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6.2 Heart
Circulatory System- Atherosclerosis and Lymph
13
Medical
Graduate
11/07/2012

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Cards

Term
4 types of microcirculation formed by small BVs
Definition
1. Usual: artery-->arteriole-->metarteriole-->capillary-->venule-->vein
-Nutritional

2. Arterovenous anastomosis: arteriole-->venule
-Non-nutritional
-Skin (heat), penis, clitoris
3. Arterial portal system: arteriole-->capillary-->arteriole
-Non-nutritional filter
-Kidney glomerulus
4. Venule portal system: venule-->capillary-->venule
-Non-nutritional filter
-Liver
Term
Atherosclerosis
Definition
-Thickening, hardening of arterial wall (NOT veins)
-Caused by atherosclerotic plaque
-Plaque composed of lipid, cells, CT deposited in tunica intima
-May cause MI and/or stroke
**Chronic inflammatory disease
Term
Atheroma
Definition
Deposit of lipid in tunica intima
-Yellow swelling on endothelial surface
-1st stage- may or may not lead to plaque
Term
Atherosclerotic plaque development
Definition
1. Endothelial cell damaged
2. Monocyte diapedesis into tunica intima
3. Monocyte differentiate into macrophage
4. Macrophage take up excess LDL (lipids) --> foam cells
5. Foam cells release GFs and cytokines acting on smooth muscle
6. Smooth muscle migrate from media into intima and surround foam cells
7. Smooth muscle produce collagen and fibronectin, forming smooth muscle cap
Term
Lipid core triggers inflammatory response attracting T cells
Definition
-Attract T-cells (IL-2) to produce metalloproteinases
-Together with T-cells weaken fibrous cap→susceptible to fracture
**Lymphocytes present in plaque=inflammation
*Fibrous cap forms underneath endothelial cells
Term
MI or stroke can be caused by plaque because
Definition
Plaque can block BV blood flow or break off and block BV in brain
Term
Endocardium is continuous with the...
Definition
Tunica intima
Term
The myocardium is continuous with the...
Definition
Tunica media
Major difference- cardiac vs. smooth muscle
Term
Risk factors for atherosclerosis
Definition
1. Hyperlipidemia- high blood [lipid/cholesterol]
2. Smoking- damage endothelial cells
3. Hypertension- physically injure BV
4. Turbulence- not under our control; damage endothelial cells at arterial branch points
Term
Unlike circulatory system, lymph flows...
Definition
In one direction- towards the heart
Term
Purpose of the circulatory system carried out by lymph
Definition
****Lymph leaves BV and becomes EC fluid- takes nutrients and oxygen to tissues
****EC fluid picks up waste products and CO2
Term
Flow of lymph is like veins:
Definition
-Valves (tunica intima with collagen and elastic fibers)
-Circulation aided by:
1. Contraction of skeletal muscle
2. pulsation of nearby A.s compress lymph vessels
3. Presence of valves permits lymph to move in one direction
4. Pressure changes due to respiratory muscles
5. Rhythmic contraction of smooth muscles of walls of lymphatic ducts and trunks
Term
Distinguishing characteristic b/t lymph capillaries and blood capillaries
Definition
Discontinuous, fragmented, indistinct basal lamina of lymph capillaries
-AF of elastic fiber system hold open lymphatic capillaries
-Anchors them to surrounding CT
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