Wikipedia
Search results
Tuesday, 21 November 2017
Why am I born?
I was born on Saturday 7th October 1995 approximately between 6:30 and 7:00pm. That is my birthday. The day that marks my first day I breathed oxygen on planet Earth. The day I exited by mother’s womb and entered humanity on planet earth as a homo sapien. A good indication of my mother’s one and only successful baby delivery is when I first cried after the placenta and umbilical cord was removed from me. Covered in blood and interstitial fluid, my eyes were still closed as the bright lights glistened in my eyes like I was facing the sun at close range. In fact, I cannot really remember what it really felt like to be transferred from my mother’s womb and into the real world. Even though the person that experienced this momentous occasion is well and truly me, why can’t I remember it not even vaguely? Even with the baby photos my parents shared with me from their precious albums, I was still taken aback by my minute stature. Another question I began to wonder is when did I become conscious of all the things around me? When did I realise that the nutrients given to me was not my mother’s breastmilk but lukewarm milk powder solution out of a bottle through a plastic dummy? Another thing that joggled my mind as well, why was I born in this era as a male homo sapien? Why wasn’t I born in a different era as a female, for instance, during the Roaring 20s, the Great Depression, the birth of the Melbourne’s Victorian Railways during the 1820s, the birth of my parents as their friend-to-be in Shanghai or as an ancient animal millions of years ago before the asteroid collided with Earth that caused the extinction of the dinosaurs? Why am I conscious in this day and age on a particular spinning rock in the vast skirts of the universe? Sadly no one really knows. The answers to these self-conscious philosophical questions sound trivial.
I also share the same birthday with 383,000 other people and I already know 2 of them: Rosario and Natasha, who live in my neighbourhood. Celebrities born on this day include American actor Slade Pearce. That means my star sign or horoscope is Libra and my zodiac animal is Pig. On this day, many Americans were listening to Fantasy by Mariah Carey, many Britons were listening to Top 5 hit Fairground by Simply Red. Many Americans were viewing Strange Days, directed by Kathryn Bigelow, watching Neon Genesis Evangelion, reading My American Journey by Colin Powell with Joseph E. Persico and playing Doom Troopers or Bureau 13.
My Chinese birth name is 邹吉恩 (Zou Ji En). In Chinese, 吉 means fortune and bravery, 恩 means empathy and helping others before oneself. My given Anglosaxon name is Gene. I don’t know why my parents named me after a hereditary unit of variant length or a random section of DNA that can only contain 4 nitrogenous bases: Adenine, Guanine, Cytosine and Thymine. I asked my father and he admitted proposing the name himself but the reason behind it was somewhat unexpected and quite peculiar. It was around a few weeks before I was expected and my parents had to answer the hardest decision ever. The doctors notified them that I was male. You can imagine my parents were over the moon because nature was basically flipping a coin with them and it turned out the revelation of my male gender was like landing a heads for them. Then what shall we name him? Kevin, Michael, John, Victor, Joe, David, Daniel/Danny, Ben, Andy, Frank, Mark, Nathan, Henry, Matthew, James, Vincent, William? Those names are the most common Anglosaxon names for Chinese and Vietnamese males living in Western societies like Australian and the USA. However my parents somehow didn’t want to give me a common name because it may not be memorable and may often cause confusion. One night my father was sitting on the toilet pondering long and hard about the best name for me. No matter how had he thought, a unique name wasn’t coming to mind and every passing second and minute, he gradually became agitated and frustrated. Then with the gushing sound of rotten egg wind blowing through his anus, followed by barnstorming logs dropped into the lake of disgust, the imaginary lightbulb above his brain suddenly lit up. The sound of his fart combined with his disgruntled words he spits out finally forcing out his droppings out somehow generated (pardon the pun) the name Gene. I don’t know whether to believe it or not and to this day I still find this story too unbelievable to be believable. Me named after an awkward natural body process and an audacious choice of words in a gross context is simply outrageous but, to be fair, unique. I wish someone would take me back to the time my parents were coming up a name for me to see the story my father told me is true, though I personally doubt it is.
In Victoria (an Australian state where I live in), your parents can choose a name for you i.e. the newborn child and submit it to the Registry of Births, Deaths and Marriages Victoria. However, under the Births, Deaths and Marriages Registration Act 1996, some names can be rejected or prohibited if it would cause stress or ridicule, and if the chosen names are obscene or offensive, non-sensical or impractical, deceptive, confusion or misleading. Obscene or offensive names can include:
- Swear words
- Descriptions of owed or sexual acts
- Racial or ethic slurs
- Words that degrade accepted standards of morality and decency
- Words that go against moral principles
- Non-sensical or impractical names may:
- Be too long
- Contain symbols without phonetic significance, like ?, @, . , %, $, (), *
- Makes statements or phrases
- Reference a public institution or public office
- Displayed in the form of initials or acronyms
http://www.momjunction.com/articles/banned-illegal-baby-names-around-the-world_00400275/#gref
In this article, there is a list of some examples of banned names in different countries around the world like UK, USA, Australia, New Zealand, Canada, England, Sweden, Saudi Arabia, Germany and Mexico. Depending on the country you live in, some countries have additional stricter naming rules than other countries which means a few weird and extraordinary names may be approved in one country but banned in other countries.
