Lecture 8

Question 1

How do we make a brain

Answer 1

Sperm and ovum fertilisation (single cell) develops into one

1x10^11 neurons in brain
2.5x10^15 connections
40 known transmitters

Question 2

Overview of neural development process

Answer 2

Sperm and egg fertilisation forms a zygote

Zygote forms blastocysts

Blastocysts form gastrula

gastrula forms a fetus -> human

Question 3

Human morula formation

Answer 3

Morulas are formed from cell division of the zygote over a 4 day period

Contained in the zona pellucida so not growth in size

Resemble a mulberry

In latter compaction stage, individual cells become less distinct

Question 4

Morula to blastocyst

Answer 4

On day 4 (morula), cells secrete fluid and outermost cells become tightly bound together in the process of compaction. Zona pellucida disappears

On day 5, inner cell mass or embryoblast forms embryo and source of pluripotent embryonic stem cells give rise to adult structures, including the nervous system. The trophoblast later forms the placenta

Question 5

Gastrulation forms primary germ layers

Answer 5

Epiblast cells form inner cell mass converge at midline and ingress at primitive streak.

Two layers (epiblast and hypoblast) are transformed into three layers (mesoderm, ectoderm, endoderm).