00:01
Which of these is least problematic during normal aging? a, the aging of the bones, b, the aging of the immune system, c, the aging of the nervous system, or d, the aging of the kidneys.
00:16
Okay, let's go through these.
00:17
First of all, bones.
00:18
Bone loss does occur in adulthood, and this is a problem because it makes the bones more fragile.
00:27
So this increases the risk of fractures, and especially in old age, the rest required for healing a fracture can be fatal.
00:36
So this is a problem, so it's not going to be a.
00:39
B, the immune system.
00:41
So the immune system also declines with age.
00:44
The thymus decreases in size, and we get a lot fewer t cells.
00:49
The adaptive immune system slows down, and healing also slows.
00:54
So overall, susceptibility to infection increases.
00:58
Big problem, so it's not going to be b.
01:00
The nervous system.
01:02
So because neurons do not divide, we get a slow loss of the number of neurons throughout life...