1. Asexual and sexual reproduction
B8 Reproduction
Asexual and sexual reproduction

2. Asexual reproduction Sexual reproduction
The process resulting in the production of genetically identical offspring from one parent.
Bacteria, fungi and some plants reproduce asexually.
Sexual reproduction
The process involving the fusion of haploid nuclei to form a diploid zygote and the production of genetically dissimilar offspring

3. Sexual reproduction in Humans
B8 Reproduction
Sexual reproduction in Humans

4. Male reproductive system
Label the male reproductive system with the following organs:
Testes, scrotum, sperm ducts, prostate gland, urethra, penis
State the functions of each of the organs by completing the table provided.
STRUCTURE
FUNCTION
Ducts connecting testes to urethra
Testes
Prostate Gland
Places sperm in the vagina of the female
Urethra
Bag containing the testes
Sperm duct
Produce the sperm
Around the urethra, secrete seminal fluids
Penis
Passes through the penis to release urine and semen
Scrotum

5. Male reproductive system
bladder
rectum
sperm duct (vas deferens)
prostrate gland
urethra
penis
testis
scrotum

6. Female reproductive system
Label the female reproductive system with the following organs:
Ovaries, oviducts, uterus, cervix, vagina
State the functions of each of the organs by completing the table provided.
STRUCTURE
FUNCTION
Ring of muscle at the entrance to the uterus
Oviducts
Receives the penis during intercourse; birth canal
Uterus
Produces ova (eggs) and female hormones
Cervix
Where fertilisation occurs; transports ova to uterus
Vagina
Foetus develops in this muscular organ
Ovaries

7. Female reproductive system
oviducts
ovaries
uterus
cervix
vagina
Reproductive system

8. Male and female gametes
The human male gamete is called a sperm cell.
The human female gamete is the ovum or egg cell.
Sperm
Ovum
constantly produced
1 matures each month
Both
200 – 500 million in one ejaculation
Haploid nucleus -(1 set of single chromosomes)
Always contain X chromosome
Contain either X or Y chromosome
immotile (moves via cilia)
motile
110μm in diameter
50μm length

9. The menstrual cycle
Uterine ling continues to thicken
Annotate the handout using the information on the next few slides.
DO NOT copy out all the notes

10. The menstrual cycle
Menstruation is the shedding of the uterine lining (period).
This occurs, on average, every 28 days in women who have gone through puberty.
Females are born with hundreds of immature egg cells in each ovary.
Every month, one follicle (containing an ovum) will mature. This is controlled by hormones from the pituitary gland.

11. The menstrual cycle – the uterus
Day 1 of the 28 day cycle is the beginning of the period – the endometrium (lining of the uterus) is shed.
After menstruation is complete, the endometrium thickens to prepare for the implantation of the zygote.
If fertilisation occurs, the endometrium will remain thick to nourish the foetus.
If no fertilisation occurs, the endometrium is shed again.
All these changes are controlled by hormones.

12. The menstrual cycle – the ovaries
During the first half of the 28 day cycle, a follicle in one ovary will mature.
On day 14, the ovum (egg) is released from the ovary and is moved down the oviduct.
The follicle in the ovary continues to make hormones in preparation for implantation.
The ovum will survive for 24h and must be fertilised in this time for pregnancy to occur
If no fertilisation occurs, the ovum is shed in the next period and a new follicle develops.
Ovulation

13. Fertilisation The fusion of a sperm cell and an ovum
Occurs in the oviduct following ovulation
Only one sperm in the millions of sperm ejaculated will fertilise the egg
The nucleus of the sperm joins to the nucleus of the egg, giving the zygote a full set of chromosomes
Only 1 sperm can
fertilise an egg
fertilisation

14. Zygote development

15. Zygote development The foetus is about 3cm long
The zygote is the fertilised egg
As the cell divides it is known as a blastocyst
Once it embeds in the endometrium, it is called an embryo
8 weeks after conception:
facial features
internal organs
the brain can signal muscle movement
the heart is fully developed
external sex organs begin to form
The foetus is about 3cm long
Fertilisation and early development

16. The amniotic sac and fluid
Placenta
Umbilical cord
Amniotic sac
The amniotic sac is filled with the amniotic fluid
The fluid supports the growing foetus and protects it from mechanical damage

17. The placenta Part of the embryo becomes the placenta The placenta is
embedded in the uterus
The foetus is connected to the placenta by the umbilical cord
Blood vessels from the foetus pass close to vessels of the mother in the uterus
Nutrients, gases and wastes are transported between the foetus and the mother
The placenta has a large surface area

18. The umbilical cord joins the foetus to the placenta
Carbon dioxide
Urea
Oxygen
Glucose
Water
Ions and vitamins
Amino acids
The umbilical cord joins the foetus to the placenta
The cord contains an artery and a vein to carry foetal blood to the placenta and back

19. Breast feeding
Breast feeding
There is a lot of controversy as to whether a mother should breast feed, and for how long.
There are a number of benefits to choosing breast feeding compared to bottle feeding with formula:
Establishes close bond between mother and baby
Baby has added immunity against infection
Breast milk contains antibodies for diseases the mother has already had
Reduce rate of SIDS (sudden infant death syndrome)
Less allergies (e.g. skin conditions and asthma) in baby
Child less likely to be overweight later
Helps woman’s uterus to shrink after birth
Helps woman to lose weight gained during pregnancy.
Can act as a birth control for the first 6 months
Convenient
Free

20. HIV – Human immunodeficiency virus
Infection with this virus can lead to AIDS – Acquired Immunodeficiency Syndrome
HIV attacks the white blood cells (lymphocytes), weakening the immune system
The body no longer produces enough antibodies against infections so it is harder to become well again
A person with AIDS often dies of diseases that a healthy person could fight off

21. The spread of HIV Transmitted in blood or semen:
Preventing HIV
Transmitted in blood or semen:
Unprotected sexual intercourse
Hypodermic needles
Unborn babies
At birth
Breast feeding
Blood transfusions
HIV cannot be cured.
Its spread must be prevented:
Use condoms during sexual intercourse
Do not reuse needles
Donated blood is screened before use in blood transfusions