Blood Vessels Flashcards
The vascular system is made up of
the vessels that carry either blood or lymph fluid through the body: (1) blood circulatory system and (2) lymphatic circulatory system.
The blood circulatory system is composed of
blood vessels.
The blood vessels consist of
arteries (large & small), veins (large & small), and capillaries.
Blood circulates within the blood vessels to where?
throughout the body (moving from the heart to the tissues, and back to the heart).
Blood circulation delivers
oxygen and nutrients to the tissues and takes away tissue waste.
The lymph vessels carry
lymphatic fluid which is a clear, colorless fluid and made of water and blood cells.
The lymphatic system is part of what system?
the immune system
The lymphatic system (func)
helps rid the body of toxins and waste.
How does the lymphatic system fulfill its function?
It does this by filtering and draining lymph away from each region of the body.
The cardiovascular system has
five general classes of blood vessels:arteries, arterioles, capillaries, venules, and veins.
Arteries carry blood
away from the heart.
As the arteries enter ____________, they ___________, and the ___________ in diameter
peripheral tissues, they branch repeatedly, and the branches decrease in diameter.
The smallest arterial branches are called
arterioles.
From the arterioles, blood moves into
capillaries,
what happens at the capillaries
diffusion between blood and interstitial fluid takes place.
From the capillaries, blood enters
small venules,
small venules, which unite to form
larger veins that return blood to the heart.
Blood leaves the heart through
the pulmonary trunk (which originates at the right ventricle) and the aorta (which originates at the left ventricle).
The pulmonary arteries that branch from the pulmonary trunk carry blood
to the lungs.
The systemic arteries that branch from the aorta distribute
blood to all other organs.
Within these organs, the vessels branch into
several hundred million tiny arterioles that supply blood to more than 10 billion capillaries.
The walls of arteries and veins have _______ layers
3
three distinct layers of veins and arteries are (from deep to superficial)
the tunica intima, tunica media, and tunica externa (AKA adventitia).
The tunica intima is the ______ layer of a blood vessel.
inner
tunica intima includes
the endothelial lining and a surrounding layer of connective tissue with a variable number of elastic fibers.
In arteries, the outer margin of the tunica intima contains
a thick layer of elastic fibers called the internal elastic membrane.
The tunica media is the ______ layer of a blood vessel.
middle
The tunica media contains
contains concentric sheets of smooth muscle tissue in a framework of loose connective tissue.
The collagen fibers bind the tunica media to
the tunica intima and tunica externa.
The tunica media is commonly the _____________ layer of the ____________
thickest, artery
The smooth muscle cells encircle the
endothelium that lines the lumen (interior space) of the blood vessel.
The tunica media is separated from the
surrounding tunica externa by a thin band of elastic fibers called the external elastic membrane
external elastic membrane are only in
arterie
The tunica externa, or tunica adventitia, is the ___________ layer of a blood vessel.
outer
The tunica externa, is a
connective tissue sheath.
In arteries, tunica externa contains
collagen fibers with scattered bands of elastic fibers.
In veins, tunica externa is generally
thicker than the tunica media and contains networks of elastic fibers and bundles of smooth muscle cells.
The connective tissue fibers of the tunica externa typically
blend into those of adjacent tissues, stabilizing and anchoring the blood vessel.
Arteries and veins supplying the same region lie
side by side.
Arteries and veins are distinct by
1) Vessel Lumen
2) Vessel Lumen Lining
3) Vessel Walls
4) Veins
Vessel Lumen (arteries)
When not opposed by blood pressure, the elastic fibers in the arterial walls recoil ➠ lumen constriction; (1) the lumen of an artery looks smaller than that of the corresponding vein. (2) The walls of arteries are relatively thick and strong ➠ lumen circular shape.
Vessel Lumen (veins)
veins tend to collapse and appear flattened.
Vessel Lumen Lining (arteries)
The endothelial lining of an artery cannot contract, so when an artery constricts, its endothelium folds. Therefore, the sectioned arteries have a pleated (folded) appearance.
Vessel Lumen Lining (veins)
The lining of a vein lacks these folds
Vessel Walls (arteries vs veins)
In general, the walls of arteries are thicker than the walls of veins.
The tunica media of an artery contains more smooth muscle and elastic fibers than a vein does. These components help resist/absorb the pressure generated by the ventricles as they pump blood into the pulmonary trunk and aorta.
Valves (arteries vs veins)
Veins typically contain valves - internal structures that prevent the
backflow of blood toward the capillaries.
In a vein, the valve appears as a slight extension/fold of the vessel wall.
Arteries do not have valves
There are three main types of arteries:
elastic, muscular, and arterioles.
Arteries relatively thick, muscular walls RESULTS IN
arteries elastic and contractile
Elasticity allows the vessel diameter
diameter to change passively in response to changes in blood pressure ➠ allows arteries to absorb the surging pressure waves that accompany the contractions of the ventricles.
Contractility (arteries)
Arterial walls can actively change diameter. When arteries are stimulated by the nervous system, the smooth muscles within the artery wall contract ➠ constricting the artery—a process called
vasoconstriction. When these smooth muscles relax, the diameter of the lumen increases—a process called vasodilation.
vasoconstriction
the smooth muscles within the artery wall contract ➠ constricting the artery
vasodilation
When these smooth muscles relax, the diameter of the lumen increases
Vasoconstriction and vasodilation affect (3x)
[1] the afterload on the heart (i.e., the resistance of the arteries) [2] the blood pressure, and [3] capillary blood flow.
Vessel contractility is also important during
the vascular phase of hemostasis, when the contraction of a damaged vessel wall helps reduce bleeding.
In traveling from the heart to peripheral capillaries, blood
passes through
elastic arteries, muscular arteries, and arterioles.
Each type of vessel represents the midpoint in a portion of a
continuum. For example,
largest muscular arteries contain a considerable amount of elastic tissue, and the smallest resemble arterioles.
Elastic arteries carry ___________ volumes of blood away from the heart.
large
Which type of arteries are the largest
Elastic arteries
The pulmonary trunk and aorta, as well as their major branches
are (which type of artery?)
elastic arteries.
elastic arteries (structure)
The walls of elastic arteries are extremely resilient because the tunica media contains a high density of elastic fibers and relatively few smooth muscle cells.
elastic arteries (function)
elastic arteries can tolerate the pressure changes of the cardiac cycle. Their expansion cushions the sudden pressure rise during
ventricular systole, and their recoil slows the drop in pressure during ventricular diastole. In this way, elastic arteries help to make blood flow continuous.
During ventricular systole, (elastic arteries func)
pressures rise rapidly, and the elastic arteries expand as the stroke volume is ejected.
During ventricular diastole, (elastic arteries func)
blood pressure within the arterial system falls and the elastic fibers recoil to their original dimensions.
By the time blood reaches the arterioles, the pressure fluctuations
have disappeared, and blood flow is continuous.
Large Vein is located at
Superior and Inferior Venae cavae and their branches
Large Vein have a
thin tunica media and large lumen
Muscular arteries, or medium-sized arteries, distribute blood to
skeletal muscles and internal organs.