Hydrophilic messengers usually bind to cytoplasmic receptors and affect gene activity. Hydrophobic messengers usually bind to receptors on the cell's surface and activate second messenger systems. Hydrophilic messengers usually bind to receptors on the nuclear membrane and affect gene activity. Hydrophilic messengers usually bind to receptors on the cell's surface and activate second messenger systems. Testosterone always generates male characteristics and estrogen always generates female characteristics.
All arteries carry blood away from the heart.
In the course of the human menstrual cycle, if no fertilized egg arrives, a. the corpus luteum degenerates. 57 Unpainful pressure on the skin causes sensory neurons to depolarize because a. the pressure causes the release of certain chemicals from compressed cells that bind to receptors on the peripheral endings of the sensory cell. Na channels that open when the membrane is deformed. An XY fetus that cannot produce testes determining factor will have a. male characteristics. The ability to locate the source of a sound depends heavily on the comparison of the timing and loudness of the sounds at the two ears.