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JohBio 32: Vertebrate Embryology [Type the date] Bio 32: Vertebrate Embryology Laboratory Guide/Notes ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 2 John Tran 2009 Frog Slides: Up to Gastrulation Term Animal Pole Check Greek/Latin Origin Box Roots . Zygote portion w/o yolk Vegetal Pole . Zygote portion w/ yolk Grey Crescent . Meroblastic Cleavage . Mer = Part Zygote portion opposite of sperm entry Mitosis Holoblastic Cleavage . Holo = Whole Mitosis Morula . Morus = Mulberry!!! Yum :] Zygote Blastula . Blastos = Sprout Morula Blastomere . Blastos = Sprout Mer = Part Blastula Definition Establishes Cranial/Caudal/Dorsal/Ventral Axis. Will be future cranial area Identify Pole contains the smaller micromeres and has a darker pigmented edge at the top. Opposite the vegetal pole Establishes Pole contains the larger Cranial/Caudal/Dorsal/Ventral yolky macromeres and Axis. Will be future caudal cells are less compacted. area. Cells are extremely Opposite the animal pole yolky at vegetal pole Establishes Look for a “wedge” that Cranial/Caudal/Dorsal/Ventral has a grayish color. It’s Axis. Will be future Dorsal where the Animal Pole area. meets the Vegetal Pole When mitotic cell division You can point to a results in unfinished cell cleavage furrow for a division. This is common for avian zygote…I liked to telolecithal eggs like reptiles point to cleavage furrows and birds because the yolk is in the blastodisc so large, cleavage does not separate the yolk When mitotic cell division You can point to a results in complete cell cleavage furrow for an division. This is very amphibian or fish common for isolecithal or zygote… mesolecithal eggs because the yolk does not hinder cell division After the union of egg and Compact, solid, “Ball” of sperm, a series of rapid cells… It should not have mitotic divisions results in an internal cavity yet... hyperplasia and a compact, MUST be solid solid, “ball” of cells Cavity of the solid Morula Look for the blastocoel. ball called a blastocoel. This If the structure looks like is the precursor structure to a “hollow ball” then it is a the gastrulating trilaminar blastula embryonic structure General term to describe any Easy! Point to any cell in cell within a blastula the blastula, large or small!!! Yay ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 3 John Tran 2009 Macromere . Macro = Large Mer = Part Blastula Micromere . Micro = Small Mer = Part Blastula Blastopore . Blastos = Sprout Pore = Passage Blastula Yolk Plug . Archenteron . Dorsal Blastopore/ Spemann’s Organizer Ectoderm . Mesoderm . Endoderm . Notochord . . . . . . . . Blastula Arc = Ancient Blastos = Sprout Pore = Passage Ecto = Outside Meso = Middle Endo = Inside Noto = Back Describes only the larger cells of the blastula. Develops structures related to vegetal pole and contains nutritious yolk Describes only the smaller cells of the blastula. Develops structures related to animal pole Results from the invagination/ involution/ epiboly of blastula. Future anus for amphibian zygotes Full of endodermal, yolk-rich cells that fills up the hole created by the blastopore. Blastula. Ancient Gut. Results from the invagination/involution of gastrulation. Roof of archenteron (dorsal region) is mesoderm while the floor (ventral region) is endoderm. Major step for gastrula and the trilaminar structures Blastula Important Organizer! Responsible for primary induction AKA Dorsal/Ventral Axis Blastula Outermost layer of trilaminar structure Blastula Middle layer of trilaminar Archenteron structure Blastula Innermost layer of trilaminar Archenteron structure Mesoderm Future vertebral column. Will be found in majority of the sections you look at Easy! Point to large cells near vegetal pole Easy! Point to small cells near the animal pole Looks like a dent in the spherical mass of cells. Near the yolk plug. On cross sections it disrupts the perfect spherical shape of the blastula Looks like a stopper or “plug” within the blastapore’s dent Another cavity in the blastula and is located close to the animal pole. Do not confuse with the blastocoel. When you see this long tube in your embryo you know it is gastrulating! Go back to the blastopore and point to a dorsal “lip” AKA part of blastopore located dorsally Point to outer most layer of cells of blastula Point to roof of archenteron Point to floor of archenteron Small dark dense circle located near dorsal portions of sections ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 4 John Tran 2009 Frog Slides: More advanced development Frog Development is straightforward and follows a straight cranial-caudal lay out. There is no flexure or torsion. Term Check Greek/Latin Origin Box Roots . Neural Ectoderm Definition Identify Early sign that a neural tube is forming. A starting feature of neurulation Primitive Ridge . Neural Ectoderm Early sign that a neural tube is forming. A starting feature of neurulation Neural Groove . Neuro = Brain Neural Ectoderm This is the future lumen of the neural tube. Is a more developed version of the primitive groove. Neural Folds . Neuro = Brain Neural Ectoderm This is the structure that allows the neural grove to become the neural tube. Is a more developed version of the primitive ridges Spinal Cord/ Neural Tube . Neuro = Brain Neural Ectoderm This becomes part of the central nervous system. Sensory info from PNS collected, integrated, and sent to spinal cord to send to the brain Segmental Plate/ Paraxial Mesoderm . Mesoderm Mesoderm that will turn into the somites (future musculature and skeletal system of organism) Slight depression or “valley” like feature in the neural ectoderm. Point towards caudal end because the tail region is less developed and more “primitive” Slight raised ridges that will later grow into more pronounced neural folds. Point towards caudal end because the tail region is less developed and more “primitive” More pronounced depression or “valley” like feature in the neural ectoderm. Point towards cranial end because this region is more developed. Neural groove may have fully closed over to become neural tube. More pronounced raised ridges running parallel to the neural grove. Point towards the cranial end because the head region is more developed. Almost same structure as the neural groove except that the neural folds fuse and forms a tube. Point towards the more cranial regions because the head region is more developed. Find the notochord. Then find aggregations of mesodermal cells lateral to the notochord. Primitive Groove ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 5 John Tran 2009 Somites . Soma = Body Mesoderm Notochord . Noto = Back Chorda Mesoderm Optic Cup . Opt = Eye Ectoderm Sensory Retina . Optic Cup Future neural cells like bipolar, horizontal, or