Full transcript
0:08all right we're doing looks like B
0:10chapter six bones and skeletal
0:14tissue all right so let start off with
0:18cartilage and Bone just like cartilage
0:20it's a connected tissue but you want to
0:24taking not that cartilage is
0:26avascular there's no blood vessels going
0:28through the cartilage
0:30so that means they're getting their
0:31oxygen and nutrients those cells of
0:34cartilage from surrounding tissues where
0:37the blood vessels are located so there's
0:39an outer connected tissue referred to as
0:42the peric condum surrounding the
0:45cartilage and through diffusion it's
0:48going to provide oxygen nutrients to
0:51cartilage but since cartilage is a
0:54vascular should you damage it as an
0:56adult it's not likely to regenerate
1:01cartilage well there's three major types
1:03of cartilage in the body uh the most
1:05abundant one is called Highland
1:08cartilage it's a little bit rigid yet
1:10somewhat
1:11flexible so it's found in areas so to
1:14give shape to an
1:16organ elastic cartilage is the uh least
1:19abundant type it's the most pliable has
1:23elastic fibers uh you're only going to
1:25find it in two areas one is in the ear
1:29and the other is is a structure called
1:30the epig glotus uh the epig glotus is
1:34what prevents solids liquids going down
1:36your trachea when you
1:39swallow and the third type of connected
1:41tissue is called fibro cartilage
1:45fibrocartilage uh you're going to find
1:46in areas to absorb compression so you
1:49find it in between your vertebrae making
1:51up what's called intervertebral disc uh
1:55you find the padding in the knee a
1:56fibral cartilage called the meniscus
2:00and you also find fibro cartilage in
2:03front of the pelvic region there's a
2:06padding called the pubic
2:09symphysis so notice in fibro cartet you
2:11got collagen fibers kind of stacked
2:14together to absorb
2:19compression okay looking at this picture
2:21here uh you're looking at the bones of
2:24the skeletal system there's 206 bones
2:27total
2:30and uh the bones in brown are referred
2:32to as axial skeletal system so those
2:35bones consist of like the skull your
2:38vertebrae and your rib cage the other
2:41bones they go under what's referred to
2:43as appendicular skeletal system those
2:46include like the ones you find in their
2:48appendages in other words making up your
2:51arms your legs your pelvic region and
2:55also your scapula and clavicles
3:00and then in the bottom right of this
3:02picture is showing us the three types of
3:05cartilage in blue again is the most
3:07abundant type it's referred to as
3:09Highland cartilage you find it like
3:11lining the sternum to your ribs you find
3:14it at the end of your lung bones and tip
3:17of the
3:18nose as
3:20well the least abundant cartilage here
3:23in this green coloration uh you find it
3:27in the ear and also the structure above
3:31the trachea called the epig glotus that
3:34prevents solids and liquids going down
3:35your
3:37trachea and then uh colorcoded here in
3:39red is referred to as fibro cartilage uh
3:42you're going to find fibro cartilage
3:44making up the uh padding in the knee to
3:47absorb
3:49compression uh in front of your pelvic
3:51region there's also a padding of
3:53fibrocartilage referred to as the
3:56pubic
3:58symphysis and then in between your
3:59vertebrae to absorb compression you have
4:02these discs made up of fial cartilage
4:05referred to as
4:07intervertebral
4:09disc oh I forgot to mention as far as
4:12Highland cartilage you also find it
4:13within your trachea helps keep the
4:15airway
4:19open now anytime you grow in
4:22length it's referred to as interstitial
4:25growth if you're growing in density or
4:29diameter Wise It's referred to as
4:31appositional growth so when bone or
4:34cartilage when you start growing
4:37in
4:38density the cells the cells that make up
4:41the Matrix the medium of the the tissue
4:44U for cartilage they're called condr
4:46sites and once they get trapped within
4:49the cartilage they're they're mature
4:51cells and the space they're trapped in
4:53is called a a
4:56Lacuna as we get older the cartilage say
4:59lining the sternum to your rib cage
5:01tends to get harder it's not as pliable
5:05as when we're younger so when they refer
5:08to calcification they're referring to it
5:10getting harder as we
5:14age and again as far as the uh the
5:17skeletal system those bones that you
5:19find in the skull the ones that make up
5:23your vertebrae your rib cage they go
5:25under what's referred to as axial
5:27skeletal system and the ones you find in
5:29your appendages pretty much are referred
5:33to as
5:37appendicular uh bones by shape um can be
5:41named so if a Bone's longer than it is
5:44wider well it's a long bone so an
5:47example like the ones in the arm your
5:49top upper arms called the humorus the
5:52ones in the forearm the radius the Ona
5:55even the ones in your fingers the
5:56flanges they're there examples of long
5:59bones
6:01femur the upper part of the leg fibula
6:04tibia the lower part of the leg they're
6:06all examples of long
6:08bones short bones well kind of just how
6:12they sound they're they're kind of small
6:15uh they're not as very long as they are
6:18wider so for short bones you find the
6:20ones in your wrists in general they're
6:22called
6:23carpal uh the ones here in the ankle
6:26tarel are examples of short bones even
6:30your uh patella the one you know as your
6:32knee bone is a example of a type of
6:35short
6:35[Music]
6:38bone now um just to go over tendons and
6:41ligaments tendon ligaments connected
6:43tissue are
6:45dense regular connected tissue so tendon
6:49is connect tissue connecting a muscle to
6:51Bone whereas a ligament it would be
6:53connecting a bone to
6:56bone flat bones um typically with flat
7:00bones they don't have a cavity within
7:03them however compared to a l bone if you
7:06cut into a lum bone there's a cavity
7:07within the long bone so flat bones just
7:10kind of like they sound they're flat
7:12they don't have a cavity between the the
7:14sides of the bone so going in a picture
7:17here example of flat bones could be like
7:20the ones making up your cranial cavity
7:23up top frontal bone temporal bone to the
7:26side aital bone to the back those are
7:29example of flat
7:33bones now some bones may not fit any of
7:35those descriptions as far as shape they
7:38look kind of irregular in shape
7:40therefore that's how they're Name by
7:42shape irregular so examples of regular
7:45bones could be like your cheekbone which
7:46is your zygomatic bone uh the upper part
7:50of the skull here your teeth here that
7:52bone there area is called
7:54maxilla you can refer to it as IR
7:57regular your mandible r bone as well
8:01your pelvic region the coxal bones are
8:04IR regular
8:05bones so that's one way you can name
8:08bones is by their
8:10shape long bone short bone flat or
8:17irregular so again picture here
8:19emphasizing the shape if it's longer
8:21than it is wider it's a long bone
8:23typically when you cut into a long bone
8:25inside you'll find a
8:27cavity uh flat bone just like they sound
8:30they look flat there's no cavity within
8:32the bone example your sternum is an
8:34example of a flat bone short bones
8:38typically most of are small like in the
8:41ankle it's a short bone your wrist those
