Paleopathology: Bone biology

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Del curso dictado por Universiteit Leiden

Osteoarchaeology: The Truth in Our Bones

252 calificaciones

Universiteit Leiden

Osteoarchaeology: The Truth in Our Bones

252 calificaciones

This course is about what we can learn from examining the human skeleton, and how we can use this knowledge to reconstruct the lives of people who lived in the past. In archaeology and anthropology, human skeletal remains can provide unique insights into the past and the present; insights that cannot be gained otherwise. These insights are explored in five main themes spread out over five weeks of learning. First, it is shown how age-at-death, sex and stature can be estimated by the close examination of (archaeological) skeletal remains. In subsequent modules it is shown how human bones can provide information about the diseases and injuries that people suffered from and what they ate. Also, it is shown how the human skeleton provides information about the kinds of activities that people engaged in and about how they migrated and moved around their landscapes. In this course, you will examine all aspects of the human skeleton that can provide us with information about these different facets of life. Together we will explore the scientific field that is known as human osteoarchaeology. - Human, because it is about us and our ancestors, - Osteo, because it is about our bones, - Archaeology, because we use this information to better understand the behaviors and events experienced by past people. During the course, you will decipher the clues left behind in the skeletons of past peoples with the methods and techniques that are presented. You may also discover some clues hidden in your own skeleton and what they reveal about the life that you are living. Want to know more? You can take a look at the course trailer here: https://www.youtube.com/watch?v=fJi22TxzpRw

De la lección

Bones to Disease and Trauma

Welcome to the second module! This week is all about disease in the past. How healthy were people really, and what diseases did they suffer from? We will show you how to answer these questions by studying the diseases that can be detected in human skeletal remains. We specifically focus on trauma including bone fractures, but also the diseases rickets and leprosy.

Paleopathology: Introduction7:02

Paleopathology: Bone biology6:31

Paleopathology: Trauma13:33

Paleopatholgy: Rickets9:29

Paleopathology: Leprosy10:35

Discussion 1, Violence5:06

Discussion 2, Modern Medicine3:02

Conoce a los instructores

Andrea Waters-Rist
Assistant Professor
Faculty of Archaeology

Welcome to the second video of the paleopathology module,

where we will focus on how the skeleton responds to disease and injury.

It's of critical importance in our field that we can determine what

is a pathological lesion and what is not.

Now, this may sound simple, but

it can be very difficult because it requires a lot of experience and

training to become familiar with the full range of normal skeletal variation.

And thus, to have a clear understanding of when something has

crossed the threshold from normal to abnormal.

There's a short fun exercise in the online forum, where you can choose

if a particular trait is pathological or merely a normal skeletal variance.

Take it now,

take it later, even both, to see how you improve after completing this module.

Understanding how the skeleton responds at a cellular level to disease and

injury helps us not only in identifying which disease was present but also, as you

will see, in determining if the disease was active at the time of death or healed.

To understand how bone reacts to disease,

we need to know about the main types of bone cells and what they do,

especially the osteoblasts, which produce unmineralized bone.

Osteoclasts, which break down bone.

And osteocytes, which are embedded within the bone tissue and

serve as the communication network.

Please watch this video which is about how, at a cellular level, your skeleton is

always turning over, called remodeling, for a short illustrative explanation.

Now, you may find there are a lot new terms in these videos,

as well as in the next one.

And to help you, we've created a file that you can find under course

documents with all of the definitions of the terms.

Next, there is another short video that explains what happens when you

break a bone.

Again, consult the definitions list if you get overwhelmed by the terms.

Before moving on to bone and reactions to disease,

I'd like to emphasize one term, which is woven bone, it's also called fibrous bone.

It's the first type of bone that gets laid down at the site of an injury.

Here are few examples.

Because it is laid down very quickly,

woven bone has a disorganized and a porous appearance.

It has an irregular thickness, and it's less dense and

weaker compared to normal cortical lamellar bone.

As the video mentioned, it is this woven bone that first bridges a break, and

it can also form in response to bone infections and even in some cancers.

A bone has only two ways in which it can respond to injury or disease.

There can be bone loss or bone gain.

And both of these responses occur on a continuum from a little to a lot.

For abnormal bone loss, there can be increased osteoclastic activity,

decreased osteoblastic activity, a combination of the first two, and finally,

normal osteoclastic and blastic activity, but a problem with mineralization.

One example of this last mechanism is a congenital condition called

osteogenesis imperfecta.

This is also know as brittle bone disease.

And it's due to an abnormal quantity or

quality of collagen, leading to weak bones that are very prone to fracture.

For abnormal bone gain, there can be increased osteoblastic activity,

decreased osteoclasic activity, a combination of the first two.

And finally, there are diseases with paired increased osteoclastic and

even more increased osteoblastic activity, for example, Paget's disease.

So because bone is limited in the ways it can respond,

it means a lot of diseases will result in similar marks or lesions.

And we call these non-specific disease, or stress markers.

Because we know they're the result of a disease or a stressor, but

we cannot necessarily attribute them to a specific sole cause.

Careful study of the appearance and distribution of the nonspecific

marker within the skeleton may permit us to arrive at its probable cause.

To do this, we consider all lesions and factors, such as the individuals age and

sex, the area and time period in which they lived,

and the prevalence of the lesions in the rest of the population.

This compilation of clues, from as many sources as possible,

is needed to undertake a differential diagnosis.

Wherein, we put forth all possible causes of the lesions and

make a case for which is the most likely.

In paleopathology,

it may never be possible to make a definitive diagnosis, and this is fine.

In this video, you've learned about the bone cells responsible for

bone deposition, resorption, and communication.

How these cells respond to repair a broken bone.

And the limited ways in which bone can respond to disease.

With this knowledge, we can fully understand the upcoming case studies.

First up, is an example of skeletal trauma from the 17th century Netherlands.

Join us to find out more.

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