ganglion, rods, and cones of the photosensitive region of the retina Pigmented Retina . Optic Cup Future pigmented region of the retina Auditory Vesicle . Ectoderm Future ear structure Endocardial Tubes/ Cardiac Mesoderm Endocardial Tubes/ cardiac Mesoderm Also called bulbis cordis This primordial structure will eventually fuse with the ventricle to help pump blood The portion of heart that pumps the blood to the rest of the body. Largest chamber of the heart Endocardial Tubes/ Cardiac Mesoderm The portion of heart that holds blood before it is pumped into ventricle. Smaller than ventricle and muscle walls are thinner Small dark dense circle located near dorsal portions of sections Huge lateral circular bulges coming out of the prosencephalon. Hard to miss Look near prosensephalon for the bulging optic cups. Point to the thicker, more lateral membrane of the optic cup Look near prosensephalon for the bulging optic cups. Point to the thinner, more medial membrane of the optic cup Located near the rhombencephalon. Look like circular dark disks on the head One of the more cranial structures out of the heart structures. Small-ish and circular In frogs, directly follows conotruncus in cranialcaudal fashion. Largest chamber of the heart with very thick muscle walls In frogs, directly follows ventricle in cranial-caudal fashion. Smaller chamber of the heart with thinner muscle walls. Mesoderm A PAIR of arteries that lie Look for two arteries in Aud = Hearing Conotruncus . Ventricle . Vent = Body Atrium . Dorsal . An atrium in greco roman architecture is a large open space in a building Dors = Back Future musculature and skeletal system of organism. Subdivided into dermatome (future dermis), myotome (future muscle), sclerotome (future skeleton) Future vertebral column. Will be found in majority of the sections you look at Future Retinal portions of the eye. Occur as evaginations from the prosencephalon They look like circular or oval shaped masses of cells lateral to the notochord. One of the easiest structures to spot ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 6 John Tran 2009 Aorta close to dorsal side. Later forms the descending aorta and contributes to the aortic arch system. The interim kidney. Sort of functional but not efficient…especially for humans mesonephric Kidney . Nephr = Kidney Mesoderm Stomodeum . Stom = Mouth Future oral cavity Foregut . For = Front Ectoderm and Endoderm contribution Endoderm Midgut . Mid = Middle Endoderm Hindgut . Hind = Behind Endoderm Middle portion of the intestinal tract. Will be the future site jejunum, ileum, and first portion of large intestine. The more caudal region of the intestinal tract. Will be future site of large intestine Proctodeum . Proct = Anus Endoderm . . The more cranial region of the intestinal tract. Will be future site of esophagus, trachea, lungs, stomach, and duodenum Future Anus the dorsolateral region of sections. They will typically be behind the pharynx/ gut Found alongside the descending aorta/dorsal aorta. Look like large, spongey, dark, circular structures. Best seen from a sagittal section. Obviously, look towards the cranial sections Look for small, dark, circular structure that is ventral to the notochord. Choose cranial range slides. Stomach is easy to spot because the lumen is usually larger Look for small, dark, circular structure that is ventral to the notochord. Choose mid range slides. Look for small, dark, circular structure that is ventral to the notochord. Choose caudal range slides ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 7 John Tran 2009 Gametes: Testicles Term Check Greek/Latin Origin Definition Box Roots Sperma = Spermatogonia Cell that will begin the Spermatagonia . Seed A which came meiotic cycle of gametes. B from PGC Primary Spermatocyte . Sperma = Seed Cyt = Cell Spermatogonia (2N, 4C) Cell that B undergoes meiosis I Secondary Spermatocyte . Sperma = Seed Cyt = Cell Primary Spermatocyte (N, 2C) Cell that undergoes meiosis II Early Spermatid . Sperma = Seed Id = Shape Secondary Spermatocyte (N,C) that begins spermiogenesis to form mature sperm. Sperm . Sperma = Seed Early Spermatid (N,C) cell that will flow into lumen. Mature. Has three distinct structures 1) Acrosome cap 2) Flagella 3) small body Seminiferous . Intermediate Extensive tubules that will Identify Usually located at the basal portion of the seminiferous tubules. They are often larger in size as well. Since these B cells undergo Meiosis they are considered “Dark” because of all the replicating DNA Usually located toward the basal portion of the seminiferous tubules. They are large in size and have a dark center (all the replicated chromosomes can be seen!) Odds are, most of the large cells you spot in the testis are primary. Start moving to the luminal region of the seminiferous tubules …This is one of the hardest ones to spot Usually located toward the luminal portion of the seminiferous tubule. They are very small and ROUND (they don’t look like mature sperm yet) Usually located at the luminal portion of the seminiferous tubule. They are small and ARROW shaped. Look for the flagella! You can see the flagella as hair like projections in the lumen Just point to a circular ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 8 John Tran 2009 Mesoderm AKA Urogential Mesoderm Tubule Basal Portion of Tubule . Bas = Bottom Luminal Portion of Tubule . Lumen means an open center of a tube Interstitial Cell/ Leydig Cell . Leydig = Scientist name Sertoli Cell . Sertoli = Scientist . . Intermediate Mesoderm AKA Urogential Mesoderm Intermediate Mesoderm AKA Urogential Mesoderm be sectioned off into lobules in the testicles. These tubules are where sperm is made and temporarily housed This is the outer rim of the seminiferous tubules. Gametes early in their development start here. Remember, development occurs from the basal to luminal direction This is the inner lumen of the seminiferous tubules. Gametes later in their development end here. Remember, development occurs from the basal to luminal direction Cells activated by ICSH and are important for endocrine functions like testosterone Cells activated by FSH and are commonly called “Nurse Cells.” They release ABP, AMH, and are also phagocytic (they eat cytoplasm shed from the spermatid) lumen. They are everywhere! Depending on how testis were cut, tubules might appear circular, oval, or really awkward shape Point to the outer rim of the seminiferous tubule Point towards the inner rim/lumen of the seminiferous tubule These are squashed looking cells that are mostly seen in between the seminiferous tubules. These cells are usually massive looking. They are oddly shaped because there are developing sperm attached to the sertoli. I look for a distinct small, dark, nucleolus because sertoli cells