For example:
— New Zealand parents aren’t allowed to name their child “Christ", “Messiah”, “Lucifer”, “Knight”, “Anal”, “4Real”, “Minister”, “Bishop”, “Saint” etc.
— American parents can’t name their child “Judge”, “King”, “Duke”, “Master”, “Queen”, “Majesty” etc.
— Australian parents can’t name their child “D*ckhead”, “LOL”, “Batman”, “Ikea”, “Snort”, “Circumcision”, “Ranga”, Hitler”, “Spinach” etc.
— But the most extraordinary banned names list in my opinion goes to Saudi Arabia. Normal harmless names like Elaine, Sandy and Alice are part of the list. Sadly this is true and I don’t understand why these seemingly ordinary girls names are viewed as offensive and bad in Saudi Arabia.
In 1991, a Swedish couple named or tried to name their newborn son this unpronounceable name “Brfxxccxxmnpcccclllmmnprxclmnckssqlbb11116”, but it translates to “Albin”. Despite their constant appeals in court, these names weren’t accepted. An American couple from New Jersey, Heath Campbell and Bethanie Zito, identify themselves as self-proclaimed Neo-Nazis hence named their children Adolf Hitler Campbell and Eva Lynn Patricia Braun.
https://www.babycenter.com/top-baby-names-2017.htm
https://www.babycenter.com/0_unusual-and-surprising-baby-names_10388919.bc
Every year, amongst the popular baby names like Emma, Olivia, Ava, Sophia and Isabella for girls, and Liam, Noah, Logan, Lucas and Mason for boys, there are always several parents who go out of their skin to come up with the some of the most unusual, weird and extraordinary names that miraculously get approved because it doesn’t break their respective government naming laws. The following websites I have shared above contains the top 50 popular and most unusual male and female baby names in previous years. Some of these weird names may be inspired by cartoon characters, authors, cosmological phenomena, movie characters, tv characters, celebrities, comedians, sports personnel, religious figures, ancient gods, comic book characters, geographical locations, flora and fauna etc. For example, some parents chose:
— Bold and powerful names e.g. Emperor, Dynasty and Queenie
— Names associated with nature e.g. Lake, Woods, Fox, Oceana
— Flavoursome names e.g. Ginger, Saffron, Miso
— Harry Potter character names e.g. Severus, Albus, Minerva, Hagrid
— Names of mountains e.g. Everest, Rainier, Zenith
— Names of abundance e.g. Lux, Fortune, Prosper, Heirness
— Names of striving virtues and values e.g. Freedom, Truth, Wisdom
— Names associated with the cosmos e.g. Andromeda, Celestial, Gemini, Starla
According to the Guiness World Records, the longest name ever belongs to British man Barnaby Usansky. His full name is Barnaby Marmaduke Aloysius Benjy Cobweb Dartagnan Egbert Felix Gaspar Humbert Ignatius Jayden Kasper Leroy Maximilian Neddy Obiajulu Pepin Quilliam Rosencrantz Sexton Teddy Upwood Vivatma Wayland Xylon Yardley Zachary Usansky. Before him was American Mr. Wolfe, aka, Adolph Blaine Charles David Earlt Frederisk Gerald Hubert Irvin John Kenneth Lloyd Martin Nero Oliver Paul Quicy Randolph Sherman Thomas Uncas Victor William Xerxes Yancy Wolfeschlegelsteinhausenbergerdorff, Senior. Notice both of their initials contain ABCDEFGHIJKLMNOPQRSTUVWXYZ, the English Alphabet.
When I checked my birthday on www.whenwasiconceived.com, I was most likely conceived during the week of January 10 - January 18, 1995. The gestation period begins when one sperm cell successfully enters the ovum fertilising it. In humans, the gestation period lasts on average 270 days (about 40 weeks). Gestation, by definition, is the carrying of an embryo or foetus inside female viviparous animals. Here are some videos I found simulating the day by day process of your first months inside your mother’s womb:
https://www.youtube.com/watch?v=LcgXN5UAMOQ
https://www.youtube.com/watch?v=1cDryDHxySw
https://en.wikipedia.org/wiki/Human_fertilization
In humans, Fertilisation officially begins when a single sperm cell enters the ovum via Acrosome reaction, occurring in the Ampulla of the fallopian tube. The sperm binds the egg through the Corona Radiata, a layer of follicle cells on the outside of a secondary oocyte. Yolk (Ooplasm) is then drawn out into a conical elevation called the “Cone of Attraction”, or “Reception Cone”, where the Spermatozoon is about to piece. The peripheral part of the yolk changes into the Perivitelline Membrane, preventing the passage of additional Spermatoza. Then the sperm reaches the Zona Pellucida, which is an extracellular matrix of Glycoproteins, with its complementary molecule on the surface of the sperm head binding to ZP3 Glycoprotein. This triggers the acrosome to burst, releasing enzymes that help sperm get through the Zona Pellucida. After the sperm successfully enters the cytoplasm of the Oocyte, its tail and outer coating disintegrate, signalling the start of the cortical reaction. Cortical granules inside the secondary oocyte fuse with the plasma membrane of the cell, causing enzymes within these granules to be expelled by exocytosis to the Zona Pellucida. This causes cross linking of Glycoproteins i.e. Enzymes catalysing the hydrolysis of ZP2 to ZP2f, hardening the matrix making it impermeable to sperm preventing more than 1 sperm cell fertilising the egg. This forms a zygote cell, or fertilised egg, initiating prenatal development. You are now officially born as 1 cell old.
