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229 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What are 3 things that the CV system supplies?
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-Oxygen
-Metabolic fuels -Heat |
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What are 3 things that the CV system removes?
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-Carbon dioxide
-Metabolic waste products -Heat |
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What is the primary way that the body attempts to maintain a constant MAP (mean arterial pressure)?
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-Neural (Reflex) control through CNS
-There is some Local control exerted as well |
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Are the two pumps in the heart connected in series or in parallel?
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Series
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What is the primary function of the large arteries?
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Pressure storage
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What is the main function of the arterioles?
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Alters resistance to flood flow
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What is the main function of the capillaries?
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Allows exchange of substances between blood and body tissues
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What is the main funciton of the veins?
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Storage of blood volume
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What is the function of the anular ring? Does it conduct electricity?
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-Anchors the heart in the horizontal plane and serves as an electrical insulator.
-No, it's an insulator |
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What are the two motions of the heart during systole?
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-Shortening of heart from apex to base
-Reduction of ventricular diamter -NET EFFECT: WRINGING MOTION |
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What is the main difference between the aorta and other arteries?
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The aorta has more elastic and fibrous tissue and the other arteries have more smooth muscle.
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What is the main difference between a muscular artery and an arteriole?
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Arterioles have less elastic tissue and smooth muscle.
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What is the main difference between venules and veins?
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Venules are just fibrous tissue but veins have elastic tissue and smooth muscle
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What is the blood pressure in the RA?
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0-5 mmHg
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What is the blood pressure in the RV?
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25/5 mmHg
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What is the blood pressure in the PA?
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25/10 mmHg
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What is the blood pressure in pulmonary capillaries?
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9 mmHg
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What is the blood pressure in the pulmonary veins?
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6-8 mmHg
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What is the blood pressure in the LA?
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5-8 mmHg
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What is the blood pressure in the aorta?
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120/80 mmHg
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What is the blood pressure in a systemic capillary?
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20 mmHg
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What is the blood pressure in a vein?
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2-6 mmHg
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In what kind of vessels does the largest drop in BP occur?
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Arterioles (drops 2/3)
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What is the relationship between flow, pressure, and resistance?
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P=QR
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Systemic vascular resistance=_____________
(In terms of CO and pressure) |
Systemic vascular resistance = (MAP-RA pressure)/CO
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Pulmonary vascular resistance =___________
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Pulmonary vascular resistance = (PA-LA)/CO
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What part of the vasculature is the resistance greatest?
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Arterioles with a lumen diameter <50 microns
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What is the relationship between blood velocity, cross-sectional area, and flow?
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Velocity (cm/sec) = Flow (cm^3/sec) / Cross-sectional area (cm^2)
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Where is the blood velocity the lowest? HINT!!!
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In the capillaries
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Where is the cross-sectional area the greatest?
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What percentage of the blood is in the veins at any one time?
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66%-75%
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What part of the body drains into the lymphatic duct?
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-Left side of body above diaphragm
-All of body below diaphragm |
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What part of the body drains into the right lymphatic trunk?
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-Right side of the body above the diaphragm
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What is the function of pericytes?
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Mesenchymal-like cells that may become fibroblast or smmooth muscle cells.
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What germ layer does the endothelial lining of the circulatory and lymphatic system come from?
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Mesoderm.
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What is the difference between vasculogenesis and angiogenesis?
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-Vasculogenesis occurs during 3rd week of development in the embryo
-Angiogenesis in sprouting of new capillaries from pre-existing capillary network |
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What are the 3 layers of the blood vessel?
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Tunica intima
Tunica media Tunica adventitia |
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What layer of blood vessels:
"Secrete von Willebrand factor and cytokines and other clotting factors" |
Tunica intima
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What layer of blood vessels:
"Contains macrophages and pericytes. Composed of loose connective tissue" |
Tunica intima
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What layer of blood vessels:
"Contains the internal elastic lamina" |
Tunica intima
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What layer of blood vessels:
"Layers of smooth muscle or elastic fibers arranged circularly. Also has Type III collagen, proteoglycans, and glycoproteins." |
Tunica media
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What layer of blood vessel:
"Contains longtitudinal Type I collagen, elastic fibers and fibroblasts." |
Tunica adventitia
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What is described:
"The blood vessels supplying large blood vessels with thick walls." |
Vaso vasorum
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What kind of blood vessel primarily controls blood systemic BP and systemic vascular resistance?
