The Nervous System
The nervous system is a network full of nerves and cells known as neurons, which are a
basic part of the nervous system that hold messages from the brain and spinal cords and sends
Chromosomes coil up tightly and become visible under a light microscope
Homologous chromosomes pair up and crossing over occures (the point of cross over is
known as the chiasma)
Nuclear membrane disintgrates and the c
THE CELL CYCLE: mitosis
Mitosis is nuclear division plus cytokinesis, and produces two identical daughter
cells during prophase, prometaphase, metaphase, anaphase, and telophase.
Interphase is often included in discussions of mitosis, but interphase is te
Sperm cells are little more than flagellated nuclei. Each consists of
a head, which has
an acrosome at its tip and
contains a haploid set of chromosomes in a compact, inactive, state.
a midpiece containing mitochondria and a single centr
Egg formation takes place in the ovaries.
the initial steps in egg production occur prior to birth. Diploid
stem cells called oogonia divide by mitosis to produce more
oogonia and primary oocytes. By the time the fetus is 20 weeks