Exam 1 Flashcards
What is dyslipidemia
A abnormal amount of lipids in the blood
True or False, inflammatory mechanisms couple dyslipidemia to atheroma formation
True
Leukocyte recruitment and expression of pro-inflammatory cytokines characterize what?
Early atherogenesis
What is thrombosis
blood clots
What causes most myocardial infarctions and most strokes?
thrombosis (blood clots)
What is another name for loose connective tissue?
areolar tissue
What are the two kinds of ordinary tissues?
Loose connective tissue (areolar tissue)
Dense ordinary connective tissue (Regular vs. Irregular)
Adipose tissue, Blood cells, Blood cell forming tissue (Myeloid or lymphatic tissue), Cartilage and Bone are all examples of what?
Special connective tissues
What process prevents blood loss
Hemostasis
What are the 4 mechanisms of hemostasis
Vascular spasm
Formation of a platelet plug
Blood coagulation
Fibrous tissue growth to seal
True or false, platelets can divide like normal cells?
False, they cannot
True or false, platelets contain actin and myosin
True
What significant role do glycoproteins play in platelets
Avoid normal endothelium but adhere to damaged areas
When platelets come in contact with a damaged area, they swell and what else happens?
Contractile proteins (actin and myosin) contract causing granule release
Once the contractile proteins in platelets contract releasing granules, what is secreted?
ADP, Thromboxane A2 and Serotonin
Is thromboxane A2 a vasoconstrictor or vasodilator
Vasoconstrictor
How long is a platelets half life? How are they eliminated?
8-12 days
Primarily by macrophage action
What are typical levels of platelets in the blood?
150,000-300,000 per micro liter
What role does PGI2 (prostacyclin) play in blood coagulation
vasodilator
stimulates platelet adenyl cyclase which suppresses release of granules
Both Thromboxane A2 and Prostacyclin are derived from what fatty acid?
Arachidonic acid
What effect does aspirin and ibuprofen have on thromboxane A2 and prostacyclin
They both block production by blocking cyclooxygenase which converts ARA (arachidonic acid) to PGG2 and PGH2 (intermediates)
Citrate and oxylate are both examples of? How do they work?
Anti-coagulants
They tie up calcium
Cumadin and Warfarin are both examples of what? How do they work?
Synthetic anti-coagulants
inhibiting Vitamin K dependent factors
What substance dissolves blood clots
Plasmin
What is the name of inactive plasmin circulating in the blood
plasminogen
Where are endogenous activators of plasminogen found in the body
Tissues, plasma, and urine
What are 2 examples of exogenous activators of plasminogen
streptokinase
tPA (tissue plasminogen activator)
True or false; clots may be liquefied (fibrinolysis) by a proteolytic enzyme called “plasmin”
True
True or false; plasminogen is the inactive form of plasmin (which liquifies clots) circulating in the blood
True
Most tissue damage from an infarction occurs upon what?
Reperfusion
True or false; reperfusion injuries are associated with high levels of reactive oxygen species causing free radicals
True
What is collateralization
Ability to open up alternative routes of blood flow to compensate for a blocked vessel
What is the extrinsic mechanism of thrombosis (blood coagulation)
initiated by chemical factors released by damaged tissues
What is the intrinsic mechanism of thrombosis (blood coagulation)
Requires only components in blood and trauma to blood or exposure to collagen
How many clotting factors does your liver make? What are they?
5, factors I (fibrinogen), II (prothrombin), VII, IX, X
Coumarin (warfarin or cumadin) are all blood thinners. How do they work?
They depress the liver’s ability to form clotting factors II, VII, IX, and X by blocking vitamin K
What is Hemophilia? Is it more common in one sex?
It is a sex linked disease causing abnormal thinning of the blood
It affects almost exclusively males
True or false; hemophilia is caused 100% of the time by a defect in clotting factor VIII
False, it is caused by clotting factor VIII 85% of cases and factor IX 15%
True or false; calcium plays no role in blood coagulation
False, calcium plays a major role
True or false; a key step in blood clotting is the conversion of fibrinogen to fibrin which requires thrombin
True
What is Antiphospholipid antibody syndrome? What does it cause?
An autoimmune disorder where body makes antibodies against phospholipids in cell membranes
Causes abnormal clot formation
True or false; being a male increases your risk of heart disease?
True
What is homocysteine?
An amino acid in the blood that may irritate blood vessels promoting atherosclerosis
Can make blood more likely to clot
True or false; SA node, AV node, and purkinje fibers are all specialized excitatory and conductive muscle fibers
True
True or false; inflammatory pathways promote thrombosis, which is responsible for myocardial infarction and most strokes
True
What is released from the endothelial wall, that promotes vasodilation and limits platelet extension
Prostacyclin (PGI2)
What is released from the platelets that promotes vasoconstriction?
