Summary Class notes - Mens- en dierkunde1

Course
- Mens- en dierkunde1
- Arie Terlouw
- 2014 - 2015
- Wageningen University (Wageningen University, Wageningen)
- Dierwetenschappen
231 Flashcards & Notes
0 Students
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Summary - Class notes - Mens- en dierkunde1

  • 1426287600 Thema 1: H3+H4 part 1

  • What is a blastomere?
    Blastomere is a large cluster of small cells formed during cleavage
  • When is the blastula stage?
    at the end of cleavage
  • What is cleavage?
    celdeling
  • Why is the animal-vegetal axis formed?
    because yolk only exists at 1 end, creating polarity
  • Which pole is the animal pole and which is the vegetal pole?
    yolk rich = vegetal
    other end = animal
  • What does isolecithal egg mean?
    Iso=equal. Eggs with little yolk that is evenly distributed. 
  • what is an mesolecithal egg?
    meso=middle. Egg with moderate amount of yolk at vegetal pole
  • What is telolecithal?
    telo=end. abundance of yolk at vegetal pole. 
  • What does meroblastic cleavage mean?
    Mero=part. That there is much yolk and therefore the cleavage is incomplete because cleavage furrows cannot cut through dense yolk. 
  • What does holoblastic cleavage mean?
    That the cleavage furrows extend completely through the egg. Little yolk is present.
  • Cleavage divides the mass of the zygote until a cluster of cells called the blastula is formed. Cells are arranged around a central fluid-filled cavity called the blastocoel.
  • What is gastrulation?
    convertion of the blastula into a 2 or 3 layered embryo.
  • What are the layers formed by gastrulation called?
    germ layers
  • What is invagination and what does it form?
    invagination is when 1 side of the blastula bends inwards. This forms a new cavity called gastrocoel, archenteron or oerdarm.
  • What is a blastopore?
    opening to the gut where invagination began.
  • Gastrula has 2 layers.
    outer layer = ectoderm (ecto=out, derm=skin).
    Inner layer = endoderm (endo=inside).
  • Mesoderm lies between ectoderm and endoderm.
  • Describe the 2 ways in which mesoderm can be formed?
    1. Schizocoely: cells arise from ventral area near blastophore lip and spread into space between archenteron and outer cell wall. --> protostomes
    2. Enterocoely: central region of archenteron wall puches outward into space between archenteron and outer body wall. --> deuterostomes
  • What is coeloom?
    body cavity completely surrounded by mesoderm.
  • What is induction?
    capacity of some cells to evoke a developmental response, such as change in cell shape in other cells. Tissues influence eachother.
  • What is the primary organizer and why?
    The dorsal lip, because it is the only tissue capable of inducing development of a secondary embryo in the host.
  • The inductive event of the primary organizer is called primary induction because it is the 1st inductive event in development.
  • What is epigenesis? And what are its 3 steps?
    view that an embryo develops and differentiates step by step from a zygote undergoing cell division. 
    1. pattern formation
    2. determination of positions in the body
    3. induction of limbs and organs appropriate for that position
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Welke 4 typen beenderen zijn er?
  1. Lange (pijp) beenderen
    Diaphyse, twee epifysen, mergholte. bv femur.
  2. Platte beenderen
    Twee cortices met spongiosa. bv frontale.
  3. Korte beenderen
    Geen mergholte bv hielbeen.
  4. Samengestelde beenderen
    Bv temporale 
Op welke 2 manieren kan been worden gevormd?
  1. Enchondrale (kraakbeen) verbening. Indirect, eerst een kraakbeen stadium. 
  2. Desmale (via fibreus bindweefsel) verbening. Direct in de huid. Oppervlakkige schedelbeenderen. Huidplaten in fossiele vissen. Sleutelbeenderen.
Wat is het belang van trabeculae?
Trabeculae richten zich naar de krachten in het bot. (wet van Wolff). Ze dragen tot 50% van de kracht op het bot. Vermindering leidt tot grote problemen, o.a. osteoporose.
Hoe is been macroscopisch opgebouwd?
  • Buitenkant: compacta = corticaal bot
  • Binnenkant: spongiosa
Wat is een osteon, waar zijn de kanalen van Volkman en leg de algemene opbouw van bot uit
Osteon is een hoofd bloedvat. Kanaal van Volkman verbinden de kanalen van Havers. 
Waaruit bestaat been?
Cellen
  • Osteoblasten: aanmaak
  • Ostercyten: mechanosensor
  • Osteoclasten: afbraak

Extracellulaire matrix
  • "Beton": hydroxyapetiet (Calcium!)
  • Vezels: collageen
Wat zijn de 3 verschillende soorten kraakbeen?
  • Fibreus. Veel collageen (ook type I). In menisci, tussenwervelschijven.
  • Elastisch. Veel elastine. In oor, neus, larynx (=strottenhoofd).
  • Hyalien. Weinig vezels (vnl collageen type II). In gewrichten, rond luchtpijp.
Waaruit bestaat kraakbeen?
  • Cellen
    - Chrondroblasten: voorlopers chondrocyten
    - Chondrocyten: kraakbeen aanmaak!!
  • Extracellulaire matrix
    - "Gelei" betsaande uit proteoglycanen en glycoproteinen
    - Vezels: collageen en elastine.
Wat zijn de 3 verschillende weefsels in het skelet?
  • Kraakbeen
  • Bot (=been)
  • Andere bindweefsels zoals ligamenten en gewrichtskapsels
Wat zijn de functies van het skelet?
  • Stevigheid
  • Bescherming
  • Beweging
  • Mineraalhuishouding
  • Bloedvorming