.) Distribution
2.) Exchange
Name the three layers of blood vessels.
1.) Tunica Intima
2.) Tunica media
3.) Tunica adventitia
Which layer of blood vessels consists of smooth muscle, collagen, and elastin?
Tunica media
What does the word "Tunica" mean in Latin?
coat
What are the three substances in the Tunica intima?
1.) Nitric oxide
2.) Endothelin-1
3.) Prostacyline
What is a potent vasoconstrictor?
Endothelin-1
Which layer of blood vessels contain the vasa vasorum?
Tunica adventitia
Which types of vessels has the largest cross-sectional area?
capillaries at 4500 cm2
Why are arteries referred to as "conduit" vessels?
Because they have relatively low and unchangeable resistance to flow and the conduct blood to the arterioles.
Why are arterioles called the "resistance" vessels?
Because they can change their diameters easily regulating blood flow through the peripheral organs.
Why are the capillaries known as the "exchange" vessels?
Because they are capable of a process called net movement of fluid.
What is the diameter of a capillary?
4-7 um
What is the diameter of a red blood cell?
8 um
If all the fluid is not reabsorped by the venous end of the capillary, where does the excess fluid go?
Lymphatic
List three causes of edema. (4)
1.) venous obstruction
2.) kidney disease
3.) Blocked lymphatic drainage
4.) Failing liver
The arterial baroreceptors primarily acts in a ___________ manner.
Negative
What does carotid sinus massage do?
It increases the firing rate of the baroreceptors which decrease the sympathetic activity and increase the parasympathetic activity.
What is the "dive reflex"? (2)
1.) It allows certain aquatic animals to respond to diving with remarkable bradycardia and intense vasoconstriction to all systemic organs except the brain and the heart.
2.) It limits oxygen use.
What is the "flight" or "fight" response? (3)
1.) It is an alerting reaction which increases skeletal muscle tenseness, which prepares the person or animal for an intense physical activity.
2.) Increase in sympathetic and decrease in parasymphetic responses.
3.) Increases BP
What are the humoral factors? (5)
1.) Anything pertaining to body fluids
2.)Circulating catecholamines
3.) The renin-angiotensin-aldosterone system
4.) Antidiuretic hormone -vasopressin
5.) Atrial natriuretic peptide
What are the circulating catecholamines? (2)
1.) Epinephrine- increases HR and arterial pulse pressure.
2.) Norepinephrine- increases MAP and arterial pulse pressure
Where does angiotension II come from?
-Kidneys produce renin. It acts upon angiotensinogen which is released from the live.
-It becomes angiotensin I.
-Angiotensin-converting enzyme comes from the endothelium of the lungs and interacts with angiotensin I and produces angiotensin II.
What does angiotensin II do?(6)
1.) It constricts resistance vessels and increases TPR.
2.) It facilitates and enhances sympathetic adrenergic effects.
3.) It acts of kidneys to increase sodium and fluid retention.
4.) It stimulates the release of vasopressin from the posterior pituitary.
5.) It stimulates thirst centers within the brain.
6.) Final outcome...increases blood volume.
What is an ACE inhibitor?
It helps the production of angiotensin II. It comes from the endothelium lining of the lungs.
When would on ACE inhibitor be used?
CHF to reduce edema and help reduce the effects of remodeling of the ventricle.
Name three factors or vasoactive substances.(5)
1.) Adenosine-regulates coronary blood flow especially during hypoxia.
2.) Hydrogen ions-increases during hypoxia and causes vasodilation.
3.) Potassium ions-cause increased blood flow in contracting skeletal muscle.
4.) HIstamine-vasodilation
5.) Bradykinin-vasodilator of arterioles
Name two endothelial factors that are powerful vasodilators.
Nitric oxide
Prostacyline
Where is the endothelin-1 located?
Tunica intima of the vessel
Name three mechanisms of exchange. (4)
1.) Diffusion
2.) Bulk transfer
3.) Vesicular transport
4.) Active trasport
Define Diffusion. (3)
1.) It is the movement of a molecule from a high concentration to a low concentration.
2.) oxygen and carbon dioxide
3.) Described in Fick's First Law
What is meant by the term, transcapillary fluid?
The fluid exchange between the intravascular and the extravascular compartments.
Define Edema.
