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Definition
-within fallopian tube -induces second meiotic division in oocyte -sperm enters egg; tail falls off head enlarges -pronucleus of egg and sperm fuse |
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Definition
-cell mass of 12 smaller cells (blastomeres) -3 days after fertilization
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Definition
Contains: -embryoblast -bastocystic cavity -surrounding trophoblast |
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| What happens when blastocyst attaches to uterine wall? |
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Definition
Attaches to uterine wall causing trophoblast to differentiate into: -syncytiotrophoblast (becomes part of uterine wall) -cytotrophoblast (outside) -hypoblast (forms on luminal surface of embryoblast) |
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Definition
-2nd weekafter fertilization -as blastyocyte sinks into uterine wall;embryoblast develops a cavity with cell attainign a columnar shape -forms a two layered embryonic disc 1. hypoblast - on luminal surface of embryoblast
2. epiblast - adjacent to amniotic cavity
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Definition
-within syncytiotrophoblast -fill with mom's blood -provide nutrients via diffusion
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Definition
-Fingerlike extensions -From cytotrophoblast to syncytiotrophoblast -First component of placenta to form
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Definition
-thickened circular structure -future site of mouth -from hypoblast cells that have become columnar in shape
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Definition
-3rd week of develpment -3 germ layers from (ectoderm, endoderm, mesoderm) -signals start of morphogenesis (body develoment)
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Term
| How is gastrulation initiated? |
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Definition
-Formation of primative streak on epiblast
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Term
Primitive streak how is it characterized? |
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Definition
-results from epiblast cells proliferating and migrating between two layers of bilaminar disc -grows caudally -characterized by: thickening at cranial end, the primitive node, and a lengthwise primitive groove = culminating at primitive pit -regresses by end of 4th week and embryo remains bilaminar at futur sites of mouth and anus
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Term
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Definition
-epiblast cells that migrate into primative groove between two lamellea -occurs as primitive streak lengthens -Some mesenchyme become mesoderm -Other migrating cells replace hypoblast forming endoderm
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Term
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Definition
epidermis and epidermal appendages, nervous system including the eye and inner ear, connective tissue of the head, and neural crest |
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Term
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Definition
skeletal muscle, blood cells, epithelium of blood vessels, visceral smooth muscle, mesothelium, reproductive and urinary organs and ureters, most of the cardiovascular system, and the connective tissue, bones, and ligaments of the trunk |
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Definition
thyroid and parathyroid glands, epithelial linings of the respitory and gastrointestinal tracts as well as their grandular components, and that of the inner ear |
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Definition
-formation of the neural tube -induced by development of notochord
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Term
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Definition
1. induce neurulation 2. define long axis of embryo 3. rigidify embryo 4. signal cells to develpe into axial muscles and bones as well as elements of the CNS 5. form parts of the intervertebral discs
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Term
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Definition
-induces thickening of ectodermal cells forming neural plate (neural plate becomes CNS and retinas) -neural groove forms along neural plate (day 18) therefore, peripheral neural folds arise and fuse -this creates neural tube which seperates from ectoderm -neural crest cells along neural folds break away prior to fusionand migrate into embryo forming stucutres
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Term
| Structures derived from neural crest cells |
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Definition
1. dorsal root ganglion of spinal chord 2. autonomic ganglia 3. parts of the ganglia of several cranial nerves 4. melanocytes 5. adrenal medulla 6. sheaths of peripheral nerves 7. dentin
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Term
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Definition
-columns of mesenchyme condensed on sides of notochord broken into cuboidal structures -cranial to caudal direction -give rise to most of the axial skeleton and its musculature and overlying dermis
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Definition
-first fully functioning organ system -arises from splanchnic mesoderm (early heart), paraxial and materal mesoderm, and neural crest
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Definition
-mesodermally-derived mesenchymal cells form blood islands which form primitive blood vessels -cells lining blood islands form endothelium of CVS which form various blood cells (in adults this is done by bone marrow and to lesser extent by spleen and liver) |
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Definition
21 days = heartbeat 3rd week = blood circulates
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28 days - formation of laryngotracheal groove at posterior end of primordial pharynx (lined by endoderm) |