8:45are short bones and then again if the
8:47bone doesn't fit any of those shapes it
8:50looks irregular in shape well that's how
8:52it's named irregular BM and so in this
8:55example we pull out a vertebrae it's an
8:58example of a regular bone by
9:01shape uh the function is your skeletal
9:03system okay well yeah it does give
9:06support uh protects organs so like your
9:09cranial cavity there's the brain within
9:12it so helps protect it your rib cage
9:15gives protection to the organs within
9:17your rib cage and your
9:19vertebrae uh protects your spinal
9:23cord bones themselves aren't directly
9:26involved in movement but since they
9:28provide a attachment sites for skeletal
9:31muscle which is the only muscle you can
9:33voluntarily control they indirectly are
9:37involved in movement so that's what they
9:39referring to here as
9:42movement uh in your bone you can also
9:44store minerals like calcium and
9:46phosphorus as a reserve where should the
9:50levels in your bloodstream fall below
9:51normal you can pull some out from your
9:54skeletal
9:55system and inside the bone where there's
9:59a cavity there's bone marrow and that's
10:01where you're going to form blood cells
10:03red blood cells white blood cells and
10:06fragments of stem cells called platelets
10:09that are
10:09necessary to form a a blood clot should
10:12you be
10:13bleeding so forming blood cells a
10:16general term is hemato
10:21poesis and the bone marrow When We're
10:23Young it's nice and red and as you get
10:25older you tend to store lipids in there
10:27as well so it may look yellow in color
10:31so that's all it's saying as you get
10:32older you can also store lipids in your
10:34bone
10:37cavities now learning the bone names is
10:39not that challenging um especially since
10:43you have more than one of certain bones
10:47um what's challenging is these landmarks
10:50learning the names of landmarks on the
10:51bone similar to if you think of a
10:54mountain has a name but on the mountain
10:56are different landmarks which have more
10:58specific Nam Nam so these landmarks
11:02could be maybe a bulge a depression or a
11:05hole within the bone and these landmarks
11:09may be attachment sites for a muscle so
11:12maybe that's an attachment where a
11:14tendon would be or maybe an attachment
11:16site for a ligament connecting a bone to
11:19bone the other thing is some of the
11:22landmarks uh maybe areas where two bones
11:25meet and get used to the word joint
11:29joint means where two bones meet so
11:31where two bones meet they may take on a
11:33particular shape or Landmark that may
11:36have a specific name as
11:38well the other thing is if it's a hole
11:42maybe a nerve's going through the hole
11:44or some blood vessels so those would
11:47also have certain specific names are
11:49also considered
11:52landmarks so these are all the different
11:54landmarks which you may find similar
11:58landmarks but on different bones so like
12:01a tuberosity is a rounded projection on
12:05a bone whereas a Crest is more of like a
12:08narrow region of a bone tro Canter the
12:12only tro Canter is located on the
12:15um the femur so it's a large irregular
12:20not so sharp blunt
12:22surface some bones may look nice and
12:24narrow like a
12:26line some may have a small rounded
12:29little projection on the bone called a
12:32tubercle um an epic condal Epi means a
12:35pun so it's right above a condal condal
12:38are usually round where another Bone's
12:40going to be uh another
12:42bone some bones like in the vertebrae in
12:46some areas there will have a process an
12:50extension in other words a process and
12:52extension of the bone and then if it's
12:54nice and narrow would look like a sharp
12:57so they refer to that as a spine
13:02all right so let's give you some
13:03examples
13:05here so like a a tuberosity large
13:08rounded
13:09projection so if we look in here where
13:11do we have a tuberosity so let's just
13:14look at this whole bone this is U called
13:16your coxal
13:18bone or you could say
13:21ocx well that's a correct word you can
13:24also say hit bone but on the copal bone
13:27are landmarks so to give you an example
13:29here is a tuberosity it's has a specific
13:32name called isio
13:35tuberosity why is it isio well when
13:37you're developing as a fetus there's
13:39three bones that fuse into one coxal
13:41bone so one is called ishio the one in
13:45front is called pubis and then the one
13:47up Top's ilium so all together they fuse
13:51into one coxal bone and this tuberosity
13:54was where the iso part was so it's
13:56called ISO tuberosity
14:00uh Crest Crest is a kind of like a
14:03narrow Ridge of a
14:04bone so up here on the csil bone is a
14:07narrow Ridge of this whole bone it's
14:10called the aliac
14:12crest and because that part of the bone
14:14was once ilum as you're developing as a
14:17fetus so the Crest is on the ilium
14:20therefore it's called ilat
14:22Crest tubercle is a small rounded
14:27projection all right
14:30so we're looking for a tubercule
14:33somewhere
14:36here and I'm
14:39looking or it says a
14:43process so up here right above this
14:47whole region here where it meets the
14:49lower bones it's called a condal and
14:51typically condal are usually round so
14:54this is bone called a femur and the L
14:56Landmark here is called a condal and if
14:59you were to turn this around you'd see
15:00the round projection here and then right
15:03above it is an epic condal Epi means
15:05right upon it and then within there is a
15:08tubercle called adductor
15:15tucco spine uh typically a spine it's a
15:19narrow prominent Ridge of a bone kind of
15:22comes to a fine
15:24point so here's the extension of your
15:27vertebrae the whole Bone's vertebrae
15:29right this extension is called a process
15:31and because it's nice and sharp it's
15:33called spinus
15:38process some more landmarks some bones
15:41may have like a region where it looks
15:44large and it's round it's referred to as
15:46a head and then where it Narrows in
15:49connecting to another area the narrow
15:52regions called a
15:54neck some bones when they meet when they
15:57meet may be nice and smooth therefore
15:59it's called a facet where it's nice and
16:01smooth and then again if it's nice and
16:04well I should say round if it's rounded
16:06projection and it meets another bone
16:08often they referred to as
16:10condal articular means to
16:12meet Ramis uh the only example RIS that
16:16we need to know is on your
16:18mandible and and it kind of looks like
16:20an arm likee extension where you got an
16:22upper part of the arm and a
16:25forearm so let's look at the examples
16:27here like so this is your
16:29rib this portion here is called the head
16:32and then where it Narrows would be the
16:33neck and where it's nice and smooth
16:36where it meets the U another let's say
16:38your vertebrae those are facets where
16:41it's nice and
16:43smooth this is bone called the mandible
16:46and the rainless it's kind of like an
16:48arm like projection try to imagine this
16:50as your upper arm here's your forearm
16:53that's the rainless portion of the
16:55mandible
16:57pondal somewhat round in this case yet
17:00it's going to meet with the upper part
17:02of the skull so that's referred to as a
17:05cond some other examples here like on
17:08the mandible you have what's called a