https://en.wikipedia.org/wiki/Implantation_(human_embryo)
In the first 8-9 days, you would undergo mitosis, replicate your own cell and cleave to form 2 cells, then 4 then 8 and so on to form a blastocyte (conceptus). Then you would undergo implantation which the fertilised egg would adhere to the wall of the uterus, which the foetus would receive oxygen and nutrients from the mother in other to continue development. Then the blastocyte would first hatch by discarding its Zona Pellucida. This is caused by Plasmin which is converted from Plasminogen by blastocyst factors.
Timeline of prenatal development illustrating foetal viability
https://embryology.med.unsw.edu.au/embryology/index.php/Implantation
https://en.wikipedia.org/wiki/Prenatal_development
(Weeks 1 - 2)
1. Adplantation = A newly hatched Blastocyst loosely adheres to the endometrial epithelium by rolling to its eventual site of implantation where it firmly attaches to. It forms an alignment with the Inner Cell Mass closest to the epithelium and stops.
2. Implantation = During this process, the blastocyte migrates in the Uterine Epithelium by day 9. At the uterine epithelial layer, there are cilia or microvilli that are involved in the adhesion process. Hormones like Oestrogen and Progesterone regulate both the activity of ciliated microvilli concentration and structure leading to differences in sizes and shapes. Cilia are long processes with epithelial cell apical membrane specialisations organised in a microtubule filled motile structure. Its concentration is controlled by Oestrogen levels. Microvilli, on the other hand are shorter processes, with microfilament filled non-motile structure. Their length is shortened by Progesterone and lengthened and thinned by Oestrogen.
- Uterodomes or Pinopods, on the apical uterine epithelium, are seen to be a marker for endometrial receptivity during a “receptivity window” suggested their presence during the luteal phase of the menstrual cycle. These transient micro protrusions inter-digitate with Microvilli on the apical syncytiotrophoblase surface of the blastocyte during initial adplantation and implantation.
To enable implantation, the uterus goes through many biological changes in order to receive the conceptus:
(a) Predecidualisation = Endometrium thickens, becoming vascularised and its glands increase in size along with its secretions 7 days after ovulation. Its surface produces Decidual Cells covering the whole area towards the uterine cavity, making up a new cell layer called the Decidua. The rest of the endometrium expresses differences between the luminal and basal surfaces. Luminal cells form the Zona Compacta, whilst basolateral cells form the Zona Spongisa containing spongy stromal cells. If pregnancy doesn’t occur, the Decidua is shed off leaving just the Decidual Trees and the uterine glands would decrease in activity and then degenerate.
(b) Decidualisation succeeds predecidualisation during pregnancy. The Decidual cells continue to proliferate and differentiate into uterine stromal cells, promoted by maternal steroid hormones, Oestrogen and Progesterone, depositing Fibrinoid and Glycogen to form epithelial plaques at anchoring villi. Bone Morphogenetic Protein 2 (BMP2) Non-active precursor protein is then cleaved by Proprotein Convertase 5/6 (PC5/6) to produce the active form of BMP2. Deletion or knockout of either BMP2 or PC6 inhibits decidualisation leading to implantation failure and female infertility.
Not only the lining of the uterus expands, but secretion from epithelial glands also changes. This is induced by increased levels of Progesterone from the Corpus Luteum targeting the Embryoblast in the Uterine Cavity before implantation to receive nourishment directly from the blood of the mother. In addition, the Endometrium secretes steroid-dependent proteins crucial for growth and implantation, including cholesterol and steroids. Implantation is then further facilitated by synthesis of matrix substances, adhesion molecules and surface receptors for the matrix substances.
A cascade of adhesive interactions occurs as follows:
— Carbohydrate-mediated binding to the Glycocalyx (a cell surface formed by transmembrane and secreted glycoproteins e.g. Mucins)
— Progress to tighter binding between Osteopontin (OPN), members of the Immunoglobulin Superfamily (IgSF), Integrin and Cadherin families, Trophinin and CD44.
— Activation of Proteases including MMPs and ADAMs
— Lateral epithelial membrane components inc. Desmosomes, detach and reassemble as Trophectoderm extends between maternal epithelial cells
3. Coagulation Plug = By day 12, your entire blastocyst has entered the uterine wall. Oestrogen then stimulates the production of mucus from glands at the opening of the uterus, the cervix, where it links the vagina. This secreted mucus forms a plug / barrier (CMP) acting in a mechanical and anti-bacterial manner.