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Arterioles
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What type of blood vessels can develop into a pre-capillary sphincter?
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Arteriole
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What type of blood vessels can develop into metarterioles?
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Arterioles
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What is a short vessel(s) that link arterioles and true capillaries?
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A metarteriole
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What is the function of a precapillary sphincter?
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Control blood flow through capillary beds
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What are two functions of pericytes?
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-Regulatory fx
-Healing fx |
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What is the difference between the continuous capillaries found in the brain and everywhere else?
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-Brain "tight" tight junctions for blood brain barrier
-Everywhere else "leaky" tight junctions |
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What are the two types of fenestrated capillaries and where are they found?
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-With and without diaphragms.
-Endocrine glands, intestines, and pancreas WITH diaphragms -Kidneys WITHOUT diaphragm |
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What is the function of fenestrated capillaries?
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-Allow diffusion of some proteins.
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Where would you find discontinuous capillaries? What are their function? HINT!!!
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-Spleen, bone marrow, liver
-Allow exchange of large particles and cells (eg RBC's) to pass. |
Also called sinusoidal capillaries.
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What blood vessels (be specific!) are the acting site for histamine and serotonin to allow extravasation of fluid?
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Postcapillary venules
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Where is ANF produced? HINT!!!
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Atrial cardiac muscle cells
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Atrial natiuretic factor
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What are the 3 layers of the heart?
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-Endocardium
-Myocardium -Epicardium |
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What layer of the heart:
"Contains the impulse conducting system of the heart" |
Endocardium
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What layer of the heart:
"Thick, complex spiraling layer of cardiac muscle cells" |
Myocardium
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What layer of the heart?
"Contains connective tissue, blood vessels, nerves, and adipose tissue" |
Epicardium
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Which of the 4 basic tissue types makes up the cardiac conducting system?
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-Muscle
-"Modified cardiac muscle cells" |
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What makes the collagen and elastic made found around the muscle cells of the elastic arteries?
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Smooth muscle cells
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What basic tissue type lines all of the blood vessels and the heart?
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Epithelium
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When depolarization spreads through the myocardium, Ca2++ channels in the t-tubule (an evagination of the lipid bilayer) open and cause the opening of RyR channels that dump large amounts of Ca2+ from the SR. What is this mechanism called?
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Calcium-induced calcium release.
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What is the the main differencec between cardiac muscle contraction and skeletal muscle contraction in regards to Ca2+?
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-Skeletal muscle can contract from just an electrical impulse (release Ca2+ from its SR)
-Cardiac muscle NEEDS extracellular Ca2+ for calcium-induced calcium release through RyR channels. |
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What does increased stretch (preload) improve cardiac function?
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Opens more binding sites for Ca2+
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What "line" of the cardiac cell?
"End of sarcomere; site of intercalated disc, insertion of thin filament; site where T-tubule, Ca channel, and SR meet" |
Z Band
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What prevents actin and myosin from forming crossbridges in the absence of Ca?
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Tropomysin is blocking the binding site of actin
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What does Ca bind to in order to expose the binding site on actin?
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Ca binds to troponin which changes the configuration of tropomysin to expose the Ca binding site on actin.
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What is the thick filament in cardiac muscle?
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Myosin
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What is the thin filament in cardiac muscle?
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Actin
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What band/line is just thin fibers in cardiac muscle?
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I band (crosses sarcomeres)
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What band/line is just thick fibers in cardiac muscle?
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H zone
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What band/line contains overlapping thick and thin fibers in cardiac muscle?
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A band (H zone is centered within A band)
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What band/lines get thinner when the cardiac muscle contracts?
