Organogenesis paper

Organogenesis paper



International class program

091 404 174

 
CHAPTER I
INTRODUCTION


a. Background
In animal development, organogenesis (organo-genesis, compound of the Greek words όργανον "that with which one works"[1], and γένεσις "origin, creation, generation"[2]) is the process by which the ectoderm, endoderm, and mesoderm develop into the internal organs of the organism. Internal organs initiate development in humans within the 3rd to 8th weeks in utero. The germ layers in organogenesis differ by three processes: folds, splits, and condensation. Developing early during this stage in chordate animals are the neural tube and notochord. Vertebrate animals all differentiate from the gastrula the same way. Vertebrates develop a neural crest that differentiates into many structures, including some bones, muscles, and components of the peripheral nervous system. The coelom of the body forms from a split of the mesoderm along the somite axis.
In animal development there is process which called organogenesis. In organogenesis we can found how the organ formed in embryo. And in this paper we will discussion about organogenesis
b. Purpose
1. To know and understanding about the meaning of organogenesis
2. To know and understanding about the derivate of ectoderm, mesoderm and endoderm in organogenesis.
c. Scope of material
1. What is organogenesis?
2. How the process in organogenesis?
 
CHAPTER II
PREVIE OF LITERATURE


Organogenesis, in embryology, the series of organized integrated processes that transforms an amorphous mass of cells into a complete organ in the developing embryo. The cells of an organ-forming region undergo differential development and movement to form an organ primordium, or anlage. Organogenesis continues until the definitive characteristics of the organ are achieved. Concurrent with this process is histogenesis; the result of both processes is a structurally and functionally complete organ. The accomplishment of organogenesis ends the period during which the developing organism is called an embryo and begins the period in which the organism is called a fetus. But also there is opinion about organogenesis, like Organogenesis or morphogenesis is embryo primitive which change to be more definitive and have form that specific in a species, organogenesis begin in last of the 3 weeks and end last of 8 weeks. By the ending of organogenesis so the external characteristic and primary is have form and the next embryo is called fetus (Amy Tenzer,dkk, 2000)
in growth between period or transition happen transformation and differentiation of the part of embryo body transformation and differentiation of body parts of the embryo from primitive forms to become the definitive shape. In this period, the embryo will have a special shape for a species. At the end of growth period, the smooth completion of the definitive form that is characteristic of an individual. During this period embryos experienced growth completion gender, character (physical and psychic character) as well as a special face for each individual.
1. Ectoderm derivatives
a. Brain and spinal cord (spinal cord)
• neural chip has been established at the time of embryo age of 18 hours incubation. Neural folds and neural clear trenches can be seen in the embryo that will become the medulla oblongata.
• at the age of 33-day embryo, neural tube has been formed and has been divided be basic brain regions, namely proensfalon, mesensefalon, and rombensefalon. At the anterior end there is still an open section, namely neorosporus anterior and in the posterior part there are still wide open area called the sinus romboidalis.
• Age 48 hours, the distribution of brain areas have been further, namely into five part (proensefalin, mesensefalon, metensefalon, telensefalon and miesensefalon)
b. Eye
• At age 33 hours, would appear as a pair of bulging eyes toward latreral from proensefalon, which called vesicle optimistic. In addition, the head ectoderm also occur thickening process which called plakoda lens.
• At age 48 hours, the optic vesicle have invaginating forming double-walled optic cup. The inside is the sensory layer of the retina and the outside is going from the retinal pigmented. While, it diesensefalon region has been formed. Narrowing the base of the optic cup is called optical and related stem of diesensefalon. In intact preparations in the optic cup ventral there is an indentation called koroidea fissure, where the passage of blood vessels and optic nerve.
• At age 72 hours, the optic cup will be flat on the part which have pigment. Along with the development of optic cup, lens plakoda invaginated too and then released as a lens vesicle which will become the cornea of the eye.
c. Ear
• At age 33 hours, the ears will appear as a thickening of the ectoderm of the head, called plakoda ears which in the area miensefalon would rombensefalon
• At age 48 hours, plakoda ear have invagination to forming vesicles of ear. These vesicles for while still associated with the ectoderm, initially through the duct endolimfatikus, but too long will be separated
d. Nose
• At age 72 hours, will appear in the form of hollow nose nose nose came from plakoda berinvaginasi telensefalon the ectoderm in the region.
e. Pituitary
Derived from the envaginasi infudibulum diensefalon ventral sac and from Ratkhe (dorsal evagination of stomodeum).
2. Mesoderm derivatives
a. extra embryonic blood vessels
• Age 24 hours, blood vessels will appear as blood islands
• At age 33 hours, blood islands would anastomosis each other to form a webbing, called venous vitelin
• At age 48 hours, venous vitelin has joined a pair of large blood vessels called veins omfalomesenterika which empties into the heart.
b. Heart
• At age 33 hours, the heart of the veer tube to the right, the part that is going to turn the ventricles.
• At age 48 hours, the heart is spinning like the letter S and is divided into venous sinuses, antrium, ventricles, and bulbus arteriosus. From the bulbus arteriosus
• In age 96 hours, the atria and ventricles consist of the left and right. Venous sinuses was fused with the right atrium.
c. Kidney
• At age 33 hours, the kidneys would appear as nefrotom the outward protrusion of intermediate mesoderm.
• At age 48 hours and 72 hours, has been formed tubules and duct mesonefros
• At age 96 hours, mesonefros already highly developed, complete with glomerolus and Bowman's capsule
d. Gonad
e. Limb
Will wing earlier than would have legs.
• At age 72 hours, the wings would sprout wings appear as a bulge in the form of protrusion from the surface latera body, buds appear on the posterior leg grow near intestine in behind.
• At the age of embryos 96 hours, would have longer legs
Organogenesis
UROGENITALIA SYSTEM (Intermediate mesoderm differentiation)
Establish a system of excretion and genitalia ductus
Primitive fish: Pronefros
High-class fish and amphibia: Mesonefros
Aves and mammals: Kidney or renal, consists of three kinds:
1. Pronefros
Very vertigal, the earliest formed
2. Mesonefros
The organs of excretion during the period of embryo
3. Metanefros
Formed the final stage and function after regression mesonefros
PRONEFROS
• Formed from segments nefrotomi
• nefrotom cells break up and form a cavity that is nefrocoel
• Tubular pronefros formed from nefrotom containing nefrocoel and empties and is associated with the coelom through nefrostom
• At the other end of the channel pronefros united to form the ductus pronefros
• ductus pronefros stretching to the posterior and united with the cloaca
• Glomerulus is a roll of the blood vessel as a branch of the dorsal aorta associated with a funnel near nefrostom
• Then go through nefrostom into pronefros to then flowed into the cloaca.
MESONEFROS
• Tubular mesonefros nefrotom formed from the posterior part of the area pronefros
• Tubular mesonefros associated with ductus pronefros
• ductus pronefros now called the ductus or ductus mesonefros Wolff
• Formation of tubules induced by ductus pronefros mesonefros, when the ductus pronefros grow stretching to the posterior body
• create a branch of the dorsal aorta blood vessels form a glomerulus coiling associated with ductus mesonefros
• Section tubules associated with gomerulus will do invagination forming Bowman's capsule
• In the area near the area where the ductus mesonefros united with the cloaca, a bulge that is growing bulge urethra
• shoots grown metanefros widened and branched by urethra into the posterior of which is going metanefros.
• Budding urethra induces tissue that forms tubules nefrogenik metanefros.
Intermediate mesoderm
• Conveniently located dorsolateral between somites and lateral mesoderm
• Establish the urogenital system:
• Kidney (forming urine), urethras (transport urine from the kidney to the bladder) and urethra (the transport urine from the bladder to the outside of the body)
• Gonad: reproductive gland primary
• nefrogenik bund is part of the urogenital ridge that forms urinary system
SEED COATING-DEVIRAT DEVIRAT MESODERM
At first seed layer of mesoderm cells to form a thin sheet of connective tissue on both sides of the midline to grow to form paraxial mesoderm, more to the lateral stay thin is called the lateral plate. With the emergence and unification of the intercellular cavity on the lateral plate tissue was split into two layers, namely:

a. Parietal mesoderm covering the amnion
b. Visceral mesoderm covering the yolk bladder.
Both these limiting membrane of a new cavity called intra-embryonic coelomic cavity, which went on yourself with an extra-embryonic selon on both sides of the embryo. Network that connects the paraxial mesoderm and lateral plate mesoderm is called intermediate. Towards the end of the third week of paraxial mesoderm split into groups epithelioid cells called somites. The couple first somites occur on the neck of the embryo. Each day there will be three somites so that by the end of the fifth week there are 42 to 44 pairs of somites. Couple this somites, 4 occipital, 8 cervical, 12 torakal, 5 lumbar, 5 sacral and 8 to 10 pairs koksigeal. Occipital somites first and up to 7 somites koksigeal latter then disappeared.
1. Differentiation of somites
By the beginning of the fourth week of epithelium cells that form the ventral wall and medial wall of the somites lose its epithelium into polymorph form and move around the dorsal cord. These cells are collectively referred to sklereton, forming tissue known as mesenchyme. They will surround the spinal cord and dorsal cord to form the vertebral column. The walls of the somites are still lagging korsal called dermatomes form a layer of new cells. Immediately after the formation of these cells failed to divide and formed a network called miotom. Each miotom prepare the muscles for the segment itself. After the cells formed dermatomes, miotom and spread below the surrounding ectoderm. Here, these cells form the dermis and subcutaneous tissue. Therefore, every somites form skleroton (component of cartilage and bone), mioton (prepare segmental muscle component) and dermatome (skin component in it segment ). As will be seen later, each dermatome mioton and each has its own segment nerve component.
2. Intermediate mesoderm
These networks are differentiated in a way that is different from the somites. In the area of the cervical and upper torakal this network segmental groups of cells that later develop into nefrotom, while more caudal form a tissue mass that is not known as chordae nefrogenik has segment which later developed into a unit of the composition of urinary excretion.
3. Layers of parietal and visceral mesoderm
Both of these layers restrict intra-embryonic coelomic. Pariental mesoderm together form the ectoderm surrounding the lateral and ventral body wall. Entoder visceral mesoderm and the embryonic form of the intestinal wall.
4. Blood and blood vessels
Blood cells and capillaries develop in the mesoderm ekstraembrional of tuft-tuft and connecting rod. By continuing budding ekstraembrional vessels formed a relationship with blood vessels embryo, thus connecting the embryo and placenta. Blood cells and intra-embryonic blood vessels including the heart tube is formed in the same way with the extra-embryonic vessels that is of the mesoderm cells that form groups of cells that form the cavity angiogenesis because merging the gap between the cells. Located in the center to form a simple blood cells while the cells located on the shores of which unite to form small vessels. Tissues and organs following consideration comes from the mesoderm:
a. Supporting tissue such as connective tissue, cartilage and bone.
b. The muscles fibers latitude and plain
c. Blood cells and lymph nodes and the wall of the heart, blood vessels and lymph vessels.
d. Kidneys, sex glands and discharge channel
e. Children kidney cortex and spleen.
5. Endoderm derivatives
a. Intestine, liver and pancreas
• At age 24 hours, the front gut has begun to take shape. Part of posterior still a primitive gut.
• At age 33, before extending to the posterior gut so gut porta front retreat located
• At age 48 hours, other than the middle intestine becomes more clear, will also form the heart which is the ventral evagination front of the intestine.
• At age 72 hours, the liver will be more branch out and form a diverticulum. At this age, intestinal bowel nporta rear and rear have been formed at the posterior end of the body, in the folds of the tail. In further developments, the more elongated front intestine and colon to the posterior to anterior extends back further. Finally, the intestine is still associated with the yolk just live in a section called the yolk stalk. In addition, the dorsal pancreas would have started to be formed as evaginasi dorsal in front of the intestine will duodenum.
b. Trachea and lung.
• At the age of 48 hour embryos, emergency intestinal front border would farinks and would esophagus there is ventral evagination is the gap larynx of trachea.
• At age 72 hours, the gap will length, forked and distal part bubble. The part that is going to inflate the lungs, which look more clearly at the age of 96 hours embryos, the branch is going bronchus and trachea tip is going.





