Growth and Development

hi everyone I'm back here so now I'm going to explain few important topics in relation to growth and development of our products so first of all dealing with growth so basically in this in this particular topic we need to learn about individual scientists and what the tagline they have given for growth so all the many clinicians have defined growth in a different phase there is no universally accepted definition of growth and these are the following clinicians which has given or defined the growth so please do just have a look okay don't try to mark up some you you try to identify the keyword and try to remember the scientist M so preferably an increasing in size is called as growth was given by good scientists so such questions are most common in this particular area so please do make a note about these lines and the scientist names like simply give the line ok increasing in size change in the proportion and prokhor so complexity which is called as growth was given by which scientist is a most probably asked question in this area the next comes is in most of the cases the growth is just an increasing in size but there are few cases where you can see growth can be regression the best example is the thymus gland okay which decreases in size as a synchronous the next comes is the development okay so these are the two scientists which has given or defined the development okay one is referred to all naturally-occurring unidirectional changes in the life of an individual from a single cell which is as I got initially that is the fusion of the sperm and OVA which is a cheese ladder converted into a multifunctional unit that is the body okay so todd has given it is progression towards maturity the next comes is the differentiation it is changed from generalized cell or a tissue to more specialized kind of tissue during the development initially if we see your embryonic cells they are generalized cells later by the stimulus these generalized cells are differentiated into different types of cells and each cell has its specific function similarly like you we are like dental students once we are done with BDS it is something like a generalized thing so once we are done with the dead videos we will go to the next level that is MDS where we are going to convert it to some speciality okay so this is something called as differentiation means converting a generalized stuff into more specialized stuff okay this is a good good area where you can see a number of questions which were previously repeated an examination point to feel and of course this is a for Marx question for us in the university exam ok so growth doesn't takes place uniformly at all the time okay it varies at few in a particular duration of time you'll have an enormous growth in a particular duration of travel you'll have less corrupt okay there seems to be a period where there will the acceleration of growth followed by there will be sudden increase in the growth or or a slight increase in the growth it's not constant okay so that area where there is a sudden increase in the growth is called as growth spurts so these are the areas which we have in our life where there will be an over a singles one is just before birth and second one is one here after birth and the third one is mixed dentition for boys it is 8 to 11 for girls it is 7 to 9 and pre-pubertal growth spurt that is in the guys it is 14 to 16 in the girls it is 11 to 13 years so what is the clinical importance of this particular age this particular is is most of your functional and orthodontic appliances it is better they show a better response during this particular age group so that's the reason buy most of your ortho treatment are done before the pubertal growth report the pivotal growth both of your auditory orthodontic treatments are done because it encourages or it responds well for your for your treatment outcome and for example if you are planning any surgical Corrections that includes the maxilla and mandible they should be carried out only after completion of these most of your permanent surgeries in the maxilla and mandible are done after the growth of maxilla and mandible preferably after fourteen to sixteen years of is the next comes is differential growth as already discussed growth is not uniform okay it doesn't grow at the same rate throughout the life different organs has different growth and different amount of growth difference in the size difference in the time and everything these things are well explained by these two curves okay one is cephalo Cardinal curve or cephalocaudal gradation growth and the second one is Simon's growth curve so we'll discuss in detail okay this is the cephalic what it means how the growth will be from head to the table okay how it varies okay this particular growth simply means that there is an axis there is an axis in the body in the body there is an axis in the body which helps in determining the growth which helps in determining the growth of an individual a comparison of body proportions prenatal postnatal is going to give an idea of this particular hypothesis for example if you take the individual preferably at two or three months of internal life had octopus 50% as you can see had occupying 50% is of the total body length particularly around three weeks of through two to three weeks of internal and life but as at the time of birth if you see at the time of birth this is at the time of birth okay the occupancy of head dropped down to 30% is when it is converting into adult when it is converting into an adult it dropped down to 12% this means at three weeks of three months of Internet and life the head occupies 50% is where as at the birth it occupies 30% is okay and coming to the next level at at at the puberty at the A's of adult it occupies only 12% this so there is a decreasing in the occupancy of the body surface area or the proportion of the head run compared to the internal life to the adult similarly if you take the the lower limb okay lower limb in the uterine life the lower limb is rudimentary okay it doesn't how your lower limb doesn't have any aspect it is considered as rudimentary but as increases the lower limb occupies more than 50% is you can see it here it is rudimentary where it occupies the 50% is this is not only in in the in the particular tone of the entire body even if you want you can compare this okay you can see this okay there is and growth evidence even in the head and the face even in the head in the face at birth okay at Birth the cranium is is in LA you can see by this is at Birth the cranium