17:10process an extension here this would be
17:12the mandibular
17:14process where it Curves in here like a u
17:17that's referred to as a notch and since
17:20it's on the mandible uh you refer to it
17:22as mandibular
17:26Notch some more Landmark names meatus is
17:29like a canal like passageway so like in
17:32your ear canal you got a
17:35meatus a sinus is a cavity within the
17:38bone so the sinuses uh they're referring
17:41to here are are within the
17:43skull a fosa is a kind of like a shallow
17:46little groove or depression within the
17:48[Music]
17:50bone and similar to fosa there's Groove
17:54uh kind of like
17:56depression a Fisher is more like a
17:59narrow slitlike opening within a bone
18:02and easy one for aiming just means a
18:04hole within a
18:05[Music]
18:07bone so let's
18:10uh have a look
18:15here so fossa kind of depression within
18:19the bone I like to think of like a bowl
18:21where the bowl Curves in or maybe like a
18:24u a pull an empty pull where it Curves
18:26in similar to inside the skull it's
18:29curving here where you can feel it curve
18:30that's a
18:32fossil a meatus is a canal likee passage
18:35So within the ear canal there's a
18:39meatus a notch typically a notch takes
18:42on a curve so here you had a notch
18:46within the bone here a grooves like a
18:48very shallow depression so it's within
18:51the mandible it's called the mandibular
18:54Groove sinuses are referred to the
18:56cavities within the skull so here is an
18:59example one of the sinuses within the
19:01skull where you actually have a total of
19:04four and easy or for amans framin are
19:07holes within the bone so to give you an
19:11example this one here is above the
19:13orbital cavity so this one's called
19:16supera orbital
19:17framing the one below it's below the
19:20orbital cavity so it's referred to as
19:22infra orbital
19:23Framing and then one on the mandible is
19:27called mental mental
19:31foramen a fisher fisher a narrow
19:34slit-like opening so if you look within
19:36the orbital cavities you could see these
19:38narrow slitlike
19:40openings So within the the top one here
19:43is called Superior orbital fissure
19:45indicating it's above another one and
19:48therefore the one below is referred to
19:50as inferior orbital
19:56Fisher now when you cut into say a long
19:59bone there's going to be areas of the
20:00bone where it looks nice and dense
20:02that's referred to as compact bone and
20:05then when you get into the middle where
20:06the cavity of the bone is there's going
20:08to be Pockets where you'll see bone
20:10missing it looks just like a
20:12sponge so they refer to that as spongy
20:15[Music]
20:17bone bones that are flat typically they
20:20don't have a cavity within the middle so
20:23you're going to see um areas where it's
20:25just spongy bone and the areas of the
20:28sponge bone that resist stress are
20:30referred to as
20:34trulite now when we get to the picture
20:36of the long bone the extension is called
20:39the shaft and all around the outer rim
20:42of the shaft and around the heads of the
20:45long bone it's
20:46Compact and inside the long bone is a
20:49cavity called meary cavity where you got
20:52red bone marrow where blood cells are
20:54produced and again as we get older you
20:57may store lipids in in there so yellow
21:00gives the appearance of the
21:05lipid the head regions well they're
21:09called epiphysis so the one that's
21:11closer toward
21:13the toward the shoulder region is called
21:16the proximal epiphysis and the one
21:18further away is going to be referred to
21:20as distal epiphysis when you grow in
21:24length uh there's an area within the
21:27bone called the epipal plate or you say
21:30epipal line basically you have Highland
21:33cartilage there and the cartilage cells
21:36called condr sites they replicate
21:39extending out the length of the bone
21:41which is first
21:43cartilage and then eventually that
21:45Highland cartilage it dies and gets
21:47replaced by bone and therefore you
21:50extend out the length of the bone and
21:52you also help modify the diameter of the
21:54bone as well to support the length
21:59at the end of the bone uh because
22:02there's Highland cartilage there as well
22:05because it meets another bone they refer
22:07to it as articular cartilage even though
22:09it's Highland it's just giving me the
22:11location that means it's going to meet
22:13another bone articulate means to meet
22:16and where two bones meet we form what's
22:18called a
22:20joint so looking at the picture
22:23here you cut let's say you did a coronal
22:26cut or a frontal cut same thing you go
22:28down the bone you'll see all along the
22:31head which is called the proximal
22:33epiphysis all along the outer rim of the
22:37diaphysis is compact bone where it's
22:40tightly condensed toward the middle as
22:43well as within the cavity there's areas
22:46where it looks like a sponge so they
22:48refer to it as spongy
22:50bone your bone is very well vascular
22:54you'll see blood vessels penetrate into
22:56the bone it's not like cartilage
22:59however you don't see blood vessels you
23:00refer to that area as
23:03avascular and at the end of the bone you
23:06also have Highland cartilage
23:08there as well as in the epipal line if
23:11you're still growing in length and the
23:14Highland cartilage at the end of the
23:16bone
23:17epiphysis because it meets another bone
23:20there they refer to it as articular
23:22cartilage that just means another Bone's
23:24going to meet there but yes it is
23:27Highland cartilage
23:30the cavity within the bone is referred
23:32to as meary cavity and that's where you
23:35find bone marrow where you produce blood
23:36cells red white and platelets but again
23:40as we get older you tend to store lipids
23:42therefore that's why you see this yellow
23:44coloration referring to there's lipids
23:49there now the
23:51outer connected tissue around cartilage
23:55is called a
23:57periostium okay okay and around the
24:00bone it's the periosteum okay so in the
24:05periosteum you got some cells there that
24:07eventually you'll see forming bone one
24:10is called
24:11osteoblast think of be and blast for
24:14bone forming they're the ones that make
24:16the bone hard and those osteoblasts once
24:19they get trapped within the bone they
24:21form a mature cell and no longer do you
24:24call it osteoblast you refer to it as an
24:26Osteo site and the little space is
24:30trapped within the bone that space is
24:31called a
24:33Lacuna now because you could store
24:35minerals like calcium phosphorus and
24:38Bone you can pull out some of that and
24:41release it into your bloodstream when
24:43blood levels of Calum phosphorus are low
24:46so the cells that contain digestive
24:48enzymes to do that they're called Osteo
24:52class both the osteoblast and the
24:55osteoclast came from a stem cell so stem
24:59cells are basically cells that can
25:00differentiate into different types of
25:04cells bone is very well vascular so
25:07you're going to see blood vessels in the
25:09bone there's also nerves going through
25:12there and the little holes within the
25:13bone and also lymphatic
25:16vessels what secures this outer
25:19periosteum tissue to your bone are
25:23connected tissue and they refer to them
25:25as Sharpie fibers
25:29so we look here here we got compact bone