4. Invasion = As more Trophoblast cells adhere and penetrate into the endometrium where they continue proliferating, they differentiate to become Syncytiotrophoblasts. The remaining trophoblasts surrounding the Inner Cell Mass differentiate to become Cytotrophoblasts. Syncytiotrophoblasts then reach and penetrate the basal membrane underneath the Decidual cells, and invade the Uterine Stroma until it’s fully embedded. Eventually, they come into contact with material blood and form Chorionic Villi, initiating the formation of Placenta. During the invasion, the Blastocyst secretes autocrine factors like Human Chorionic Gondaotrophin (hCG) and Insulin-like Growth Factor 2 (IGF2), targeting itself and Decidual Cells which loosens them, helping it prevent the embryo from being rejected by the maternal immune system. This triggers the final decidualisation preventing menstruation. Syncytiotrophoblasts dislodge Decidual cells by degrading cell adhesion molecules linking the Decidual Cells together and its extracellular matrix between them. This occurs because syncytiotrophoblasts secretes Tumour Necrosis Factor-Alpha (TNF-α), which inhibits the expression of Cadherins and β-Catenin. Serine Endopeptidases and Matrix Metalloproteinases help degrade the extracellular matrix. Examples like Collagenases, Gelatinases and Stromelysins degrade Types I, II, III, IV & V Collagen and Gelatin. Immunosuppressive agents like:
— Platelet-Activating Factor (PAF)
— Early Pregnancy Factor
— Human Chorionic Gonnadotropin (hCG)
— Prostaglandin E2,
— Interleukin 1-α (IL-1α)
— IL-6
— Leukamia Inhibitory Factor (LIF)
— Colony-Stimulating Factor.
Other factors secreted by the Blastocyst include:
- Embryo-derived Histamine-Releasing Factor
- Tissue Plasminogen Activator and Inhibitor
- Estradiol
- β1 Integrins
- Fibroblast Growth Factor (FGF)
- CTYL-1
- Transforming Growth Factor Alpha (TGF-α)
- Inhibin
https://en.wikipedia.org/wiki/Embryogenesis
5. Embryogenesis (Week 3 - 10)
= A process by which the embryo forms and develops during the early stages of prenatal development beginning with the fertilisation of the ovum (egg cell) by a sperm cell (Spermatozoon). Once fertilised, the ovum becomes a zygote, a single diploid cell. It then undergoes mitotic divisions with cleavage (no significant growth) and cellular differentiation leading to development of a multicellular embryo. After 4 initial cell divisions forming 16 cells becoming a Morula. Different cells derived from each cleavage, up to the Blastula Stage, are called Blastomeres. Specifically, holoblastic (total) cleavage occurs in mammals because they have little yolk in their eggs which are the source of maternal nourishment via placenta or milk. Whereas meroblastic (partial) cleavage occurs in animals whose eggs have more yolk like birds and reptiles. In holoblastic eggs, the first cleavage occurs along the vegetal-animal axis of the egg, followed by a 2nd cleavage perpendicular to the first. From then on, the spatial arrangement of Blastomeres can follow various patterns, due to different planes of cleavage. The end of cleavage is known as Midblastula Transition, coinciding with the onset of zygotic transcription.
After the 7th cleavage, the embryo contains 128 cells forming a Blastula. It usually consists of a spherical layer of cells (Blastoderm) surrounding a yolk-filled cavity (Blastocoel). Mammals at this stage form a Blastocyst, characterised by the Inner Cell Mass distinct from surrounding Blastula. Cells of the Trophoblast form the Ectoderm of the Chorion, which help develop the placenta. On the deep surface of the Inner Cell Mass situates a layer of flattened cells called the Endoderm, which differentiates and forms a yolk sac. Spaces between the remaining cells of the mass, and by enlargement and coalescence of these spaces, form an Amniotic Cavity. The floor of this cavity is formed by the Embryonic Disc, composed of a layer of Prismatic Cells called the Ectoderm, which lies in apposition with the Endoderm.
On the narrower, posterior end of the Embryonic disk appears an opaque Primitive Streak that extends along the middle of the disk. On the anterior end of the primitive streak is a knob-like thickening called the Primitive Node. A shallow, Primitive Groove appears on the surface of the primitive streak and the anterior end of the primitive groove communicates by means of the Blastopore with the yolk sac. The Primitive Streak is produced by thickening of the axial part of the Ectoderm, which divide, multiply and grow downward to blend in with cells of the subjacent Endoderm. A 3rd layer of cells develops from the sides of the primitive streak called the Mesoderm, which extend laterally between the Ectoderm and Endoderm. The caudal end of the primitive streak forms the Cloacal Membrane. The Blastoderm now consists of the 3 cell layers: Ectoderm, Mesoderm and Endoderm, which give rise to certain tissues of the body.
