Lecture 7

Question 1

Differences between pulmonary and systemic circulation (3)

Answer 1

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

Question 2

Regulation of pulmonary blood flow - affectors (2) and effectors (1) a.k.a. Hypoxic pulmonary vasoconstriction

Answer 2

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

Question 3

Brain regulation of blood flow affector and effect; what other dynamic is active in brain blood flow?

Answer 3

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

Question 4

What is special about the structure of the capillaries in the kidney?

Answer 4

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

Question 5

Hydrostatic pressures inside the kidneys; blood flow through the kidneys

Answer 5

50 at the afferent arteriole, 20 at the efferent; 1.2-1.3 l/min

Question 6

Glomerular filtration rate

Answer 6

180l/day or 125ml/min

Question 7

hepatic circulation is special because

Answer 7

it is connected in series through the portal vein

Question 8

splanchnic bloodflow

Answer 8

1250ml/min ~25% of cardiac output

Question 9

Cirrhosis scarring causes

Answer 9

increased portal hypertension leads to ascites

Question 10

Cutaneous regulation of blood flow/location of apical skin

Answer 10

sympathetic tone controls the skin, which is richly innervated; nose, lips, ears, hands and feet

Question 11

Nonapical skin uses what to increase vasodilation

Answer 11

bradykinin

Question 12

what can you give to a baby with a patent ductus arteriosus before surgery?

Answer 12

cyclooxygenases

Question 13

coronary artery dominance stats (R, L, Neither)

Answer 13

R: 50%
L: 20%
N: 30%

Question 14

names of direct branches to the heart compartments from myocardium

Answer 14

arteriosinusoidal, arterioluminal, thebesian

Question 15

coronary blood flow stats: consumption as a percentage of body mass

Answer 15

0.5% body mass, 3-4% consumption of blood; 10-12% consumption of oxygen

Question 16

tissue pressure in left ventricle and how right ventricular blood flow compares

Answer 16

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

Question 17

sympathetic stimulation of the heart produces

Answer 17

primarily: tachycardia and increased contractility; secondarily: vasodilation
note: sympathetic tone does exist as alpha-adrenergic blockers will further vasodilate the vessels

Question 18

parasympathetic stimulation of heart

Answer 18

you can get vasodilation, but the concommitant decrease in metabolic activity will cause more vasoconstriction than the vasodilation can overcome

Question 19

oxygen extraction in the coronary circulation: efficiency and rate

Answer 19

very efficient: 70% extraction vs. 15% in skeletal muscle; this effect means that the heart must increase flow to increase supply of O2

Question 20

coronary blood supply affectors and effectors (list affectors that cause vasodilation)

Answer 20

affectors
increased pCO2, osmolarity, temperature
decreased pH, pO2

effectors
K channels, prostaglandins, nitric oxide and adenosine

Question 21

oxygen consumption in the heart and heat consumption

Answer 21

6-8 ml/min/100g; 10-12% heat production

Question 22

determinants of oxygen demand by the heart

Answer 22

heart rate, wall tension, contractility

Question 23

three heart oxygen consumption indices

which is used the most?

Answer 23

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

Question 24

acute thrombus (trigger?)

Answer 24

an event can occur if an atherosclerotic plaque buildup bursts and the blood clots around it causing a thrombus derived occlusion of the vessel

Question 25

heart disease and the double

Answer 25

since blood flow to the heart is the only way for the heart to increase blood supply, there is an “ischemic threshold” (which is a double measurement) that causes angina because blood supply is less than the demand

Question 26

treatment of angina

Answer 26

correct the supply/demand imbalance by increasing the supply (vasodilators- calcium channel blockers) or by lessening the demand (beta-channel blockers)

surgeons can use balloons, stents or bypass

Question 27

Prinzmetal’s or Variant angina: definition and treatment

Answer 27

angina caused by coronary spasm, resulting in a severe drop in supply; treatment is calcium channel blockers with or without nitrates