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106 Cards in this Set
- Front
- Back
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What happens to the cardiac muscle when stretched during diastole?
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it increases its strength
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Describe Starling's law
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direct relationship between amount of blood
in heart at end of diastole and force of contraction during next systole |
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Define Preload
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left ventricular diastolic pressure
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How will an increase in preload affect CO?
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it will increase it to some extent
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What happens when left ventricular pressures
greatly increase? |
blood backs up in pulmonary circulation
causing pulmonary edema |
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Define Afterload
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resistance to blood ejected into
aorta from left ventricle |
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What affect does decreased afterload have on the heart?
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it allows the heart to contract more rapidly
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Increased afterload causes what affect on the workload of the heart?
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increased workload with increased O2 demand
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Heart rate is influenced by what?
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nervous, hormonal and chemical factors
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Define Ejection Fraction
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amount of blood ejected by ventricles in systole
Normal is 60-75% |
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Strength of heart contraction is influenced by:
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-changes in Preload
-sympathetic stimulation due to increased need -ionotopic agents that affect contractility as epinephrine, norepinephrine, thyroid hormone and calcium levels |
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What is the normal CO for a resting adult
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5L/minute
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Describe Tunica intima
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innermost layer of blood vessel. Made of endothelium,
connective tissue and basement membrane |
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Describe Tunica media
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middle layer of smooth muscle and elastic fibers
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Describe Tunica Externa
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outer layer of connective tissue, elastic and collagenous fibers
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What is the internal cavity of a blood vessel called?
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lumen
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What is Total Peripheral Resistance?
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-sum of all resistive forces that impede blood flow
-reflects tone of vessels and viscosity of the blood |
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what does blood pressure maintain?
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tissue perfusion
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What does SBP reflect?
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ejectin of blood into the aorta
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What is SBP determined by?
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SV during systole and elasticity of aorta
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What is DBP
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stored pressure in aorta during diastole
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What does DBP depend on?
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-ability of arteries to stretch and
competency of aortic valve -when TPR increased, DBP increases |
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Describe Pulse Pressure
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-SBP-DBP (Usually 40)
-increases when more blood is ejected into arterial circulation -decreases when resistance to outflow decreases |
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What does short term regulation (autoregulation) do?
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corrects temporary imbalance and maintains
BP during life threatening events |
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What controls short term regulation?
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Nervous mechanisms: baroreceptors,
chemoreceptors, ANS and CNS -horman - RAA and ADH |
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Describe long term regulation
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kidneys relate through sodium and water imbalance
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Describe affects of aging on CVS
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-arthersclerosis present in majority of elderly
may have inc SBP w/ delayed ventricular relaxation -can maintain CO during excercise by dilating LV |
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Define: Arteriosclerosis
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abnormal thickening and hardening of arterial walls
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Arteriosclerosis is caused by accumulation of what?
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smooth muscle cells and collagen fibers in tunica
intima causing stiffness and hardening narrowing lumen |
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A cause of Arteriosclerosis is...
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changes in lipid, cholesterol and
phospholipid metabolism in tunica intima |
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What can arteriosclerosis cause?
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worsen HTN
decrease tissue perfusion cause aneurysms |
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Define Athersclerosis
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form of arteriosclerosis where hardening caused
by deposits of fat and fibrin over 20-40 yrs |
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What does Athersclerosis lead to
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CAD
Cerebrovascular disease and edeath |
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Athersclerosis is primarily a disease of what part of the vessel?
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tunica intima
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What does the acculumulation of lipids
and deposits of cholesterol to to endothelium? |
damage endothelium and cause platelet
aggregation and inflammatory resposne |
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what affect do macrophages have in Athersclerosis?
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release enzymes that oxidize LDL and further injure vessel wall
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What are foam cells?
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macrophages filled with oxidized LDL
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What does an accumulation of foam cells cause?
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a lesion called the fatty streak
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What part of Athersclerosis can be reversed?
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fatty streak. No obstruction of
blood vessel at this stage |
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What is a fibrous plaque?
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formation of scar and connective tissue
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Waht does a fibrous plaque develop from?
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the fatty streak. Bexomes white, elevated
thickening of the intima with core of lipid covered w/ a fibrous cap of connective tissue and smooth muscle |
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What is a complicated lesion?
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occurs when plaques hemorrhage, ulcerate and form scar tissue
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What is an atheroma?
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The disintegration of the tunica intima.
