* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Chapter 13- The neural crest
Biological neuron model wikipedia , lookup
Multielectrode array wikipedia , lookup
Clinical neurochemistry wikipedia , lookup
Axon guidance wikipedia , lookup
Synaptogenesis wikipedia , lookup
Convolutional neural network wikipedia , lookup
Stimulus (physiology) wikipedia , lookup
Neuroanatomy wikipedia , lookup
Neural correlates of consciousness wikipedia , lookup
Feature detection (nervous system) wikipedia , lookup
Artificial neural network wikipedia , lookup
Metastability in the brain wikipedia , lookup
Subventricular zone wikipedia , lookup
Optogenetics wikipedia , lookup
Nervous system network models wikipedia , lookup
Types of artificial neural networks wikipedia , lookup
Neuropsychopharmacology wikipedia , lookup
Recurrent neural network wikipedia , lookup
Neural binding wikipedia , lookup
Channelrhodopsin wikipedia , lookup
The neural crest Chapter 13- The neural crest Recall lineages Ectoderm-skin/nerves Mesoderm-Blood, heart, kidney, bones Endoderm- Gut and associated organs Recall- Ectoderm has three fates 1._________ 2.Neural crest cells 3. _________ Fig. 12.3 ___________(skin) ______________ ______________ __________________ This process is called ______________ The neural crest Neural crest cell fate depends largely on where they _______ Potential cell fates include- The neural crest is a ________ structure 1. _______ and _______ 2. ________ of adrenal gland (produces ___________) 3. ______________ cells of epidermis 4. Skeletal/connective tissue of ___________ Neural crest- four functional ____________ A. ___________- cartilage, bone, neurons, glia of face B. __________ C. ________- parasympathetic ganglia D. ________- melanocytes (produce pigment); sensory and sympathetic neurons, medulla Fig. 13.1 Sensory pathways- conduct info to brain-, spinal cord A quick review of nerve nomenclature 1. _____________ nervous system -“____________ controlled muscles”- CNS sends signals to _______ muscles of heart, blood vessels, iris, pancreas liver, digestive tract, kidney 1.___________- -homeostasis of body systems, originate from hindbrain 2. ___________- fright and flight reactions- originate form spinal chord 2. ______ nervous system-“__________ controlled organs”- CNS sends signals to ________ muscles communication between various parts of the body (e.g. thallumus, cerebellum) with muscles Figure not in text The neural crest A. Start with the _____Neural crest Two major paths taken Path 1-cells travel ______epidermis, become melanocytes, colonize hair and skin follicles Epidermis __________ __________ _________ Path 2-cells to _____ of __________ and through anterior sclerotome to become sympathetic and sensory ________ Fig. 13.2 This is a _______ Note – Sclerotome will become vertebral cartilage The neural crest How do these neural crest cells know where to migrate? 1. Epidermis secrete ____________________ - BMP-4 and –7 induce neural crest cells to produce slug and RhoB - Slug dissociates cell-cell tight junctions 2. ____________ expression is also lost then regained once reaching final destination 3. __________ proteins in extracellular matrix guide cells • Neural crest cells have Eph ___________ • Trunk sclerotome express Eph ________ • Binding of Eph receptor to Eph ligand interferes with migration • Thus, Eph proteins tell neural crest cells where _____ to go Neural Crest cells Fig. 13.4 Ephrinin sclerotome 4. __________ factor allows continued proliferation 5. Other chemotactic and maintenance factors The neural crest •Trunk neural crest cells are __________ (can become many cell types) However, it may be that only certain populations of cells are pluripotent • Some _________________ have been identified that dictate cell fate: ________ Sympathetic and Trunk neural crest cell ___________ parasympathetic neurons Sensory neuron ___________ recently shown to convert neural crest cells to sensory neurons in mice •Expose cells to Wnt1 - cells become sensory neurons •If do same experiment in B-cat -/- mice- no effect Lee et al, Science 303, 1020-1023 (Feb. 2004) The neural crest Final cell fate is determined by final ______________ __________ Neuron Fig. 13.6- Fate of a trunk neural crest cell is influenced by _____ and ______________ Neural crest Cell __________ Cell The neural crest B. The _________ neural crest Like the trunk neural crest cells, these can produce glia, ________ and _____________ But, only __________ neural crest cells can produce cartilage and bone Rhombomeres Recall – the neural tube subdivides into forebrain, midbrain and hindbrain • The hind brain then further subdivides into ________________ • Each rhombomere is a __________, each produces ganglia, but each has a distinct _____ •Rhombomeres sit behind the ________________ Pharyngeal arches Fig. 13.1 The neural crest Three paths for ________ neural crest cells: Pharyngeal arches Rhombomeres in hind brain of ____________ 1 1. Rhombomere ____- to 1st Ph. Arch 2 2. Rhombo. _- to 2nd Ph. Arch Incus, Malleus, jaw cartilege Stapes, Styloid Process 3 4 3. Rhombo. __ to 3rd and 4th Ph. Arch Hyoid bone, thyroid cartilage Fig. 13.7 Rhombomeres _______ do not migrate through arches Fate map of pharyngial arches contributions to face formation The neural crest What determines distinct fates of cranial neural crest cells? Answer- The combination of ______ genes Evidence 1. _______ KO- neural crest cells of 2nd Ph. Arch transformed into ___ Ph. Arch structures 2. Hoxa-1 and Hoxb-1 double KO- no _____________ migration + retinoic No ear WT acid 3. Retinoic acid induces more ______ expression of certain Hox genesInduces rhombomeres 2 and 3 to assume role of rhombomeres _________ Fig. 13.8 How is neuronal ______ achieved?? 5 ways1. Blocking ____ signal allows formation of dorsal neural tube (recall chapter 12) 2. __________ specifies _______ fate (not epidermal or glial) 3. Initial __________ determines neuronal type 4. Migration ___________ further dictates specificity 5. Specific _________ made with target organs or other neurons 3 parts described 1. __________ selection- axons travel along a given route 2. __________ selection- axons reach a target, then bind to specific cells 3. _________ selection- axons now refine interactions- bind to only a subset of possible targets A. 5 Hypotheses for pathway selection- 1. _____________- Growth cone can adhere to certain cells, but not others • ________ – a glycoprotein which appears to pave the road for several axonal migrations • ________ 2. _______________- Growth cone can adhere to certain cells, but not others 3. ____________ hypothesis- in ______, a neuron can precisely follow the path of a prior neuron Kallmann syndrome- an infertile man with lack of smell Reason- a single protein directs migration of both __________ axons and _______________ nerve cells 4. ___________a. _______ (recall Fig 13.4) – Growth cones contain Eph _______- binding prevents migration into undesirable areas b. ___________ proteins- important in directing axon turns Hypotheses for pathway selection- (Cont.) 5. _______________a. ____________ are chemotactic Fig. 13.20 Rat dorsal spine explant Neuron Outgrowth Neutrin producing cell •Netrins are homologues of the ____________ in C. Elegans Loss of Unc-6 prevents migration of both sensory (to ventral) and motor (to dorsal) neurons Fig. 13.21 Sensory Neuron Motor WT Neuron b. _______________ are repulsive Unc-6 -/- B. Hypotheses for_________ selection- 0 min 2 min Target cells secrete short-range chemotactic or _____________ factors Example- NT-3 attracts axons C. Hypotheses for _______ selection- Fig. 13.25 Growth cone makes contact with a cell, ______________ receptors cluster on target cell surface, and a ______ is formed 6 min 10 min Fig. 13.24 Additional axons synapse target cell, but eventually only _________ remains