Full transcript
0:01uh good morning everyone hope you're
0:03doing all fine
0:05i am gerald b herron a micro hsb
0:08professor and i am tasked to deliver a
0:12lecture on bones and cartilages
0:17at the end of this lecture
0:19these are our intended learning outcomes
0:21to differentiate the types of bone to
0:24describe the different types of osteon
0:26cells
0:27discuss the aversion system or
0:31the osteon to differentiate the types of
0:34cartilages its trauma and its growth and
0:37to discuss the common clinical
0:39conditions affecting the bones and
0:41cartilages
0:44right let's talk about the bone first
0:47as generally speaking when you say bone
0:49the functions are the following it
0:51provides us solid support
0:54protects us the vital organs especially
0:56the ribcage protecting our lungs
0:58and heart and also the brain not the
1:01skull
1:02or the cranial bones protecting our
1:04brain it is also served as an attachment
1:06for muscles
1:07tendons and ligaments and it also acts
1:11as levers
1:13bones also is a reservoir of different
1:16types of ions such as calcium phosphate
1:20and other ions in our body
1:23but before we discuss the bond itself
1:25let's talk about the cells
1:28in the bone
1:29all right the first one is the osteo
1:31progenitor cells when we say
1:34osteoporosis or cells they are
1:36undifferentiated cells that are that are
1:38capable of mitosis
1:41uh this is also known as your
1:43mesenchymal bone cells okay also present
1:46ourselves
1:47are also known as your mesenchymal stem
1:50cells
1:51they have the potential to proliferate
1:54and different shape into the next type
1:56of bone cell which is
1:58your osteoblast
2:00and also this type of poster progenitor
2:03cells they have role in bone growth and
2:06repair
2:09next would be the osteoblast or the bone
2:12forming cells basically their function
2:15is to synthesize
2:17what is known as your osteoid that is
2:20the organic component of the bone matrix
2:23so
2:24in other words osteoblast bone formation
2:27okay also blessed
2:29osteoid synthesis
2:31now the osteoblasts are found at the
2:33lining surfaces of the bone matrix
2:37and there are two types of osteoblast we
2:40have an active
2:41osteoblast and you have inactive
2:44osteoblast the main difference is that
2:47look at the shape of the cell they are
2:49both osteobus but
2:51the active osteoblasts are cuboidal or
2:54columnar in shape while your inactive
2:57osteoblasts are squamous or flat cells
3:04okay like in this illustration
3:07um if you look closely in the um
3:11characteristics of your awesomeness
3:13daylight
3:15okay they are found at the lining now
3:18these are all osteoblasts the main
3:21difference of an active and inactive
3:24is or are their shape okay if this one
3:28is a columnar or cuboidal we will call
3:31this one as active osteoblast now there
3:35are other pictures that i'll be showing
3:36later if it is a flat or squamous that
3:40means it is inactive
3:42okay now as a review austin osteoblasts
3:45here they light the periosteum they are
3:48involved in bone formation or they
3:50synthesize the osteoid
3:54okay after osteoblast let's go now to
3:56the parenchyma of the bone which is your
4:00osteocyte they are the mature cells
4:03and their shape is flat and almond shape
4:06with projections and that projections
4:09are actually your cytoplasmic processes
4:12the osteocytes class they are found in
4:14the cavities known as your
4:17lacunae okay they are found in between
4:20the bone matrix layers and the function
4:23of the ostrocytes is for bone matrix
4:27maintenance or it maintains bone matrix
4:30and in the
4:32osteocytes as well we may find
4:35um canaliculi a bone cannoli serves as
4:38communication or conduit of nutrients in
4:43between the osteocytes
4:45okay let me show you
4:47another picture or illustration of these
4:49different types of bone cells
4:51um
4:53from the previous slide
4:54these are all
4:56osteocytes
4:58okay there are fog in
5:00[Music]
5:01uh the bone matrix
5:03now after bone formation that are
5:07um
5:08that that's the role of the osteoblast
5:10it goes in the bone matrix and this now
5:14will become your osteocytes or the
5:16mature bone cells
5:18if the osteoblast function is to
5:21uh for bone or bone formation the
5:24osteocytes
5:26sorry the osteoblast is for bone
5:28formation the osteocytes on the other
5:30hand is it maintains
5:32this bone matrix okay
5:36it maintains bone matrix
5:41okay this is another illustration
5:43showing you the bone cells here and its
5:46cytoplasmic processes if you look
5:48closely
5:50this is a high power magnification
5:52showing you these finger-like
5:53projections these are known as your
5:55bone canaliculi their function is uh it
5:59will serve as communication
6:01of one osteocyte from another osteocyte
6:04and also they serve as a kadui of
6:07nutrients
6:08they supply nutrients one from each
6:10other
6:11it's these are the finger-like
6:13projections as i mentioned they are
6:15known as your bone cannaliculi
6:20okay and last
6:21bone cell is not actually comes from
6:25your osteoporosis cell the osteoplast
6:28they are motile
6:30multinucleated giant cells
6:33and their role our function is basically
6:36bone
6:37resorption okay bone
6:40resorption
6:41they are produced by the fusion of bone
6:44marrow there are monocytes
6:46and basically when we say bone
6:48absorption or bone absorption they erode
6:51the bone matrix during bone remodeling
6:54okay
6:55again
6:56important note
6:58that osteoplast does not come from
7:01they don't come from ostra project or
7:03cell they are from
7:05or they are derived from the monocyte
7:08phagocyte system
7:10okay meaning
7:12um
7:13they are derived from the bone marrow
7:15that i monocytes okay all right if your
7:19osteocyte now they lie
7:21inside or they lie
7:23in lacunae
7:25the osteoclast on the other hand they
7:28lie within this so-called resorption
7:31lacunae or your house ships
7:35okay this is a structure where you're