are in interphase. Also located toward the basal layer. Also look for oval nucleus…these are really hard to find :[ ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 9 John Tran 2009 Gametes: Ovary Term Primordial Follicle Check Greek/Latin Origin Box Roots . Follicle = Intermediate Contains Mesoderm cavity AKA Urogential Mesoderm Primary Follicle . Follicle = Contains cavity Primordial Follicle Secondary Follicle/ Mature Follicle/ Graafian Follicle . Follicle = Contains cavity Primary Follicle Cumulus Oophorous . Col = Column Oo = Egg Follicular Cells Corona Radiata . Coron = Crown Radia = Follicular Cells Definition Females start with these basic structures for housing their gametes. It is a small ring of follicular cells that surround the primary oocyte arrested at prophase I (2N, 4C) Identify There should be plenty of these to find. Look for small circle like structures. There is one simple ring of follicular cells around a larger central primary oocyte . They are always clustered at the basal region. Once FSH start during sexual Look for a structure maturation, select number of similar to the primordial primordial follicles are chosen follicle. However, two to finish meiosis I and differences exist. 1) the development. Ovum is larger 2) There are concentric rings of follicular cells surrounding the ovum. I usually see between 2-5 rings…it has developed to make the theca interna/externa yet These follicles will rupture Look for a large circular sending the ovum directly into structures. There are the oviducts for transport to usually not that many in the uterus. an ovary. Look for the following features 1) Large antrum 2) Cumulus oophorous 3) Close to the basal edge of the ovary…sometimes you can see the theca interna/externa pretty well defined as well This is a support stalk that This structure is easiest to suspends the ovum in the find in the Graafian center of the fluid filled Follicles. You can antrum. It’s made of usually see this column granulosa cells like structure that lifts the ovum into the center of the antrum. Made up of a follicular cells Look closely at a that form a barrier around the secondary oocyte. Notice ovum. Their purpose is to that there is a ring of cells ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 10 John Tran 2009 Spokes Theca Interna . Theca = Case Interna = Inside Develops from ovary interstitium Theca Externa . Theca = Case Externa = Outside Develops from ovary interstitium Follicular Cells/ Granulosa Cells . Primary Oocyte . Oo = Egg PGC Secondary Oocyte . Oo = Egg Primary Oocyte Antrum . Blood Vessels of Ovary . protect the ovum and is a major player during fertilization. Sperm must break through this layer to access the underlying zona pellucida Will be future portion of corpus luteum that provides progesterone Will be future portion of corpus luteum but as collagenous and structural support Intermediate These cells make up the Mesoderm follicle AKA Urogential Mesoderm Develops in the graffian follicle Females start with primary oocyte at birth. They are arrested at Prophase I until onset of puberty (2N, 4C) Once primary Oocyte finish Meiosis I they start Meiosis II but arrest at Metaphase II (1N, 2C)…Meiosis II will only finish if a sperm enters Large fluid filled space of the follicle. Surrounds the ovum with liquor folliculi Name should be selfexplanatory. that surround the ovum. This is the corona radiata. Innermost concentric rings of follicular cells surrounding the follicle. Found easiest on graaffian follicles Outermost concentric rings of follicular cells surrounding the follicle. Found easiest on graffian follicles They are all over the place. I like to find a primordial follicle and point to the ring around the ovum because those are follicular cells Find the ovum in a primordial follicle Find the ovum in a mature follicle Find a graafian follicle and point to the large cavity in the center. If you look at the center of the ovary, you notice these weird twisted shapes that are fairly large… these are the blood vessels for the ovary… that’s why I used to avoid the center portions of the ovary…there isn’t much to find ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 11 John Tran 2009 18 Hour Chick Embryo Chick Embryo is barely forming… you don’t really see an outline of a body yet but you see the start of neurulation Term Definition Identify Area Pellucida Check Greek/Latin Origin Box Roots . Luc = Bright Area of blastoderm that the developing embryo lies on. Area Opaca . Area of blastoderm that the developing vasculature forms. Further separated into area vasculosa and area vitellina Blood Islands . Primitive Streak . Midline thickening, denotes site of neurlation to form the neural tube Hensens Node . Thickened portion of primitive streak. Important organizer during neurulation. Comparable to Spemanns’s organizer in amphibians Central and Bright. Oval Shaped. Looks like a halo around the embryo Peripheral and Dark compared to the central area pellucida. Should see spots…that’s the blood islands Small dark spots that surround developing embryo. They are found more often towards the caudal end of embryo Point directly to the dorsal midline portion of sections. It’s where the future spine will be ect Streak also appears “Fuzzy” it looks like a red smear/smudge obvious towards more caudal regions Look along midline axis. Towards the center there is a darker node or “spot”. This dark spot is pretty distinct Primitive Groove Primitive Ridge . . . Opac = Shady Mesoderm This will form into the future vasculature for the chick. Future vitelline arteries and veins Neural Ectoderm Early sign that a neural tube is forming. A starting feature of neurulation Neural Ectoderm Early sign that a neural tube is forming. A starting feature of neurulation Slight depression or “valley” like feature in the neural ectoderm. Point towards caudal end because the tail region is less developed and more “primitive” Slight raised ridges that will later grow into more pronounced neural folds. Point towards caudal end because the tail region is ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 12 John Tran 2009 Neural Groove . Neuro = Brain Neural Ectoderm This is the future lumen of the neural tube. Is a more developed version of the primitive groove. Neural Folds . Neuro = Brain Neural Ectoderm This is the structure that allows the neural grove to become the neural tube. Ridges along the grove fold over. Is a more developed version of the primitive ridge less developed and more “primitive” More pronounced depression or “valley” like feature in the neural ectoderm. Point towards cranial end because this region is more developed. Neural groove may have fully closed over to become neural tube. More pronounced raised ridges running parallel to the neural grove. Point towards the cranial end because the head region is more developed. ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 13 John Tran 2009 24 Hour chick Embryo: Chick is still forming in a linear fashion but major neural features are more defined. The Head process is also more obvious Term Area Pellucida Area Opaca Check Greek/Latin Origin Box Roots . Luc = Bright . Opac = Shady Blood Islands . Mesoderm Cranial Neuropore . Skin Ectoderm . Head Mesenchyme . Mesoderm Cranial Intestinal Portal . Endoderm Neural Groove . Neuro = Brain Neural Ectoderm Neural Folds . Neuro = Neural Neuro = Brain Pore = Passage Ecto = Outer Neural Ectoderm Ectoderm Definition Identify Area of blastoderm that the developing embryo lies on. Area of blastoderm that the developing vasculature forms. Further separated into area vasculosa and area vitellina This will form into the future vasculature for the chick. Future vitelline arteries and veins Central and Bright. Oval Shaped Peripheral and Dark compared to the central embryo. Should see spots…that’s the blood islands Small dark spots that surround developing embryo. They are found more often towards the caudal end of embryo Looks like a small indent in the prosencephalon When the neural tube forms, the cranial region isn’t closed of yet. This is the cranial opening. This is the outermost layer of cells that surround all of the other internal structures. This mesoderm forms the head muscle and connective tissue. Assumes a messy mesenchymal organization Will open up into the foregut. Occurs because the hypoblast/endoderm needs to form a digestive tract. This is the future lumen of the neural tube. Is a more developed version of the primitive groove. This is the structure that Point to outer most layer/membrane in cross sections. Easy! Pick a cross section and point towards the messy looking arrangement of cells found in between the brain structures and the skin ectoderm Looks like a dark upside down semi circle. Found near the cranial region…obviously. Best seen on whole mounts More pronounced depression or “valley” like feature in the neural ectoderm. Point towards cranial end because this region is more developed. Neural groove may have fully closed over to become neural tube. More pronounced raised ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 14 John Tran 2009 Brain Ectoderm allows the neural grove to become the neural tube. Ridges along the grove fold over. Spinal Cord/ Neural Tube . Neural Ectoderm Synonymous with neural tube. This becomes part of the central nervous system. Segmental Plate/ Paraxial Mesoderm . Mesoderm Somites . Soma = Body Mesoderm Notochord . Noto = Back Mesoderm Splan = ? Pleur = Side Mesoderm and Endoderm Mesoderm that will turn into the somites (future musculature and skeletal system of organism) Future musculature and skeletal system of organism. Subdivided into dermatome (future skin), myotome (future Muscle), sclerotome (future skeleton) Future vertebral column. Will be found in about 75 percent of the sections you look at Forms structures like Yolk Sac and Allantois Soma = Body Pleaur = Side Mesoderm and Ectoderm Forms structures like Amnion and Chorion Lateral Mesoderm This is an internal cavity that will hold various organs in the body. Occurs from the delamination of lateral mesoderm into Splanchnopleure . Somatopleure . Coelom . ridges running parallel to the neural grove. Point towards the cranial end because the head region is more developed. Almost same structure as the neural groove except that the grove folds over and forms a tube. Point towards the more cranial regions because the head region is more developed. Find the notochord. Then find aggregations of mesodermal cells lateral to the notochord. They look like circular or oval shaped masses of cells lateral to the notochord. One of the easiest structures to spot Small dark circle located near dorsal portions of sections Easiest to spot towards midsection cross sections. Point towards the double membrane located ventral laterally (endoderm + splanchnic mesoderm) Easiest to spot towards midsection cross sections. Point towards the double membrane located dorsal laterally (ectoderm + somatic mesoderm) Easiest to spot towards midsection cross sections. Located the dorsal somatopleure and the ventral ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 15 John Tran 2009 somatic and splanchnic mesoderm. splanchnopleure. There should be a large white void space in between these two membranes… look back at the lab hand book because the coelom can look very different 33 Hour Chick Embryo: Chick is still forming in a linear fashion but cardio features can now be seen Term Telencephalon Check Greek/Latin Box Roots Tele = Far End Cepha = Head Origin Definition Identify Neural Tube (Forebrain) Part of prosencephalon. Forms future cerebral hemispheres (Forebrain) Part of prosencephalon. Forms future thalamus and hypothalamus. Also forms the third ventricle (Midbrain) Forms the future midbrain structures 1st Cranial most section. Might want to look for the cranial neuropore as an additional structure 2nd cranial most section. Might want to look for optic vesicles as an additional structure. 3d cranial most section. Diencephalon Dien = ? Cepha = Head Neural Tube Mesencephalon Mes = Middle Cepha = Head Met = ? Cepha = Head Neural Tube Metencephalon . Mylencephalon . Mylen = ? Cepha = Head Neural Tube Cranial Neuropore . Neuro = Brain Pore = Passage Neural Ectoderm Fund = Down Diencephalon Infundibulum Neural Tube (Hindbrain) Part of rhombencephalon. Forms future cerebellum and pons (Hindbrain) Part of rhombencephalon. Forms future medulla When the neural tube forms, the cranial region isn’t closed of yet. This is the cranial opening. The downward evagination from diencephalon floor. Forms the pituitary gland with rathkes 4th cranial most section 5th cranial most section… kind of looks narrow and thinner Looks like a small indent in the prosencephalon It’s a darker spot on the diencephalon floor. In cross sections it actually dips down from ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 16 John Tran 2009 Optic Vessicles Opt = Eyes Neural tube but specifically Diencephalon Cranial Intestinal Portal Pore = Passage Endoderm Somites Soma = Body Mesoderm Conotruncus . Ventricle . Sinoatrial Endocardial Tubes/ Mesoderm Vent = Body Endocardial Tubes/ Mesoderm An atrium in greco roman architecture is a large open space in a building Endocardial Tubes/ Mesoderm Ectoderm Neural Crest Cells Notochord Noto = pouch Outward evagination of diencephalon that then forms optic cups/stalk to make the eye Will open up into the foregut Future musculature and skeletal system of organism. Subdivided into dermatome (future skin), myotome (future muscle), sclerotome (future skeleton) Also called bulbis cordis. Will