What is the half-life of the radioactive isotopes? a. a radioactive isotope decreased to one-half its original amount in 18 months.

answer: the blood-brain barrier is a layer of specialized membranes and cell processes designed to keep undesirable substances from passing from the bloodstream into the precious tissues of the brain. while the blood-brain barrier does keep most bad things out of the central nervous system, it is not impermeable.

explanation:

homeostasis is the tendency towards a relatively stable equilibrium between interdependent elements, especially as maintained by physiological processes. and this is how it applies to the integumentary system. back to top. skin functions in homeostasis include protection, regulation of body temperature, sensory reception, water balance, synthesis of vitamins and hormones, and absorption of materials. when body temperature falls, the sweat glands constrict and sweat production decreases.