Heart Lecture (#2) - Skilling Flashcards
Where is most of the blood? Venous or Arterial side?
Venous side - veins are more distinctable
What are the two different types of arteries?
Muscular and non-muscular
What are the different layers of arteries?
Adventitial - Holds everything together
Initmal Layer - in contact with the blood
Medial layer - in between
What is unique about the tunica intima?
It is composed of endothelial cells - one of the few surfaces that can maintain blood in a liquid state. Blood should not clot there; keep moving
Also possesses many mechanisms that can go awry and lead to atherosclerosis
Arteries have elastic layers and concentric layers of smooth muscle cells
What is unique about the tunica adventitia?
Outermost layer of the artery - possible roles in artierial homeostasis and pathology
Contains collagen fibrils that contribute to the strength of the artery
Other cells found here: mast cells & fibroblasts
Vasa vasorum and nerve fibers are localized here
What is unique about atherosclerosis?
3 different theories prove to play a role in CVD
Atherosclerosis diffusely affects certain regions preferentially in large and medium arteries. At the same time, it produces focal stenosis in certain areas of affected vessels much more than in other areas
Few diseases have an longer “incubation” period than atherosclerosis:
- Begins shortly after birth
- Hyperlipidemia at 200
- Infants have total cholesterol levels at 100
Do you want more anticoagulants or procoagulants?
You want a 50/50 balance
What kind of cells are only seen in atherosclerosis?
Foam cells
smooth muscle cells proliferate and migrate - large arteries become smaller - attacked by LDL
- Intima is injured - blood clots - disrupts blood flow
- -or can break off and become an emboli
What is the one biggest risk factor by far for developing PAD
Cigarette smoking, others aren’t even close
DM is distant 2nd (95% CI)
What’s the deal with Arteriogenic ED?
Age of Onset for ED and CAD is often similar!
ED can be a warning sign of CAD in asymptomatic men
ASCVD and ED share the same risk factors - smoking, diabetes, hypercholesterolemia, hypertension
Factors decreasing blood supply to the limb?
Flow limiting lesion Impaired vasodilation (decreased NO; reduced responsiveness to vasodilators) Accentuated vasoconstriction Abnormal rheology (reduced RBC deformability, increased leukocyte adhesiveness, platelet aggregation, microthombosis, increased fibrinogen)
What affects Hemodynamics (flow through an artery)?
Directly proportional to perfusion pressure
Inversely proportional to vascular resistance
E.g. high vascular resistance (small artery) slows down blood flow
Which organs have highest percentage of cardiac output?
- Liver - 27%
- Kidney - 22%
(Portal) - Brain - 14%
What does relaxation of arterioles and precapilary sphincters do?
Increase tissue blood flow
In response to decreased tissue O2
What connects arteries and veins?
Arteriovenous anastomosis in the subcutaneous tissue
Capillaries get nothing if there is a disruption above
What is the Cardinal Symptom of PAD!
Calf pain (intermittent claudication)
It appears with exercise and resolves with rest
-Reliable, reproducible, and consistent
Location of sxs relates to site of most PROXIMAL arterial stenosis
What is a collateral vessel?
Small vessel that forms to bypass blockage
Most common DDX of Exertional Leg Pain??
Lumbrosacral radiculopathy (neurogenic claudication) -Leg pain caused by neuropathy