Formation of the Early Nervous System
In front of the primitive steak, 2 Neural Folds are formed by a folding up of the Ectoderm, 1 on either side of the middle line formed by the streak. They commence some distance behind the anterior end of the Embryonic Disk, where they are continuous with each other, and from there gradually extend backward, 1 on either side of the anterior end of the Primitive Streak. Between these folds is a shallow median groove called the Neural Groove. The neural groove deepens as the neural folds elevates, and ultimately the folds meet and coalesce in the middle line and convert the groove into a closed tube called the Neural Tube. This ectodermal wall forms the rudiment of the nervous system. After that, the Blastopore no longer opens on the surface but into the closed canal of the neural tube, and thus the Neurenteric Canal is established between the neural tube and primitive digestive tube. Coalescence of the neural folds occurs initially in the Hindbrain, extending forwards and backwards. Then the front opening (Anterior Neuropore) of the tube closes at the anterior end of the future brain, forming a recess that is in contact temporarily with the overlying endoderm. Before the neural groove is closed, a ridge of ectodermal cells appears along the prominent margin of each neural fold called the Neural Crest (Ganglion Ridge). This develops the Spinal and Cranial Nerve Ganglia and Ganglia of the Sympathetic Nervous System. By upward growth of the mesoderm, the neural tube ultimately separates from the overlying ectoderm.
The cephalic end of the neural groove exhibits several dilatations. When the tube is shut, this forms 3 primary cerebral vesicles and correspond respectively to the future “Forebrain” (Prosencephalon), “Midbrain” (Mesencephalon), & “Hindbrain” (Rhombencephalon). The walls of these vesicles develop into nervous tissue and neuroglia of the brain, and their cavities are modified to form its ventricles. Remaining tube forms the Spinal Cord (Medulla Spinalis) including its nervous and neuroglial elements, while the cavity persists as the Central Canal.
Extension of the Mesoderm takes place throughout the embryonic and extra-embryonic areas of the ovum. In front of the neural tube, the Mesoderm extended forward in the form of 2 Crescentic masses, which meet in the middle line enclosing behind them as area devoid of Mesoderm. Over this area, Ectoderm and Endoderm directly contact with each other and constitutes the Buccopharyngeal Membrane, forming the early Septum between the Primitive mouth and Pharnyx.
— In front of the Buccopharyngeal Membrane, the Pericardium develops afterward, therefore this region is designated the pericardial area.
— The Proamninotic Area is where the Proamnion develops in front of the Pericardial Area, though this area never forms in humans.
— At the hind end of the embryo, the Ectoderm and Endoderm come into apposition and form the cloacal membrane.
https://en.wikipedia.org/wiki/Gastrulation
During gastrulation, cells migrate to the interior of the Blastula, subsequently forming 2 (Diploblastic) or 3 (Triploblastic) germ layers, forming a Gastrula. Diploblastic animals don’t have a Mesoderm.
— Ectoderm gives rise to Epidermis, Nervous System and to the Neural Crest in the developing crest.
— Endoderm gives rise to Epithelium of the digestive system and respiratory system, and organs associated with the Digestive system like Liver and Pancreas.
— Mesoderm gives rise to Muscle, Bone and Connective Tissue. In vertebrates, Mesoderm derivatives include Notochord, Heart, Blood vessels, Cartilage of the ribs and vertebrae, and the Dermis.
https://en.wikipedia.org/wiki/Organogenesis
Following gastrulation, cells in the body are either organised into sheets of connected cells (as in epithelia), or as a mesh of isolated cells, like Mesenchyme. Different combinations of different processes occur to place cells in the embryo’s interior:
— Epiboly = Expansion of 1 cell sheet over other cells
— Ingression = Migration of individual cells into the embryo
— Invagination = Infolding of cell sheet into embryo forming the mouth, anus and archenteron
— Delamination = Splitting or migrating of 1 sheet into 2 sheets
— Involution = Inturning of cell sheet over the basal surface of an outer layer
— Polar Proliferation = Cells at the polar ends of the Blastula / Gastrula proliferate
— Heavy RNA Transcription — Using embryonic genes, up to this point RNAs used were maternal (stored in the unfertilised egg)
— Major differentiation processes losing the cells’ totipotentiality
Somitogenesis = The process by which somites form. Somites are bilaterally paired blocks of mesoderm that form along the anterior-posterior axis of the developing embryo in segmented animals. In vertebrates, somites give rise to skeletal muscle, Cartilage, Tendons, Endothelial Cells and Dermis.
— Somites form from the Paraxial (Somitic) Mesoderm by budding off “rostrally” as Somitomeres which are whorls of Paraxial Mesoderm Cells, compact and separate into discrete bodies. This tissue then undergoes convergent extension as the primitive streak regresses (gastrulation of the embryo). The Notochord extends from the base of the head to the tail. This periodic nature of these splitting events suggests somitogenesis occurs via a clock-wavefront model, in which waves of developmental signals causes periodic formation of new somites. Immature somites are then compacted into an outer layer (Epithelium) and an inner mass (Mesenchyme). Somites themselves are specified according to their location by the Hox homeotic genes, as the segmented Paraxial Mesoderm are determined by the position along the anterior-posterior axis before Somitogenesis.