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Definition
-generates larynx, pharynx, bronchi, and bronchiolar tree of lungs and associated glands (endoderm)
-supporitng structures (connective tissue, cartilage, and bronchial smooth muscle from mesoderm) |
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Term
Larynx and Trachea Respitory System Develoment and Completion |
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Definition
-combined structur splitting form foregut -gives rise to repitory buds --> into developing pleural cavities --> results in bronchial tree --> components which are responsible for gas exchane -complete at 32 weeks
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Term
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Definition
-earliest stage alimentary tract is closed system -bordered rosterally by oropharyngeal membrane and caudally by cloacal membrane -lined by endoderm which gives rise to majority of epithilium in GI
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Term
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Definition
Stomodeum (primitive mouth)
Proctodeum (primitive anus) -Both lined b ectoderm
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Term
| Division on alimentary canal |
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Definition
1. foregut 2. midgut 3. hindgut
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Term
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Definition
-larnyx and pharnyx split off -esophagus splits from trachea and elongates caudal -stomach and proximal duodenum are dilation on esophagus (further differentiation of epithelial lining and grandular component) rotates 90 degress -liver, bilary tree, gall bladder arise from hepatic diverticulum as distal end of foregut (liver is major site of blood cell formation) -pancreas develops from paried pancreatic buds; ends differentiate into exocrine protion and endocrine portion arises from cells located between the ducts
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Term
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Definition
Contains: 1. distal duodenum and remaining small intestine 2. large intestine up to mid-portion of transverse colon -rotates 90 degrees counterclockwise -intestines herniate into umbilical cord = further rotation
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Term
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Definition
most distal portion of alimentary canal 1. about distal 1/2 of transverse colon, descending colon, and rectum 2. epithelium of urinary bladder and urethra cloaca is terminus
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Term
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Definition
-end of hindgut -where gastrointestinal endoderm is opposed to surface of ectoderm -mesenchyme (urorectal septum) divides cloaca into dorsal rectum and anal canal and a ventral urogential sinus
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Term
| Urogential System Derived? |
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Definition
-derived from mesodermal urogenital ridge located on either side of dorsal aorta
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3 stages: -pronephric (nonfunctional) -mesonephric (briefly functional) -metanephric (permenant) form week 5-9
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Term
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Definition
By way of reciprocal induction: 1. metanephric diverticulum - from mesonephric duct; stalk becomes ureters and ends form collectin ducts and renal calyces 2. metanephrogenic blastema - future kidney arises from caudal end of nephrogenic cord which will become peirced by metanephric diverticulum -kidney moves cranially form pelvis -cranial end of urogenital sinus dilates to form urninary blasser (middle portion forms urethra)
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| Primary Sex Characteristics |
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Definition
7th week -gonads form during 5th week when mesonephric kidney proliferate forming gonadal ridge -fingerlike projections of epithelium penetrate mesenchyme forming gonadal chords -gonadal chords give inddiferent gonade outer cortex and inner medulla
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Definition
cortex = ovary medulla degenerates
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Definition
medulla= testis cortex degenerates
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Term
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Definition
-form gamates -originate in yolk sac near umbilical cord -migrate to gonadal ridges and eventually gonadal cords |
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Term
| Primordial Germ Cells (females) |
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Definition
-mesothelium lining in abdominal cavity grows into ovary and germ cells migrate in -cellular cords then break resulting in isolated clusters of cells called primordial follicles made of oogonium (germ cell) surrounded by follicular cells -oogonia differentiate in primary oocytes b4 birth -after birth no more primary oocytes formed
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Term
| Skeletal Muscle Development |
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Definition
-except iris and esophagus; skeletal muscle derived from mesoderm -Most form before birth -Some completed by end of first year of life |
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Term
| Myoblasts - Skeletal Muscle |
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Definition
-progenitor cells descend from mesenchyme |
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Term
Role of Myoblasts Define myotubes |
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Definition
1. elongation and fusion of myoblasts -->forms myotubes Myotubes - long, multinucleated cells that generally acquire cytoplasmic myofilaments and myofibrils
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Term
