Additional Notes Module 4: Structure and Function of Blood Vessels Flashcards
____ by the heart flows through a series of vessels known as arteries, arterioles, capillaries, venules, and veins before returning to the heart.
Blood pumped
____ transport blood away from the heart and branch into smaller vessels, forming arterioles.
Arteries
____ distribute blood to capillary beds, the sites of exchange with the body tissues.
Arterioles
_____ lead back to small vessels known as venules that flow into the larger veins and eventually back to the heart.
Capillaries
The _____ system is a relatively high-pressure system, so arteries have thick walls that appear round in cross section.
arterial
The ____ system is a lower-pressure system, containing veins that have larger lumens and thinner walls.They often appear flattened.
venous
Arteries, arterioles, venules, and veins are composed of ____ tunics
three
three tunics known as the
tunica intima, tunica media, and tunica externa.
Capillaries have only a tunica ____ layer.
intima
The tunica _____ is a thin layer composed of a simple squamous epithelium known as endothelium and a small amount of connective tissue.
intima
The tunica ____ is a thicker area composed of variable amounts of smooth muscle and connective tissue. It is the thickest layer in all but the largest arteries.
media
The tunica ____ is primarily a layer of connective tissue, although in veins, it also contains some smooth muscle.
externa
Blood flow through vessels can be dramatically influenced by _____ and ____ in their walls.
vasoconstriction, vasodilation
Very small artery that leads to a capillary
Arteriole
Short vessel connecting an arteriole directly to a venule and bypassing the capillary beds
Arteriovenous anastomosis
Blood vessel that conducts blood away from the heart; may be a conducting or distributing vessel
Artery
Ability of a vein to distend and store blood
Capacitance
Veins
Capacitance vessels
Smallest of blood vessels where physical exchange occurs between the blood and tissue cells surrounded by interstitial fluid
Capillary
Network of 10-100 capillaries connecting arterioles to venules
Capillary bed
Most common type of capillary, found in virtually all tissues except epithelia and cartilage; contains very small gaps in the endothelial lining that permit exchange
Continuous capillary
Artery with abundant elastic fibers located closer to the heart, which maintains the pressure gradient and conducts blood to smaller branches
Elastic artery
Membrane composed of elastic fibers that separates the tunica media from the tunica externa; seen in larger arteries
External elastic membrane
Type of capillary with pores or fenestrations in the endothelium that allow for rapid passage of certain small materials
Fenestrated capillary
Membrane composed of elastic fibers that separates the tunica intima from the tunica media; seen in large arteries
Internal elastic membrane
Interior of a tubular structure such as a blood vessel or a portion of the alimentary canal through which blood, chyme, or other substances travel
Lumen
Short vessel arising from a terminal arteriole that branches to supply a capillary bed
Metarteriole
Blood flow through the capillaries
Microcirculation:
Artery with abundant smooth muscle in the tunica media that branches to distribute blood to the arteriole network
Muscular artery
Small nerve fibers found in arteries and veins that trigger contraction of the smooth muscle in their walls
Nervi vasorum
Distribution of blood into the capillaries so the tissues can be supplied
Perfusion
Circular rings of smooth muscle that surround the entrance to a capillary and regulate blood flow into that capillary
Precapillary sphincters
Rarest type of capillary, which has extremely large intercellular gaps in the basement membrane in addition to clefts and fenestrations; found in areas such as the bone marrow and liver where passage of large molecules occurs
Sinusoid capillary
Continuation of the metarteriole that enables blood to bypass a capillary bed and flow directly into a venule, creating a vascular shunt
Thoroughfare channel
Outermost layer or tunic of a vessel (except capillaries)
Tunica externa
Innermost lining or tunic of a vessel
Tunica intima
Middle layer or tunic of a vessel (except capillaries)
Tunica media
Small blood vessels located within the walls or tunics of larger vessels that supply nourishment to and remove wastes from the cells of the vessels
Vasa Vasorum
Continuation of the metarteriole and thoroughfare channel that allows blood to bypass the capillary beds to flow directly from the arterial to the venous circulation
Vascular shunt
Constriction of the smooth muscle of a blood vessel, resulting in a decreased vascular diameter
Vasoconstriction
Relaxation of the smooth muscle in the wall of a blood vessel, resulting in an increased vascular diameter
Vasodilation
Irregular, pulsating flow of blood through capillaries and related structures
Vasomotion
Blood vessels that conducts blood toward the heart
Vein
Volume of blood contained within systemic veins in the integument, bone marrow, and liver that can be returned to the heart for circulation, if needed
Venous reserve
Small vessel leading from the capillaries to veins
Venule