Once the cells of Pre-somitic Mesoderm are in place following cell migration, oscillatory expression of genes begins in these cells as if regulated by a developmental “clock” i.e. “Clock and Wave” Mechanism. These genes include members of the FGF family, Wnt and Notch pathway. As the signalling wavefront slowly progresses anteriorly to contact cells in the permissive state, they undergo EMT (Epithelial-Mesenchymal Transition) and pinch off from the posterior Pre-somitic Mesoderm, forming a Somite boundary and resetting the process for a new somite. Activation of Notch cyclically activates a cascade of genes critical for the somites to separate from the main paraxial body. Depending on the species, this is controlled by different processes such as a negative feedback loop in zebrafish or FGF and Wnt clocks affect the Notch clock in chicks and mice. Studies have found that Shh (Sonic Hedgehog) protein is involved in cellular inter-dependency and are expressed within pre-somitic mesoderm during somitogenesis. Pathways involving the Eph Receptor and Ephrin family of proteins are found to coordinate the physical separation of somites and formation of borders and new adhesions between different cells. Fibronectins and Cadherins are found to help the appropriate cells localise with each other. The mechanism that terminates somitogenesis is currently unknown and many theories have been proposed in numerous studies such as inhibition of BMP signalling by Noggin (Wnt target gene) that suppresses the EMT necessary for splitting off of somites from bands of pre-somitic mesoderm.
https://en.wikipedia.org/wiki/Fetus
(6) Foetal Development (Week 10 onwards)
= At this stage, the developing embryo can be recognised as a human, characterised by presence of all the major body organs, albeit not fully developed and functional and yet situated in their final anatomical location.
— Weeks 9 - 16: At this point in development, the head makes up about 1/2 of the foetus size and the entire foetus is about 30 mm long, weighing about 8 grams. The hands, feet, brain and other organs like heart and lungs are present but have minimal function. The genitalia starts to the form and the placenta becomes functional. Also uncontrolled movements and twitches occur as muscles, the brain and pathways begin their development.
— Weeks 17 - 25: Pregnant women would begin to feel foetal movements. By then the foetus is about 20cm long.
— Weeks 26 - 38: During this period:
The amount of body fat increases
- Lungs are still immature
- Thalamic brain connections that mediate sensory input start to form
- Bones are fully developed but are still soft and pliable
- Iron, Calcium and Phosphorus levels increase
- Fingernails reach the end of the fingertips.
- Fine Hair (Lanugo) begin to disappear except on the upper arms and shoulders
- Small breast buds appear
- Head hair becomes coarser and thicker
- Foetus is 48-53 cm long, when born.
Not all babies weigh, look, or develop exactly the same way. This suggests maternal, placental and foetal may affect its growth.
— Maternal factors include Weight, Body Mass Index (BMI), Nutrition, Emotional Stress, Toxin exposure e.g. Tobacco, Alcohol, Heroin, Cocaine and other narcotics, and Uterine Blood Flow
— Placental factors include Size, Microstructure (densities and architecture), Umbilical blood flow, transporters and binding proteins, nutrient utilisation and nutrient production
— Fetal factors include Fetus genome, nutrient production, and hormone output.
https://en.wikipedia.org/wiki/Childbirth
(7) Childbirth (Between Week 38 and 42)
= Labour and Delivery — This process marks the end of pregnancy when 1 or more babies leaves the woman’s uterus by vaginal passage or C-Section (caesarian section). For those who are currently pregnant, if your water is about to break, the most prominent sign of you going into labour is strong repetitive uterine contractions. You would then begin to feel distressed, fearful, anxious depending on your experience of prior childbirth, cultural ideas of the pain of childbirth, mobility during labour. You would experience menstrual cramps as the pain increases during uterine contractions. During the latter stages of gestation, Oxytocin levels increase to evoke feelings of contentment, reductions in anxiety, and feelings of calmness and security around the mate. It also helps during labour when the foetus stimulates the cervix and vagina.
There are 6 phases of a typical vertex delivery during vaginal delivery.
(1) Engagement of the foetal head in the transverse position. The baby’s head is facing across the pelvis at 1 or other of the mother’s hips
(2) Descent and Flexion of the foetal head
(3) Internal Rotation — Foetal head rotates 90 degrees to the Occipital-Anterior Position so that the baby’s face is towards the mother’s rectum.
(4) Delivery by Extension — Foetal head passes out of the birth canal. Its head tilts forwards so that the crown of its head leads the way through the vagina
(5) Restitution — Foetal head turns through 45 degrees to restore its normal relationship with the shoulders, which are still at an angle.
(6) External Rotation — Shoulders repeat the corkscrew movements of the head, which can be seen in the final movements of the foetal head
1st Stage:
(a) Latent Phase = At this point the woman begins to perceive regular uterine contractions. Cervical effacement (Thinning and stretching of the Cervix), and cervical dilation occurs during the closing weeks of pregnancy and nears completion by the end of the latent phase.
(b) Active Phase = Depending on where you live e.g. USA, UK and Sweden, the criteria to determine this phase of labour includes 3-4 contractions every 10 mins, rupture of membranes and cervical dilation 3-5 cm for multiparous women. Health care providers would perform a cervical exam to evaluate the cervical dilation, effacement and station to calculate a Bishop score. This score is used to predict the success of induction of labour.
