Arterial Study Guide Cut

Arteries

Muscular-walled blood vessels

Move blood away from heart

High pressure vessels

Arterial Layers

Tunic intima

Tunic media

Tunic Externa(adventitia)

Tunic intima

Inner lining of endothelial cells

Damage may lead to arteriosclerosis and atherosclerosis

Tunica media

2 components

Smooth Muscle and Nerves

Tunic Media Smooth Muscle

Smooth muscle that regulates blood flow

Nerves in tunic media

Alpha-adrenergic fibers: vasoconstriction

Beta-adrenergic fibers: vasodilation

Calcium's role in the tunica media

Ca²⁺ causes smooth muscle contraction → vasoconstriction

inhibitors can block this

Tunica externa (adventitia)

Connective tissue outer covering

Endothelium as Active Tissue

 Fluid filtration

 Maintain blood vessel tone

 Semipermeable barrier

 Neutrophil chemotaxis

 Hormone secretion

Endothelium Secreting Hormones

Nitric Oxide

Endothelin

VEGF

C-type

Prostacyclin

Thromboxane A2

Von willebrand factor

Nitric Oxide

Stimulates vasodilation

Endothelin

stimulates vessel constriction

VEGF

Vascular Endothelial Growth Factor

angiogenesis

Thromboxane A2

clotting activation

Prostacyclin

clotting inhibition

Von willebrand factor

Also activates clotting

To raise BP….

Increase CO

Increase PVR(Peripheral vascular resistance)

Thrombus risk

Sluggish, stagnant, or turbulent blood flow

Stroke volume

Amount of blood ejected per beat (mL)

Cardiac output

HR × SV

Baroreceptors

Sense stretch of vessel wall and send signals to cardioregulatory center

cardioregulatory center

medulla and pons

BP too high: what happens?

‒ Activate PNS

Decrease HR, contractility, vasoconstriction