7:39also blessed
7:41um
7:42are deposited
7:43or they are launched in hal ships the
7:45queen osteocess if it is an osta site
7:48they are launched in lakunila okay
7:53okay this is an example or an
7:55illustration of the different types of
7:57bone cells
7:59no as mentioned a while ago if it is
8:01found at the lining of the periosteum it
8:05is your osteoblast
8:07now this one is the b here stands for
8:09bone matrix and what maintains the mono
8:11matrix as i mentioned a while ago are
8:14your osteocytes
8:15okay these are all osteocytes
8:18what is that cell called that is derived
8:21from the fusion of bone marrow derived
8:23monocyte
8:25monocyte phagocyte system this is a
8:28multi-multi-nucleated
8:30giant cell called your osteoclast
8:34okay
8:34function of this cell
8:36at the cursor at the pointer it's it is
8:40involved in bone
8:41resorption no why this large multi
8:45nucleated this uh oscillator says
8:48um three or four three or f uh for
8:52nucleus well in this one no
8:56it is also multinucleated and it is
8:59large okay
9:02okay this is another uh slide showing
9:04the different bone cells okay these are
9:07all your osteoblasts
9:10lining the periosteum
9:13your osteoclasts
9:15they are multinucleated giant cells and
9:18they are for bone desorption
9:21what our oc stands for the oc stands for
9:24osteocytes and they are found in the
9:26bone matrix because their function is
9:28really to maintain it to maintain
9:31the bone matrix
9:34okay this is a good illustration of the
9:36different types of bone cells this is
9:38taken from junkera and as you all know
9:40look at this uh area right here
9:44this are all
9:46osteoblasts
9:48okay they are involved with bone
9:49formation
9:51and if you look closely if this one is a
9:53flat
9:55a flat awesome plus they are in active
9:58osteoblast well in this look at this
10:01particular
10:02or specific osteoblast this is more of a
10:06column marker herboidal osteoblasts and
10:09this one is an active osteoblast
10:12look closely they will try to penetrate
10:15this matrix to become your osteocyte
10:19right and this are your mature
10:21osteocyte which maintains this bone
10:24matrix
10:25okay
10:26um another cell is this multinucleated
10:29zion cell called
10:30your osteoclast and that is for
10:33bone
10:34resorption
10:36okay
10:38okay this is a picture from the
10:40laboratory this is a slide of um
10:44osteoclast no uh doc why is it that the
10:48oscar class is found at the bone matrix
10:51no uh as um
10:53the description of the oscar class they
10:55are motile so they can be found at the
10:58lining or they can be found
11:01inside the bone matrix
11:03but you have to take note that
11:05for for you to be able to
11:07um identify this cell you have to look
11:11you have to
11:12meet the criteria that is large and they
11:14are multi-nucleated as seen by this line
11:18okay again what's the function officer
11:21of your oster class it is for bone
11:23resorption what if we ask you in the
11:26practical exam i identify the structure
11:29that is pointed right now if it is
11:31structure that's pointed
11:33it is your house ship's lacunae but if
11:36we ask you what is the cell pointed it
11:40is your osteoclast
11:42okay where it is derived not from the
11:45also progenitor cells but they are
11:47derived from the monocyte phagocyte
11:49system
11:50okay what's the function of the cell
11:52pointed
11:53bone resorption
11:56okay this is another picture the
11:59laboratory
12:00um
12:01where your osteoclast not this is a
12:04multinucleated design cell is found
12:06inside the bone matrix
12:09okay
12:10let's apply this in medicine we have the
12:12so-called
12:13osteopetrosis this is a genetic disease
12:16where it is characterized by having a
12:18dense heavy bones or marbled bones
12:22and the um main culprit is that the bone
12:25resorption of the osteoporosis is
12:28actually defective
12:30now as you learned
12:32bone absorption is defective what
12:35specific bone cell is defective that you
12:38are talking about it is your
12:41osteoclast
12:42okay
12:44in osteoporotrosis still there is an
12:46overgrowth and thickening of your bones
12:48as such there will be obliteration of
12:51the biomarro marrow cavities um
12:54presenting to you with anemia and loss
12:56of wbcs as you all know if there are
12:59loss
13:00or if there is loss of wbc we are prone
13:03to infection and as we all know if there
13:06is anemia signs and symptoms such as
13:08leasy fatigue ability parallel
13:13those are the common characteristics of
13:16being anemic okay
13:19all right this is an example of an x-ray
13:22showing you
13:23osteoporosis but in this picture
13:26this is the normal chest x-ray sorry
13:29normal x-ray of the pelvis and of the
13:32femor right
13:35and
13:36osteoporosis not um there is an
13:39increased bone thickness and density
13:42now that's why it is um it really looks
13:44like a marbled bones whereas the normal
13:48x-ray
13:49uh there is uh this is a healthy bone
13:52thickness and density compared to your
13:54osteoporosis which is or which has an
13:57increased bone thickness and that is
13:59very characteristic of her osteopetrosis
14:02again the defective
14:04cell here is the osteoclast
14:09okay
14:10let's continue
14:12let's go to the bone matrix itself there
14:15is inorganic
14:16and organic part the inorganic bone
14:19matrix is usually 50
14:22and the most abundant the responsible
14:24for hardness of the bone is your calcium
14:28hydroxyapatite
14:30okay but not just the culture of
14:32hydroxyapatite that is responsible for
14:34being for the bone being in organic
14:37there are presence of some ions such as
14:40your bicarbonate side shape magnesium
14:43sodium potassium ions and also calcium
14:46phosphate no but the most abundant
14:49if as in examination in organic bone
14:53matrix would be the calcium
14:55hydroxyapatite
14:58the organic one is composed of type 1
15:01collagen as you've learned in the
