BMS2011 Lecture Notes - Lecture 2: Lateral Plate Mesoderm, Axial Skeleton, Oligocene
30 May 2018
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Week 1: Body plans and primate lineages
Body plans
Environment= problems /selective pressures
Phenotype (eg, structure of hair in grizzly bears -> insulation)
Genotype (slight change in DNA)
Adaptation = solutions
Morphology (Grizzly bear -> Polar bear)
• Subphylum vertebrata
o Vertebral column
o Cranium: first arch -> mandible, second -> free suspended bone that helps with vocalisation
• Phylum Chordata
Notochord
o Neurenteric canal: blastopore
o Tube -> flattens out -> chord (mesodermal tissue that is solid mass)
o Differentiation of cells around notochord defines adult morphology
o Mesoderm becomes vertebrate around notochord
o Remnants in vertebral column become intervertebral disc
Dorsal nerve tube
o Neural crest cells: 4th germ layer, expressed in different organs and
forms aspects of peripheral and melanocytes
o Neural tube: tube of ectoderm -> brain and spinal cord
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Coelom
o Trilaminar disc folds on either side
o Seals off ventral
o Defines body contour
o Ectoderm becomes epithelial
Post-anal tail
o Disc is also folding cranially and caudally (folding side to side and
head to tail)
o Helps isolate yolk
Pharyngeal
pouches/slits
o Differentiate into different structures (eg. Arteries, nerves, blocks of
mesoderm, cartilage, bone)
o External depressions: pharyngeal cleft
(eg. First cleft becomes ear canal)
o Internal depressions: pharyngeal pouches
(eg. First pouch becomes Eustachian tube, third becomes thymus)
Endostyle (Thyroid)
• Bilateral asymmetrical gynandromorphy:
Asymmetrical division of sex chromosomes during early stage (8-64) mitosis
(eg. Butterfly half male, half female)
Week 1: Embryo implants
-> ICM develops
->Epiblast = primary germ layers
->hypoblast
Epiblast and hypoblast = bilaminar disc
Week 3: primitive streak and gastrulation
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Phenotype (eg, structure of hair in grizzly bears -> insulation) Morphology (grizzly bear -> polar bear: subphylum vertebrata, vertebral column, cranium: first arch -> mandible, second -> free suspended bone that helps with vocalisation, phylum chordata. Notochord: neurenteric canal: blastopore, tube -> flattens out -> chord (mesodermal tissue that is solid mass, differentiation of cells around notochord defines adult morphology, mesoderm becomes vertebrate around notochord, remnants in vertebral column become intervertebral disc. Dorsal nerve tube: neural crest cells: 4th germ layer, expressed in different organs and forms aspects of peripheral and melanocytes, neural tube: tube of ectoderm -> brain and spinal cord. Coelom: trilaminar disc folds on either side. External depressions: pharyngeal cleft (eg. first cleft becomes ear canal) Internal depressions: pharyngeal pouches (eg. first pouch becomes eustachian tube, third becomes thymus) Asymmetrical division of sex chromosomes during early stage (8-64) mitosis (eg. butterfly half male, half female)