25:31and there you see the outer connected
25:33tissue called the per osteum and the
25:36fibers that secure it onto the bone
25:38they're referred to as Sharpie fibers
25:41and again bone is very well vascular
25:43you're going to see blood vessels
25:44penetra to the Bone the cavity again is
25:47referred to as meary
25:50cavity
25:52the
25:54inside part of there there's a connected
25:56tissue lines the cavity
25:58the connect tissue that lines the inner
26:00cavity is called endosteum Endo means
26:04within so periosteum connect tissue
26:07surrounding the bone and the connect
26:10tissue lining the cavity is referred to
26:13as osum in both those
26:17tissues that's where uh let me jump back
26:20that's where you're going to see
26:21osteoblast and osto
26:25class and then again when the osto blast
26:28or within the bone itself it's you
26:31referred to it as now an Osteo side a
26:33mature
26:36cell all right um when we look at a flat
26:39bone there is no cavity within the flat
26:41flat bone basically in the middle is a
26:44spongy bone kind of like um when I was
26:46told as a student think of a sandwich
26:49you got two sides here a compact bone
26:51and in the middle spongy
26:53bone the areas where the spongy bone is
26:56kind of like in columns to to resist
26:58stress that is referred to as turula I
27:02like to think of tubula kind of like the
27:03framework of a house as it's being built
27:06so that can resist
27:08stress so here you're looking at the
27:10flat bones of the uh the
27:14skull there there is bone
27:17marrow in the cavities as well as within
27:20the spongy
27:21bone and in red bone marrow that's where
27:24you form blood cells you also have says
27:26here in the femur the humor there's
27:29cavities there with red bone
27:33marrow and some here in what newborn
27:40infants the cells that are in bone
27:44remember there's Osteo blast think of be
27:46blast those are the ones that form bone
27:48and when they get trapped in the bone
27:50it's an Osteo site now it's mature and
27:53then there's
27:54osteoclast which can digest the bone and
27:56release calcium phosphorus from the bone
27:59into your bloodstream when it's needed
28:01both the osteoblast and osteoclast came
28:04from a stem cell that's what they're
28:06referring to here a fancy name for stem
28:09cell osteogenic cells where do we find
28:12them we find them in the outer connected
28:14tissue around the bone Nole within the
28:16cavity in the bone called the
28:19ostium so here's a a drawing of our stem
28:23cell and that stem cell can
28:24differentiate into into either an osto
28:28blast bone forming or an osto class and
28:33osto
28:34class um contain digestive enzymes to
28:37release calcium
28:38phosphorus they refer to it as when
28:42calcium phosphorus is put into your
28:44bloodstream that's called bone
28:46resorption I know it sounds kind of
28:48backwards like you would think
28:49resorption is Into The Bone but no it's
28:52when the osteoclast break bone down and
28:55the resorption is occurring into the
28:57bloodstream where you put calcium
28:59phosphorus in the
29:01blood when the Osteo blast gets trapped
29:03in The Matrix of the bone it's no longer
29:05refer to as osteoblast you can refer to
29:08it now as an Osteo
29:12site so picture of our
29:15osteocyte and then to the right here is
29:18the bone resorption cell where contains
29:21digestive enzymes to break bone Down
29:23release calcium phosphorus in the blood
29:25it's called an Osteo class their bone
29:28resorbing
29:31cells now the functional unit of any
29:35system is the smallest component that
29:37does its overall job so let me give you
29:40an example like your nervous system the
29:42functional unit the smallest component
29:44would be a nerve cell for
29:47bone it's a round circular region
29:50they're referred to as osteons that's
29:53how I like to remember them it's a
29:54little easier than saying hsan system so
29:58those are the functional units of the
30:00skeletal system and if you look here
30:03these little ring patterns kind of like
30:05similar what you would see if you cut a
30:07tree that's the
30:13osteon and within the ring patterns
30:15you're going to have Lamela lamelas are
30:17these ring structures surrounding or
30:19making up the osteon and within the
30:22Lamela are fibers collagen fibers that
30:25you find in connected tissue so here
30:28collagen fibers are to resist twisting
30:30forces and in the middle of each osteon
30:33is a canal an opening called the central
30:37Canal where you're going to find blood
30:39vessels nerves going through each
30:42osteon within the central canal and just
30:46to take note of this uh osteon look at
30:48the collagen fibers in each ring pattern
30:50the Lamela for each ring the collagen
30:53fibers are arranged in opposite
30:55directions so that way you can resist
30:58twisting
31:01forces so functional unit again of the
31:04skeletal systems called an oon these are
31:07these round circular regions within
31:09compact
31:10bone The Matrix of the bone that you
31:13find making up the rings of the osteon
31:15are referred to as Lamela where you got
31:17collagen fibers and then the hole within
31:20each osteon where you find blood vessels
31:23and nerves going through that hole is
31:26called the central Canal that's how I
31:29like to name it or if you want
31:32perversion
31:37Canal okay now going down in osteon the
31:41central Canal is going straight down now
31:44these openings go at right angles where
31:46you got blood vessels nerves going
31:48through those ones that at right angles
31:50are called perating or Vulcan canals so
31:54let's have a look at the picture so take
31:56one of these ring structures that's our
31:58osteon and the hole in the middle is the
32:01central
32:03canal and then the ones that go at right
32:06angles you can see over here in the
32:08drawing those canals are referred to as
32:10Perforating or Vulcan canals take your
32:16pick and then the osto blast we
32:19mentioned that once it gets trapped in
32:21the bone it's now a mature Cell It's
32:24called an Osteo site and that space that
32:26it gets trapped within is referred to as
32:28a
32:30Lacuna so let me magnify let me find the
32:34slide where I'm looking for this picture
32:35here on the bottom
32:37left so here's our Osteo site it was
32:41putting down bone and then it got
32:43trapped and once it's trapped it's a
32:46mature cell now so you refer to as Osteo
32:48site site means
32:50cell the space it's trapped within is
32:53the
32:55Lacuna you're going to notice that in
32:58the central Canal there's also coming
33:00off of it these little slitlike openings
33:02within the bone called canaliculi think
33:05of canals canol liuli is
33:08plural if you want to say singular then
33:11you call these little narrow slitlike
33:13openings Canal
33:15lulus so these cells the osteocytes are
33:19getting their oxygen nutrients from
33:21blood vessels located in the central
33:23canal through diffusion
33:30so the osto site once it's trapped in
33:32the Lacuna right it's getting oxygen
33:35nutrients from slitlike openings called
33:37canaliculi for plural or you say
33:39canaliculus for
33:42singular back to our picture here this
33:45is the whole compact bone in the middles
33:47of the cavity the outer connected tissue