15:03connective tissue the classification of
15:06bones are actually type 1 collagen to be
15:09specific they are of organic component
15:12they are
15:13composed of proteoglycan aggregates
15:16multi-adhesive glycoproteins such as
15:18their austronectin and osteocalcin the
15:21organic bone matrix also is associated
15:23with minerals that is responsible for
15:26collagen fiber formation that being said
15:29that is responsible for the hardness and
15:31resistance of bone tissue okay that is
15:36the organic component of our body the
15:39inorganic component as mentioned is
15:41because of calcium
15:43hydroxyapatite the organic one it's
15:45because of the collagen fibers
15:47specifically type one collagen
15:51okay
15:54okay let's move on after organic and
15:57inorganic component of the bone let's go
15:59to the fibrous coverings of the body we
16:02have three the periosteum
16:05the endosteum
16:08sorry the periosteum and industrium
16:11sorry the
16:12periosteum is outer inner layer when you
16:15say outer layer they are composed of a
16:18dense connective tissue some of the
16:20blood vessels or collagen bundles and
16:22the fibroblast and as we've learned
16:24during your lecture in connective tissue
16:27your fibroblasts are actually the
16:28parenchyma of your connective tissues
16:31okay
16:32in the periosteum also of the bone you
16:34may also find sharpies fibers there are
16:37perforating collagen fibers that
16:39penetrates the bone matrix and that
16:42actually com that actually binds their
16:44periosteum to bone so what am i talking
16:47about let's see
16:49in illustration here
16:51the periosteum here has inner and outer
16:55layer the outer layer is composed of
16:58this area your perforating fibers are
17:01your sharpies fibers and that binds
17:03their periosteum here
17:06that's the outer layer and the bone
17:08itself
17:10okay are we clear this is the bone
17:12itself
17:13from this tip of the pointer up to this
17:14area but what binds the periosteum the
17:18outer layer of the bone to the bone
17:20itself is your perforating fibers or
17:23your sharp base
17:24fibers okay so as mentioned your
17:27periosteum has fibers there and that's
17:29the outer part let's go back to
17:33the periosteum inner layer
17:36the inner layer on the other hand it's
17:38more of cellular not these are the bone
17:40cells that we've
17:42learned
17:43um from the first part of the lecture
17:46the bone lining cells the osteoblasts
17:48and the austroprogenitor cells so
17:50basically the inner layer of the
17:52periosteum they nourish the oceans
17:54tissue and they provide continuous
17:57supply of new osteoblasts thus i mean
18:00because
18:01of the presence of the osso progenitors
18:04also progenitor cells becoming
18:06osteoblasts
18:08okay
18:09that's your periosteum your endosteum
18:12um cover small trabecular bond matrix
18:15they are thinner and they also contain
18:18the different types of bone cells the
18:20bone lining cells your osteoblasts your
18:23osteoporogenatory cells
18:25okay
18:27yeah so this is taken from jungkera this
18:29is an illustration showing you
18:31a
18:32a
18:33cross-section
18:35of diaphysis of the humerus so in here
18:38as mentioned this is the periosteum and
18:40we have endostemin
18:42the outer and the inner layer they're
18:44perforating fibers or sharpies fibers
18:47and from this tip of the pointer up to
18:49this area is your compact point
18:52inner inside is
18:55more of the spongy bone that's the two
18:57types of bone which we'll be talking
18:59about in detail in a little later
19:03okay
19:04all right so
19:05as um we learned during the first day of
19:08orientation micro hsp we have this
19:12a compact bone okay the compact bone is
19:15um
19:16the the unit
19:18is the aversion system or what we call
19:21your osteon and this will be um
19:24discussed to you in a little while this
19:27is just an overview of the aversion
19:30system a version system
19:33is composed of the version canal
19:36and the contents of the aversion canal
19:38are
19:39uh let's put it this way vine no vein
19:43artery and nerve that's the composition
19:46of your aversion
19:48canal
19:49okay the aversion system composed of a
19:52version candle in this one are actually
19:55your parenchyma or your osteocytes
19:59okay let's uh put it in a
20:02high power magnification this is your
20:04uh osteocyte
20:06they are lodged in what we call
20:09your lacunae
20:10the cytoplasmic processes or the finger
20:13like projection
20:14are what you call your bone canaliculi
20:16now and as a review their function is to
20:19provide communication uh between
20:21osteocyte and it is a conduit of
20:24nutrients from one also site to another
20:27okay
20:30okay uh let's apply it to medicine after
20:33learning about osteoporosis that's gonna
20:35do osteoporosis
20:37osteoporosis meaning you have a porous
20:40bone this is um evidently uh common
20:44in immobilized patients and some of the
20:47post-menopausal women they are more
20:49prone for having osteoporosis in this
20:52medical condition the bone resorption
20:55exceeds
20:57bone pharmacoid so from the learnings
21:00that we had a while ago the osteoclast
21:05functions as bonus orbital exceeds
21:08bone
21:09formation or exceeds osteoblast
21:12having said that the osteoporosis has a
21:15reduced bone mineral density as well as
21:18calcium loss from the bones
21:21okay so
21:22in this osteoporosis if you notice if
21:25you have a reduced bone mineral density
21:28it this one will look like
21:30the bones will look like
21:33sorry but this is the normal bone
21:36and if you have osteoporosis
21:39this one will create a they will be
21:42reduced mineral content not reducing
21:45calcium so you are prone to fracture in
21:48the future if you have osteoporosis
21:51now how do we diagnose osteoporosis we
21:54usually diagnose this using your
21:56essential dxa
21:59that's the most common use bone
22:01measurement test used to screen for
22:03osteoporosis we use