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I band and H zone
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What band/lines get thicker with contraction of cardiac muscle?
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The A band
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What causes the "power stroke" of the myosin head?
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The release of ADP/Pi and Mg from the myosin head.
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How do positive ionotropes (catecholamines such as isoproterenol or norepi) augment the contractile state?
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Inceasing the amount of Ca available to the actin/myosin complex
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During diastole, what removes the Ca from the cytoplasm?
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-75% is removes via the SERCA pump (SR-Ca-ATPase) whicch requires ATP
-25% goes out passively via a Na+ antiporter (3Na:1Ca). |
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What is the "tension in wall of ventricle prior to contraction"?
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Preload (affected by end diastolic volume)
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What directly causes the increase in cardiac output seen during exercise?
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Increased venous return (resulting in increased preload)
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What is "the pressure in the ventricular wall during systole"?
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Afterload (falls as blood is ejected). Laplace's Law: radius is shrinking wall is getting thicker.
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What effect does increased afterload have on ventricular performance?
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Degrades ventricular performance by increasing the time of isometric contraction (delaying ejection), reducing the velocity of shortening (slowing ejection), and decreases the extent of shortening (lower SV).
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What are the 4 major variables affecting cardiac output?
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-Preload
-Afterload -Heart Rate -Contractility |
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Both cardiac muscle and skeletal muscle increase contractility by increasing the frequency of stimulation. How else do 1) cardiac and 2) skeletal muscle increase contractility?
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1) Cardiac muscle increases the amount of Ca2+ available via beta-adrenergic receptors
2) Skeletal muscle recruits additional fibers |
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Beta-adrenergic stimulation by isoproterenol affects which component of contractility?
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-Contractility
-Maybe also heart rate? |
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What are 4 effects of exercise on the heart?
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-Increase preload (improved venous return)
-Decrease afterload (vasodilation) -Sympathetic (beta-adrenergic) stimulation -Increased HR |
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What are the effects of ACh on ion channels in the sinoatrial node?
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-Decreases Na+ permeability
-Decreases Ca2+ permeability -Increases K+ permeability -HYPERPOLARIZATION |
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What are the 3 ways that parasympathetic stimulation slows the heart rate?
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-Pacemaker potential starts more negative
-Depolarizes more slowly -Has to depolarize farther to reach threshold |
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What are the effects of norepinephrine on ion channels in the sinoatrial node?
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-Increases Na+ permeability
-Increases Ca2+ permeability -Decreases K+ permeability -DEPOLARIZATION |
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What is the formula for electrical potential between two terminals?
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Positive terminal - negative terminal
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Are the depolarization and repolarization vectors in the same direction for cardiac muscle?
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Yes, always from direction of negative-->positive electrical potentials measured outside the cell (Lec 13:19)
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Is the AV node capable of bidirectional conduction?
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No, only antegrade conduction is possible
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What are the 3 lead systems of an EKG? Which is bipolar?
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-Bipolar limb leads
-Unipolar augmented limb leads -Unipolar precordial leads (chest leads) |
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What valves are open during isovolumetric contraction?
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None!
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Are the ventricles functioning as pumps connected in parallel or in series?
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Series
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During ventricular systole, what valves are open?
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Aortic and pulmonic
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What valves are open during isovolumetric relaxation?
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None!
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What valves are closing during S2?
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Aortic and Pulmonic
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What heard sound would be heart while observing the dicrotic notch?
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S2 (closure of aortic valve)
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Rapid ventricular filling occurs during the first 1/3 of systole. Then comes ________. Finally, the atrial kick provides the final 25% of ventricular volume.
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Diastasis is the period of relatively little ventricular filling.
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What causes the pressure change of the "a" wave in the atria?
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Atrial contraction
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What causes the pressure change of the "c" wave in the atria?
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Backward bulging on the AV valves
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What causes the pressure change of the "x" descent in the atria?
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Ventricular emptying causes a fall in thoracic pressure and volume which causes atrial pressure to fall as well.