2nd Stage:
- Foetal Expulsion = Stimulated by Prostaglandins and Oxytocin, the expulsion stage begins when the cervix is fully dilated, and concludes when the baby is born. As pressure on the cervix increases, women would feel the sensation of pelvic pressure and have the urge to begin pushing. The head of the baby is fully engaged in the pelvis, where the widest diameter of the head passes below the pelvic inlet. The foetal head continues downwards into the pelvis, below the pubic arch and out through the vaginal Introitus (opening). When you notice the foetal head at the vaginal orifice, this is called “crowning”. The woman will feel excruciating burning or stinging pain.
Sometimes the amniotic sac will not rupture during labour or pushing, meaning the intact can be born with the membranes intact. This is called “delivery en caul”.
https://en.wikipedia.org/wiki/Placental_expulsion
3rd Stage (Involution Stage):
- Placenta Delivery = Placenta expulsion begins as a physiological separation from the wall of the uterus, which on average takes about 10 - 12 mins. Maturation of the foetal hypothalamus activates the HPA (Hypothalamic-Pituitary Adrenal) axis which initiates labour through 2 hormonal mechanisms.
— Foetal ACTH increases foetal Cortical which acts by 2 mechanisms:
(a) Increases Prostaglandin F2α —> Abolishing the Progesterone block —> Lowering the Oxytocin receptor threshold —> Increasing expression of Relaxin —> Stretching the pelvic ligaments
(b) Increases expression of PTGS in Foetal Trophoblast cells
— PTGS —> Produces Prostaglandin E2 —> Catalyses transformation of Pregnanlone to C-19 steroids such as Oestrogen.
— Oestrogen then increases vaginal lubrication, softens collagen fibre structures in the cervix, vaginal and associated tissues, increases contraction associate proteins i.e. Connexins and increases placental shedding by physiological inflammation, which may lead to placentitis (retention of membranes).
— The Posterior Pituitary of the Foetus starts to increase production of Oxytocin, stimulating the maternal myometrium to contract.
— In the 7th month of pregnancy, MHC-I increase in the interplacentomal arcade reducing the bi- and tri-nucleate cells, which are a source of immune suppression. By the 9th month, endometrial lining thins (due to loss of trophoblast cells) exposing the endometrium directly to the foetal trophoblast epithelium. With increased exposure to maternal MHC-1 Complexes, TH-1 Cells & Macrophages induce apoptosis of trophoblast cells and endometrial epithelial cells, facilitating placental release. TH-1 Cells also attract phagocytic leukocytes into the Placentome at separation, allowing further degradation of the extracellular matrix.
— Umbilical Cord Clamping = Surgeons use special clamps to help cut the umbilical cord attached to the foetus. This is painless due to the lack of nerve activity. After the cord is clamped and cut, the newborn wears a plastic clip on the navel area until the compressed region of the cord has dried and sealed.
https://en.wikipedia.org/wiki/Umbilical_cord#Clamping_and_cutting
Congratulations, you are now officially born and everyone who has witnessed your birth welcomes you to humanity.
4th Stage
= Postnatal or Postpartum Stage beings immediately after the birth of a child and extends for about 6 weeks. Your mother’s physiological returns to normal including hormone levels and uterus size and the newborn gradually adjusts to life outside of the mother’s body.
https://www.scientificamerican.com/article/when-does-consciousness-arise/
When do babies first become conscious? Is it when it's inside the womb, at birth just exiting the womb or during early childhood? How can you prove that someone is conscious? We can agree an infant is awake, laughing and curious of its surroundings, crawling and grimacing at every surface and texture. But is that the same as experiencing pain, seeing your mother’s breast, tasting her breastmilk, or seeing a colourful toy train? The definition of consciousness refers to the state of being aware of your own state, existence, emotions, thoughts, motivations, intentions and surroundings. However babies don’t have the awareness to know their own emotions, state of mind and motivations. If you ask a young boy why he performed a particular action like calling someone a rude name or teasing someone about their misfortunes, they would just shrug and often reply “ I don’t know - I find it funny, my friends find it funny so I think it’s a good idea to do so.” Nevertheless their bodies subconsciously and autonomously continue to process complex and novel visual stimuli and attends to mysterious sounds and sights in its reality, preferentially faces of humans. As a child, your limited visual acuity would only allow you to see random coloured blobs in your visual field, but thalami-cortical circuitry perceives your surroundings more clearly. If you’re a mother, you may not be aware that your baby is actually listening to you speak relative to other people’s voices while it develops inside your womb. This suggests unborn babies have an inherent sense of musicality. Although maternal speech inside the womb sounds muffled and ambiguous, the infant’s vestibular system adequately detects statistical and frequency regularities to help it distinguish the mother’s voice, language and speech pattern from other people. This distinction is implanted into its prenatal memory before exiting the womb. Once the moment you’ve been waiting for arrives, not long after you’ve cut off its umbilical cord and cleaned the fluids around it, it will begin to imitate you. If you’re a parent, and you stick out your tongue and waggle it, your newborn will mimic this gesture by combining visual information with proprioceptive feedback from its own movements. Furthermore, babies are thought to have linguistic capabilities to imitate the tone, pitch, volume and frequency of your speech pattern as it experiences its first new years in humanity. This would suggest human babies have a basic level of unreflective, present-oriented consciousness.