ultimately fuse with the ventricle to help heart pump blood The portion of heart that pumps the blood to the rest of the body. Largest chamber of the heart The portion of heart that holds blood before it is pumped into ventricle. Smaller than ventricle and muscle walls are thinner Dorsal NCC result in melanocytes. Ventral NCC result in peripheral nervous system. Head NCC form muscles and connective tissue in the head Chordamesoderm Future vertebral diencephalon floor Large lateral circular protruding structures from diencephalon Looks like a dark upside down semi circle. Found near the cranial region…obviously They look like circular or oval shaped masses of cells lateral to the notochord. One of the easiest structures to spot On whole mounts, conotruncus looks darker, located more cranially, and more medial On wholemounts, ventricle looks larger, lighter, located more laterally…kind of sticks out from the body of the embryo. Caudal to the bulbis cordis On wholemounts, sinoatrial region looks like a dark little bubble located directly caudad from the ventricle Aggregations of mesenchymal cells lateral to the spinal cord Small dark circle ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 17 John Tran 2009 Back Coelom . Splanchnopleaure . Mesoderm Lateral Mesoderm column. Will be found in about 75 percent of the sections you look at This is an internal cavity that will hold various organs in the body. Occurs from the delamination of lateral mesoderm into somatic and splanchnic mesoderm. Splan = ? Pleur = Side Mesoderm and Endoderm Forms structures like Yolk Sac and Allantois Somatopleure . Soma = Body Pleaur = Side Mesoderm and Ectoderm Forms structures like Amnion and Chorion Neural Groove . Neuro = Brain Neural Ectoderm This is the future lumen of the neural tube. Is a more developed version of the primitive groove. Neural Folds . Neuro = Brain Neural Ectoderm This is the structure that allows the neural grove to become the neural tube. Ridges along the grove fold over. Spinal Cord/ Neural Tube . Neural Ectoderm Synonymous with neural tube. This becomes part of the central nervous system. located near dorsal portions of sections Easiest to spot towards midsection cross sections. Located the dorsal somatopleure and the ventral splanchnopleure. There should be a large white void space in between these two membranes Easiest to spot towards midsection cross sections. Point towards the double membrane located ventral laterally Easiest to spot towards midsection cross sections. Point towards the double membrane located dorsal laterally More pronounced depression or “valley” like feature in the neural ectoderm. Point towards the caudal region because cranial regions already fused into neural tube More pronounced raised ridges running parallel to the neural grove. Point towards the caudal region because cranial regions already fused into neural tube Almost same structure as the neural groove except that the grove folds over and ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 18 John Tran 2009 forms a tube. Point towards the more cranial regions because the head region is more developed. 48 Hour Chick Embryo: Chick now turns on its left side. The embryonic vasculature and blood vessels are the major changes in the chick. Term Definition Identify Stomodeum Check Greek/Latin Origin Box Roots Stom = Ectoderm and Mouth Endoderm contributions Future oral cavity Pharynx . ??? Endoderm Inner endodermal region of highly complex pharyngeal arch region. Basically the back of throat Foregut . For = Before Endoderm Future esophagus, trachea, lungs, stomach, and accessory digestive organs. Stomach . Endoderm Where the food is stored! Yay this one is easy Best seen in whole mount. Point towards region between optic cup and 1st pharyngeal arch. Looks like a hollow pouch… kind of hard to find at this stage This structure is caudal to the stomodeum. Find a cross section and then point to the large, ventral, medial, hole that is around the pharyngeal arches This structure is caudal to the pharynx. Find a cross section and then point to the large, ventral, hole that is past the pharyngeal arches. Look for a developing heart IE ventricles to make sure you have gone down caudally enough This structure is caudal to the Foregut. Find a cross section ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 19 John Tran 2009 Duodenum . Allantois Dorsal Aorta Old latin name meant 12 fingers breadth…I don’t know what that means :[ ??? Endoderm Part of the small intestine. Small intestine sub divisions are Duodenum, Jejunum, Ileum Endoderm Dor = Back Aeiro- rise or left Ventr = Body Aeiro = rise or lift Pre = Before Card = Heart Ven = Come Cardiac Mesoderm Contributes to the excretory system and the future cloaca…1/4 embryonic membranes…used for nitrogenous waste disposal Part of circulatory system, forms future descending aorta Part of circulatory system, forms future aortic sac Mesoderm Part of circulatory system, returns blood to the heart Ventral Aorta . Cardiac Mesoderm Precardinal Veins . Postcardinal Veins . Post = After Card = Heart Ven = Come Mesoderm Part of circulatory system, returns blood to the heart Internal Carotid Arteries . Card = Heart Mesoderm Part of circulatory system, returns blood to the heart and then point to an extra large ventral hole This structure is caudal to the Foregut and Stomach. Find a cross section and then point to large, ventral, hole that is found near the liver rudiment Look towards the tail bud sections and point towards a small opening close to ventral surface… it’s not very large Look for pair of blood vessels located dorsal medial to the gut Look for pair of blood vessels located ventral medial to the gut Look for circular structures (slightly larger than the arteries) located dorsal lateral to the gut (lateral to the dorsal aorta)…found towards cranial regions…thus the prefix “pre” Look for circular structures (slightly larger than the arteries) located dorsal lateral to the gut (lateral to the dorsal aorta)… found towards caudal regions…thus the prefix “post” Look for circular structures (slightly larger than the ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 20 John Tran 2009 Mesoderm… Pumps blood from left related to aortic ventricle into the sac and circulatory system precursor ventral aorta Aortic Trunk Ventricle Atrium . Sinus Venosus . Pericardial Cavity . Descending Aorta . Ventr = Body Endocardial Tubes/ cardiac Mesoderm The portion of heart that pumps the blood to the rest of the body. Largest chamber of the heart An atrium in greco roman architecture is a large open space in a building Sinus = Hollow Ven = Come Endocardial Tubes/ cardiac Mesoderm The portion of heart that holds blood before it is pumped into ventricle. Smaller than ventricle and muscle walls are thinner