May occlude the vessel or invade muscular layer |
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What causes and occlusion
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complicated lesion increases in size
and lumen narrows causing total occlusiotn or thrombus formation especially at bifurcations |
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What can impaired endothelia injury lead to?
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impaired ability to regenerate
(smoking, stress, HTN) |
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Describe lipid infiltration
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elevated chol. may cause WBC's to interact w/.
endothelial lining more frequently |
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What happens when fatty streaks enlarge
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endothelial cells pulled apart exposing tunica adventia
allowing for platelet aggregation and thrombus |
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What causes smooth muscle proliferation
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endothelial injury allow platelets, chol and other blood
components to come in contact with smooth muscle stimulating abnormal proliferation |
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What are the non-modifiable risk factors of athersclerosis?
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age - increases with age
gender - women protected by estrogen until menopause race - greater incidence in AA hereditary - occur earlier due to lipoprotein anc chol metabolism |
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What are the modifiable risk factors of athersclerosis?
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Increased serum lipid levels - fatty diet
HTN - control with drugs, lifestyle changes diabetes - keep in control obesity - excercise and lose weight |
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List the clinical manifestations of athersclerosis
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symptoms depend on vessel affected - stroke/heart attack
HTN develops if it causes vascular resistance |
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athersclerosis is an insidious process of...
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inadequate tissue perfusion
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What is included in the evaluation of athersclerosis?
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physical exam
identify risk factors lab work EKG, non-invasive US nuclear scanning, arteriograms |
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What is the treatment for athersclerosis?
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Decrease fat intake <30% of calories 10% from saturated fat
cholesterol <200 mg/dl LDL < 130 mg/dl take cholesterol decreasing drugs if diet does not work |
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Describe HTN
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sustained elevation of systemic blood pressure
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What risks increase with HTN?
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cardiac disease
stroke renal failure vascular disease |
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Give the parameters of HTN
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pre - 120-139 and 80-89
HTN stage 1 140-159 and 90-99 HTN stage 2 160 > and 100 > |
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What role does family history play in HTN?
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may be due to abnormal Na+ balance or calcium transport
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What affect does race have on HTN?
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AA get HTN earlier. May be due to abnromal renin levels
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What affect does stress have on HTN?
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due to increase in catecholamine
(increase in vasoconstriction) |
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What affect does diabetes have on HTN?
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abnormal lipid metabolism
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Describe secondary HTN
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associated with another disease
(renal, ateriosclerosis) |
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Waht is isolated HTN caused by?
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increased peripheral resistance from rigid aorta,m
aortic valve insufficiency, or patent ductus ateriosus. Rigid aorta more common seen in elderly |
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What is complicated HTN?
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sustained primary HTN that causes eventual damage to vessels
leading to CHF, CAD, MI aneruysms intermittent claudication and gangrene from peripheral vascular disease, renal failure, blindness and stroke |
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Describe malignant HTN
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develop a rapidly progressing increase of BP with diastolic above 140 that leads to cerebral edema and LOC
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What can malignant HTN cause?
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cardiac failure
retinopathy stroke |
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Who is malignant HTN seen in?
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younger people, esp AA men
Pregnancy |
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What are the three theories of HTN?
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overactive RAA system
overactive sympathetic nervous system inherited sodium and water rentention worsened by diet |
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Give the first step in the process of HTN
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prolonged vasoconstriction and inc pressure cause vessel
wall to thicken as arterial smooth muscle hypertrophies. Caused by inc CO, PR or both |
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Give the secondstep in the process of HTN
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as tunica intima and media thicken,
the lumen narrows permanently |
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Give the third step in the process of HTN
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injury to vessel wall causes inflammatory
response due to histamine, leukotriene and prostaglandins |
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Give the fourth step in the process of HTN
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permeability increases cause Na, Ca, H20 and plasma to
enter vessel walls increasing thickening and muscle contraction |
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Give the fifth step in the process of HTN
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HTN aggravates athersclerosis making vessel lumen smaller
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What are the clinical manifestations of HTN?
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asymptomatic in early stages
dx if SBP >140 or DBP>90 on two or more occasions |
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What is the tx of HTN?
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lifestyle
combination of drugs (diuretics, ACE inhibitors, CCB's, BB's) |
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Define thrombus
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blood clot that remains attached to vessel
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Define thromboembolus
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detached thrombus
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Define thrombophlebitis
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thrombus formation associated with
inflammation in veins |
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Define embolism
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-bolus of matter circulating in blood stream
-could be thromboembolus, air bubble, aggregate of amniotic fluid during delivery, fat from fractured long bone, aggregate of bacteriam cancer cells, or foreign substance |
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What are the risk factors of a thrombus?