Thromboxane A2
A traumatized vessel will constrict; most of this constriction is due to what
local myogenic spasm
True or false; plasmin dissolves blood clots
true
True or false; the conversion of fibrinogen to fibrin is not a crucial step in blood coagulation
false, it is
Fibrinogen and prothrombin along with factors VII, IX, and X are produced by what organ?
Liver
True or false; Ca++ is vital in blood clotting except for the first two intrinsic steps
True
True or false; the SA node lacks a stable resting polarized state
true
At a normal resting membrane potential of -85 mV, what ion is closest to its nernst equilibrium potential?
K+
A 2-3 times elevation in extracellular fluid of what ion can cause flaccidity and weakness of cardiac muslce in part by decreasing the resign membrane potential
K+
If end diastolic volume = 160 mL and end systolic volume = 120 mL what is the ejection fraction
25% (40/160)
What percentage of blood from the atrial to the ventricle is actively pumped?
25-30%
Norepinephrine binds to which cardiac receptors?
Beta
Acetylcholine binds to which cardiac receptors?
Muscarinic
At rest, if you block both divisions of the autonomic nervous system (increase sympathetic) what would expect heart rate to do/
HR will increase and strength of contraction with decrease
What allows the action potential to spread from one cardiac cell to an adjacent cardiac cell, and therefore allows the heart to behave as a syncytium
Intercalated discs
Reperfusion injury following infection is primarily associated with what?
Free radical production
Increased stretch on the ventricular fibers during filling have what effect on calcium influx into the ventricular cells?
Increase (promotes more forceful contraction)
True or false; thyroxine has a positive inotropic effect on the ventricle
true
A wave of depolarization moving toward the positive recording electrode would create what type of deflection
negative deflection
When does myocardial blood flow peak in the left ventricle
at the onset of diastole
When does myocardial blood flow peak in the right ventricle
mid systole
True or false; 70% of oxygen is most body can take from blood
true
If the sympathetic nerves to the heart are cut and then the SNS is stimulated the heart rate will still increase, why?
circuating norepinephrine and epinephrine from the adrenal medulla
The preferred energy substrate of ventricular cardiac cells is what?
fatty acids
At a constant operating pressure what happens to the wall tension as the radius of that chamber decreases
decreases
No consistent relationship of P waves to QRS complexes describes what AV block
3rd
Prolonged PR interval describes what AV block
1st
Some waves getting through and others not describes what AV block
2nd
If you block fast Na+ channels in a typical cardiac muscle cell using “tetradotoxin” what will be observed
depolarization is slowed
True or false; as heart rate increases, cycle length decreases and diastole shortens more than systole
true
Most of the energy consumed by the heart for work is utilized for what?
Pressurization of blood by the ventricles (key word is energy consumed for WORK) Heat is what energy source is typically absorbed by heart
What is syncytium?
Means many acting as one
like the intercalated disc in the heart
How long is the duration of an action potential in the heart/
.2-.3 seconds
Are Na+ channels fast or slow in heart? What about Ca+/Na+?
Na+ Fast
Ca+/Na+ slow
In relation to Na+, Ca+, and K+ how does permeability change in the heart
Na+ ^ at onset of depol, decrease during repol
Ca++ ^ at onset of depol, decrease during repol
K+ decreased onset of depol, ^ during repol
True or false; membrane permeability is dependent on ion channels
true
before initial depolarization how many millivolts is the heart resting at
-85 millivolts
after depolarization during the beat how many millivolts is the heart at
+20 millivolts
After the initial spike after depolarization how long does the membrane remain depolarized for (plateau)
.2 seconds
True or false; a ventricular contraction can last as much as 15 times longer than a skeletal muscle contraction
true
True or false, as the slow Ca++/Na+ channels are open the permeability for K+ decreases causing a prolonged plateau at the end of depolarization
true
After the slow Ca++/Na+ channel closes K+ permeability rises again allowing efflux of K+ and a rapid repolarization
The Na+/K+ pump in the heart pumps Na+ out and brings K+ in a what ratio? What is the net loss/gain?
