Human reproduction (Part 5 - Fertilisation and placenta)

Question 1

Copulation

Answer 1

Releasing sperm into the female reproductive tract

Question 2

Insemination

Answer 2

release of semen into the cervix during copulation

Question 3

Seminal fluid

Answer 3

contains H20
Contains alkali
Contains sugars

Question 4

Survival of sperm and eggs

Answer 4

Sperm - 5 days after (insemination)

Eggs - 2 days after (ovulation)

Question 5

When is the fertile period

Answer 5

Day 9 -18

Question 6

Birth control

Answer 6

Artificially controlling number of children born

Question 7

Contraception

Answer 7

artificially preventing fertilisation or implantation

Question 8

Types of contraception

Answer 8

Natural - Coitus interruptus 
            - Rythm method
Physical  - condoms
Chemical - Pill + Spermicides
Surgical - Vasectomy + Tubal ligation

Question 9

Fertilistaion

Answer 9

Fusion of haploid gametes to produce a diplod zygote

Question 10

Development of the blastocyst

Answer 10

Zygote divides by mitosis
Forms Morula (solid clump)
Forms a blastocyst (Hollow ball)
This sequence of division is called cleavage

Question 11

Blastocyst structure

Answer 11

Outer layer - Trophoblast
Inner layer - Embryo cells
(Blastocyst implants itself to endometrium about 7 days after fertilisation)

Question 12

Implantation

Answer 12

Attachment of the blastocyst to the lining of the uterus

Question 13

Placenta

Answer 13

Support organ formed from the tissues of the mother and foetus

Question 14

What is the placenta made up of?

Answer 14

• The endometrium…from the mother
• The trophoblastic layer…from the foetus

(fully formed about 12 weeks after fertilisation)

Question 15

amnion

Answer 15

encloses the amniotic fluid

Question 16

amniotic fluid

Answer 16

protects the foetus, acts as a ‘shock absorber’

Question 17

Umbilical cord

Answer 17

Transport of materials between the foetus and the placenta

Question 18

functions of the placenta

Answer 18

• Release of prgesterone
• Nutrients and O2 from mother to foetal blood
• CO2 and other wastes from foetal blood to mother
• Antibodies move from the mothers blood into the foetal blood - passive immunity

(Blood does not mix!)

Question 19

Adaption of placenta

Answer 19

Walls of blood vessels are thin - easier movement of materials
Walls of blood vessels are folded - Greater surface area
Large number of capillaries - rich blood supply, faster exchange of materials