Ch. 18 Disorders of Blood Flow and Blood Pressure Flashcards
What are the 3 walls of blood vessels from outermost to innermost?
- Tunica Externa/Adventitia
- Tunica Media
- Tunica Intima
Describe the Tunica Externa
- primarily loosely woven collagen fibers that protect the blood vessel and anchor it to the surrounding tissue
- nerve fibers
Describe the Tunica Media
-mainly of circulatory arranged smooth muscle cells and sheets of elastin
describe the tunica intima
single layer of flattened endothelial cells with minimal underlying subendothelial connective tissue
What does the endothelium of blood vessels do?
- versatile, lots of functions
- selective permeability (inflammatory response)
- helps modulate blood flow
- vascular resistance (dilate/constrict)
- helps with platelet adhesion
- regulates inflammatory actions
What are some dysfunctions that can occur with the endothelium of blood vessels?
- thrombus formation w/o injury
- atherosclerosis
- Hypersensitive vascular lesions
- erectile dysfunction
- retina disorders
- kidney disorders
Arteries, arterioles, capillaries
arteries: main transporters of oxygenated blood
arterioles: diameter is adjusted to regulate blood flow
capillaries: diffusion occurs across thin walls
give examples of large, medium, and small arteries
large: aorta
medium: coronary and renal
small: arteries and arterioles
Hyperlipidemia/Hyperlipoproteinemia
increased lipids in the blood
describe the pathology behind hyperlipidemia
-because lipids, namely cholesterol and triglycerides, are insoluble in plasma, they are encapsulated by special fat carrying proteins called lipoproteins for transport in the blood.
what are the 5 types of lipoproteins?
- chylomicrons
- Very-low density lipoprotein (VLDL)
- intermediate-density lipoprotein (IDL)
- low-density lipoprotein (LDL)
- high-density lipoprotein (HDL)
how are lipoproteins classified?
based on their density
chylomicrons
lowest density
- 80-90% triglycerides
- 2% protein
VLDL
- converted to LDL in the body
- 65% triglycerides
- 10% cholesterol
- 5-10% protein
LDL
- “bad cholesterol”
- main carrier of cholesterol; 50% cholesterol
- 10% triglycerides
- 25% protein
HDL
- “good/healthy cholesterol”
- 5% triglycerides
- 20% cholesterol
- 50% protein
why is HDL considered “good cholesterol”?
- it participates in reverse transport of cholesterol – that is, carrying cholesterol from the peripheral tissues back to the liver (to get rid of it)
Hypercholesteremia
- increased levels of cholesterol in the blood
- usually multifactorial
- primary (develops independent of other causes) or secondary (associated with other health problems/behaviors)
What are some examples of causes of primary hypercholesteremia?
- genetic base
- defect in the synthesize of apoproteins
- lack/deficiencies in receptors
- defects in handling of cholesterol in the cell that are genetically determined
what are some examples of causes of secondary hypercholesteremia?
- lifestyle causes
- diet- high calorie intake
- obesity (high triglycerides)
- sedentary lifestyle
- diabetes mellitus (high triglycerides)
how is hypercholesteremia diagnosed?
blood lipid studies
-could also be part of screening
how is hypercholesteremia managed?
- goal is to decrease LDL( main carrier of cholesterol)
- dietary changes; reduce calories, stay away from saturated fats (vegetable fats > animal fats)
- stop smoking
- medications: lipid lowering medications ( decrease cholesterol production, block cholesterol absorption, remove cholesterol from blood)
Atherosclerosis
- hardening of the blood vessels
- denotes the formation of fibrous fatty lesions in the intimal lining of the large and medium sized arteries (aorta, coronary arteries, cerebral arteries)
- once plaques form, more elements stick to it and it can build up and form a blockage (risk of breaking off and going to organs)
Atherosclerosis is the leading cause of what?
coronary artery disease, stoke, and peripheral artery disease
what are some modifiable risk factors for atherosclerosis?
-smoking, obesity, HTN, salt intake, exercise, about on Hyperlipidemia, diabetic
what are some constitutional (unmodifiable) risk factors for atherosclerosis?
- age, sex, genetics
- family history
- men age 45 and older
- women age 55 and older or who experienced premature menopause with estrogen replacement
what are the three types of lesions associated with development of atherosclerosis?
- fatty streak
- fibrous atheromatous plaque
- complicated lesion
which two types of lesions are responsible for the clinically significant manifestations of atherosclerosis?
- fibrous atheromatous plaque and complicated lesions
what are fatty streaks?
- thin, flat, yellow, intimal discolorations that progressively enlarge by becoming thicker and slightly elevated as they grow in length
- common within the first year of a child’s life (normal?)
what is the most important complication of atherosclerosis?
thrombosis
what are the stages of atherosclerosis development?
- endothelial cell injury (smoking, elevated LDL, HTN)
- migration of inflammatory cells- endothelial cells being to express selective adhesion molecules that bind monocytes. after monocytes adhere they migrate between the endothelial cells to localize in the intima, transform into macrophages and engulf lipoproteins (largely LDL)
- smooth muscle cell proliferation and lipid deposition- activated macrophages release toxic oxygen species that oxidize LDL resulting in the formation of FOAM CELLS. macrophages also produce growth factors that contribute to the migration and proliferation of smooth muscle cells.
- gradual development of the atheromatous plaque with a lipid core - cap forms over foam cells. the cap can erode, ulcerate, and break free
foam cells are the primary component of what vascular disease?
atherosclerosis
Clinical manifestations of atherosclerosis
- depends on the vessels involved and the extent of vessel obstruction
- carotid arteries can actually be cleaned out
- coronary arteries,
- aortic artery
- legs
- brain
Vasculitides
- a group of vascular disorders that cause inflammatory injury and necrosis of the blood vessel wall (i.e. vasculitis) and necrosis of the blood vessel wall (vein capillary) .
- vasculitis may result from direct injury to the vessel, infectious agents or immune processes or they may develop secondary to other disease states such as systemic lupus erythematosus
- classified: small vessel, medium vessel, large vessel
what autoimmune disorder is associated with small vessel Vasculitides?
-scleroderma
what autoimmune disorder is associated with large vessel Vasculitides?
rheumatoid arthritis