hello anatomy colleagues this is dr alsup and in this video we will be talking about the
potential effects of aging on bone tissue as well as a very pertinent clinical connection
for this session which is osteoporosis so we have a lot of interesting things to discuss here
as mentioned aging and osteoporosis but also the effects of exercise on bone
i hope as you have been viewing these videos you always come back to
these learning objectives slides and try to answer these questions on your own or more importantly in
your own words if you can do that then you are in such excellent shape for your assessments
so if you haven't yet started doing it get on it and i promise this will be time well spent
in terms of your studying for this course all right so during the time frame of birth
to approximately adolescence more bone tissue is produced than is lost during those natural
processes of bone remodeling or bone formation in younger adults the rate of bone resorption to
and deposition kind of even out and so they're around the same however with increasing age
the rates change due to numerous factors of one of which being a
decrease in the levels of sex hormones and osteoclast activity can really begin to
outpace osteoblasts so this leads to two main effects on osseous tissue with aging adults
the first is going to be loss of bone mass which occurs because of demineralization
or the loss of those appropriate calcium levels or other minerals from the bony extracellular
matrix and this can start to occur as early as 30 in certain individuals particularly women
another major effect of aging is the increase of brittleness in bone due to slowing of
collagen production recall that collagen is the organic material in the extracellular matrix and
is very important in terms of tensile stress strength so with the loss of tensile strength
bones will become brittle and more likely to fracture and sometimes even shatter so all of this
sounds no good right and let's further explore the loss of bone through a specific condition
now osteopenia will equal low bone mass so lower than what you would have in a healthy bone
so this osteopenia will put an individual at an increased risk of osteoporosis and so osteoporosis
is just a condition of overly porous bone or more extreme low bone mass so you can see in a normal
bone you have these trabeculae and of course between the trabeculae you have spaces but in
an osteoporotic bone those spaces will increase and the trabeculae will decrease in terms of size
so this increase of space is going to have a lot of implications in terms of fracture etc
now simply put an individual with osteoporosis
that bone resorption so that bone breakdown will occur at a much faster pace than bone deposition
and this is often due to the depletion of calcium in the body with calcium being
lost too quickly sometimes through urine or sweat than what is taken in by diet
now osteoporosis can affect the entire skeleton but certain bones are more likely to fracture due
to higher concentrations of spongy bone such as the vertebrae carpal bones the ends of the
femur particularly that proximal end of the femur and with severe osteoporosis you can sometimes
see what is referred to as shrinkage of the vertebrae causing increased curvature
and this what's really happening here is you have all these mini fractures
occurring in the bodies of the vertebrae so these are the bodies of the vertebrae these are almost
completely composed of spongy bone except for a layer of compact bone so you'll have a fracture
or multiple fractures within that spongy bone leading to a mini collapse of these
bones which will increase the curvature and can actually lead to height loss with time
another main thing to consider and it could be because of many fractures
is that one of the the main symptoms of osteoporosis is going to be bone pain
osteoporosis mainly affects individuals that are middle aged or of advanced age and there is also
a higher incident rate incidence rate in women than men and this is due to one of two factors
women's bones tend to but certainly are not always but they tend to be smaller than men's so more
likely to have greater effects with bone loss on these smaller bones or comparatively smaller bones
additionally estrogen production tends to slow with earlier ages than testosterone and we
know that sex hormones will initiate osteoblast activity but i want to note that there are other
risk factors such as family history so a family history of osteoporosis certain ancestry such
as european or asian ancestries small body builds just in general so a a male or um any individual
with a smaller body build will just have a higher incidence of or a risk factor for osteoporosis
inactive lifestyles this is a big one as well smoking just to name a few of the risk factors
now knowing what you know regarding the mechanisms that lead to osteoporosis and
what causes osteoporosis what are some areas that you can address
in order to treat osteoporosis so what are some potential ways think of what you can do
or what you can speed up or what you can slow down in order to treat osteoporosis
so i like to so you can pause the video and just kind of brainstorm and i'm not
talking about telling any specific type of drugs but think about what type of
cells you could speed up or slow down and i like to break it down in kind of that way so
um slowing down bone loss or increasing bone building so either one of these the slowing
down of bone loss or the increasing of osteoblast activity this can be done through medicines so
anti-reabsorptive drugs and or bone building drugs that can help inhibit osteoclasts or increase
osteoblast activity and i'm not really going to get into the specific names or types of these
drugs here but there is certainly a plethora that are used for these purposes additionally carefully
and safely incorporating weight-bearing exercise can initiate osteoblasts as well
so that stress and strain that weight-bearing exercise puts on bone tissue will often
initiate that deposition of minerals and production of collagen through the osteoblasts
so those main mechanical stresses on bone result from the pull of muscles when they contract
specifically the skeletal muscle because those are the ones that are attaching to bone as well as the
pull of good old gravity so people of all ages can and should strengthen their bones by engaging in
weight-bearing exercise with of course considering any underlying conditions and making sure you're
safe to do so under a physician's recommendation i am not a physician so make sure you know while
i can talk about the mechanisms that can occur um with osteoblast activity increasing with
exercise you always want to make sure that it's safe to do so on an individual level
now before we finish let's make sure we understand a basic concept from this video
so true or false bone deposition occurs at a faster rate than resorption or bone resorption
in an individual with osteoporosis so pause the video if you don't if you want to think it through
but when you are ready let's discuss how false is the correct answer here it is actually bone
resorption that is going to occur at a faster rate than bone deposition when you're talking
about an individual with osteoporosis so that is a core concept here if you have missed this
i would make sure to review this again and please reach out to me with any questions
thank you for your time and attention here and have a great day