22:05um
22:06uh hip and lumbar spine no that's the
22:09the most diagnostic essential dual
22:13absorption
22:15okay this is usually done
22:17uh the screening usually for 65 result
22:20than above but um for those patients who
22:23have an increased risk for osteoporosis
22:25less than six less than 65 we may
22:27actually use also essential dxa we may
22:30actually use also peripheral dxa
22:34peripheral dxa not just like the central
22:36dxa but the difference is that for the
22:39peripheral dxa we use the
22:41hands and foot
22:42not to test for osteoporosis how do we
22:46how do we interpret that okay the dexa
22:49scan that's the essential
22:52dxa the dexa scan the normal is up to
22:55negative one okay i got this from the
22:58american
22:59um
23:01society of
23:02um
23:03osteoporosis
23:05uh osteopenia is from negative 1 to
23:08negative 2.49 and the osteoporosis
23:11diagnosis is 2.5 negative 2.5 and above
23:14what's the implication of that if you
23:17have a normal dexa scan no sabinito keep
23:20living your life
23:21now you see see you in 10 to 15 years
23:23for a next can so basically
23:26um
23:2710 to 15 years would be the screening
23:30after a initial screening and if if
23:32that's normal no that's good keep living
23:35your life but if you fall under the
23:38osteopenia turns out you're getting
23:40older what's the
23:42uh recommendation you return for a
23:44repeat scan after two to five years
23:46depending on severity meaning if you are
23:49osteopenic
23:50no less than two to five years if you
23:52have uh symptoms
23:54um
23:55show me osteopenia
23:57no um you you may actually go to
24:00your family doctor or medical
24:02practitioner or orthopedics or rehab
24:05doctor
24:06for a consultation but if you happen to
24:09be osteoporotic no your dexa scan falls
24:13from negative 2.5 and above what are the
24:16clinical risk factors you may be at rest
24:18for experiencing a fracture
24:20okay talk with the provider about
24:22fracture reduction and medication to
24:24develop a treatment plan that is right
24:26for you
24:27all right now no clinical factors no
24:30skepticism about meditation trees
24:32treatment is perfectly appropriate
24:34i have a doctor that will discuss your
24:38hair plans if you are
24:40scanned or
24:41diagnosed with osteoporosis and this
24:44you can actually consider medication
24:46treatment as well as non-medication
24:48interventions such as physical
24:50rehabilitation or physical therapy
24:52but um right now we have so many studies
24:56on osteoporosis we can give by
24:58bisphosphonates calcium supplements
25:00vitamin d combination with calcium those
25:04are the pharmacologic treatment but
25:07as i mentioned you may actually start
25:09screening
25:10less than 65 years old not just for 65
25:13alone
25:14if you have an increased risk for
25:16osteoporosis
25:18okay
25:20let's go now to the types of bones as i
25:22mentioned a while ago we have two types
25:23of bond compact and cortical bone your
25:26compact bone composed of eighty percent
25:29of the total
25:31bone mass okay your compact bone is also
25:33known as your cortical bone
25:36while your cancellous bone or trabecular
25:39bone or your sponge bone are actually
25:41found in the deeper areas they are
25:43composed of numerous interconnecting
25:46cavities that in contrast to your
25:50compact bone or cortical bone which is
25:5280
25:53your sponge bone will only comprise of
25:55the 20 of the total
25:58bone mass okay this is a good
26:00illustration
26:02on how your compact bone that is your
26:04cortical bone
26:06compared
26:07to the 20
26:09of the cancellous trabecular or spongy
26:12bone okay
26:14um
26:15that cancellous bone this is in
26:17a combination
26:19with the bone marrow okay the bone
26:22marrow that is where all the blood lines
26:25are originated okay so going back here
26:28in this illustration
26:30from this tip of the pointer so as we
26:33learned kanina this is the periosteum
26:35the bone covering from the tip of the
26:38pointer right here
26:40up to this area
26:42is your
26:43compact point and this whole area
26:46is actually your
26:48spongebob order tubercular and that only
26:52comprises of
26:5320
26:55okay
26:56this is uh this will not be good in your
26:58examination but this worth mentioning
27:00this is uh tackled during our skeletal
27:03system lecture in
27:04gross anatomy we have long bones
27:07short bones and flat bones
27:10yeah but uh in microscopic human
27:12structural biology bone organization is
27:15actually important and there are two
27:17types of bone organization we have
27:20lamellar bone and none lamellar bone
27:23okay
27:24the miller bone first
27:26is actually a bone organization in
27:28adults it's either you have a compact or
27:30spongy bone and are characterized by
27:33multiple layers or lamellae of calcified
27:37matrix
27:38lamellae are organized either parallel
27:41to each other or concentrically around
27:43the central column and there are four
27:44types of lamellae which we'll be talking
27:46about in a little bit later type 1
27:50collagen fibers are aligned in parallel
27:52in each laminae uh as of this time you
27:55have to take note that bone has type 1
27:58collagen fibers okay now basically the
28:02lamellar bone is the compact and spongy
28:04bone and it is composed of lamellae of
28:07calcified nutrients
28:09okay
28:10in the compact bone we have the osteon
28:13or aversion system
28:15and as mentioned a while ago aversion
28:17canal is composed of blood vessels
28:20nerves
28:21veins loose connective tissue and
28:23dustium which is
28:25composed of your different types of
28:28bones and linings okay the lacunae is a
28:31structure in which
28:33your osteocyte is launched
28:36and as mentioned a while ago your bone
28:38cannoli is your finger like projection
28:41that is found in the osteocyte okay
28:44this is austria's austrian or the
28:47aversion system
28:48this is a virgin canal or
28:50we may call this one essential canal