This is where the blood returns to the heart. Enters sinus venosus before the atrium Peri = Around Card = Heart Cardiac mesoderm Cardiac mesoderm Mesoderm This is the hollow chamber that holds the heart…I think of it as a coelom-ish structure for the heart This is the fusion of the dorsal aorta. Imporatant arteries) located ventral lateral to the gut… found mainly in cranial regions This is one of the most cranial structures of the heart. If you are moving in cranial-caudal fashion through slides, should be first part of heart you see in sections Should be caudad to the aortic trunk. Look for a large hollow circular structure flanked by endocardium and myocardium. Easiest way to differentiate from atrium is that Ventricle has thick muscle walls Should be caudad to the ventricle. Look for a large hollow circular structure. It has thin muscle walls This is the most caudal structure in the heart. Move through all the sections until you reach this caudal portion. Don’t confuse with the ventricle (the ventricle is really big so choose the smaller circular structure) Point to any area lateral to the atrium or ventricle. This is the pericardial space Look at sections caudad to the heart. ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 21 John Tran 2009 structure for the mesonephric kidneys that will later form Dermatome Derm = Skin Sommites Forms the future dermis Myotome Myo = ? Sommites Forms the future muscles . Scler = hard Sommites Forms the future skeleton Splanchnopleaure . Splan = ? Pleur = Side Mesoderm and Endoderm Forms structures like Yolk Sac and Allantois Sclerotome Somatopleure . Soma = Body Pleaur = Side Mesoderm and Ectoderm Forms structures like Amnion and Chorion Amnion . ??? Sommatopleure Chorion . ??? Sommatopleure Yolk Sac . ??? Splanchnopleure Telencephalon . Tele = Far End Neural Tube ¼ Extra embryonic membrane. Responsible for providing aqueous environment ¼ Extra embryonic membrane. Responsible for providing gas exchange ¼ Extra embryonic membrane. Responsible for nutrients Part of prosencephalon. Forms future cerebral Look the dorsal medial region of the sections. Look for one large circular structure. I like choosing sections towards tail region…Part of sommite located closest to skin ectoderm I like choosing sections towards tail region…In between dermatome and myotome I like choosing sections towards tail region…Part of sommite located closest to the neural tube Easiest to spot towards midsection cross sections. Point towards the double membrane located ventral laterally Easiest to spot towards midsection cross sections. Point towards the double membrane located dorsal laterally Go to whole mount: Point to large bubble sac like structure around embryo Hard to differentiate from Amnion. Point to same region as the Amnion The whole embryo kind of sits on the entire yolk sac Cranial most section. Might want to look ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 22 John Tran 2009 Cepha = Head hemispheres Diencephalon . Dien = ? Cepha = Head Neural Tube Part of prosencephalon. Forms future thalamus and hypothalamus. Also forms the third ventricle Mesencephalon . Neural Tube Forms the future midbrain structures Metencephalon . Mes = Middle Cepha = Head Met = ? Cepha = Head Mylencephalon . Infundibulum . Rathkes Pouch . Isthmus . Cranial Flexure . Cran = Brain Flex = Bend Neural Tube Eye Cups . Opt = Eye Ectoderm Turns the 33 hour chick embryo’s linear body lay out to this twisted body lay out. Term used to describe how head is twisted to the left side Future Eye Pigmented Retina . Ectoderm Future neural cells like Mylen = ? Cepha = Head Fund = Down Neural Tube Part of rhombencephalon. Forms future cerebellum and pons Neural Tube Part of rhombencephalon. Forms future medulla Diencephalon The downward evagination from diencephalon floor. Forms the pituitary gland with rathkes pouch Oral Cavity The upward evagination from oral cavity. Forms the anterior pituitary gland with the infundibulum. Neural tube: A constriction of the Mesencephalon neural tube between the and mesencephalon and Metencephalon metencephalon for the cranial neuropore as an additional structure Very cranial section. Might want to look for optic vessicles as an additional structure. First large neural bulge Second large neural bulge Third large neural bulge Fourth large neural bulge… kind of looks narrow and thinner It’s a darker spot on the diencephalon floor It’s the little circular bubble that is near te infundibulum. It evaginates from the stomodeum. Easiest to spot on a whole mount. Find a “dent” in between the mesencephalon and metencephalon on the dorsal side. Easiest to spot on a whole mount. Just point to the head region Huge circular bulges coming out of the prosencephalon. Hard to miss Look near ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 23 John Tran 2009 bipolar, horizontal, or ganglion cells in the eye Sensory Retina . Auditory Vessicles . Tail Buds . . . . . Aud = Hearing Ectoderm Future photoreactive cells like rods and cones Ectoderm Future inner ear Mesoderm Forms the primitive tail prosensephalon for the bulging optic cups. Thinner structure than pigmented. It is located more medial Look near prosensephalon for the bulging optic cups. Thicker structure than sensory. It is located more laterally. Located near the mylencephalon. Look like circular outgrowths from the head One of the most caudal structures. Go all the way to the end of your slides ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 24 John Tran 2009 72 Hour Chick Embryo Stomodeum . Stom = Mouth Ectoderm and Endoderm contributions Pharynx . ??? Endoderm Esophagus . Oesopho = Gullet Phagus = Eat Endoderm of foregut Trachea . Ventral Diverticulum of foregut Lung Buds . Bifurcation of the primordial trachea Future oral cavity Best seen in whole mount. Point towards region between optic cup and 1st pharyngeal arch. Looks like a hollow pouch… kind of hard to find Inner endodermal region This structure is of highly complex caudal to the pharyngeal arch region. stomodeum. Find a Basically the back of cross section and then throat. Caudal to the point to the large, stomodeum but cranial to ventral, hole that is the larynx around the pharyngeal arches This is how food goes Parallel to the trachea from the mouth to the but located dorsal. stomach. Small circular structure near/after the pharyngeal area This is the future Parallel to the windpipe. Brings air esophagus but located down into the bronchi ventral. Small circular structure near the pharyngeal area…caudally the lung buds can be found This will mature into the Look for a pair of two full Lungs. Responsible circular structures for respiration ventral lateral to the esophagus. They’re easy to spot because they look like bubbles ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 