33:50again is called Perry oium secured to
33:53the Bone through fibers called Sharpie
33:56fibers the functional unit of the bone
33:59these circular Rings they are called
34:01osteons the canal in the middle is
34:03called Central
34:05Canal the openings go at right angles
34:08they're Perforating canals or vcan
34:11canals and then on the bottom picture
34:13here this is an actual slide of the the
34:17bone you may recognize it from the lab
34:20on the far bottom right that's the
34:22osteon and those little dark regions
34:24represent the osteocytes within a Luna
34:29the picture right next to it looks more
34:31three-dimensional more likely that's
34:33from an electron
34:38microscope okay now recollect that flat
34:41bones they don't there's no cavity so
34:43it's basically spongy bone and the areas
34:46to put down and resist stress that area
34:49of the spongy bow is called
34:52tulate so you don't see the ring light
34:55patterns in spongy bone there
34:58they have irregularly arranged Lamela
35:01osteocytes but they also have canals
35:04called
35:05canaliculi there are blood vessels there
35:07so it's still
35:09vascular and the smallest vessel is
35:12providing oxygen and nutrients are
35:17capillaries so here again our osteon
35:21kind of like they didn't draw it all
35:22circular all around and in The Middle's
35:25the central
35:26Canal the the cell trapped in Luna is
35:29now mature it's called an Osteo
35:32site and the canals you call them
35:35canaliculi for plural or canaliculus for
35:43singular okay so the stem cells called
35:45osteogenic cells are the ones that can
35:47differentiate and make
35:50osteoblast or a osteop class and don't
35:55forget the osteoblast comes mature when
35:58it's trapped in Lacuna and therefore
36:00then you refer to it as Osteo
36:04site just like any other connected
36:07tissue what makes up or you find similar
36:11in connected tissue is a non-living
36:13component called The
36:15Matrix so the
36:19matrix consist of anything non-living
36:22like proteins
36:24minerals here it says proteoglycans
36:27glyco proteins they call that ground
36:29substance and you may see fibers so we
36:33saw in bone there's collagen fibers
36:35right to resist stress so these two
36:38components make up the Matrix of
36:41bone and the cells that put down the
36:44bone that make it nice and hard are the
36:47Osteo blast and the hard portion of bone
36:51is referred to in general as osteoid
36:58what makes bone hard is basically
37:00mineral salts that they refer to as
37:02hydroxy appetite made by Osteo blast so
37:0865% are these mineral salts called
37:10hydroxy appetite mainly it's calcium
37:13phosphate crystals they give bone the
37:16hardness and resistance to stress or in
37:19this case says also
37:24compression okay let's go to the next
37:38PowerPoint make sure I'm recording yes
37:41it looks like I'm
37:42recording and let's bring this magnifi
37:46so this is the second part of the um
37:50PowerPoints so when you form a bone for
37:53the very first time uh it's referred to
37:55is what we got here Osteo Genesis so
37:58there's different stages here it looks
38:01like when you develop as an embryo fetus
38:04what you first have is Highland
38:06cartilage and eventually you start
38:08replacing that Highland cartilage and
38:10putting down bone and this begins around
38:12the second month of
38:14development after birth most of the
38:17skeletal systems car um sorry most of
38:20it's bone already but there are areas
38:23within the bone where it's still
38:24Highland cartilage so so you'll still
38:28grow in length as long as that Highland
38:30cartilage within the bone is still
38:32living and once those cells of Highland
38:35cartilage are dead you can no longer
38:37grow in
38:38length the other thing you're you're
38:40going to be doing after that throughout
38:42the rest of your life is just adding two
38:45areas where bone is needed or taking out
38:48depends on the compression and forces
38:51you put on your skeletal system and that
38:54is called bone
38:55remodeling so after you're done growing
38:57and length the thing you'll be doing
38:59consistently throughout your life is
39:01called bone
39:03remodeling two types of forming bone for
39:06the very first
39:08time when you form the flat bones of the
39:11skeletal system like your clavicles yes
39:15your clavicles is a flat bone even
39:17though you think it be long
39:19bone or the ones of the skull then when
39:23you form those for the very first time
39:24it's called
39:26intramembranous
39:29oifc then after that the majority of
39:31other bones they go through a process by
39:33just replacing Highland cartilage with
39:36bone and that's referred to as
39:39endochondral
39:44oifc so let's have a look here what are
39:47we doing for the first time I believe
39:49this one's going to be in and brinis
39:51oifc we're going to be forming a flat
39:53bone now if you can remember from the
39:56chapter 4 all connected tissues come
39:59from an embryonic tissue called mezanine
40:02so you have these mesim cells here and
40:05they eventually were going to going to
40:08differentiate into Osteo blast and it's
40:13the osteoblast remember that are putting
40:15down bone making it hard so once it
40:18starts getting hard in this area it's
40:21called an OIC
40:25Center some of the the osteoblasts are
40:28now trapped within the Matrix the hard
40:30part of the bone no longer is osteoblast
40:33you can refer to now as an Osteo
40:38site bone is very well vascular at some
40:40point of development you'll see blood
40:42vessels penetrate into the in this case
40:45spongy
40:46bone and then the cells in the outer
40:50region you will eventually going to form
40:53the outer connected tissue called the
40:55per osteum
41:00so this is basically what you have at
41:02the end of forming a flat bone got two
41:04sides of compact bone and in the middle
41:07is spongy bone and then the outer
41:10connected tissue is the per oium and
41:13that's where you're going to find
41:15osteoblast and Osteo
41:18class the actual cells trapped within
41:20the heart portion of the bone well then
41:23you refer to it no cells as osteocytes
41:30the other type of forming bone for the
41:32very first time is called endochondral
41:34oifc basically you're just replacing
41:37Highland cartet cells that are dying
41:40replacing it with
41:43bone so let's take this one step at a
41:46time so at week
41:49nine this stage development referred to
41:52as a fetus you could see most of the
41:54bones is Highland cartilage
41:57Highland cartilage cells start to die
42:00then osteoblast start replacing there
42:02with bone and where it's hard is
42:04referred to as an
42:06oifc
42:09Center you see the cartet cells start
42:12dying more they're being limited toward
42:14the head regions of the bone called the
42:17epiphysis and in the middle now you
42:19start forming the cavity called the
42:21medular
42:23cavity then you see blood vessels
42:26penetrate into the cavity bones very
42:28well
42:30vascular you'll start seeing carage
42:32cells more dying within the heads of the
42:36epiphysis forming what's called a
42:38secondary OIC
42:40Center and then at
42:42Birth this is basically uh from after
42:45birth from childhood to adolescence is
42:47what you have you're going to have areas
42:50of live cartet cells if you're still