28:53uh lacunae is the structure
28:56the cell pointed is
28:58osteocyte okay in the practical exam if
29:01this one is um
29:03uh pointed take note of the question if
29:07the structure
29:08point uh identify structure pointed
29:12lacunae
29:13cell pointed
29:15osteocyte okay
29:17cell pointed osteocyte what is the
29:19function of the cell pointed your answer
29:22would be it maintains bone matrix
29:25okay
29:26identify the structure pointed the
29:29finger like projection those are your
29:30bone canaliculate and identify the
29:32function of that finger like projection
29:35communication
29:36or conduit between osteocytes okay doc
29:40what is this concentric lamellae all
29:42right
29:43concentric lamellae
29:45is um
29:46let's let's put it this way lamellae is
29:48this one one lamellae
29:51another lamellae
30:00another lamellae can you see
30:03no uh did you understand the laminae we
30:06call
30:11[Music]
30:15but if it this one is surrounding the
30:17central canal it is specifically called
30:20your concentric lamellae and there are
30:22three other types of family which will
30:24be discussed in a way
30:26okay
30:28okay uh what else that you need to
30:30uh
30:31to know in the aversion system or osteon
30:34uh it is a long cylinder parallel to the
30:38long axis of the diaphysis
30:40and there are more collagen each and we
30:42have the so-called voltmon's canal your
30:46volkman's canal is actually air
30:48perforating canal and that
30:50canal communicates with another
30:53essential planet so basically if this
30:56one is a one aversion system and this is
30:58the central canal the structure that is
31:00being pointed right now is actually your
31:03perforating canal or your
31:05uh walkman's canal no they communicate
31:08one block that one conversion system to
31:11another aversion system
31:13so basically if a version systems are
31:16involved it is your
31:18volkman's canal but from
31:21if you look closely here if the
31:23ostocytes communicate with another all
31:25society it is actually your bone
31:28cannaliculi okay
31:30one osta side to another oscar site bone
31:32cannon nicolai if it is um
31:35one central canal or one aversion system
31:37to another aversion system it is called
31:40your
31:40uh vachman's canal no pokemon scandal or
31:44perforating
31:47all right in this picture we've talked
31:49about the concentric lamellae in this
31:52slide we'll be talking the rest of the
31:54laminae
31:57as mentioned a while ago if the laminate
31:59is organized around the central panel it
32:01is called concentric lamellae but what
32:04if your lamily is
32:06found between an impact osteon so let's
32:09go back to this picture
32:11this is one osteon
32:14this is another osteo this is another
32:16austrian reversion system the lamellae
32:19that is found in between
32:22an intact osteon is what we call our
32:24term as your
32:41is our interstitial laminate your
32:43external and inner what is the
32:45difference of that external is located
32:47immediately beneath the periosteum and
32:49as you all know the periosteum is found
32:52outside thus the term external your
32:55inner or internal circumferential
32:57laminae is found
32:59around the marrow cavities and as you
33:01all know the marrow cavities is found um
33:04more deeper than the compact bone no
33:07picture
33:10okay sorry now this one is the external
33:13circumferential lamellae meaning they
33:15are found
33:18more of outside that's the term external
33:21the internal here the internal
33:23circumferential family are found in the
33:25or near the marrow cavities that's the
33:28term internet okay so you have to take
33:31note the different types of
33:34the lamellae
33:36all right so as mentioned available
33:38there are two types of bone organization
33:40one is lamellar the other is non-laminar
33:44and this is known as your
33:46woven bone they are usually temporary
33:49that is comprised of a random
33:51distribution of still type 1 collagen
33:54but you have to take note of the red one
33:58it is this is the first bond tissue to
34:00appear in embryonic development and
34:03please take note they are the first one
34:05to appear in fraction
34:07repair okay
34:09they are fractured they are involved in
34:11fracture repair thus they are usually
34:13temporary okay they are being replaced
34:16in adults by lamellar bone and they have
34:19a lower mineral content and they have
34:22less strength than your lamellar bone
34:24obviously because they are usually
34:27temporary
34:29okay
34:30so there are two types of woven that are
34:32two types of bone organization let's go
34:34to the two types of growth
34:37the acquisitional growth is growth in
34:40circumference basically while your
34:42interstitial growth as opposed to your
34:44oppositional they are
34:46growth in length
34:48right
34:49growth in circumference a positional
34:52interstitial is growth in length
34:56okay what about development you have two
34:58types your intra membranous and
35:00endochondral the main difference is that
35:03look at the intra membranous the awesome
35:06blast as you all know they will
35:08differentiate directly from the
35:09mesenchymal cell or the oscillator cells
35:12and begin secreting posterior no and
35:15this is the type of bonuses that we've
35:18discussed in the first part of the
35:19lecture intra membranous
35:22what about the endocontrol the
35:24endochondral is justified
35:27as the pre-existing matrix of hyaline
35:30cartilage
35:32is eroded
35:33okay and they were invaded by the
35:35osteoblasts which begin austrian
35:38production
35:40osteoblasts will begin austrian
35:43production but in the endochondral there
35:46is a pre-existing matrix
35:48now the erosion of this pre-existing
35:50matrix will be um invaded eventually by
35:54the australis and this is what we call
35:56your endochondral ossification
35:59okay
36:00let's um
36:02discuss apply this in medicine your
36:04ostrogen is imperfecta is also a brittle