3:2
Net loss of +1
True or false; there is a protein that allows Ca++ from inside the cell to be exchanged for a Na+
True
If the Na+/K+ pump is inhibited and the Ca++ exchange protein is reduced, Ca++ will accumulate in the cell causing what
an increase in contractile strength
When is the absolute refractory period
during plateau
When does the relative refractory period occur
during repolarization
What is considered the normal pacemaker of the heart
SA node
True or false; the SA node is considered self excitatory
true
True or false; in the SA node only the slow Ca++/Na+ channel is operational
true
Which node spontaneously depolarizes at fastest rate
SA node
True or false; the AV node speeds the onset of depolarization entering the ventricle
False; it delays the wave of depolarization from entering ventricle
This allows the atria to contract slightly ahead of ventricle (.1 sec)
True or false; in absence of SA node the AV node can act as a pacemaker
true
True or false; as heart rate increases cycle length decreases
true
During systole what is happening?
isovolumic contraction
ejection of blood
During diastole what is happening
isovolumic relaxation
rapid inflow of blood
atrial systole
What valves are opened/closed during systole
Ventricles are in isovolumic contraction so, Pulmonic and Aortic valves are open, and Mitral and Tricuspid valves are closed
What valves are opened/closed during diastole
Ventricles are now in Isovolumic relaxation, so pulmonic and aortic valves are closed, blood inflow, mitral and tricuspid valves are open
What is End Diastolic Volume (EDV)? What is End Systolic Volume (ESV)? What is Stroke volume (EDV-ESV)
EDV= volume of ventricles filling with blood end of diastole
ESV= volume of blood exiting ventricles end of systole
Stroke volume= is calculated EDV-ESV
What is the Ejection fraction? What is a normal ejection fraction
Stroke volume divided by end diastolic volume multiplied by 100 (SV/EDV x 100)
50-60%
Which valves are considered thin and weak, supported by chord tendineae to prevent prolapse and papillary muscles
Mitral and tricuspid valves or the atrial valves
Which valves are considered the semilunar valves and stronger than the other
Aortic and pulmonic valves or ventricular valves
What term describes when a valve isn’t opening fully
stenotic
What term describes when a valve isn’t closing properly
insufficient
If a valve is stenotic (not opening fully) or insufficient (not closing all the way) what would be the phenotype
A heart mummer (they are audible)
What could it mean if you heard a heart murmur during systole
aortic and pulmonary stenosis
or
mitral and tricuspid insufficiency
What could it mean if you heard a heart murmur during diastole
aortic and pulmonary insufficiency
or
mitral and tricuspid stenosis
What would it mean if you heard a heart murmur during both systole and diastole
patient ducutus arteriosis
or
combined valvular defect
True or false; as tension on the ventricle wall increases (i.e. the radius is increasing) what would you expect the force of contraction to be
increased
What does chronotropic mean
anything that affects heart rate
What does dromotropic mean
anything that affects conduction velocity
What does inotropic mean
anything that affects strength of contraction
True or false; caffeine would be an example of a chronotropic agent
true
True or false; increased stretch on the SA node will increase heart rate
true
stretch on SA node will increase Ca++ and/or Na+ permeability which increases heart rate
What is the Frank-Starling law?
The heart will pump all the blood that is sent to it within physiological limits
What does SNS stimulation do to the heart
increases heart rate, strength of contraction, and conduction velocity
What does parasympathetic stimulation do to the heart
decreases heart rate, strength of contraction, and conduction velocity
What would stretch on the right atrium do to SNS
Cause SNS to release catacholamines try and increase heart rate and contraction to deal with extra inflow of blood
This is called Brainbridge reflex
What would thyroid hormones do to heart
Act Inotropic (increase strength of contraction) chronotropic (increase in heart rate)
How does body temperature effect the heart
Increased heat with cause an increase in heart rate and a temporary increase in contractile strength (prolonged fever will cause decrease in strength due to exhaustion of metabolic systems)
Decreased heat will cause a decrease in heart rate and strength of contraction
Can the heart use different energy sources outside of fatty acids?
yes, the heart just prefers to use fatty acids
75% of the energy the heart utilizes is converted to what? What is the remaining 25% utilized for
heat
remaining is used for work
What is the normal rate of an EKG
around 60-80 bps
What is a EKG rating of greater than 100 bps mean? What about less than 50?
> 100 is considered tachycardia
<50 is considered bradycardia
How long should the PR interval be on an EKG
about .16 seconds
If the PR interval on a EKG is >.20 seconds what is that considered
1st AV block
Which waves of a electrocardiograph are considered depolarization waves? Which are repolarization
P and QRS complex are depolarization
and T wave is the repolarization
If troponins are found in blood what does that say about the heart
troponins are only released when myocardial necrosis has taken place
True or false; after a myocardial infarction damaged cells loose their ability to repolarize
true
What is characteristic of a 1st degree AV block
depolarization from atria to ventricle is delayed
What is characteristic of a 2nd degree AV block
Some depol waves pass and others do not
What is characteristic of a 3rd degree AV block
All depol waves from atria to ventricles are blocked