25 John Tran 2009 Stomach . Endoderm of foregut Where the food is stored! Yay this one is easy Duodenum . Old latin name meant 12 fingers breadth…I don’t know what that means :[ Endoderm of foregut Part of the small intestine. Order of small intestine sub divisions are Duodenum, Jejenum, Ileum Jejunum . ??? Endoderm midgut Part of the small intestine. Order of small intestine sub divisions are Duodenum, Jejenum, Ileum Ileum . ??? Endoderm midgut Part of the small intestine. Order of small intestine sub divisions are Duodenum, Jejenum, Ileum Cloaca . ??? Endoderm Where the digestive tract and the urinary tract excrete their waste. This cloaca will divide in growing from the foregut This structure is caudal to the Foregut. Find a cross section and then point to an extra large ventral hole. I distinguish the stomach from the duodenum or esophagus because the stomach should have a thicker tissue lining. The lumen is also larger as wel. This structure is caudal to the Stomach. Find a cross section and then point to large, ventral, hole that is found near the liver rudiment…the duodenum is usually surrounded by the dark spotty tissue of the liver This structure is caudal to the Duodenum and Stomach. Find a cross section and then point to large, ventral, hole that is caudal to the liver This structure is caudal to the jejunum. Find a cross section and then point to large, ventral, hole that is found towards the more caudal sections Look towards the tail bud at the most caudal setions. It will be the largest, most medial, ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 26 John Tran 2009 Dorsal Aorta . Ventral Aorta . Precardinal Vein . Postcardinal Vein humans and mamals so that the urinary tract is separate from the digestive tract… but vertberates like birds still have a single cloaca Part of circulatory system, forms future descending aorta Part of circulatory system, forms future aortic sac circular lumen. You might see a septum that divides the cloaca into two circular lumens…this is normal Look for circular lumen located dorsal lateral to the gut Look for circular lumen located ventral lateral to the gut Look for circular lumen (slightly larger than the arteries) located lateral to the dorsal aorta…found towards cranial regions Look for circular lumen (slightly larger than the arteries) located lateral to the dorsal aorta… found towards caudal regions Look for circular structures (slightly larger than the arteries) located ventral lateral to the gut… found only in cranial regions Look for one circular lumen located dorsal medial… It’s the same place where dorsal aorta used to be…remember to look at sections that are caudad to the heart (if not the dorsal aorta have not fused yet) This is hard. You have to keep track of Dor = Back Aeiro- rise or left Ventr = Body Aeiro = rise or lift Pre = Before Card = Heart Ven = Come Mesoderm Mesoderm Part of circulatory system, forms, returns blood to the heart . Post = After Card = Heart Ven = Come Mesoderm Part of circulatory system, forms, returns blood to the heart Internal Carotid Arteries . Card = Heart Mesoderm Part of circulatory system, returns blood to the heart Descending Aorta . Dorsal Aorta 1,2,3 aortic arch . Mesoderm The fusion of the two dorsal aorta. This fusion occurs once you move caudad to the developing heart. Is an important structure for the mesonephric kidneys and will branch out to make the glomeruli (capillaries) for the mesonephric kidney Part of the complex pharyngeal arch Mesoderm ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 27 John Tran 2009 system…will form arteries, veins found in the head and neck Conotruncus AKA Bulbis Cordis . Bul = Bulb Chord = Cord … I guess it describes the shape Endocardial Tubes/ cardiac Mesoderm Also called bulbis cordis. Will eventually fuse with the primitive ventricle to form adult ventricle Ventricle . Ventr = Body Endocardial Tubes/ cardiac Mesoderm The portion of heart that pumps the blood to the rest of the body. Largest chamber of the heart Atrium . An atrium in greco roman architecture is a large open space in a building Endocardial Tubes/ cardiac Mesoderm The portion of heart that holds blood before it is pumped into ventricle. Smaller than ventricle and muscle walls are thinner Sinus Venosus . Sinus = Hollow Ven = Come Cardiac mesoderm This is where the blood returns to the heart. Enters sinus venosus before the atrium all the arches and count them to know which arch number you are on. Arches are basically blood vessels so look for circular lumens. They always come in a pair (left and right) and are located lateral from the pharynx It is located cranial to the ventricle. One of the earliest structures you will spot on a section if you are moving in cranial caudal fashion. Look for the typical circular lumen near cardiac region Should be caudad to the bulbis cordis. Look for an extra large hollow circular structure flanked by endocardium and myocardium. Easiest way to differentiate from atrium is that Ventricle has thick muscle walls Should be caudad to the ventricle. Look for a large hollow circular structure. It has thin muscle walls when compared to the ventricle. This is the most caudal structure in the heart. Move through all the sections until you reach this caudal portion. Don’t confuse with the ventricle (the ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 28 John Tran 2009 Vitelline Artery . Vitell = Yolk This is the oxygenated blood that will flow into the embryo Vitelline Vein . Vitell = Yolk This is the deoxygenated blood that will drain out of the embryo Wing Bud . Apical Ectodermal Ridge . Sommatic Mesoderm Amnion . . Somatic Mesodermal Mesenchyme This wing bud will extend out in progress zones to fully form wings on either side of the body Ecto = Outer Skin Ectoderm This is the leading edge of how the bud forms, extends, and matures into a fully developed wing ??? Sommatopleure ¼ Extra embryonic membrane. Responsible for providing aqueous environment ventricle is really big so choose the smaller circular structure) You can find this pretty easily on a whole mount. Look for a dark and large artery that transverses the embryo at mid section… You can find this easiest on a cross section. Look for two large circular lumens that appear caudally from the liver region. Veins need to drain blood to the liver/ ductus venosus first. Remember blood vessels are always circular lumens and veins tend to have larger lumens than arteries Obvious. Look at lateral sides of the body and you will see these bud shaped outgrowths of mesodermal mesnechyme. Verify by spotting the darker edge of the apical ectodermal ridge Look for the darker, thicker, outer rim pf skin ectoderm that surrounds the wing bud. Go to whole mount: Point to large bubble sac like structure around