Edema is when you have an increase in fluid volume within the interstitial space due to an imbalance of filtration to reabsorption and lymphatic flow.
How do we treat edema?
Give diuretics to reduce blood volume and venous pressure.
Define the term "energy"
The capacity of doing work and over coming resistance.
When discussing hemodynamics, potential energy is defined as...
A combination of intravascular pressure and gravitational potential energy. It is often referring to the pumping action of the heart.
When referring to the right atrium, hydrostatic pressure is considered...
To be about 0 mmHg
Viscosity is measured in units of ...
Poise
Poiseuille's formula solve for a number of variables. Name as many variables as you can. (5)
1.) Change in pressure
2.) Length of vessel.
3.) Viscosity
4.) Flow rate or Q
5.) Radius
What has the greatest effect on resistance?
Radius
What are the two constants in Poiseuille's formula?
1.) 8
2.) pi (pie)
Why is vascular tone important?
It keeps the arterial pressure high enough so we don't pass out when we stand up.
Define Elastin.
It is the property that allows stretch within the vessel.
Define Transmural Pressure
It is the difference in pressure measured on the outside of a vessel or chamber compared to pressure measured on the inside of a vessel or chambers.
A stenosis that reduces the diameter by _____ or the area by _______is a hemodynamically significant lesion.
50% , 75%
The basic flow formula is analogus to what other formula?
Ohms Law, which deals with electricity.
Why do we need to keep mean arterial at the ideal level?
Because it is the driving pressure that delivers oxygenated blood to the rest of the body.
If long term regulation of low mean arterial pressure was needed, the kidneys would...
A. Increase urine output
B. Decrease urine output
C. Shut down and let the baroreceptors kick in.
Decrease urine output.
The valsalva maneuver...
A. Increases venous return
B. Leads to decreased HR
C. Leads to peripheral vasodilation
D. Leads to decreased venous return
Leads to decreased venous return
If you go from lying to standing, you could expect all of the changes except...
A. Decrease in baroreceptor input.
B. Decrease in cardiac parasympathetic nerve activity.
C. Decreases in heart rate and cardiac contractility.
D. Increases in arterial and venous pressure in the lower extremities.
Decreases in heart rate and cardiac contractility.
All of the following can occur if we stand a patient suddenly from a lying position after an exam except...
A. Lightheadedness
B. Bradycardia
C. Decreased in venous return and cardiac output.
D. Reduced BP
Bradycardia
All of the following occur with arteriosclerosis except.
A. A modest rise in mean arterial pressure.
B. The maximum heart rate attainable decreases.
C. Impaired sensitivity to B-adrenergic receptor stimulation.
D. Increases in stroke volume.
Increases in stroke volume
All are the symptoms of shock except...
A. Pale, cold, sweaty skin
B. Pulse is slow
C. Mean arterial pressure is low
D. Urine output is impaired
Pulse is slow.
Decompensatory mechanisms will likely activate if blood pressure drops to.
A. 60 mmHg
B. 90 mmHg
C. 75 mmHg
D. Whatever the pulse pressure is.
60 mmHg
An untrained middle-aged adult doing dynamic type of exercise would experience all of the following except...
C. An increase in total peripheral resistance.
A well-trained athlete exercising would experience all of the following except...
A. Increase in arterial blood pressure during resting and excercising states.
B. Increase in cardiac stroke volume
C. Decrease in resting heart rate.
D. Increase in circulating blood volume.
Increase in arterial blood pressure during resting and excercising states.
Cardiac reserve is defined by all of the following except...
A. The potential for increasing cardiac output.
B. How many more times than average the heart can produce when needed.
C. The amount of oxygen used in one minute.
D. 6-7 times the normal resting amount.
The amount of oxygen used in one minute.
The effects of aging can be described as all of the following except...
A. Getting older, slower, stiffer, and drier.
B. Altering the physiological processes.
C. Influencing the rate of the various homeostatic mechanisms.
D. A normal processes
Influencing the rate of the various homeostatic mechanisms.
Changes that occur in the vascular bed with age include all of the following except...
A. An increase in total peripheral vascular resistance.
B. A decrease in arterial compliance
C. A decrease in capillary density in some tissues.
D. A decrease in total peripheral vascular resistance.
A decrease in total peripheral vascular resistance.