36:06bone disease this is a group of related
36:08congenital disorders
36:10now as definition or as defined
36:12osteoblasts produce deficient amounts or
36:16they have defective type 1 collagen due
36:19to a genetic mutation so this is an
36:21example of your elsogenesis imperfecta
36:25it is genetic
36:26no as you can see this is this is the
36:28mother which scares the gene that is
36:32being passed
36:33through
36:34um
36:36by her three children
36:37okay
36:38this is actually uh i did i just made it
36:42myself the abcdefg of osteogenesis
36:45imperfecta it is an autosomal dominant
36:48the patients here has blue sclera c
36:51would be collagen production impaired
36:53type 1 specifically deafness
36:55easy brews ability f would be the
36:58fragile bond or if they are fractured
37:00prone energy is a genetic disorder so i
37:02hope this one helps you
37:04in studying the osteogenesis imperfecta
37:08okay
37:09now let's move on to the second part of
37:11this
37:12um lecture you have the cartilages okay
37:16your cartilage is a tough and flexible
37:19connective tissue it is composed of an
37:21exocellular matrix
37:23the gags or the glycosaminoglycans and
37:26proteoglycans interacting with each
37:29other interacts with collagen and
37:31elastic fibers and they will form it
37:33they forms from an embryonic mess and
37:36can just take the bone they form from
37:39embryonic mesenchymal cells okay so
37:42galindi and semester came and as you all
37:44know the mesenchyme in the bone is also
37:47known as the ostroprogenitory cells
37:50okay so basically this is a summary of
37:52the three cartilages that we will be
37:55learning today this are the hyaline the
37:58fibrocartilage and the elastic cartilage
38:01i'll help you memorize all these things
38:03okay
38:04now look at this picture class
38:07if you notice the blue ones are actually
38:09the distribution of your hyaline
38:11cartilage this they're found in the
38:14costal cartilage your articular
38:16cartilage of the joints
38:18where else also actually in the joints
38:20the hyaline cartilage they are found at
38:23the respiratory tract cartilages you
38:26have the larynx the trachea and of your
38:31uh in the lux okay
38:33your epiglottis sorry your elastic
38:35cartilage that's the second
38:38uh type of cartilage
38:40look at at the elastic cartilage
38:42cartilage that are found in e right e as
38:45in elastic they are found in epic lotus
38:48and in the ears
38:51elastic cartilage
38:52ears epiglottis because they are
38:55composed not just the collagen fibers
38:58but also e elastic fibers
39:01okay that's the glue there e
39:05uh and the last one would be the
39:06fibrocartilage they are um primarily
39:09located at the pubic symphysis and the
39:11intervertebral disc now let's talk about
39:14the functions in general of the
39:15cartilage they forms the framework now
39:18supporting soft tissues they also
39:21provide a shock absorbing and sliding
39:23airflow joints as seen in the previous
39:25slide
39:26distributional cartilage
39:28they facilitate in bone movement and
39:30they are also essential for the
39:32development and growth of bones before
39:35and after breath
39:37okay general characteristic number one
39:40cartilages are a vascular meaning they
39:43don't have
39:44vascular or blood supply
39:47so the nutrients uh are received by the
39:50diffusion from your perichondrium
39:53perichondrium will be talk uh we will be
39:55talking about that in a little later
39:57they have low metabolic activity the
39:59cartilages and they thought as opposed
40:02to your bones they don't have lymphatic
40:05vessels and nerves okay so basically no
40:09nerves no vessels no blood supply their
40:12nutrients are received from the
40:14pericondium
40:16okay
40:18now if bones has osteocytes your co your
40:22your cartilage also has chondrocytes
40:25your chondrocytes take note they
40:27synthesize and secrete the extracellular
40:31matrix right they're also located or
40:34lodged in the matrix cavity just like
40:36your bones with this lacunae
40:39okay
40:40again chondrocytes are launched in the
40:43lacunae your osteocytes are large
40:50which are which your osteoclasts are
40:54launched into okay
40:57what is extracellular matrix now
40:59basically the excellent matrix is
41:01composed of fibers either collagen and
41:03elastic fibers found in the cartilage
41:06and also as mentioned a while ago during
41:08the introduction of cartilage the gags
41:10and proteoglycans that will make up your
41:12ground substance the fibers and the
41:15ground substance yen and composition of
41:17extracellular matrix and who synthesize
41:20and secrete that extracellular matrix is
41:22actually the chondrocytes or your
41:25cartilage cells
41:27okay listen
41:28uh is taken from junkera
41:30now this one is your type 2 collagen
41:33fiber fibril
41:35actually
41:36cartilage type 2 bug type 1
41:39collagen bones okay so this is the
41:42hyaluronan
41:44hyaluronan
41:46link protein whereas the core protein
41:49and this one is the collagen type 2 and
41:52this is an example of your chondroitin
41:54sulfate
41:55if that extracellular matrix and fibers
41:59combine that will make up your
42:02extracellular
42:03matrix okay so your ground substance is
42:06made up of these gags or
42:08glycosaminoglycans or hyaluronan
42:10and your proteoglycan in combination
42:13with the collagen elastic fibers that
42:15would make up your extracellular checks
42:17and what synthesize
42:19and secret that it's the cartilage cells
42:23okay
42:25okay let's talk about the types of
42:27cartilage
42:29uh one by one
42:30the most abundant is the hyaline
42:32cartilage and as i mentioned a while ago
42:35in the
42:36pictures the distribution of the
42:38cartilage these are the location
42:40locations of your hyaline cartilage
42:43articular surfaces of a movable joint
42:46walls of larger respiratory passages
42:49your ventral ends of the ribs
42:51articulating with the sternum your
