Lecture 7 Flashcards
Differences between pulmonary and systemic circulation (3)
1) Lower pressure (93 systemic, 14 pulmonary)
2) Lower resistance (18.2 systemic, 1.8 pulmonary)
3) Pulmonary resistance decreases when cardiac output increases; due to recruitment and distention
Regulation of pulmonary blood flow - affectors (2) and effectors (1) a.k.a. Hypoxic pulmonary vasoconstriction
Affectors - pO2 and pH; drops in either cause the lungs to shift bloodflow to active alveoli
Effectors - shift in the IRK channels causes depolarization and vasoconstriction to the affected area
Brain regulation of blood flow affector and effect; what other dynamic is active in brain blood flow?
pCO2 is the affector - high pCO2 results in vasodilation, low has the opposite effect;
brain also shows increased blood flow to areas that are highly active
What is special about the structure of the capillaries in the kidney?
There are two arterioles in series in the kidneys, first the afferent arteriole which feeds the glomerular capillaries, and then the efferent arteriole which feeds the peritubular capillaries
Hydrostatic pressures inside the kidneys; blood flow through the kidneys
50 at the afferent arteriole, 20 at the efferent; 1.2-1.3 l/min
Glomerular filtration rate
180l/day or 125ml/min
hepatic circulation is special because
it is connected in series through the portal vein
splanchnic bloodflow
1250ml/min ~25% of cardiac output
Cirrhosis scarring causes
increased portal hypertension leads to ascites
Cutaneous regulation of blood flow/location of apical skin
sympathetic tone controls the skin, which is richly innervated; nose, lips, ears, hands and feet
Nonapical skin uses what to increase vasodilation
bradykinin
what can you give to a baby with a patent ductus arteriosus before surgery?
cyclooxygenases
coronary artery dominance stats (R, L, Neither)
R: 50%
L: 20%
N: 30%
names of direct branches to the heart compartments from myocardium
arteriosinusoidal, arterioluminal, thebesian
coronary blood flow stats: consumption as a percentage of body mass
0.5% body mass, 3-4% consumption of blood; 10-12% consumption of oxygen
tissue pressure in left ventricle and how right ventricular blood flow compares
tissue pressure is greatest in left ventricle during systole meaning that blood flow to left ventricle is minimal; ergo left ventricular blood flow happens during diastole; right ventricular blood flow peaks during systole
sympathetic stimulation of the heart produces
primarily: tachycardia and increased contractility; secondarily: vasodilation
note: sympathetic tone does exist as alpha-adrenergic blockers will further vasodilate the vessels
parasympathetic stimulation of heart
you can get vasodilation, but the concommitant decrease in metabolic activity will cause more vasoconstriction than the vasodilation can overcome
oxygen extraction in the coronary circulation: efficiency and rate
very efficient: 70% extraction vs. 15% in skeletal muscle; this effect means that the heart must increase flow to increase supply of O2
coronary blood supply affectors and effectors (list affectors that cause vasodilation)
affectors
increased pCO2, osmolarity, temperature
decreased pH, pO2
effectors
K channels, prostaglandins, nitric oxide and adenosine
oxygen consumption in the heart and heat consumption
6-8 ml/min/100g; 10-12% heat production
determinants of oxygen demand by the heart
heart rate, wall tension, contractility
three heart oxygen consumption indices
which is used the most?
double product, triple product and tension
double = stroke volume x heart rate triple = the above x ejection time tension = pressure - time index
double product used the most
acute thrombus (trigger?)
an event can occur if an atherosclerotic plaque buildup bursts and the blood clots around it causing a thrombus derived occlusion of the vessel