42:52growing in length located in a plate
42:54called the epipal plate or you could say
42:58epipal
42:59line and then at the end of the Lum bone
43:02is also Highland
43:04cartilage and because there is where it
43:06articulates with another bone they refer
43:09to it as articular cartilage remember
43:12articulate means to meet another bone in
43:14this
43:15case so this is what you have at Birth
43:18you'll grow in length as cartet cells
43:21reproduce and once the car cells are
43:24dead in the epipal plate you'll no
43:26longer grow in LAN length the only thing
43:28you'll be doing from then on out is
43:29referred to as bone
43:35remodeling growing in length in general
43:38is referred to as interstitial growth
43:41growing in density or diameter wise is
43:44referred to as appositional
43:49growth what happens as you grow in
43:51length well the cartilage cells in the
43:54epipal plate will proliferate which
43:57means they'll replicate and increase in
43:59number they'll get larger in size which
44:02is
44:03hypertrophy then they'll start to harden
44:06which is calcify and die eventually then
44:09they're replace by bone by osteoblast
44:13and when it's replaced by bone that's
44:15area where it's
44:18hardening so here imagine in the drawing
44:21top left there's the aripal
44:24plate in the basil layer of the pistal
44:28plate the carlet cells are doing mitosis
44:32they're replicating and they extend out
44:34the length on both sides of the epipal
44:37plate they're getting larger they
44:42hypertrophy and as cells die in the
44:46epipal plate those cartilage cells die
44:48they're being eventually replaced by
44:50bone and what's replacing them with bone
44:52or Osteo
44:54blast so as long as cartet cells are
44:57alive in the epipal plate you could
45:00still be developing in length which is
45:02called interstitial
45:06growth what stimulates growth well
45:09hormones right thyroid hormone would
45:13step up the process of growing in length
45:17testosterone estrogen those hormones Al
45:20also help with growing in length so
45:23you'll see a grow spurt around where you
45:25make more of these hormones during a
45:27Time called
45:31puberty this is a picture when you grow
45:33in
45:34length you'll notice that the diameter
45:37of these little red lines indicate the
45:39length prior to growing and when you
45:42grow in length you also modify the
45:44diameter of the bone so there's some
45:47bone remodeling going on here so that
45:49way you can support the length as you
45:52grow
45:57now how does your body know where to put
45:58bone or take bone from it's basically on
46:01the stress that you put upon the bone so
46:04if you don't let's say put so much
46:06stress on the bone you'll take more out
46:10and vice versa The more stress you put
46:11on the bone you'll want to put more
46:13there to resist the stress that's being
46:16put upon
46:17it similar to working out your muscles
46:20you know how do you know where to put
46:22more protein so it make the muscle
46:24larger well when you work it out more
46:27so that's basically how you know where
46:29to put bone down or take
46:31out it does require a diet rich in
46:34proteins vitamins calcium phosphorus
46:38magnesium and
46:44manganese again you'll put bone down
46:47where it's needed or take out if it's
46:49not
46:50needed I don't want to have to read
46:52specifically here
46:55is you do want to recognized it's the
46:57osto class the ones that contain
46:59digestive enzymes so they have lomes
47:03that can break the Matrix of bone down
47:05to release calcium and phosphorus in
47:07your blood when it's needed so these
47:10cells are responsible for what's called
47:13bone resorption not putting into the
47:16bone but doing the resorption by putting
47:18into your bloodstream putting in calcium
47:22and
47:25phosphorus so here as these cells break
47:28the Matrix down to
47:29Bone the calcium phosphorus will travel
47:33across the cells and eventually enter
47:36the fluid called interstitial fluid
47:38which is found between your blood
47:40vessels and tissues and then eventually
47:43you will enter your your
47:48bloodstream what else controls where you
47:50want to put bone or make more of um here
47:54they're referring to how do you know
47:55when to take calcium out or to put
47:58calcium into the bone okay not
48:00necessarily where to put bone down or
48:02take out through hormones
48:06okay and the forces again how do you
48:09know we put more bone down or take out
48:11the stress you put upon
48:13it so there's two hormones that help
48:16maintain constant calcium levels in your
48:18bloodstream one's called parathyroid
48:21hormone and the other one's called Cal
48:24tonin
48:27why do you even need calcium well
48:30calcium is needed for neurons which is a
48:32nerve cell to communicate to
48:34targets so in other words in order to
48:37release neurotransmitters you need
48:38calcium neurotransmitters are the
48:40chemicals used by neurons to communicate
48:43to targets you also need calciums for
48:46your skeletal muscle cardiac muscle even
48:49smooth muscle to contract you need
48:52calcium to form a blood clot should you
48:54have a slight tear in a vessel you need
48:57calcium for glands to release their
48:59products we already mentioned nerve
49:01cells you need it to release neurot
49:04transmitters looks like you need calcium
49:07also to promote cell
49:12division so going back to which hormones
49:15help maintain constant calcium levels in
49:17the bloodstream one is called par
49:21thyroid
49:22hormone in your thyroid
49:25gland let's see they have have a picture
49:27here yes they do so in the neck region
49:29your cervical region the neck there is a
49:33thyroid gland you're probably familiar
49:36with thyroid hormone that it'll increase
49:38your
49:39metabolism that is one hormone but if
49:42you turn your thyroid gland around
49:45you'll see little psize glands embedded
49:47within it those are called par thyroid
49:51glands so should calcium levels fall
49:54below normal in the bloodstream these
49:56paradroid glands will release the
49:58hormone called
50:00parid hormone that will travel
50:03eventually to your skeletal system and
50:07cause Osteo class to start breaking bone
50:11down to release calcium into your
50:14bloodstream to bring calcium levels back
50:16to
50:19normal so again let's say blood calcium
50:22levels drop that stimulates parid glands
50:25to make periid hormone parathyroid
50:28hormone stimulates osteoclast to break
50:31the Matrix of bone Down release calcium
50:33in the
50:34bloodstream returning them back to
50:37[Music]
50:38normal parathyroid hormone another
50:42Target is promotes the synthesis of
50:46vitamin D at the kidneys you need
50:49Vitamin D in order to absorb calcium
50:52therefore the more vitamin D available
50:55the more you'll absorb more calcium from
50:57your
51:01diet all right now what if you took
51:04calcium supplements and now it's high in
51:07the bloodstream now you want to promote
51:09and take the calcium and put it into
51:11your bone so after you let's say you
51:15took supplements the calcium levels in
51:16the bloodstream are high there's other
51:19cells in your thyroid gland called
51:21paraphilic cells they make a hormone
51:24that does the opposite of parad hormone
51:28so these paraphilic cells make