42:53epiphyseal planes of long bones and the
42:55embryo there are temporary skeleton that
42:58is replaced by bone if you notice okay
43:02in the embryo
43:04there are temporary skeleton replaced by
43:07bone this is known as your endochondral
43:09ossification now basically they are at
43:12the cartilage first
43:14that is being eroded by the osteoblast
43:17and then they will secrete they will
43:19synthesize to australia and that is your
43:21endochondral pacification
43:24right
43:26so yeah these are the locations of your
43:28hyaline cartilage okay though basically
43:31this one is your hyaline cartilage it is
43:34uh
43:35uh
43:36characterized by by having a drought
43:38plus appearance of the bone of the
43:41extracellular matrix
43:44distribution of muscles this cells
43:47actually are your chondrocytes or your
43:49cartilage cells
43:51now p here stands for your perichondrium
43:55and nutrients
44:02[Music]
44:04extracellular matrix
44:06now look at this uh closely your
44:09chondrocytes or your cartilage cells are
44:11your parenchyma of your cartilage okay
44:15the shape of which they are actually
44:17sorry they're arranged in singly like
44:20this one or in isogenous group in groups
44:24in three like three this one
44:27[Music]
44:28description
44:30no singly or single s-i-g-l-y
44:34or in isogenous groups
44:37okay the matrix as mentioned a while ago
44:40they are composed of collagen mostly
44:42fiber mostly type 2
44:45the most abundant proteoglycan is your
44:48agriculture and the chondroid
44:50chondronectin are multi-adhesive
44:52glycoprotein which binds to the guts and
44:55collagen type two
44:56um
44:57for it to become for it to become
45:00adhered to the conscious side
45:02to become extracellular matrix
45:07um
45:08gags or glycosaminoglycans and
45:11mycology to become extracellular matrix
45:15your chondrocytes are
45:17mentioned available they are arranged in
45:19singly or any exogenous group
45:21and as mentioned they are lodged in the
45:24lacunae
45:25uh where our conscious sides
45:28come from they come from the
45:30chondroplasts and this young chondrocyte
45:32the chondrocytes they are elliptical in
45:35shape and they are found in the
45:36periphery of cartilages actually they
45:38are found in the perichondrium this is a
45:41conjo blast
45:43this is in the perichondrium if this
45:45conjugate becomes mature it goes up it
45:48goes down to your matrix becoming your
45:51chondrocyte okay and take note okay the
45:55perichondrium is a layer of dense
45:57irregular connective tissue okay take
46:01note okay perichondrium if i if asked
46:04what is the fundamental type of fish of
46:06the perichondrium we'll answer
46:08connective tissue what is the subtype
46:11it's the connective tissue proper and
46:13what is the specific subtype it is a
46:15dense irregular connective tissue
46:20okay
46:23it covers all hyaline cartilage except
46:27the articular cartilage take note of
46:29this covers all hyaline cartilage the
46:32locations of hyaline cartilage except
46:34the articular cartilage
46:38okay okay this is a picture of a tree
46:42no this is uh taken from the
46:45laboratory this is your lining
46:46epithelium
46:48this is the layer
46:49uh line epithelium lamina propia
46:53now this is the submucosal arena and
46:55they are uh
46:57comprised of your tracheal glands and
46:59this one actually are or is your
47:02tracheal cartilage or your hyaline
47:04cartilage
47:05now if you this one is your
47:09high power magnification showing you the
47:11different chondrocytes
47:13found in the matrix they are in singly
47:17or in esogenous groups now what is this
47:20class this is the layer of a dense
47:23irregular connective tissue called your
47:25perichondrium
47:27chondroblasts are here
47:29now once they are they become mature it
47:32goes to your extracellular matrix the
47:34characteristic of the hyaline cartilage
47:37is the ground glass appearance of your
47:41extracellular matrix
47:43no we will be comparing this to the
47:45elastic cartilage
47:47in a way
47:48okay yeah so this one is in highest
47:51magnification show me your chondrocytes
47:55arranged in singly or in isogenous
47:58groups okay yeah simply actually this is
48:00an exogenous groups
48:03okay singly or in estrogens
48:07okay as compared to our
48:09hyaline cartilage your elastic cartilage
48:12they're actually similar but they have
48:14abundance of elastic fibers they also
48:17have collagen type 2 but they have
48:20abundance of elastic fibers where are
48:22they located as mentioned e not elastic
48:26elastic fibers elastic cartilage they
48:29are found in the ears the oracle in
48:31their ear the external auditory canal
48:34auditory tubes and your epiglottis
48:37except for the e the cuneiform cartilage
48:39in larynx
48:42they are found in the in those locations
48:45the elastic cartilage now this is a
48:47picture of your hyaline cartilage now
48:51look at the ground glass appearance
48:54of your bone matrix
48:56offside of the extracellular matrix in
48:58the hyaline cartilage
49:00now look at the elastic cartilage what
49:03do you notice the fibers here are um
49:07they appear dirty as opposed to this
49:10homogenous
49:11homogeneous extracellular matrix of the
49:14highland cartilage okay what else you
49:17want five breasts
49:22uh dirty looking appearance uh take out
49:26of the congo sites in both of the island
49:29and in the elastic they're
49:31actually the same now they are arranged
49:33insanely or in isogenous groups and
49:36they're large also in the lacunae
49:40okay so this is taken from junkera these
49:42two pictures the hyaline and the elastic
49:45cartilage please take note of the of
49:47their differences this is the epiglottis
49:51in the laboratory right
49:53uh they are lying
49:55by stratified squamous non-keratinized
49:58uh what else so this one right here
50:04is
50:05your perichondrium
50:07this one right here is also the layer of
50:10a perichondrium and as mentioned a while
50:12ago they are a
