Disorders of Blood Flow and Blood Pressure Regulation Flashcards
Understand the basics of the Renin-Angiotensin-Aldosterone System
renin is an enzyme that is synthesized, stored, and released by kidney juxtaglomerular cells. renin release occurs w/ decrease bp, extracellular fluid volume. most renin leaves the kidney. in bloodstream, renin converts an inactive circulating plasma protein, angiotensinogen to angiotensin 1. angiotensin I is converted to angiotensin II while blood is flowing thr the lungs, catalyzed by angiotensin-converting enzyme produced in the endothelium of lung blood vessels.
angiotensin II finction in short and long term bp regulation.
Understand and calculate mean arterial pressure
the average pressure in a pt’s arteries during one cardiac cycle; considered a better indicator of perfuction to vital organs than systolic blood pressure (SBP)
MAP = SBP + (2xDBP)/3
Understand hypercholesterolemia and the importance related to HDL and LDL lipoproteins
Serum cholesterol levels: 240mg/dL or greater. Levels that could contribute to a heart attack, stroke, or other cardiovascular events associated w/ atherosclerosis.
Low-density lipoprotein (LDL): main carrier of cholesterol
High-density lipoprotein (HDL): 50% protein
HDL facilitates reverse transport of cholesterol (carrying cholesterol from peripheral tissue back to the liver, where it is secreted into the bile). exercise, moderate alcohol consumption, and certain lipid medications increase HDL levels; whereas smoking, the metabolic syndrome, and excess alcohol consumption are associated w. decreased levels of HDL.
Dyslipidemia - increased triglycerides, increased total blood cholesterol, decreased HDL cholesterol. associated w/ obesity - chemical activity of adipose tissue
Describe the development of atherosclerosis
hardening of the arteries characterized by the formation of fibrofatty lesion in the intimal lining of large & medium sized arteries.
endothelial cell injury –> migration of inflammatory cells –> lipid accumulation (macrophages become foam cells, attach to lipids, apoptosis of foam cells leave necrotic cell material and lipid in vessel wall) –> plague structure (superficial fibrous cap)
Know the P’s of acute aeterial obstruction
1.) pistol shot (acute onset)
2.) pallor
3.) polar (cold)
4.) pulselessness
5.) pain
6.) paresthesia
7.) paralysis
Differentiate Raynaud’s disease and phenomenon. Know the pathologic etiology of these disorders
functional disorder caused by intense vasospasm of the arteries and arterioles in the fingers and less often toes
precipitated by exposure to cold or strong emotions and is usually limited to the fingers. cause of vasospasm unknown
associated w/ previous vessel injury
Distinguish between pathology and manifestations of aortic aneurysms and dissection of the aorta
aneurysm: an abnormal localized dilation of a blood vessel. can occur in the arteries and veins, most common in the aorta.
true aneurysm is bounded by a complete vessel wall, and the blood remains within the vascular compartment.
a dissecting aneurysm is a false aneurysm resulting from a tear in the intimal layer of the vessel that allows blood to enter the vessel wall, dissecting its layers to create a blood-filled cavity. dissection in the aorta is a life-threatening condition.
aortic aneurysms develop more frequently in males after the age of 50 yrs who smoke cigarettes.
most common site is the ascending aorta and second most common site is thoracic aorta
major symptom of a dissecting aneurysm is abrupt presence of pain described as tearing or rippling.
Describe venous return of blood from lower extremities and how it relates to the development of varicose veins
blood from the skin and subcutaneous tissues in the legs collects in superficial veins and is then transported across the communicating veins into the deeper venous channels and return to the heart. the venous system has valves that prevent retrograde flow of blood.
varicose veins: dilated, torturous veins of the lower extremities are common & often lead to secondary problems of venous insufficiency. 80-90% of venous blood from lower extremities is transported through deep channels. varicose veins develop when flow in deep channels is impaired or blocked.
Describe the pathology of venous insufficiency and relate this to the development of stasis dermatitis and venous ulcers. Know Virchow’s Triad
chronic venous insufficiency: the pathophysiologic condition of persistent venous hypertension on the structure and function of the venous system of the lower extremities. leads to tissue congestion, edema, and eventual impairment of tissue nutrition.
stasis dermatitis: in advanced venous insufficiency; impaired tissue nutrition causes stasis dermatitis and stasis or venous ulcers.
virchow’s triad: stasis of blood, increased blood coagulability, vessel wall injury
Define hypertension and identify the blood pressure limits that are used to clinically identify the presence of hypertension. Differentiate hypertensive emergency from hypertensive urgency
sustained condition of elevation of bp within the arterial circuit.
normal: systolic < 120 and diastolic < 80
elevated: systolic 120-129 and diastolic < 80
high blood pressure (hypertension) stage 1: systolic 130-139 or diastolic 80-89
high blood pressure (hypertension) stage 2: systolic 140 or higher or diastolic 90 or higher
hypertensive crisis: systolic > 180 and/or diastolic >120
Largest cause of secondary hypertension is renal disease
hypertensive emergency: BP elevation is associated w/ ongoing neurological, myocardial, hematological, or renal target organ disease (TOD)
hypertensive urgency: potential for TOD is great & likely to occur if BP is not controlled. occurs on chronic stable complication.
- stable angina, old MI, CCF, CRF, TIA, old CVA
Identify the organs most commonly affected by hypertension and the target-organ damage associated with each
heart (angina (due to myocardial ischemia, MI, HF), brain, chronic kidney disease or kidney failure, peripheral artery disease, retinopathy, sexual dysfunction