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What causes the "v" wave on the pressure tracing of the atria?
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Continued inflow of blood from the veins while AV valves are closed.
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What causes the "y" descent on the pressure tracing of the atria?
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The opening of the AV valves allowing rapid draining of the atria. Next will follow diastasis and finally the "a" wave as the atria contract.
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You can also observe intracardiac events by measuring pressure in the jugular vein. What corresponds to the "a" wave?
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Atrial contraction
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You can also observe intracardiac events by measuring pressure in the jugular vein. What corresponds to the "c" wave?
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Bulging of the tricuspid valve backward during ventricular contraction
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You can also observe intracardiac events by measuring pressure in the jugular vein. What corresponds to the "v" wave?
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Filling of the atria from venous blood while AV valves are still closed.
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Given an end diastolic volume of 110mL and an end systolic volume of 40mL, what is the ejection fraction?
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(110-40)/110=63.6%
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What could cause an S3 sound to be heard?
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May be normal in younger people and trained athletes but may be caused by heart failure in older patients.
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What can cause you to hear an S4 heart sound?
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The atrial kick into a stiff ventricle.
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What valves are attached to papillary muscles and then to chordae tendinae?
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Mitral and tricuspid
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What valves close passively?
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The semilunar (aortic and pulmonic)
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What is the function of the papillary muscles?
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Prevent the AV valves from bulging backward into the atria.
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Which valves have higher velocity (smaller diameter) and snappier closing?
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Semilunar valves
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Which valves closes first, mitral or tricuspid?
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Typically the mitral
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Which valve closes first, aortic or pulmonic?
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Typically the aortic
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What is "delta P" in the equation Q=(delta P)/Restistance? Give the formula for systemic and pulmonary circuits.
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"Delta P":
-MAP - Right Atrial Pressure -Mean PA pressure - wedge pressure (left atrial pressure) |
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What is the formula for pulmonary perfusion pressure?
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Mean PA pressure - Left atrial pressure (simple "Delta P" in the Magic Triangle)
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What is the formula for total resistance through a parallel system?
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1/total R = 1/R1 + 1/R2 + 1/R3
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What is the formula for total resistance through a series system?
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Total R = R1 + R2 + R3
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What is an example of a physiologic parallel system of resistances?
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Most of the body!
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What is an example of a physiologic series system of resistances?
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GI tract and kidney
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What is the formula for compliance?
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Delta V/Delta P
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What is the mean systemic filling pressure?
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The driving pressure in the venous system that returns blood to the right atrium.
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What effect does angiotensin have on aldosterone?
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Angiotensin stimulates secretion of aldosterone. Recall that angiotensin is there to raise blood pressure and aldosterone also works to raise blood pressure by hanging onto Na+ and therefore volume.
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What is the formula for cardiac index?
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Cardiac index = CO/BSA
BSA in M^2 |
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What is the difference between contractility and inotropic state?
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Contractility more accurately describes effects in vivo because it takes into account both preload and afterload
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On a graph of ventricular pressure vs time, how do you identify the contractility of the ventricle?
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It's the slope of the line
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There are two factors that can increase cardiac work. Which requires more energy?
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Pressure work requires more energy and more oxygen.
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What is one example of increasing "volume work"?
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Dynamic exercise increases SV, HR, and CO
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What are 3 factors that influence the post diastolic volume?
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-Preload (filling pressure)
-Filling time -Compliance of the chamber (=V/P) |
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What are two methods by which the heart intrinsically regulates itself in response to changing venous volumes?
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-Frank-Starling mechanism
-SA node frequency in response to atrial stretch |
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Where does sympathetic innervation primarily occur? What neurotransmitter and what receptor is utilized?
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-Ventricles
-Norepinephrine binds to beta-adrenergic receptors |
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What does parasympathetic innervation primarily occur? What neurotransmitter and what receptor are utilized?
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-SA node and AV conduction tissue
-Acetylcholine binds to muscarinic receptors |
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What does the right vagus nerve primarily innervate? The left vagus?