occupies a major content okay a major content when compared with the face which is also less but as is increases your face will increase in the proportion when compared to that of the cranium so this is can be seen in comparison of the cranium to that of the face also the next comes is this this is the growth curve okay the growth curve so there were few diagram based questions asked in relation to this growth curve also they have simply without giving a title they have simply label it as a this has B this as C this as the simple so they have simply given this diagram and they have asked you to identify identify which tissue growth in the particular growth curve is B or C or T such question sir can be asked and given once in the aims examination - okay so let's go deep into this so this particular growth or the body of the tissue can be categorized into four types okay so type one is lymphoid type 2 is neural tissue and the third type is either genital or jungle general tissue and the fourth one is Kjetil okay you have four one one is lymphoid tissue second one is neural tissue third one is general tissue and fourth one is serrated so the curve is projected on that it starts from the birth and it's up to the adult so what is going to happen because I can ask questions so lymphoid tissue pulsates rapidly in the late childhood and reaches almost 20 percent is sorry almost 200 percentage of the adult size when compared to the adult size for example if you take this lymphoid tissue this is your lymphoid tissue it grows grows grows increases in size and it become 200 times of the adult one this is that ultra so when compared to the adult one at late childhood it will be become 200 times more this adaptation is basically to protect because lymphoid and the lymphocytes are basically to protect the child from infection so child require more lymphoid tissue to protect them from infection and compared to the adult the next comes is the neural tissue neural tissue grows very rapidly and reaches the adult size at six to seven years okay you can see this neural tissue is growing animosity and reaches a value which is almost the same of adult okay at 6 to 7 years of s this is 6 to 7 years of a is the neural tissue grows to the size of adult the next comes is the general tissue okay you can see the general bond going steeps again increases so coming to the general tissue general issue or a visceral tissue consists of muscles bones and other organs these tissues exhibits an S shape we can see an S shaped here a shape growth okay up to I mean up to 2 to 3 years of is followed by a sudden slow growth between 3 to 10 years you have a you have a constant growth here again further increases okay so your your general tissue is a shape growth curve first it increases and has a constant value again it increases coming to the genital tissue up to puberty your genital tissue will be of 0 something like very very less growth okay but however the growth rapid at the puberty and reaches the adult size I hope you are very clear with this curves okay so most preferably they can ask your diagram based question just by giving ABCD and they may ask you to identify which tissue it is the next important aspect that we have to make a note he support this okay so if you take the mechanism of the growth of a bone bone can grow either by deposition the the remodeling of bone is a combination of deposition and resorption okay the position means depositing of bone resorption means this option so combination of these two is called as bone remodeling okay and the second one is the change that occurs in the bone okay that change the changes that the bone deposits entries resorption can produce the following changes one is changing the size the second one is changing the shape the third one is changing the proportion and the fourth one is changing the relationship of bone to the adjacent structures so all these are most commonly seen so here in this content you have to learn about two different terms one is drift and second one is displacement and displacement is again of two types one is primary displacement and the second one is secondary displacement so coming to the drift the drift is nothing but a cortical drift most of the bones grows by interplay of bone deposition and resorption so whenever a combination of deposition and resorption occur there will be result in the movement of the bone towards the deposit area that is a positive area so this change this change of displacement is called as cortical drift okay the next one next one is the important term that is displacement so as already discussed displacement can be either primary or secondary primary displacement is basically due to the growth of the old structure which is leading to the displacement the best example is the growth of the maxilla the maxillary growth because of the growth at the tuberosity reason the growth at that shoe broster is is what is doing it is pushing the mandible forward and downward so this is primarily because the movement or the primary displacement is basically due to its one growth and the secondary is if the bone get displaced as a result of the growth and the enlargement of the adjacent bone because of the addition bone if it is get displaced then it is called as secondary displacement the best example is the growth of the cranium here the cranium is getting is grown and and it is pushing the mandible forward and downward so a magazine laughs our word and downward this moment is called as secondary displacement so please try to differentiate the primary and secondary displacement because these are the areas which are really focused in the recent aimed section the next important aspect is about this okay so this is they can give you a diagram based and loss principle and loss expansion principle okay here a v-shape one the inner surface of the v-shaped is deposition and outer surface of the v-shaped is the desorption okay simple very simple and most of the structures in the body they follow this V principle ok the inside is the deposition the outside is the resorption and this V pattern is followed in number of reasons okay you can add these examples because these examples are most commonly asked that is the base of the mandible second one is ends of long bones and the third one is mandibular body and the fourth one is the the palate okay so these are the areas where you can see this type of the type of expansion or V type of bone formation in the growth okay I'm done for now so we'll be continuing in the next session thank you signing off from team MDS come