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Natural sciences

Grade 9

Life processes: healthy life

Module 7

Human reproduction

  • Reproduction is the process by which offspring are created.
  • During this process, GAMETES (generative sex cells) have to unite.
  • The male gametes are called SPERM CELLS and female gametes are OVA , or egg cells. Both gametes carry the genetic characteristics of the new individual.

Sperm cell and ovum

  • In both sexes, gametes only begin to be produced after PUBERTY . Hormones from the brain control maturation.
  • The cells are formed in the sexual organs, namely in the TESTES of the male and in the OVARIA of the female.

Male sexual organs:

    1. 2 TESTES in the external SCROTUM
  • SPERM TUBES that carry sperm cells from the testes to the PROSTATE GLAND and other glands.
  • The PENIS , which is responsible for transferring the SEMEN (sperm cells and nutrients) to the female system. The release of semen is called EJACULATION .

Female sexual organs:

    1. Two FALLOPIAN TUBES for guiding the ova from the ovaries. FERTILIZATION normally occurs here.
  • A UTERUS situated just behind the bladder and in which an infant will develop.
  • A VAGINA that receives the sperm cells from the penis and which also serves as birth canal.

Male and female sexual organs:

The menstrual cycle:

    1. A cycle that commences in girls once they have reached puberty (commencement varies between the ages of 10 and 15).
  • This cycle prepares the female body for possible pregnancy.
  • It involves the thickening of the ENDOMETRIUM inside the lower portion of the uterus in the area where an embryo will attach itself.
  • Various hormones such as progesterone and ESTROGEN are involved in preparing the body for possible pregnancy. The levels of these hormones rise and recede and cause a variety of changes that may be very uncomfortable for a girl, e.g. moodiness, tenderness of the breasts, water retention.
  • Halfway through the cycle, the egg cell (ovum) is released from the ovary. This is known as ovulation .
  • The normal duration of the cycle is 28 days. At the end of this period the endo­metrial layer loosens from the uterus and is discarded. This casting off of the endometrial tissue is known as MENSTRUATION and the process takes 3 to 7 days.
  • Girls use protective sanitary pads or tampons to absorb the flow of blood.

Fertilization: the combination of a male sperm cell with a female ovum to form a zygote

    1. This occurs in the Fallopian tube
  • A special chemical membrane develops immediately to prevent other sperm from penetrating the ovum.

Pregnancy:

    1. The zygote immediately begins to divide repeatedly to form an embryo .
  • A chemical message that travels through the woman’s body stimulates further changes.
  • The developing EMBRYO attaches itself to the ENDOMETRIUM , the lining of the wall of the UTERUS . This process is known as IMPLANTATION .
  • A PLACENTA develops where the embryo is attached and this nourishes the embryo while it is developing into a foetus. The foetus is attached to the placenta by means of the UMBILICAL CHORD .
  • The developing foetus is supplied with nutrients and oxygen through the UMBILICAL CHORD and waste materials from the foetus, like carbon dioxide, are also removed through this chord.
  • When the embryo is nine weeks old, it is called a FOETUS.
  • The development of the foetus is completed in approximately 280 days or 9 months.

Class Activity: Discussion on reproduction

1. Explain what is meant by:

a) IMPLANTATION

b) OVULATION

c) FOETUS

d) PUBERTY

e) MENSTRUATION

2. What is the function of the following?

Testis

Ovaries

Penis

Scrotum

Uterus

Fallopian tubes

Placenta

Umbilical chord

3. What is an ECTOPIC PREGNANCY?

4. Explain how the following sets of twins develop:

a) identical or monozygotic (uniovular) twins;

b) non-identical or dizygotic (fraternal) twins

c) Siamese twins

5. What determines whether the baby will be male or female? Explain.

Assessment: CLASS DISCUSSION

Were you able to complete the table and answer the questions?

[LO 1.3]

Assessment

Learning Outcomes 1 : Scientific Investigation

The learner will be able to act confidently on curiosity about natural phenomena, and to investigate relationships and solve problems in scientific, technological and environmental contexts.

We know this when the learner:

  • evaluates data and communicates findings.

Memorandum

CLASS ACTIVITY: GROUP DISCUSSION- REPRODUCTION

1. a) implantation of embryo into the wall of the uterus

b) release of ovum from ovary

c) developing embryo after two months

d) sexually mature phase in boys and girls

e) shedding of preparatory layer in the monthly cycle

2. Complete:

Umbilical cord Tube connecting foetus and placenta

3. a pregnancy in which the embryo is implanted in the wall of the Fallopian tube instead of the uterus

4. a) a single zygote that divides early in its development – identical information; always of the same sex

b) two zygotes and two different sperm cells; two different individuals

c) uncompleted identical division

5. father donating X or Y chromosome

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
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Source:  OpenStax, Natural sciences grade 9. OpenStax CNX. Sep 15, 2009 Download for free at http://cnx.org/content/col11069/1.1
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