https://en.wikipedia.org/wiki/Consciousness
The word consciousness was first mentioned by John Locke in his 1690 work “Essay Concerning Human Understanding”. He defined it as “the perception of what passes in a man’s own mind which the same definition appeared later in 1755 in Samuel Johnson’s Dictionary. Conscious was first derived in the 1500s from Latin conscius (con- “together” and scio “to know”) but this Latin word did not share the same modern definition. It originally meant “knowing with” or “having joint or common knowledge with another.” In fact, the phrase conscius sibi meaning “knowing with oneself” or “sharing knowledge with oneself about something” shares a similar figurative meaning of “knowing what one knows” in the modern English word “conscious”.
Philosophers have long debated about the the properties of consciousness since Descartes and Locke. Back then it was difficult to confirm whether consciousness is fundamentally coherent, and prove how it can be recognised in real life and on computing machines and then explained mechanistically, whether there are connections with language. They couldn’t understand consciousness in a way that requires dualistic distinction between mental and physical properties. Advancing technology has helped gained understanding into the mysteries of consciousness in many scientific fields like cognitive science, psychology, anthropology, neuropsychology, neuroscience and medicine. However there is still no universal definition on consciousness that every person can agree on.
Relevant to this discussion, how do you prove that someone or any living organism is conscious? By asking someone whether they can hear me, see me, touch me, recognise that I’m in their field of view? Maybe? What about the brain? Imaging techniques like EEG (Electroencephalogram) and fMRI (functional Magnetic Resonance Imaging) have identified high-frequency (γ) gamma bands oscillations in brain activity along the primary visual pathway, as well as specific and non-specific thalamocortical systems via synchronous oscillations according to Rodolfo Llinás. Studies have found that brain activity in sensory pathways are insufficient to produce consciousness. However, higher brain centres in Prefrontal Cortex are found to be involved in executive functions. There is evidence to suggest that “top-down” flow of neural activity (Frontal Cortex —> Sensory Areas) is more predictive of conscious awareness than “bottom-up” flow of activity (Sensory Areas —> Frontal Cortex). Nikos Logothetis and his colleagues discovered visually responsive neurons in the Temporal Lobe reflect the visual perception in situations where conflicting visual images are presented to different eyes (i.e. Bistable percepts during binocular rivalry). In 2011, Graziano and Kastner proposed the “attention schema” theory of awareness which suggests specific cortical areas in the Superior Temporal Sulcus and the Temporo-Parietal Junction, are responsible for building the construct of awareness and attribute it other people and oneself. But babies’ eyes are closed hence cannot visually sense any objects in the outside world so they can’t pay attention. Also it’s impossible to directly measure a baby’s neural activity as it develops inside the womb using today’s neural stimulating techniques.
The outside environment is not like a foetus’ uterine environment: suspended in a warm and dark cave, connected to the placenta that pumps blood, nutrients and hormones into its developing body and brain while the foetus sleeps. Experiments conducted on pre-term foetuses of rats and lamb pups used ultrasound and EEG recordings to show the 3rd-trimester foetus is always in 1 of 2 sleep states. In REM (Rapid Eye Movement) Sleep, there is increased EEG activity usually associated with breathing, swallowing, lucking and moving the eyes but no large-scale body movements were observed. In Non-REM (slow-wave) sleep), no breathing, no eye movements and tonic muscle activity were observed. What is interesting is that the placenta maintains a low oxygen pressure, warm and cushioned uterine environment filled with a range of neuroinhibitory and sleep-inducing molecules produced by by the placenta and the foetus itself e.g. Prostaglandin D2, Adenosine, Allopregnanolone and Pregnanolone. When surgeons cut the umbilical cord whilst maintaining oxygen levels to the foetus, it is evident that the placenta plays a role in sedating the foetus. The embryo can now move and breathe continuously moving crying noises. But one question still remains. Do babies in the foetus dream when in REM sleep? If they could, what would they dream of? When people awaken during REM sleep they report vivid dreams with extensive narratives highlighting their conscious experience and memorable feeling. But babies don’t have the ability to consciously remember anything it experiences right? American psychologist David Foulkes suggests dreaming is a gradual cognitive development linked to the capacity to imagine things visually and to visuospatial skills. Therefore preschoolers often dream about static and plain story lines with no characters involvement, feelings and memories. But what if an organism was in an isolation chamber with no memories, no experience, no social interaction and no capacity to imagine anything at all? What would it dream? Nothing? No one really knows. No one has tried to experiment it with their own children. Here’s another question, if your fate already scripted before you were even born or can it be altered during your lifetime changing the course of future events? I’ll try to answer these complex questions about fate, consciousness and the soul in another post.
Subscribe to:
Post Comments (Atom)
















No comments:
Post a Comment