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-SA node
-AV conduction tissue |
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What are 2 potential causes of turbulent blood flood?
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-Branching of a vessel
-Plaque |
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At what hemoglobin values should you begin to worry about blood flow?
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Hemoglobin >60.
Especially in NICU patients |
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True or false:
Gas exchange occurs in small arterioles, capillaries, and small venules |
True
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What causes the discontinuous flow of blood through the capillaries?
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Precapillary smooth muscle rhythmic contractions. This can increase when metabolic needs are higher
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Where are fenestrated kidneys found?
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Kidney and intestine
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Where are discontinuous capillaries found?
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Spleen, liver, bone marrow
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What type of capillary bed is the blood brain barrier?
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Continuous
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What are 4 factors that change diffusion?
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-Size
-Charge -Solubility -Capillary permeability |
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The net force of the fluid force in the capillaries is out of the cell. What happens to this fluid?
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Lympatics take up the filtered fluid that is not reabsorbed
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What is the function of the anchoring filaments in the capillaries of the lympatic system?
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They tether the walls of the capillaries to the extracellular matrix to prevent collapsing and enhance filling of the lymphatic capillaries. They help to draw in fluid, acting like a sponge.
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What are 2 substances that change the permeability of capillaries resulting in edema?
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-Kinins
-Histamine |
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What is-
"A transverse plane through the 4th ICS (at the level of the right atrium); the standard reference point to measure venous pressure in the body" |
The phlebostatic axis.
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What is the static function of the venous system?
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Stores blood. Measured by compliance= V/P
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What is the compliace of the venous system as compared to the arterial system?
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About 30 times greater!
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Is volume expansion better accomplished during stressed or unstressed state?
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Stressed state so that the blood goes to increase BP faster
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What is the dynamic function of the venous system?
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Regulate the return of the blood to the heart
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How do you increase or decrease the mean systemic filling pressure?
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Increase or decrease blood volume.
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In the absence of a Swann catheter, what can you use to estimate contractility of the heart?
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Pulse pressure
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Would you find the pale staining, conductive cells of the heart towards the inside or outside of the heart?
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Insides (towards the chamber)
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How can you tell the difference between Purkinje cells and standard cardiac muscle cells.
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Purkinje cells are larger and paler staining than standard cardiac muscle cells
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What secretes the extracellular matrix?
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The smooth muscle cell
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What determines the maximum velocity of Phase 0 of contraction as well as conduction velocity?
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The number of Na+ channels available
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Are there fast Na channels in nodal tissue?
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NO!
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Does the PR interval change during exercise?
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Yes! Conduction through the AV node is sped up by catecholamines but slowed down by vagal stimulation
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What is:
"early stimulation (I.e. faster rate) results in smaller, slower AP due to reduced Ca channel availability" |
Decremental Conduction in the AV node
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Are Ca channels or Na channels more susceptible to catechoamines?
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Ca channels
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What "kicks in if the sinus node fails or the AV node fails"?
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Subsidiary pacemaker cells
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What is it called when the spontaneous impulses of the AV node is overridden by the SA node?
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Overdrive suppression
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What does decreased potassium cause?
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-Prolongs QT interval
-Arrhythmias (Na and Ca channels can partial recover and re-open, causing a secondary AP) |
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What frequently causes atrial flutter?
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Reentry impulse going around and around the tricuspid valve.
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What is another name for a reentrant tachycardia?
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Circus movement
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What are the 3 conditions necessary for a reentry tachycardia?
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-Heterogeneous refractoriness
-Slow conduction -Unidirectional block |
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What is the difference between anatomic reentry and functional reentry?
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-Anatomic - fixed structure with a stable rate and EKG (atrial flutter or WPW)
-Functional - Diffuse abnormalities cause a moving area of temporary block (a fib, v fib, torsades) |
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What are the 2 causes of bradycardia?
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-Failure of impulse formation (vagal, ischemia, drugs)
-Failure of impulse conduction (heart block) |
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What do the mechanoreceptors in the carotid sinus respond to?
