Quiz 1 upper & lower arterial Flashcards
Circulatory system
transportation and distribution of essential substances to tissues and removal of by-products of metabolism
T or F:
veins and arteries at the foot are located distally?
True.
It is suppose to relate to the trunk (heart).
Pulmonary circulation
Right ventricle propels blood to the
lungs for O2 and CO2 exchange. Carries deoxygenated blood from RV to alveoli in lungs Returns oxygenated blood to LA
Systemic circulation
Left ventricle propels blood to all other tissues of the body. Arteries and arterioles carry oxygenated blood from LV to systemic capillaries Veins and venules return deoxygenated blood to RA. All systemic arteries branch from the aorta. Bronchial arteries are also part of systemic
All veins drain into SVC, IVC or coronary sinus
Flow of Blood through the heart
SVC/IVC -> Right Atrium -> Tricuspid Valve -> Right Ventricle -> Pulmonary Artery (to the lungs) -> Pulmonary Veins (4) –> Left Atrium -> Mitral Valve -> Left Ventricle -> Aorta (rest of body)
Pulmonary Trunk
Pulmonary Circulation
Emerges from RV (anterior heart). Passes superiorly, posteriorly and to left
Divides into 2 branches: Rt. and Lt. pulmonary a.
**After birth, PA only arteries to carry deoxygenated blood
Pulmonary veins (n=4)
Exit lungs
Carry oxygenated blood to LA
**After birth, PV only veins to carry oxygenated blood
Intima (tunica intima)
Innermost layer Thin lining of endothelial and elastic fibers
**Most susceptible layer to damage due to direct contact with blood flow (trauma)
Present in all vessels
Media (tunica media)
Middle layer Smooth muscle cells and elastic fibers
Responsible for round shape of arteries
Assists in passively contracting with diastole to propel blood toward heart (
Adventitia (tunica externa or adventitia)
Outermost layer
Longitudinal collagen fibers (fibrous tissue) ! Also contains nerves and vasa vasorum
Vasa Vasorum
Blood supply to the blood vessel itself is from the
vasa vasorum and intima. These are vessels that feed the vessel.Vasa vasorum can only reach so far into vessel. Rest of blood supply to vessel comes from intma. Therefore, any intimal damage decreases blood flow getting to the vessel itself
Arteries
Medium sized arteries Relatively thick walls
Large amount of smooth muscle
Distribute blood to various parts of body
Ex: brachial artery, radial artery
Arterioles
Delivers blood to capillaries
- *Key role in regulating blood flow from arteries to capillaries
- *Change in diameter significantly affects BP. Known as resistance vessels
Vasoconstriction
Contraction of arteriolar smooth muscle Increases resistance
Decreases blood flow to capillaries
Vasodilation
Relaxation of arteriolar smooth muscle Decreases resistance
Increases blood flow to capillaries
Capillaries
Many capillaries arise from each arteriole Connects arterioles to venules (Called microcirculation) Blood flow velocity becomes quite slow in the capillaries
Consist of short tubes with walls one cell thick Thin walls and slow blood flow (Steady Flow). Ideal conditions for exchange of substances between blood and tissues.
Capillary Function
Even though the smallest, capillaries are the most important vessel functionally
Prime function Transport essential materials to
and from cells. Since this occurs at the capillary,
these structures are functionally important
Blood Volume - Systemic
Systemic - 83% Greatest in veins and venules – 67% Capillaries – 5% Aorta, arteries and arterioles – 11%
Blood Volume - Pulmonary
Pulmonary - 17%
Equally divided among arterial, capillary and venous channels
Venules
Several capillaries unite
Collect blood from capillaries and drain into veins
Veins
Distensible to adapt to variations in blood volume and pressure
Cannot stand high pressure Lumen is larger than corresponding artery Collapse under extrinsic pressure
Venous Sinus
Vein with thin endothelial wall, no smooth muscle
Surrounding dense connective tissue replaces tunica media and externa. Examples:
Dural venous sinuses, Blood from brain to heart , Coronary sinus, Main vein of heart
Receives almost all venous blood from myocardium
Fetal Circulation:
Ductus Venosus
Bypasses fetal liver
Fetal umbilical vein to IVC shunt
Nothing to process
Becomes ligamentum venosum
Fetal Circulation:
Ductus Arteriosus
Bypasses fetal lungs
Connects PA to descending aorta
Becomes ligamentum arteriosum
Indirect Testing
Looking at one part of the body to evaluate a
different part of the body
Ex: Pressure testing: sampling the PTA to evaluate the SFA
Direct Testing
The transducer is evaluating whatever is beneath it
Ex: Duplex imaging