8/26 Lecture 1 Flashcards
If you cut the optic nerve in a salamander embryo eye will it be able to see? If not will it ever be able to tai sight?
It will not be able to see, however, will be able to regain sight.
How will the salamander be able to regain sight?
Salamanders have incredibly regenerative abilities.
True or false. Nerves grow from a cell body?
true
How does the axon grow to make a connection to the brain for a function of sight?
The axon grows out of the optic cup to the roof of the midbrain.
So in a salamander how must the eye be taken out and placed back in for the animal to regain sight?
In the same orientation as it was taken out.
Is the target address always the same for an axon growing from a specific cell?
Theoretically yes
What is the evidence that an axon growing from a specific cell always has the same target?
EXPT:
1. Take dye and inject it into the anterior portion of the optic cup.
- Cut both optic cups on the optic stalk.
- Take both optic cups out and rotate them 180 degrees.
- All images the salamander sees will be the same image but inverted.
- Feed the salamander it can see the worm but bites it foot.
What is a new development made regarding fibroblast cells?
They can be reprogrammed by changing the environment to make specific transcription factors that will make them different. Thymus gland conducted in a test tube of a mouse.
Cheetahs do not reject other cheetahs body parts. Normally humans do. WHat experiment has been in the process regarding this subject manner and with what organ does it mainly deal with?
Making mice organs transplantable to other mice bodies without rejection.
Blood.
What is parabiosis?
Pairing up of living organisms.
What is the importance of parabiosis in regards to creating an indefinite postponement of death?
EXPT:
1. Take a nude mouse and make an incision on the side exposing the mesoderm cells.
- Take another nude mouse and make an incision into the mesoderm exposing them.
- Suture the two mice together making conjoin twins.
- They will make a conjoined blood capillary network.
- If you take an old nude mouse and a young nude mouse and conjoin them the old mouse is rejuvenated by the blood of the new mouse.
ontogeny
individual development
When does life begin?
Life does not begin or end it is on a continuum. The living cells from an egg and sperm come together and reorganize to produce the offspring
WHat is the ion responsible for the start of parthenogenesis in sea urchins?
Ca2+
What will the calcium ion cause the female cell to do?
develop, IP3 pathways
How do we get male and female bodies?
Mechanisms to make male and female bodies from a basic neutral pattern.
How is a cell competent?
Competent relative to the packaging of its genome
How is a cell specified?
When the competence is being restricted and the cell is moving in a certain developmental direction.
How is a cell determined?
A switch gene is turned on and development proceeds in one way. Going that one way is called differentiation.
What is the order of cell development?
competence specification determination differentiation
WHat is an example of how cells function in an environment with regards to competence specification determination differentiation?
Cells respond and are told what to do by their neighbors. Female oocytes in the ovaries are told what to do by surrounding follicular cells. Fertilization is possible because the necessary information stored messenger RNA that through which they can respond to build the machinery for fertilization.
series of events through developmental biology
fertilization cleavage blastula gastrulation body plan organogenesis metamorphosis gametogenesis death
what is cleavage?
mitotic cell division
Why is it when the signal of calcium ion enters into the system the cell can engage in cleavage?
This cell has no neighbors and theoretically the neighbors are the ones that give instructions to the cell what to do. This cell can proceed into cleavage because this cell has maternal genetic effect…instruction given from mom. In the eggs are instructions that when exposed to the nuclei they know what to do next.
All vertebrates have the same body plan therefore they all have the same what?
Genes that tell them how to develop with regards to that body plan.
What is the sonic hedgehog protein important in development?
limb development. neural differentiation. Making sure the motor neurons come from the ventral portion of the neural tube.
What do cells use to communicate?
paracrine factors
What is the pathway of sonic hedgehog?
sonic hedgehog—> Patched (receptor)—> Smoothed (signal transducer)—> Ci protein (transcription activator)
What is the evidence of the sonic hedgehog protein?
A mice made homozygous for a mutant allele of sonic hedgehog will exhibit facial and limb deformations such as a single eye in the center of the forehead=cyclopia