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Stretch- this is significant because a stiffer carotid will allow greater pressure without stretching so the baroreceptors won't be stimulated.
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What is the carotid body sensitive to?
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It's a chemoreceptor sensitive to changes in blood composition (pH, CO2, O2, etc)
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Which cranial nerve carries impulses from the carotid sinus to the brainstem?
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CN IX
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What are the 3 efferent systems to achieve homeostasis in the cardiovascular system?
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-Sympathetic
-Parasympathetic -Endocrine |
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Where is the vasomotor center (Guyton's) located?
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Pons and medulla
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What effect does sympathetic stimulation have on the venous system?
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-Decreases compliance
-Decreases volume |
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What effect does sympathetic stimulation have SVR (in the arterioles)
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Increases vascular resistance
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What effect does epinephrine have?
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Increase HR
Increase contractility |
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What effect does norepinephrine have?
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Constrict blood vessels
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What effect does angiotensin have?
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Constrict blood vessels
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What effect does vasopressin have?
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Constrict blood vessels
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Where are the atrial mechanoreceptors found?
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Both left and right atria
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When do Type A atrial stretch receptors fire?
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During atrial contraction (A wave of atrial pressure graph)
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When do Type B atrial stretch receptors fire?
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During atrial diastole (V wave of atrial pressure graph)
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What is the difference between atrial baroreceptors and arterial baroreceptors?
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-Atrial baroreceptors are sensitive to low pressures (0-15 mmHg) and small pressure changes whereas arterial baroreceptors are sensitive to higher pressures (50-150 mmHg).
-Arterial baroreceptors output to the brainstem while atrial baroreceptors output to the hypothalamic-pituitary pathway and effect release of vasopressin/ADH. |
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What are the short and long term responses to vasopressin (ADH)?
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Short term- vasoconstriction
Long term- inhibit urine formation to increase volume |
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What happens if arterial blood pressure to the brain falls lower than 40mmHg?
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Vasoconstriction and increased heart rate
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What happens if CSF pressure gets within 30-40 mmHg of MAP?
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Vasoconstriction and bradycardia (Cushing Response)
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What happens with the "Diving Reflex"?
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-Vasoconstriction and bradycardia
(Trigeminal stimulated --> brainstem --> Vagus response |
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Describe the pathway when BP decreases.
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-Baroceptor output decreases
-Increase in sympathetic output from CNS and decrease in parasympathetic output from CNS -Increase in CO and SVR |
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Describe the pathway when BP increases.
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-Increase in baroreceptor output
-Decrease in sympathetic output from CNS and increase in parasympathetic output from CNS - |
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What is the difference between neural control and local control of blood flow?
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Neural control-needs of whole body-vasoconstriction of arterioles
Local control-needs of individual organ-vasodilation of arteries and arterioles |
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What is described:
"After sympathetic innervation is removed, blood vessel will initially dilate and then constrict to original flow levels" |
Basal tone
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What is described:
"Organ/tissue's ability to maintain constant blood flow in the face of a change in perfusion pressure" |
Autoregulation
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There are two theories of autoregulation- myogenic and metabolic. What are the 2 subtheories under myogenic?
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-Change in ionic permeabilities
-Endothelium hypothesis with NO (vasodilator) and some unknown vasoconstrictor |
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What are several potential vasodilators proposed by the metabolic theory of autoregulation?
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-Adenosine
-Hypoxia -K+ -H+ -CO2 -Osmolality |
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What is the difference between functional hyperemia and reactive hyperemia?
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-Functional hyperemia is when blood flow changes in response to changing metabolic demand
-Reactive hyperemia is when blood flow increases after a period of restriction to "pay back" the O2 debt. Areas under the curves should be equal. |
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What are the relative pressures in Zone 1?
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PA>Pa>PV
PA=Alveolar Pa=arterial PV=capillary/venous pressure |
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What is the effect of atelectasis on pulmonary circulation? Hyperexpansion?