51:31calcitonin calcitonin once released in
51:34your bloodstream travels to your
51:36skeletal system and stimulates Osteo
51:40blast Osteo blast will uptake the
51:44calcium from your bloodstream and put it
51:46into your
51:50bone so let's just quick review calcium
51:54levels fall below normal
51:56parathyroid glands make parathyroid
51:59hormone stimulating Osteo class to do
52:03bone resorption break down the bone
52:06release the calcium and phosphorus in
52:08your blood that's where the resorption
52:10is
52:12occurring vice versa calci levels are
52:15high in the blood that stimulates the
52:17release of
52:19calcitonin which stimulates Osteo blast
52:23to take up the calcium stored in your
52:26bone
52:28we're not going to focus down here on
52:30this hormone called
52:31leptin looks like this is a different
52:33hormone that influences your bones
52:38density in other words the thickness by
52:40inhibiting
52:44osteoblast so you inhibit osteoblast
52:47well you're not going to make it so
52:49dense it' be less
52:53dense all right back in the day if
52:55someone disced Ed something they got to
52:57name it I'm sure that Stills apply uh
53:00Wolf's Law I think it's just common
53:03Logic the let's say the more you use a
53:06bone The more stress you put upon it
53:08that's where you want to add more bone
53:10so it's going to be denser so let's say
53:12if you're right-handed use your right
53:14hand more the bones within the right
53:17hand are going to be a lot more dense
53:19compared to the bones in the left hand
53:22so that's all that it means wol SL The
53:24more stress you put on the bone the
53:26denser of the bone will be to resist the
53:30stress bones where they curve you don't
53:33want them to
53:34buckle you're going to see more bone
53:37being put down in that area to resist
53:42buckling spongy bone where there's more
53:44stress you're going to put more spongy
53:46bone in columns to resist the stress so
53:49that area where you're resisting stress
53:51in the spongy Bones called
53:54tubic when you work out your mind
53:56muscles your skeletal muscle they're
53:59attached to your bone so the more you
54:01work out a muscle you don't want it to
54:03disattach from your bone the Bone's
54:07going to form a more
54:08prominent
54:10uh prominent region to attach to the
54:13tendon so that way the muscle doesn't
54:16disattach so large bony projections will
54:18occur where heavy active muscles
54:23attach bone is uniquely designed where
54:26where you put stress upon it it can
54:28because it's arranged in a certain way
54:30can produce a counter stress so you're
54:33looking at a picture of your femur which
54:35is in the upper part of the leg you put
54:38most of your body's weight right on the
54:40fur's head and the way because of the
54:42bone is made it produces a counter Force
54:46to resist the
54:47stress can you overwhelm its ability
54:50yeah sure keep putting more weight but
54:53the main idea is because of the unique
54:55way bone is made it's to resist
55:02stress okay no one likes to break
55:05anything we break a bone it's called a
55:08fracture sometimes when you fracture a
55:10bone the bone may come out of its normal
55:13alignment if so they refer to that as
55:16displace if the bone fracture does not
55:20come into the alignment then it's
55:22referred to as non
55:24displace sometimes you may have a
55:26fracture and it doesn't go all the way
55:28through or across the bone then it's
55:30referred to as
55:32incomplete if the break cures all
55:35through or all across the bone then it's
55:41complete how did the fracture occur did
55:44it go across well then it's
55:47transverse if it went straight down up
55:49and down it's referred to as
55:53linear the ones I don't like to
55:55visualize
55:57uh I don't like to see anything fracture
55:59especially in sports but I I don't want
56:02to visualize any bone penetrating the
56:04skin if it does they refer to that as
56:06open or compound whereas if the bone
56:10fractures it does not penetrate the skin
56:13you refer to it as simple or
56:17close fractures can also be described in
56:21the location of the fracture the
56:23appearance of the fracture or what
56:25caused the fracture
56:29so here you're looking at a communed
56:31fracture where the bone breaks in
56:32several pieces fortunately as we get
56:35older you take more bone out than you
56:38put in and therefore becomes more
56:40brittle and areas where there's stress
56:43as you get older it may fracture in more
56:45than one piece therefore it's referred
56:48to as communed fracture where it
56:51fragments into three or more pieces
56:54commonly happens in as as we get
56:57older compression just like it sound
57:00what caused the fracture physical
57:03compression so this occurs where most
57:05compression in the body happens in your
57:12vertebrae spiral well this one's common
57:15in sports where you may see someone try
57:17to change their position quickly and
57:19change directions or attempt to and the
57:22buone can't take that resistance and it
57:25fractures in a spot
57:27spiral way that's a spiral
57:31fracture
57:33epipal well at some point in time when
57:35we're growing in L still those cells in
57:38the epipal plate are going to die and
57:42that's it you're done growing in
57:44length sometimes should you have a
57:47separation here at the epipal plate well
57:51then it's called an epipal
57:53fracture tends to occur where cartet
57:56cells are dying and hardening of this
57:58area is
58:02occurring depressed fracture what caused
58:05it and it was physically pushed upon so
58:08that's what they mean by depressed
58:10fracture a green stick similar to like
58:13trying to break a green stick won't
58:15break all the way
58:16through so when we're young our bones
58:19aren't fully hardened they're somewhat
58:21still pliable so if a fracture occurs it
58:24may not completely go all the the way
58:26through therefore it's referred to as
58:28green stick where the bone still what
58:31somewhat
58:33pliable here it says bone breaks
58:36incompletely much in the way a green
58:38stick or twig breaks only one side of
58:41the shaft breaks the other side bends
58:44common in children's whose Bones have
58:46relatively more organic Matrix they're
58:49more flexible than those of adults
58:52you'll notice kids take Falls in here
58:54and they're okay versus as an adult
58:57we're not as flexible it's hardened
58:59you're more likely to break
59:03bones when you fracture bone you
59:05probably torn vessels within the bone
59:07causing
59:08bleeding so here hematoma
59:15forms basically blood clotting you have
59:19the vessel bleeding so hemorr referring
59:21to the bleeding you want to form a clot
59:23so you want to form what's called a
59:24hematoma
59:26because vessels are leaking fluid the
59:28site becomes swollen and as pressure
59:31builds it'll interpret it as painful and
59:34it's inflamed it's warm because more
59:36blood flow is going to the
59:38area so here you have a fracture blood
59:41vessels are torn you're bleeding you
59:44eventually want to form a hematoma this
59:46blood
59:48clot then you want to start repair so
59:51you want to start putting down replacing
59:53the collagen fibers so you form what's
59:56called a
59:57fibrocartilagenous
59:59callus white blood cells yes they'll
1:00:02come to the area they're fiic will fagos