embryo…directly ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 29 John Tran 2009 next to the chorion Chorion . ??? Sommatopleure ¼ Extra embryonic membrane. Responsible for providing gas exchange Yolk Sac . ??? Splanchnopleure ¼ Extra embryonic membrane. Responsible for nutrients Allantois . ??? Splanchnopleure ¼ Extra embryonic membrane. Responsible for waste disposal. Telencephalon . Tele = Far End Cepha = Head Neural Tube Part of prosencephalon. Forms future cerebral hemispheres Diencephalon . Dien = ? Cepha = Head Neural Tube Part of prosencephalon. Forms future thalamus and hypothalamus. Also forms the third ventricle Mesencephalon . Mes = Middle Cepha = Head Neural Tube Forms the future midbrain structures Metencephalon . Met = ? Cepha = Head Neural Tube Myelencephalon . Mylen = ? Cepha = Head Neural Tube Part of rhombencephalon. Forms future cerebellum and pons Part of rhombencephalon. Forms future medulla Go to whole mount: Hard to differentiate from Amnion. Point to same region as the Amnion on a whole mount…directly next to the amnion Go to whole mount: The whole chick embryo kind of sits on the entire yolk sac Go to whole mount: Look towards the tail bud sections and point towards a small light colored bubble close to ventral surface… it’s not very large In cranial caudal direction it is the 1st Cranial most section. Might want to look for the nasal pits as verification structure In cranial caudal direction it is the 2nd Cranial most section. Might want to look for optic vessicles, pineal gland, or infundibulum as verification structures. In cranial caudal direction it is the 3d Cranial most section. I usually look for the isthmus as a verification In cranial caudal direction it is the 4th Cranial most section. In cranial caudal direction it is the 5th Cranial most section. I like to look for the ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 30 John Tran 2009 Infundibulum . Rathkes Pouch . Pharyngeal Groove/Cleft . Pharyngeal Pouch Fund = Down Diencephalon The downward evagination from diencephalon floor. Forms the posterior pituitary gland Oral Cavity The upward evagination from oral cavity. Forms the anterior pituitary gland Related to the pharynx Pharyngeal Ectoderm Refer to the Pharyngeal Handout . Related to the pharynx Pharyngeal Endoderm Refer to the Pharyngeal Handout Pharyngeal Arch . Related to the pharynx Mandiubular Process . Mandible = Jaw This is the mass of tissue that will surround the aortic arches. Each arch #1-4 will also house a cranial nerve. Pharyngeal Arch 1 Forms the future lower jaw….the mandible! Jaws are really auditory vesicles as verification It’s a darker spot on the diencephalon floor. In cross sections, you can actually see a bubble pop out from the brain (this is the evagination) It’s the little circular bubble that is near the infundibulum. It evaginates from the stomodeum. Go to sections where the pharyngeal area is. Point to the grooves from OUTSIDE the pharyngeal area. Its called a groove because it looks like outside the pharynx the ectoderm got sucked down and made a groove Go to sections where the pharyngeal area is. Point to the pouches from INSIDE the pharyngeal area…its called a pouch because it looks like the pharynx “pouched out” Find the aortic arch. Then there should be a dark, mesenchymal, mass of tissue that surrounds the blood vessel (looks like somite structures but located near the pharynx instead) Go to pharyngeal arch 1. Point to the caudal portion of the tisssue ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 31 John Tran 2009 Pharyngeal Arch 1 powerful… lots of force when chewing food Forms the future top portion of the jaw! Jaws are really powerful… lots of force when chewing food Associated with semilunar ganglion. Is the fifth cranial nerve. Composed of the opthalic, mandibular, and maxillary branches Maxiallary Process . Trigeminal Nerve . Tri = Three First Aortic Arch Acousticofacialis Nerve . Combo of Acoustic and Facial nerves Second Aortic Arch Responsible for two nerves, Auditory nerve and the facial nerve. Spinal Ganglion . Neural Crest Cell Ganglia are cluster of neural cells. They are important for the sensory information being consolidated from the PNS before being sent to the CNS Eye Cup . Evagination from lateral sides of Diencephalon Forms future retina. Remember there is the thicker sensory retina and the thinner pigmented retina Pigemented Retina . Eye Cup Thin outer layers of the optic cups that contain pigment granules mass. Closer to the pharynx Go to pharyngeal arch 1. Point to the cranial portion of the tissue mass. Closer to the stomodeum Very easy to spot. Look towards the mesencephalon. It is one of the first cranial nerves you can spot. Look for three, dark, circular spots located laterally on each side of the brain. Usually located proximal to the auditory vesicles (obviously since nerve deals with hearing). It is a big dark spot located on the lateral sides of the brain. Usually around the mylencephalon region. All ganglia look the same, they are small, circular, dark, spots. The spinal ganglia are located directly lateral to the neural tube so they are very easy to find. Look for the lateral bulges/bulges around the diencephalon. Bulges look huge on cross sections but eye cups look like round dark spots on a whole mount Locate eye cups. Point towards to the thin outer layer…will look darker ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 32 John Tran 2009 Sensory Retina . Eye Cup Nasal Pit . Facial Bulges Lateral Nasal Process . Medial Nasal Process . Mesonephric Duct . Mesopnephric Tubule . . . . . . . . The thick inner layers of the optic cups, will form the future rods, cones, bipolar cells ect Future nose and nasal cavity Locate eye cups. Point towards the thick inner layer Locate the mylencephalon region. Look at ventral lateral region of the head. There are dark, thick, invaginating portions of skin ectoderm Facial Bulges Future side cheek portion Locate the nasal pit. of face Point towards the side of the nasal pit more lateral on the head Facial Bulges Future top lip portion of Locate the nasal pit. face Point towards the side of the nasal pit more medial on the head Intermediate Embryonic Kidney, site A longitudinal Mesoderm where all the waste structure the stretches from urogential drains the length of latter region half of the body. One circular lumen located on each lateral side in the mesonephric kidney Intermediate Embryonic Kidney, site This is the mess of mesoderm where the waste is tubules (look like from urogenital filtered scattered holes from a region sponge) that runs parallel to the dorsal aorta ______________________________________________________________________________ Vertebrate Embryology Lab Notes, Page 33 John Tran 2009 . . . . . . . . . . . . . . . . . . .