Organogenesis of frog.

Gunawan rahmil

Early organogenesis in a frog embryo.
The archenteron develops from endoderm. The dorsal ectoderm folds to form the neural plate. The neural plate pinches off to generate the neural tube, which will develop into the brain and the spinal cord. The notochord forms from mesoderm. Other mesoderm cells form tissue that line the coelom. The somites will give rise to segmental structures such as vertebrae


Organogenesis in a chick embryo.
a. Early organogenesis.
The archenteron forms when lateral folds pinch the embryo away from the yolk.
The notochord, neural tube, and somites form much as they do in the frog.

b. Late organogenesis.
Rudiments of most major organs have already formed on day 3. Blood vessels connect the embryo to extraembryonic membrane

 
CHAPTER IV
CLOSING
a. Conclusion
1. Organogenesis, in embryology, the series of organized integrated processes that transforms an amorphous mass of cells into a complete organ in the developing embryo. The cells of an organ-forming region undergo differential development and movement to form an organ primordium, or anlage. Organogenesis continues until the definitive characteristics of the organ are achieved. Concurrent with this process is histogenesis; the result of both processes is a structurally and functionally complete organ. The accomplishment of organogenesis ends the period during which the developing organism is called an embryo and begins the period in which the organism is called a fetus.
2. Organogenesis begin from the primary layer, they are ectoderm, mesoderm and endoderm:
a. Ectoderm derivates
1. Brain and spinal cord (spinal cord)
2. Eye
3. Ear
4. Nose
5. Pituitary

b. Mesoderm derivatives
1. extra embryonic blood vessels
2. Heart
3. Kidney
4. Gonad
5. Limb
c. Endoderm derivatives
1. Intestine, liver and pancreas
2. Trachea and lung.
b. Suggestion
by this paper I hope the reader can get some knowledge and can give me suggest.




 
BIBLIOGRAPHY

Anonymous a, http://zona8b.blogspot.com/feeds/posts/default?orderby=updated

Anonymous b, http://ipaspenli.blogspot.com/2009/08/sistem-reproduksi-manusia.html

Anonymous c, http://www.britannica.com/EBchecked/topic/432178/organogenesis

Anonymous d, http://iqbalali.com/2008/02/13/pembentukan-janin/