50:14layer of intense irregular connective
50:17tissue okay
50:18now from this tip of the pointer up to
50:21this area that's the whole elastic
50:23cartilage that is found in the
50:26epiglottis sorry the the organic focus
50:29right now is epiglottis
50:31they are characterized by having a
50:33abundance of elastic fibers look at
50:36these fibers
50:38they really appear dirty or in
50:41disorganized manners but also there they
50:43have collagen fibers not type 2 collagen
50:46fibers this is a high power
50:49multiplication of the elastic cartilage
50:52showing you the elastic fibers okay
50:55as
50:57a similar to the hyaline cartilage they
50:59have also chondrocytes
51:01that are arranged in singly or in
51:03isoleucus groups
51:05okay
51:06so those are the difference and
51:08similarities of hyaline and elastic okay
51:11and the last type of cartilage would be
51:14a combination of hyaline and dense
51:16connective tissue this is known as your
51:19fibro cartilage okay
51:22the chondrocytes okay the chondrocytes
51:25here are smaller and they are uh
51:28arranged singly or in esogenous
51:31aggregates
51:35if you're hyline and
51:38elastic cartilage they are arranged in
51:40singly or esogenous the fibrocartilage
51:44are a uniform tile they are arranged not
51:47the heart the conscious sites are
51:49arranged in rose
51:51okay don't answer a cd or a lantern
51:54exogenous aggregates they are arranged
51:56in a rows
51:58right they produce type 2 collagen now
52:01where are they located the
52:02fibrocartilage just mentioned a while
52:03ago they are located in the
52:05intervertebral disc and in pubic
52:08symphysis
52:09all right in the laboratory we usually
52:12use
52:13this uh slide now this is your
52:15intervertebral disc no the cells pointed
52:19right now are actually your
52:21chondrocytes
52:23and they are arranged in rows
52:26okay
52:27they are ancient it was there they have
52:28collagen
52:30type two button
52:31but the arrangement of the chondrocytes
52:33here are in
52:35rows
52:36this is your intervertebral
52:38disc
52:39okay
52:40now what is the most important thing
52:42that you have to know in the
52:43fibrocartilage they are they don't have
52:47identifiable
52:48perichondrium no don't um
52:52don't forget about this the old capstan
52:54the red fat no identifiable
52:57perichondrium in the fibrocartilage
53:00um
53:01while hyaline and elastic they do have
53:03perichondrium
53:05okay
53:07all right
53:09then so we've discussed the three types
53:11of cartilage now this is just a summary
53:13picture of the hyaline cartilage
53:18your elastic cartilage compare this one
53:20hyaline has homogeneous extracellular
53:23matrix while your fiber cartilage has
53:26dirty looking as opposed to their
53:28hyaline and the fibrocartilage
53:31and they have lacunae in uh
53:34they have conscious sides lodged in
53:36lacunae there are ancient rose the
53:38chondrocytes and they don't have
53:40pericondrio okay take note also the
53:43locations of
53:46the different cartilages the hyaline the
53:48elastic and the fibrocartilage
53:51all right also just like the bones
53:54your cartilage formation
53:56would be uh
53:58coming from the embryonic mesenchyme
54:01okay these are your mesenchymal cells
54:03that's the precar the that's the
54:05precursor of all types of cartilage now
54:08germitosis letter b
54:10mitosis and
54:12differentiation
54:13this one will become they're
54:15chondroblasts they are separated from
54:17one
54:18another and then they will become your
54:21chondrocytes here
54:23they are
54:24arranged in isogenous group some are in
54:27singly so
54:29um
54:31so from the mesenchymal to chondroblast
54:33to chondrocyte and from forming an
54:36exogenous group that is your formation
54:39of your cartilage cells
54:42okay what else two types you have the
54:44interstitial position i'll just just
54:46read on that but i have to end up in
54:49medicine now they have chondroma which
54:52is a benign suramar and the condors are
54:55common obviously because of the term
54:57sarcoma that becomes
54:59a malignant type of tumor but they are
55:01slowly growing they seldom metastasize
55:04and they are easily removed by surgery
55:06okay why why is it that they are slowly
55:09growing as mentioned a while ago they
55:11don't have blood supply
55:13vascular supply for the show mars are
55:16very much important in neoplastic uh
55:19show bars are in malignant proliferation
55:24now they're easily removed by surgery
55:26because they're slowly growing they
55:28don't have vascular supply okay
55:32yeah so please take note of this table
55:36all right now basically i we have
55:38discussed this three cartilages the
55:40hyaline
55:42the elastic and the fiber cartilage now
55:44let me just emphasize on this one not
55:47the presence of
55:49a perichondrium yes except for the
55:52articular cartilages
55:54uh all elastic cartilages um
55:57they have perichondrium no identifiable
56:00perichondrium
56:02main locations as discussed a while ago
56:05please take note but the main function
56:08no i want you to take note of this your
56:10hyaline cartilage their main function is
56:13to provide smooth low friction surfaces
56:16in joints that's why all joints
56:19they have hyaline cartilage they're also
56:21structural support for respiratory i'm
56:25talking about trachea
56:27in the inner inner lungs they are all
56:30hyaline cartilage what about elastic
56:33cartilage elastic cartilage uh they
56:36provide flexible shape and support of
56:38soft tissues while your fibro cartilage
56:41look they provide cushioning pencil
56:44strength and resistance to tearing and
56:47compression okay
56:49i know generally speaking they provide
56:52support but please take note of the
56:54individual function
56:55of each cartilages
56:58okay
57:00all right so that ends the lecture on
57:02bones and cartilages
57:05thank you for listening and if you have
57:06queries feel free to message me
57:08anytime
57:10thank you