Vascular System and Regional Circulation I is part of the The Cardiovascular System section of Physiology. Practise 28 exam-style MCQs for NEET PG, FMGE, INI-CET and NEET SS, each with the correct answer and a detailed explanation.
Veins as capacitance vessels, the inverse-square velocity rule, pulmonary vascular resistance mechanisms and the 2% bronchial circulation share headline these Vascular System and Regional Circulation I MCQs, which test regional circulation as high-yield NEET PG practice.
Veins have the capacity to store large amount of blood- "Capacitance vessels" They have less elastic tissue and less smooth muscle in their walls Reference: Ganong, 25th edition page.567
Velocity is inversely proportional to the square of radius V∝l/r 2 So, if the diameter is reduced to half, velocity increases by four times Reference: Ganong, 25th edition page no.571
Increasing cardiac output or pulmonary artery pressure causes pulmonary vascular resistance (PVR) to passively decrease due to two mechanisms-distention of the perfused vessels, and recruitment of more parallel vascular beds. At high lung volumes, the pulmonary capillaries ("alveolar" vessels) are stretched and compressed causing an increased PVR. At low lung volumes, the "extraalveolar" blood vessels are compressed, increasing PVR. The lowest PVR occurs near FRC. Decreasing PO2 or increasing PCO2 or H+ concentration causes PVR to rise. The sympathetic nervous system has little effect on PVR under physiologic conditions, but experimentally, stimulation of sympathetic nerves will constrict the pulmonary vessels, causing increased PVR. Reference: Ganong, pp 661-664. Levitzky, pp 92-107.
Bronchial circulation supplies oxygenated blood to the lungs through bronchial arteries Bronchial circulation constitutes about 2% of the cardiac output Bronchial arteries supply lung till the level of terminal bronchioles Bronchial circulation doesn't contribute to gaseous exchange Reference: Ganong, 25th edition page no.637
DLCO is increased in polycythemia Reference: Ganong, 25th edition page no.639
With the first diaphragmatic respiration in extrauterine life, the lungs replace the placenta as the organ of gas exchange and the infant's PaO2 increases, which attenuates the hypoxic pulmonary vasoconstriction present in the fetus, causing pulmonary vascular resistance and pressures to decrease. The increased PaO2 constricts the systemic vessels, and, coupled with elimination of the placental circulation, which contributes 40% of the cardiac output in the fetus, results in a rise in systemic vascular resistance. Five of the six vascular channels functionally close at birth, but the ductus arteriosus remains open normally for ~48 hours (though ductal flow is reversed from that in fetal life). Reference: Ganong, pp 628-629.
Bile acids are absorbed in ileum as a part of enterohepatic circulation Reference: Ganong, 25 th edition page no. 478
In circulation, testosterone binds with, Gonadal steroid - binding globulin (GBG) or Sex Hormone-binding globulin (SHBG) - 65% Albumin-33% So, The decrease in sex hormone binding globulin (SHBG) will have maximum effect on testosterone. Reference: Ganong, 25th edition Page no.417
Veins as capacitance vessels, the inverse-square velocity rule, pulmonary vascular resistance mechanisms and the 2% bronchial circulation share headline these Vascular System and Regional Circulation I MCQs, which test regional circulation as high-yield NEET PG practice.
MedLadder includes 28 curated MCQs for Vascular System and Regional Circulation I under Physiology (The Cardiovascular System), covering NEET PG, FMGE, INI-CET and NEET SS preparation.
