Blood Vessel Review

Blood vessels circulation order

heart - arteries - arterioles - capillaries - venules - veins - heart

Arteries

carry blood way from the heart

Veins

carry blood toward the heart

Capillaries

exchange vessels

Tunic Intima

innermost endothelial layer and reduces friction

Tunic media

contains smooth muscle and elastic fibers and controls vasoconstriction and vasodilation

Tunica externa

connective tissue that protects and anchors the vessel

Vasa Vasorum

supply the walls of large arteries and veins

Elastic arteries

large arteries near the heart that stretch and recoil

Muscular arteries

distribute blood to specific organs

Arterioles

are small resistance vessels and major control points for blood pressure

Metarterioles

connect arterioles to capillaries and help regulate capillary blood flow

Baroreceptors

detect blood pressure/stretch and are found in carotid sinuses and aortic arch

Chemoreceptors

detect O2, CO2, and pH and are found in carotid bodies and aortic bodies

Capillaries

one cell layer thick and allow exchange of gases, nutrients, hormones, and wastes

Types of capillaries

continuous, fenestrated, and sinusoidal

Continuous capillaries

least permeable and common in muscle, skin, and lungs

Fenestrated capillaries

has pores and are found in kidneys, small intestines, and endocrine glands

Sinusoidal capillaries

most permeable and found in the liver, spleen, and bone marrow

Capillary beds include

terminal arteriole, metarteriole, true capillaries, precapillary sphincters, and venule

Veins have

thin walls, large lumens, low pressure, valves and act as blood resovoirs

Blood flow depends on

pressure difference and resistance

Where is blood pressure high?

arteries

Where is blood pressure low?

Veins

Resistance inreases with

longer veins, higher viscosity, smaller radius

Vasoconstriction

narrows vessels and increases resistance

Vasodilation

widens vessels and decreases resistance

Capillary exchange

filtration at the arterial end and reabsorption at the venous end

Edema is caused by

increased capillary pressure, decreased plasma proteins, increased permeability, or lymphatic blockage

Venous return

helped by pressure gradient skeletal muscle pump, respiratory pump, venoconstriction, and blood volume