| Smooth Muscle Development |
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Definition
-derived from splanchnic mesenchyme that surrounds endoderm og GI tract -cells remain mononuclear because myoblasts do NOT fuse during development |
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Term
| Cardiac Muscle Development |
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Definition
-arise from primordial heart -do NOT fuse with meighbors -adhere to adjacent cardiac muscle cells -->intercalated disc marks site of undegenerated cell membranes |
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Term
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Definition
-most primitive landmark of the nervous system -leads to formation of two intermediate entities: -->neural tube (brain + spinal cord CNS)
-->nerual crest (PNS and ANS)
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Term
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Definition
-formed by fusion of neural folds -cranial 2/3 = brain; rest is spinal cord -neural tube thickens enclosing neural canal -->neural canal becomes ventricular sys of CNS -differentiates into speerate parts of the CNS -neural tube cranial to 4th pair of somites will form brain |
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Term
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Definition
ventricular system of CNS
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Term
| Dilations (vesicles) of neural tube |
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Definition
1. forebrain (prosencephalon) divides into: -telencephlon (cerebral hemi, retinas, optic nerves) -diencephalon (thalmus, hypothalamus, pineal gland) 2. midbrain (mesencephalon) never subdivides; shows little modification 3. hindbrain (rhombencephalon) divides into: metencephalon (pons, cerebellum) myelencephalon (medulla oblongata) (most caudal)
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Term
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Definition
-primitive nerve cells that differentiate from neuroepitheium of neural plate -generate elongated cellular process and become neurons and ependymal cells that line ventricles and spinal canal -some crest cells migrate to CNS and become glioblasts |
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Term
| Glioblasts Differntiate to? |
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Definition
differentiate into --> Schwann cells --> astrocytes --> oligodendrocytes |
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Term
| What is Pharyngeal Apparatus |
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Definition
-early in 4th week -migration of neural crest cells to rostral end -becomes most of lateral and ventral structures of head an dneck -future pharynx, larynx, mouth, nasal cavities and face -at end; 4 pairs o protuberences visibles along future head and neck region (seperated by pharyngeal grooves) |
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Term
| What happens with primitive mouth (stomodeum) |
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Definition
as pharyngeal apparatus develops, stomodeum seperates from surface ectoderm by oropharyngeal membrane this membrane ruptures --> alimentary canal has contact with the amniotic environment |
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Term
| What does the Pharyngeal Apparatus consisit of? |
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Definition
Consists of: 1. Pharyngeal Arches 2. Pharyngeal Pouches 3. Pharyngeal Grooves 4. Membranes
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Term
| All pharyngeal arches contain: |
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Definition
1. artery 2. cartilage rod (develops into skeleton of the arch) 3. muscle 4. sensory and motor nerves that supply elements of the arch (cranial nerves) |
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Term
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Definition
Forms: a. maxillary prominence=maxilla and zygomatic bones b. mandibular prominence=mandibul and squamous portion of temporal bone -Meckel's Cartilage forms incus and malleus of inner ear and sphenomandibular ligament c. muscles of mastication d. supplied by CN V (trigeminal nerve) |
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Term
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Definition
Forms: a. majority of hyoid bone b. Reichert's cartilage --> stapes of inner ear and stylohyoid ligament c. muscles of facial expression d. supplied by CN VII (facial nerve) |
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Term
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Definition
Forms: a. leser parts of hyoid bone b. supplied by CN IX (glossopharyngeal nerve) |
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Term
| Fourth and Sixth Pharyngeal Arch |
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Definition
Forms: a. laryngeal cartilages (except epiglottis) b. muscles of palatal, pharyngeals and laryngeal c. supplied by CN X (vagus nerve) |
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Term
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Definition
Regresses and forms no derivatives
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Term
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Definition
-paired blind-ended extensions of developing pharynx -lined by endoderm -4 in total |
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Definition
Forms: structures of the ear -->tympanic membrane -->tympanic cavity -->auditory tube |
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Definition
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Definition
Forms: a. inferior parathyroid glands b. thymus |
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Definition
Forms: superior parathyroid glands |
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Definition
-only first pair persists after birth -->become the ear canals
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