Human Reproduction

Question 1

What is a gonad?

Answer 1

An organ that produces sex cells in animals

Question 2

What is ejaculation?

Answer 2

The release of semen from the penis

Question 3

What are the associated glands?

Answer 3

Seminal vesicles, prostate and cowper’s gland

Question 4

What are secondary sexual characteristics?

Answer 4

Features that distinguish males from females, apart from the sex organs themselves

Question 5

What is the function of FSH in males?

Answer 5

Causes sperm producing cells in testes to divide by meiosis and produce sperm

Question 6

What the function of LH in males?

Answer 6

Stimulates the testes to produce testosterone

Question 7

What is infertility?

Answer 7

Inability to produce offspring

Question 8

Give an example of male infertility?

Answer 8

Low sperm count

Question 9

What is ovulation?

Answer 9

The release of an egg from the ovary

Question 10

What is the menstrual cycle?

Answer 10

Series of events that occurs every 28 days on average in the female if fertilisation has not taken place.

Question 11

Day 1-5 menstrual cycle

Answer 11

Endometrium breaks down and is shed- period. Meiosis occurs in ovary to produce egg. New egg surrounded by graafian follicle.

Question 12

Days 6-14 menstrual cycle

Answer 12

Developing graafian follicle produces oestrogen. It causes endometrium to thicken again and prevents new egg developing.

Question 13

Day 14 menstrual cycle

Answer 13

Ovulation occurs when graafian follicle bursts to release egg. Eggs passes to abdomen and then to fallopian tube. Egg available for fertilisation for 48hrs.

Question 14

Days 14-28 menstrual cycle

Answer 14

Remains of graafian follicle develop into corpus luteum. This makes progesterone which causes endometrium to thicken more. Progesterone prevents new eggs forming. Egg will die by day 16. If not fertilised, corpus luteum starts to degenerate by day 22. This causes drop in progesterone which leads to menstruation on day 28

Question 15

Example of female infertility?

Answer 15

Endocrine gland failure

Question 16

Give an example of a menstrual disorder

Answer 16

Fibroids

Question 17

What is insemination?

Answer 17

The release of semen into the vagina, just outside the cervix.

Question 18

How do sperm enter egg?

Answer 18

Acrosome (head of sperm) contains enzymes that digest an opening into the egg. Sperm loses tail and head enter. Causes egg to produce fertilisation membrane which stops other sperm entering.

Question 19

What is fertilisation?

Answer 19

When the nucleus of the sperm fuses with the nucleus of the egg, forming a diploid zygote.

Question 20

What is birth control?

Answer 20

Methods taken to limit the number of children that are born

Question 21

What is an abortion?

Answer 21

Termination of a pregnancy

Question 22

What is contraception?

Answer 22

Deliberate prevention of fertilisation or pregnancy

Question 23

What is implantation?

Answer 23

The embedding of the fertilised egg into the lining of the uterus

Question 24

What is IVF?

Answer 24

Involves the removing of eggs from an ovary and fertilising them outside the body

Question 25

what is a morula?

Answer 25

A solid ball of cells formed from a zygote by mitosis

Question 26

What is a blastocyst?

Answer 26

A hollow ball of cells formed from a morula

Question 27

What are germ layers?

Answer 27

The basic layers of cells in the blastocyst from which all adult tissues and organs will form.

Question 28

What is gestation?

Answer 28

The length of time spent in the uterus from fertilisation to birth.

Question 29

What is lactation?

Answer 29

The secretion of milk by the mammary glands of the female.

Question 30

What is the function of the placenta?

Answer 30

1. Provide embryo with oxygen, food, antibiotics, hormones, etc 2. Remove carbon dioxide, salts and urea from embryo

Question 31

Describe zygote development

Answer 31

1) fertilised 2) zygote divides rapidly. Becomes a morula after 3 days 3) 5 days after fertilisation, morula forms hollow ball of cells called a blastocyst. Outer cells form trophoblast. This will form membrane around embryo. Inner cells will form embryo. 4) blastocyst pushed down fallopian tube to uterus.

Question 32

How does the embryo develop?

Answer 32

1. 10 days after fertilisation, inner cells form embryonic disc. This develops into the 3 germ layers. The middle layer (mesoderm) divides into an outer and inner layer. Gap between them (coelom) allows organs to develop. 2. After 4 weeks from fertilisation, heart forms and beats, brain and umbilical cord forms. 3. Week 5, organs and limbs start to form. 4. Week 6, eyes visible and mouth,nose and ears form. 5. Week 8, tail is gone. Face is human and major organs formed. Gonads distinguishable and cartilage turns to bone. It is a foetus 6. Week 8 onwards, foetus grows. 7. Third mth, eyes low in face and widely spaced. Ossification occurs, muscles and nerves become coordinated, foetus kicks, sucks thumb and grows milk teeth. 8. Gestation lasts 266 days (38 weeks/9 mths).

Question 33

Describe birth

Answer 33

1. During pregnancy progesterone and oestrogen produced in great amounts. After week 12, placenta makes them. 2. Immediately before birth placenta stops producing progesterone. Uterus contracts 3. Pituitary gland produces oxytocin. This causes labour. 4. Labour divided into 3 stages. 5. Stage 1 (12hrs), contractions push foetus down to cervix. Waters break. 6. Stage 2 (20mins-1hr), cervix dilates. Baby pushed out. Umbilical cord clamped and cut. 7. Stage 3 (within 5-30mins of birth), afterbirth expelled.

Question 34

Describe lactation

Answer 34

1. Breasts produce colostrum for first few days. 2. During pregnancy, progesterone prevents production if prolactin. Once baby born prolactin produced and milk is produced. 3. Once breast- feeding stops, breasts stop producing milk.

Question 35

What are the benefits of breast- feeding?

Answer 35

1. Contains ideal balance of nutrients 2. Antibiotics 3. Reduces risk of breast cancer.

Question 36

What does the ectoderm produce?

Answer 36

Skin, nails, hair, nervous system

Question 37

What does the mesoderm produce?

Answer 37

Muscles, skeleton, organs

Question 38

What does the endoderm produce?

Answer 38

Inner lining of digestive, respiratory and excretory systems