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Both cause increased vascular resistance
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What happens during segmental hypoxia?
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-Blood vessels constrict causing shunting of blood to well oxygenated areas of the lung. Can restrict flow almost down to zero for small segments.
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What happens during diffuse hypoxia?
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Vasoconstriction of whole lung causes pulmonary hypertension
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What crosses the blood brain barrier by diffusion alone?
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CO2
O2 Lipids |
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What effect does hyperventilation have on ICP?
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Hyperventilation decreases ICP (decreased CO2 causes vasoconstriction thereby reducing ICP)
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What effect does CO2 have on cerebral circulation?
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Increased CO2 increases blood flow
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Do H+, K+, and adenosine cross the blood brain barrier?
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NO! Therefore the brain can't see what's happening in the blood. Rather, it can only see what's happening in the CSF.
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What are 2 functions of the endothelium in the brain?
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-Produces NO
-Forms blood brain barrier |
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Where do you find sympathetic (adrenergic) innervation in the brain?
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Pial and Circle of Willis vessels but they have MINIMAL effect
NEURAL CONTROL OF BRAIN MINIMAL |
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Where do you find parasympathetic (cholinergic) innervation in the brain?
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Pial vessels only but there is NO known function
NEURAL CONTROL OF BRAIN MINIMAL |
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From whence doth the coronary arteries arise?
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From the aorta just beyond aortic valve
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What are "conduit vessels"?
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Large arteries and veins
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What are "resistance vessels"?
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Precapillary arterioles
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What are "exchange vessels"?
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Capillaries
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What are "capacitance vessels"?
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Venules
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The heart can't do anaerobic metabolism and can't extract more O2 from the blood than normal so what is the only way that the heart can increase the amount of O2 that it gets?
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Increase blood flow
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How does heart failure develop?
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-Decreased muscle fiber shortening in systole
-Decreased muscle fiber relaxation in diastole |
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What stage of ischemic stress:
10sec-10 minutes |
Acute
Fully reversible |
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What stage of ischemic stress:
10min-10hours |
Subacute
Slowly reversible and irreversible |
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What stage of ischemic stress:
over 10 hours |
Sustained
Very slowly reversible and irreversible |
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What are the most important determinants of myocardial O2 consumption?
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SBP and HR
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What is the most important influence controlling coronary blood flow?
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Metabolic regulation of microvessels to adust coronary vessel tone.
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Does most coronary blood flow occur during systole or diastole?
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Diastole
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What effect does "shear force" have on coronary blood flow?
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Increasing shear forces causes a release of NO, a vasodilator.
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Why is intramyocardial pressure important to consider when considering the O2 demands of the heart?
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Intramyocardial pressures in the LV are high enough during systole to halt most coronary blood flow. Therefore flow through coronary arteries occurs during diastole.
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The biggest influence on coronary blood flow is the release of metabolic substrates. What are some of those substrates?
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-NO
-Prostacyclin -Adenosine |
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What changes in coronary occlusive disease to affect coronary blood flow?
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Usually conduit vessel resistance is small relative to microvessel resistance. However, in pathologic states, the microvessels dilate more to compensate until they're fully dilated. At that point, the coronary blood flow is largely dependent on blood pressure. This leaves the heart particularly vulnerable to low BP
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What are 3 ways that pulmonary vascular resistance is decreased at birth?
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-Gradual decrease over last trimester
-Drastic decrease when lungs are expanded at irth -Increase in O2 at birth causes local production of NO (potent vasodilator) |
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What 4 things causes the ductus arteriosus to close?
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-Increase in O2
-Decrease in CO2 -Increase in pH -Decrease in prostaglandins |
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What is the mechanism for HTN with pheochromocytoma?
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Increased catecholamines
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What is the mechanism for HTN with primary aldosteronism?
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Increase in aldosterone --> reabsorption of Na+ and water
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In primary HTN, where is BP increased?
-Arterial pressure? -Capillary pressure? -Venous pressure? |
Only arterial pressure
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