1:00:05size dead tissue hopefully they get rid
1:00:08of anything foreign should something
1:00:09foreign be
1:00:11there and then Osteo blast start putting
1:00:13down spongy bone and now we're going to
1:00:16connect the separated ends with collagen
1:00:19fibers so fiber blasts make collagen
1:00:22fibers to connect both
1:00:24ends now it says the massive repair
1:00:27tissue is now called a fibro carus
1:00:31callus so picture here of our
1:00:34fibrocartilagenous
1:00:37callus the next thing you want to do now
1:00:39is make it a little more rigid harder so
1:00:42neutri form a bony or hard callus this
1:00:46continues until the union is formed in
1:00:48approximately two months you connect the
1:00:51ends approximately takes two months
1:00:56so now it's nice and hard the only thing
1:00:58here it doesn't quite look like what we
1:01:00had before so the last thing we want to
1:01:02do is remodel it so it looks similar to
1:01:04what you had before that's called bone
1:01:07remodeling and it's going to respond to
1:01:10the stress you put on the bone until
1:01:12finally resembles to what you originally
1:01:15had prior to the
1:01:18injury so there's the bone
1:01:21remodeling now yes bone can repair
1:01:24unfortunately as we get get older it
1:01:27takes
1:01:30longer this is just what we went
1:01:34through
1:01:35some imbalances or diseases of the
1:01:39skeletal system one is oste malaia and
1:01:42rickets um basically you're not putting
1:01:45calcium down enough where it's needed
1:01:48and because the bone is not as rigid as
1:01:50it should be May bow out where stress
1:01:53occurs so if this is the case happens in
1:01:56children they refer to it as rickets
1:01:59cause causes bowed out areas like in the
1:02:02bones of the leg and other says bone
1:02:05deform deformities what's the cause well
1:02:08you need what in order to absorb calcium
1:02:11vitamin D either you're deficient in the
1:02:15vitamin D or you're not getting enough
1:02:17from let's say your diet as
1:02:21well unfortunately as we get older
1:02:24instead of putting more bone
1:02:26into our skeletal system making it nice
1:02:28and dense we tend to take more out and
1:02:31as you take more out instead of looking
1:02:33nice and compact looks more like a
1:02:35sponge therefore takes on appearance of
1:02:38spongy bone basically bone resorption
1:02:42which is means taking out is outpacing
1:02:44bone deposit as we get older and the
1:02:47areas of the bone where you took more
1:02:48out now it looks like a sponge now it's
1:02:52more susceptible to fracturing or
1:02:54breaking
1:02:56risk factors uh estrogen ladies so
1:02:59estrogen does help to absorb calcium or
1:03:02even maybe a lack of calcium in the diet
1:03:05or inefficiency to absorb it because
1:03:07you're not getting enough vitamin D
1:03:10petite body form immobility basically if
1:03:14you don't use and put some little stress
1:03:16on your bones you'll take more out so
1:03:19your is some some point where you do
1:03:22want to do moderate exercise so that you
1:03:25could tell your body hey we need to put
1:03:27more bone down here and yet not totally
1:03:30just relaxed where you're going to be
1:03:31able just to take it out so moderate
1:03:34exercise will help put bone down where
1:03:37it's
1:03:37needed fortunately as we get older we
1:03:40make less thyroid hormone so low amounts
1:03:43of thyroid stimulating hormone will also
1:03:46decrease the density of our bones and
1:03:50diabetes in diabetes there's excess
1:03:53amounts of sugar in the bloodstream
1:03:55cause damage to capillaries capillaries
1:03:58are providing oxygen nutrients to
1:04:00tissues you can't provide oxygen
1:04:03nutrients to tissues tissue dies
1:04:07okay so up top is an area where the
1:04:11bone areas where yeah it kind of looks
1:04:14like a sponge but look at the density of
1:04:16the bone versus the
1:04:18bottom you could see you're taking more
1:04:21out as you age and it looks more like
1:04:23spongy bone it's not as dense
1:04:29so how do we keep osteoporosis at Bay
1:04:32well supplements like calcium vitamin
1:04:37D I'm not sure about the fluoride in the
1:04:40water
1:04:42um I wouldn't go so much with that at
1:04:45some point may be damaging take too much
1:04:48fluoride moderate exercise we already
1:04:51mentioned that you want to tell your
1:04:53nervous system or you need to put bone
1:04:55where it's needed by moderate
1:04:58exercise hormone replacement I guess
1:05:01some point in time ladies you're all
1:05:02going to go through menopause so
1:05:04estrogen replacement therapy would help
1:05:07to slow down bone loss some drugs that
1:05:11I'm unaware of here will help increase
1:05:14bone mineral density as
1:05:17well pades disease is excessive
1:05:20halfhazard bone formation and breakdown
1:05:23usually occurs where most compression
1:05:25occurs like in the vertebrae that
1:05:27protects your spinal cord your pelvic
1:05:30region femur or
1:05:32skull so
1:05:33basically it's always a balance of how
1:05:36much Compact and spongy bone you have to
1:05:39be normal now when you start putting
1:05:41more spongy bone down than compact bone
1:05:45that's not good so that lead to here
1:05:47pades disease what can cause that it
1:05:50says what unknown possibly
1:05:53viral treatment includes supplements
1:05:56like calcitonin and bif phosphinates
1:06:01as you develop When developing as an
1:06:04embryo you'll start replacing cartilage
1:06:07Highland cartilage with bone so at
1:06:09certain stages if you took a um it says
1:06:12here an x-ray or sonogram you can also
1:06:14determine the age of the development due
1:06:17to the hardening of the bone at what
1:06:20stage you're at and at Birth pretty much
1:06:24they resemble an adult it says here at
1:06:26Birth most long bones are well aifi
1:06:29which means Harden except at the epipal
1:06:33plate where there's live cartet cells so
1:06:36that you can grow in length once the
1:06:39cartet cells in the epipal flate are
1:06:42dead you can no longer grow in length
1:06:45the next thing you'll do throughout your
1:06:46life is referred to as bone remodeling
1:06:49you're adding to or taking
1:06:52out here you're looking at a probably an
1:06:56infant not or somewhere between newborn
1:06:59and infant you're going to notice they
1:07:01may have these soft spots on the skull
1:07:03called
1:07:04fontanels that keep the skull somewhat
1:07:06pliable so that way at Birth they can
1:07:09get through Mom's birth canal the other
1:07:12thing they do they allow some growth and
1:07:14then after a year the soft spots of the
1:07:17skull called fontanels will harden into
1:07:19what's called
1:07:22sutures okay I believe this is the end
1:07:24of the chapter
1:07:28oh no not quite let's finish it out
1:07:30nearly all bones completely oi by your
1:07:3220s unfortunately as we get older the
1:07:35density
1:07:37decreases also your environment may have
1:07:39an effect on your skeletal system as
1:07:42well your genetics as well to keep it at
1:07:45bay may also play
1:07:47roles and but again in old age we're all
1:07:49going to go through some form of
1:07:51osteoporosis we're taking out called
1:07:54resorption is outpacing bone
1:07:59deposit okay now it's done I'll stop
1:08:02share and I'll see you next time where
1:08:04we'll do the next chapter