Which of the following situations could result in maternal antibodies attacking fetal blood cells during a second pregnancy?

a) Lumen of follicle: Iodide is actively transported into follicular cells, then secreted into the follicular lumen, where it becomes oxidized and incorporated into thyroglobulin during the synthesis of thyroid hormones (T3 and T4).

b) Secretory vesicles inside follicular cells: These vesicles may contain thyroglobulin, but iodide is concentrated in the lumen for hormone synthesis.

c) Golgi apparatus of parafollicular cells: Parafollicular (C) cells produce calcitonin, not thyroid hormones.

d) Cytoplasm of follicular cells: While iodide is transported into the cytoplasm briefly, its major functional location is in the lumen.

a) The location of the tissue or organ with respect to the circulatory path: Hormones are carried through the entire bloodstream, so all tissues are exposed. Proximity doesn’t determine responsiveness.

b) The membrane potential of the cells of the target organ: Membrane potential may affect nerve impulse conduction, but not hormone specificity.

c) the presence of the appropriate receptors on the cells of the target tissue or organ: Hormones act only on target cells that express specific receptors for them. No receptor = no response.

d) All hormones stimulate any and all cell types because hormones are powerful and nonspecific: Hormones are highly specific and only act on cells with matching receptors.