NURS2003 Chapter Notes - Chapter 2: Testicle, Blood Test, Ejaculation
CHAPTER 2 – PRENATAL DEVELOPMENT, PREGNANCY AND BIRTH
The First Step: Fertilisation
Every culture cherishes pregnant women
Some build in rituals to announce the baby after a certain point during pregnancy
and many use charms to ward off foetal harm
Pregnancy is a time of intense mixed emotions – joyous expectations coupled
with uneasy fears
Female reproductive system:
Uterus: the pear-shaped muscular organ in a woman’s abdomen that houses
the developing baby
Lined with a velvety tissue (endometrium) which thickens in preparation for
becoming pregnant
If pregnancy does not occur, it sheds at the end of the monthly cycle
during menstruation
Cervix: the neck, or narrow lower portion of the uterus
Protrudes into the vagina
During pregnancy, this thick uterine neck must be strong enough to stay
intact for 9 months under the pressure of the expanding uterus and be
flexible enough to open fully at birth
Fallopian tube: one of a pair of slim, pipe-like structures that connect the
ovaries with the uterus
Branches from the upper ends of the uterus
Serve as conduits to the uterus
Ovary: one of a pair of almond-shaped organs that contain a woman’s ova or
eggs
Feathery ends of the fallopian tubes surround the ovaries
Ovum: an egg cell containing the genetic material contributed by the mother
to the baby
The process of fertilisation:
Fertilisation: the union of sperm and egg
Begins at ovulation
find more resources at oneclass.com
find more resources at oneclass.com
Ovulation: the moment during a woman’s monthly cycle when an ovum is
expelled from the ovary
Occurs typically around day 14 of a woman’s cycle
The feathery ends of the fallopian tube react to signals showing the site of
rupture move to that location
As they suction the ovum in, the fallopian tube begins rigorous
contractions that launch the ovum on its 3-day journey toward the uterus
Hormones: chemical substances released in the bloodstream that target and
change organs and tissues
Orchestrates the process of ovulation as well as other events that program
pregnancy
Testes: male organs that manufacture sperm
Continually manufactures sperm
During sexual intercourse, sperm released during ejaculation are expelled
into the vagina where a small proportion enter the body of the uterus and
wend their way up the fallopian tubes
To promote pregnancy, it’s best to have intercourse right around ovulation
The genetics of fertilisation:
Chromosome: a threadlike strand of DNA located in the nucleus of every cell
that carries the genes, which transmit hereditary information
Every cell in our body contains 46 chromosomes with the exception of the
sperm and ova which contains 23 chromosomes each
When the nuclei of these 2 cells (gametes) combine at fertilisation, their
chromosomes align in pairs to comprise of 46
DNA (deoxyribonucleic acid): the material that makes up genes, which bear
our hereditary characteristics
Gene: a segment of DNA that contains a chemical blueprint for manufacturing
a particular protein
Functions as the templates for creating the proteins responsible for
carrying out all the physical processes of life
Prenatal Development
find more resources at oneclass.com
find more resources at oneclass.com
First 2 Weeks: The Germinal Stage
Germinal stage: the first 14 days of prenatal development, from fertilisation to
full implantation
The time when cell mass has not yet fully attached to the wall of the uterus
Zygote: a fertilised ovum
Within 36 hours it makes its first cell division
Continually divides every 12 to 15 hours as it wends its way on a roughly
3-day trip down the fallopian tube
When the mass of cells passes into the uterine cavity, it sheds its outer
wall and differentiates into layers – some destined to form the pregnancy
support structures, others to comprise the cells of the child-to-be
Blastocyst: the hollow sphere of cells formed during the germinal stage in
preparation for implantation
Ball of roughly 100 cells
Implantation: the process in which a blastocyst becomes embedded in the
uterine wall
The blastocyst seeks a landing site on an upper section of the uterus
Hormones have prepared the uterus to receive the cell mass
Outer layer of blastocyst develops projections
At about day 9, these tentacles burrow in
From this landing zone, blood vessel proliferate that will make up the
placenta
Placenta: the structure projecting from the wall of the uterus during pregnancy
through which the developing baby absorbs nutrients
Week 3 to Week 8: The Embryonic Stage
Embryonic stage: the second stage of prenatal development, lasting from
week 3 to week 8
All the major organs are constructed
Neural tube: a cylindrical structure that forms along the back of the embryo
and develops into the brain and spinal cord
At around the same time, rudiments of the nervous system appear
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Chapter 2 prenatal development, pregnancy and birth. Some build in rituals to announce the baby after a certain point during pregnancy and many use charms to ward off foetal harm. Pregnancy is a time of intense mixed emotions joyous expectations coupled with uneasy fears. Uterus: the pear-shaped muscular organ in a woman"s abdomen that houses the developing baby. Lined with a velvety tissue (endometrium) which thickens in preparation for becoming pregnant. If pregnancy does not occur, it sheds at the end of the monthly cycle during menstruation. Cervix: the neck, or narrow lower portion of the uterus. During pregnancy, this thick uterine neck must be strong enough to stay intact for 9 months under the pressure of the expanding uterus and be flexible enough to open fully at birth. Fallopian tube: one of a pair of slim, pipe-like structures that connect the ovaries with the uterus. Branches from the upper ends of the uterus.
