Patho Chapter 26/28

Arteries

Carry blood away from the heart

Veins

Return blood to the heart

Capillaries

Smallest blood vessels responsible for the exchange between blood and insterstitial fluid

Vascular endothelium

The inner lining of all blood vessels; multifunctional tissue; regulates thrombosis and controls transfer of molecules and vasodilation

Vascular smooth muscle 

Regulates blood pressure and systemic resistance

Systolic pressure

Exerted when blood is ejected from ventricles (contract) - 120 mmHg

Diastolic pressure

Sustained pressure when ventricles relax - 80mmHg

Pulse pressure

The difference between your systolic and diastolic blood pressure

Pressure volume

Blood _______ is directly proportional to blood _______

Vasoconstriction increased

Sympathetic branch of ANS: increased output = _________ and _________ BP; peripheral resistance increases

Vasodilation decreased

Sympathetic branch of ANS: decreased output = _________ and _________ BP

Cardiac output

The volume of blood pumped by a ventricle in 1 minute

Baroreceptors

Stretch-sensitive receptors located in the walls of carotid sinuses and aortic arch

Baroreceptor reflex

Negative feedback loop involving pressure sensors and the autonomic nervous system; primary neural mechanism; acute BP regulation managed by SNS

Renin-angiotensin-aldosterone

The most important for long-term BP control; activated when BP or blood volume is too low

Hormonal mechanism

The complex, long-term process that primarily controls BP by adjusting blood volume and systemic vascular resistance; antidiuretic hormone, renin-angiotensin-aldosterone, epinephrine

Chylomicrons

Lipoproteins that transport dietary triglycerides

VLDL

Lipoproteins that transport triglycerides synthesized in the liver

LDL

Lipoprotein that is the main carrier of cholesterol from the liver to the cells; contributes to atheroma formation

HDL

Lipoprotein that transports cholesterol away from the peripheral cells to the liver; “good lipoprotein”; made up of 50% protein

Chylomicrons, VLDL, LDL, HDL

Lipoproteins from low density to high density 

Hypercholesterolemia

Serum cholesterol levels 240 mg/dL or greater; could contribute to heart attack, stroke, or other events associated with atherosclerosis 

Primary secondary

_______ hypercholesterolemia describes elevated cholesterol levels that develop independent of other health problems or lifestyle behaviors; _______ hypercholesterolemia is associated with other health problems and behaviors

Arteriosclerosis

general term for all types of degenerative changes, loss of elasticity and hardening in arteries

Atherosclerosis

The presence of atheromas in large arteries; arterial lumen gradually narrows and may become obstructed

Atheroma

Plaque consisting of lipids, calcium, and possible clots

Stable plaque

Plaque that have thick fibrous caps, partially block vessels, and do not tend to form clots or emboli

Unstable plaque

Plaque that has thin fibrous caps, can rupture and cause a clot to form, and may completely block the artery or become an embolus

Age, gender, and genes

Non-modifiable risk factors for atherosclerosis 

Fatty streaks

Thin, flat yellow intimal discolorations that progressively enlarge throughout the progression of atherosclerosis 

Fibrous atheromatous plaque

The accumulation of intracellular and extracellular lipids, proliferation of vascular smooth muscle cells, and formation of scar tissue

Complicated lesion

Contains hemorrhage, ulceration, and scar tissue deposits

Peripheral arterial disease

Narrowing or occlusion of arteries of lower extremities due to the build up of atherosclerotic plaques; initially asymptomatic 

Acute arterial occlusion

sudden blockage of blood flow as a result of thrombus or embolus; common with existing peripheral arterial disease 

Pistol shot, pulselessness, paralysis, paraesthesia, pallor, polar

The 6 Ps of acute arterial occlusion

Thromboangiitis Obliterans 

Rare progressive, non-atherosclerotic, inflammatory disease characterized by inflammation of small arteries, narrowing and occlusion, and reduced blood flow; can lead to gangrene; Buerger’s disease

Aneurism

Localized dilation and weakening of the arterial wall; usually develops from a defect in the medial layer

Saccular

Aneurism that has a bulging wall on the side

Fusiform

Aneurism that has circumferential dilation along a section of artery; round on both sides

Dissecting

Aneurism that develops when there is a tear in the intima of the wall and blood continues to dissect or separate tissues

Berry aneurism 

Aneurism often found in the circle of Willis in the brain circulation; small spherical vessel dilation

Fusiform or saccular aneurism

Aneurism often found in the thoracic and abdominal aorta; gradual and progressive enlargement of the aorta

Varicose veins

Irregular, dilated, tortuous areas of superficial veins; may develop from defect in vein walls or valves

Thrombophlebitis

Thrombus development in an inflamed vein; often unnoticed; may cause aching, burning, or tenderness in the affected area

Virchow’s Triad

Stasis of blood or sluggish blood flow, endothelial injury, increased blood coagulability; risk factors associated with venous thrombosis 

Primary hypertension

The most common type of hypertension; develops gradually over many years with no identifiable cause

Secondary hypertension

Hypertension that results from renal or endocrine disease, pheochromocytoma (benign tumor of the adrenal medulla)

Malignant or resistant hypertension

Hypertension that is uncontrollable, severe, and rapidly progressive with many complications; diastolic pressure is extremely high

Electrocardiogram

Records the electrical activity of the heart

P wave

Depolarization of the atria; contraction

QRS wave

Depolarization of the ventricles; contraction

T wave

Repolarization of the ventricles; relaxation

P-R interval

The beginning of atrial excitation to the beginning of ventricular excitation

S-T segment

The entire ventricular myocardium depolarized

Q-T interval

The beginning of ventricular depolarization through ventricular repolarization

Arrhythmias

Deviations from normal cardiac rate or rhythm; can cause reduction of the efficiency of the heart’s pumping cycle

SA node 

The pacemaker of the heart (normal 60-100 bpm) rate can be altered

Sick sinus syndrome

Marked by altering bradycardia and tachycardia - Tachy-Brady Syndrome

Premature atrial contractions or beats

Extra contraction or ectopic beats due to irritable atrial muscle cells outside conduction pathway

Atrial flutter

Atrial heart rate of 160 to 350 beats/min; AV node delays conduction; ventricular rate slower

Atrial fibrillation

Atrial rate over 350 beats/min; Causes pooling of blood in the atria, thrombus

formation is a risk

Heart blocks

Conduction excessively delayed or stopped at the AV node or Bundle of His

First degree block

conduction delay between atrial and ventricular contractions; prolonged PR

Second degree block

Every second to third atrial beat dropped at the AV node; progressive long PR

Third degree block

No transmission from the atria to the ventricles; normal atrial rate and ventricular rate; 30-40 bpm

Bundle branch block

Interference with conduction in one of the bundle branches; Right and left contract asynchronously

Ventricular tachycardia

Ventricles contract 100-200 bpm; likely to reduce cardiac output as reduced diastole occurs

Ventricular fibrillation

Muscle fibers contract independently and rapidly no cardiac output; cardiac standstill (asystole) occurs if not treated immediately