Arteries, Capillaries, Veins

List the arteries (biggest to smallest)

Elastic arteries, muscular arteries, arterioles

Describe elastic arteries

3 tunics, lots of elastic fibers (pump the blood by recoiling) Ex: aorta

Descrive muscular arteries

3 tunics, fewer elastic fibers, smaller but thicker tunica media; majority of vasoconstriction

Describe vasoconstriction

Controlled constriction and dilation of blood vessels (face blushing)

Describe arterioles

Tunica intima and media only, microscopic, no elastic fibers, can completely shut off blood flow

What are the three types of capillaries

Continuous, fenestrated, and sinusoid (discontinuous)

Describe and list what is in continuous capillaries

Most common, all tissues; Gas and waste exchange;

Endothelium (simple squamous et), Intercellular clefts, Plasma (O2 and CO2), Diapedesis (WBC’s leaving the capillary by changing shape)

Describe and list what is in fenestrated capillaries

Extra plasma leakage, Endothelium (simple squamous et), Intercellular clefts, Plasma (O2 and CO2), Diapedesis (WBC’s leaving the capillary by changing shape); Ex: Kidney (filter) and synovial membrane (make synovial fluid)

Describe and list what is in sinusoid (discontinuous) capillaries

Endothelium (simple squamous et), Intercellular clefts, Plasma (O2 and CO2), Diapedesis (WBC’s leaving the capillary by changing shape), Gap of intercellular clefts (allows RBCs to leave and come back), Ex: Red marrow (new RBCs), liver and spleen (old RBCs)

List the capillary bed

Endothelium (arteriole and venule), Tunica media (arteriole), Plasma, Precapillary spincter (directs blood flow into capillaries), Lymphatic capillaries (carries lymph fluid and pick up excess plasma)

What are the two types of veins (smallest to biggest)

Venule and Vein

Describe venules

Typically only endothelium

Describe veins (inner to outer layer)

Endothelium (tunica intima), Tunica media, Tunica adventitia; Lumen is larger, Tunics are thinner, No vasoconstriction, Have skeletal muscle, pumps, and valves

Describe varicose veins

Muscle and skin with elastin fibers helps push the blood; Elastin decreases as we age causing blood to pool, causes valves weaken; Treatment: compression socks

Deep vein thrombosis

Blood clot (swelling and inflammation below the valve); Cause: lack of activity

What is an embolism

A piece of a blood clot that travels; Common to travel to lungs (pulmonary embolism, clots arteries in lungs (aka coach class syndrome)

What are the steps to blood clotting

1. Platelets secrete clotting factor; 2) Clotting factors react with proteins in blood to create fibers; 3) RBC’s trapped in fibers; 4)Macrophages clear clot when vessel is repaired

Arteriosclerosis

Hardening of the arteries

What are the two types of arteriosclerosis

Atherosclerosis and hypertensive arteriosclerosis

Describe Atherosclerosis

“Fat arteries”; Macrophages eat fat in the blood, becoming foam cells (macrophages with no function); Cause plaque beneath endothelium

What does plaque beneath the endothelium do

Block lumen; causes ischemia (lack of O2 in tissues); Tear endothelium which causes RBCs rupture which causes blood clot

Describe hypertensive arteriosclerosis

Hardening of arteries due to high bp; High bp which causes more tunica adventitia which causes less flexible RBCs (repeats cycle)

Describe a heart attack

no blood to part of the heart, causing heart tissue to die (caused by clot)

Describe a stroke

no blood to part of the brain, causing brain tissue to die (caused by clot)

Describe an aneurysm

Congenital (genetic) defect in an arterial wall; Weak, thin wall that cannot take high bp, causes to pop; 15% causes strokes

Describe AVM

when capillaries tangle (can pop), congenital (genetic)

Describe Angiopathy

High concentration of glucose, damages capillaries; starts at the toes and can lead to amputations