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stasis of blood
increased coagulability of blood vessel wall injury from HTN or CHF |
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Trauma to intima lining of a vessel leads to...
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thrombus formation
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What does the imflammatory response from clotting cascade cause?
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pain, swelling, redness in affected area
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What can happen if a thrombus grows large enough?
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occludes artery leading to ischemia
of tissue supplied by artery |
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What can happen if thrombus dislodges?
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travels thu vascular system until occludes
vessel in systemic or pulmonary area (PE) |
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Describe Venous thrombus
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more common and due to decreased pressure
in veins due to immobility (DVT) |
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What are the symptoms of DVT?
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tender, red and swollen in leg
Positive Homan's sign if occludes vein, skin turns red to blue purple |
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Describe arterial thrombus
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most commonly from left ventricle after MI,
valve disease, CHF or arrhythmia |
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What are the signs of an arterial thrombus
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-if occludes vessel may have ischemia to tissues distal
resulting in necrosis or organ dysfunction -if in extremities, pale, cool, pulseless and painful |
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How is a thrombus evaluated?
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doppler UD gives velocity of blood and areas affected
venogram - dye in veins shows areas affected arteriogram - possible to see narrowing or occlusion measure extremity to note increased edema |
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What is the treatment for a thrombus?
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bedrest to prevent embolus
anticoagulants TED hose |
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What is the highest cause of CAD?
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atherosclerosis
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What is hyperhomocysteinemia
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lack of enzyme that breaks down homocysteine or a nutritional deficiency of folate, B12 or B6. Results in increased LDL's
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Define Myocardial Ischemia
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a decrease in O2 resulting in INSULT to cardiac muscle
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Myocardial Ischemia occurs when? (1 of 3 ways)
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narrowing more than 50%. Cannot dilate to increase blood flow when there is increased cardiac demand.
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Myocardial Ischemia occurs when? (2 of 3 ways)
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reduced supply due to hypotension or bleeding, increased HR with dec filling time, hypoxemia due to shock or respiratory disease
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Myocardial Ischemia occurs when? (3 of 3 ways)
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increased demand due to HTN, increased ventribular volume, hypertrophy of ventricle, increased due to stress, excercise hyperthyroidism, or icnreased viscosity of blood
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Give the pathophysiology of Myocardial ischemia
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-cells become hypoxic and injury can occur in 10 seconds. Myocardium cool and cyanotic
-Cells use ANAEROBIC metabolism causing increased lactic acid and H+ release -acidosis increases damaging of lyosomal enzymes -MYOCARDIAL CELLS REMAINVIABLE FOR ONLY 20 MINUTES IF BLOOD FLOW NOT RETURNED |
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What are the clinical manifestations of Myocardial ischemia?
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Angina pectoris caused by lactic acid build-up or stretching of ischemic myocardium that irritates nerve fibers
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What is stable angina?
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associated with athersclerosis
Vessels cannot dilate in response to increased demand Caused by excercise, stress, cold Relieved by rest and NTG |
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What is unstable angina?
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changing pattern and unpredictable
may occur at rest and signal impending infarction gets worse with each attack may be caused by CAD and spasm Not relieved by rest |
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What is Prinzmetal angina?
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-caused by vasospasm w w/o CAD
-occurs during REM stage of sleep -May be due to increased movement of calcium in muslce, inc activity sympathetic NC or prostaglandin production -occurs same time of day |
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How is Myocardial Ischemia evaluated?
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-physical exam shows extra heart sounds
-EKG during angina show depressed ST and T wave inversion -Thallium study shows cold spot (occlusion) -Stress test - see EKG changes during excercise -Cardiac Cath |
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How is Myocardial Ischemia treated?
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NTG or vasocilator
CCB/BB decrease irritability of cells or release of catecholamines ASA/Persantin keep blood thin Angioplasty - ballooning CABG |
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What is Myocardial Infarction?
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death to cardiac muscle
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What causes MI?
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Blood flow impaired by thrombosis, ulcreation and hemorrhage of atherosclerosis plaque, vasospasm, or sudden increase in O2 demand. Usually thrombus
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Where at at what percent do MI's occur?
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Left coronary artery 40-50%
Right coronary artery 30-40% Left circumflex 15-25% |
