Q. Resting membrane potential of a neuron?
A. −70 mV
Footnote: Due to K⁺ leak channels and Na⁺/K⁺ ATPase. Skeletal muscle ≈ −90 mV.
Q. When does the aortic valve open?
A. End of isovolumetric contraction
Footnote: LV pressure just exceeds aortic pressure → semilunar valves open.
Q. Primary site of iron absorption?
A. Duodenum
Footnote: Acidic environment keeps iron in Fe²⁺ form for absorption.
While the Duodenum is the primary site, the proximal Jejunum is also significantly involved
Q. Normal CSF pressure?
A. 10–20 cm H₂O
Footnote: <10 suggests low pressure, >25 suggests raised ICP.
Q. Major inhibitory neurotransmitter in spinal cord?
A. Glycine
Footnote: Glycine dominates spinal inhibition; GABA dominates brain inhibition.
Q. Molecule with highest oxygen affinity?
A. Myoglobin
Footnote: Monomeric, no cooperativity, hyperbolic dissociation curve. Myoglobin > HbF > HbA.
Q. Effect of V1 receptor activation?
A. Vasoconstriction
Footnote: V1 → IP₃/DAG → Ca²⁺ release → smooth muscle contraction.
V1 (V1a) Vascular Smooth Muscle IP_3 / DAG Vasoconstriction (increases TPR)
V2 Renal Collecting Ducts cAMP Water reabsorption (inserts Aquaporin-2)
V3 (V1b) Anterior Pituitary IP_3 / DAG ACTH release
Q. Determinant of systolic blood pressure?
A. Cardiac output
Footnote: Systolic BP reflects pump strength; diastolic BP reflects total peripheral resistance.
Q. Vagus-mediated gastric secretion occurs in which phase?
A. Cephalic phase
Footnote: Sight, smell, thought of food → vagal stimulation.
Q. How does myelin increase conduction velocity?
A. Increases membrane resistance and decreases capacitance
Footnote: Prevents current leakage and allows saltatory conduction between nodes.
