B16 Sexual reproduction in humans

Question 1

Ovaries function

Answer 1

Where the egg is produced and produces 2 of the female sex hormones

Question 2

Fallopian tubes (oviduct) function

Answer 2

Connect ovaries to uterus, where fertilization occurs

Question 3

Uterus function

Answer 3

Site of implantation of embryo and fetus development

Question 4

Cervix function

Answer 4

Narrow neck of uterus, dilates during labor

Question 5

Vagina function

Answer 5

Accepts the penis during intercourse. The baby is passed through this during birth

Question 6

Route of egg

Answer 6

1) Released by one of the ovaries approx. every 28 days
2) Passes into end of the Fallopian tube and moves downward
3) If egg met by sperm, fertilization occurs before or just after it reaches uterus
4) The sperm nucleus fuses with egg nucleus to form a zygote (conception)
5) If egg not fertilized, it passes out through vagina

Question 7

Headpiece of sperm

Answer 7

Contains nucleus and bag of enzymes that help penetrate egg. (the acrosome and nucleus)

Question 8

Midpiece of sperm

Answer 8

Has many mitochondria to generate energy for swimming (the mitochondrion)

Question 9

Tail of sex cells

Answer 9

Egg- none

Sperm- Long flagellum that propels sperm in its swim to the egg

Question 10

Sex cells mobility

Answer 10

Egg- Not mobile on their own; they are moved by small contractions of the oviducts
Sperm- long flagellum to propel it

Question 11

Size of sex cells

Answer 11

Egg- 0.1mm in diameter

Sperm- Microscopic

Question 12

Jelly coat of sex cells

Answer 12

Egg- Acts as protection to the ovum

Sperm- None

Question 13

Mitochondria of sex cells

Answer 13

Egg- very few

Sperm- Many to generate energy for swimming

Question 14

Nutrient reserve of sex cells

Answer 14

Egg- Very large, the egg may be in oviduct for several days. It also fuels early development of embryo
Sperm- None

Question 15

Digestive enzymes of sex cells

Answer 15

Egg- None

Sperm- Helps it burrogh through egg

Question 16

Number of sex cells released

Answer 16

Egg- usually one per menstrual cycle

Sperm- Millions

Question 17

Adolescence/ puberty

Answer 17

The transition from a sexually immature child into a sexually mature adult

Question 18

Male sex hormone

Answer 18

Testosterone

Question 19

Female sex hormones

Answer 19

Progesterone and oestrogen

Question 20

Zygote

Answer 20

A fertilized egg cell

Question 21

Ovulation

Answer 21

The release of an egg from the ovaries which happens around 14 days into the menstrual cycle

Question 22

Purpose of thick uterus lining

Answer 22

In preparation for fertilization and to acomodate a fetus

Question 23

Corpus lutem

Answer 23

AKA yellow body, an empty follicle that develops 21 days into the menstrual cycle

Question 24

Use of oestrogen

Answer 24

Causes uterus wall to thicken, and help causes ovulation

Question 25

Use of progesterone

Answer 25

Maintains uterus wall and stops other eggs from developing. The fall in progesterone starts menstruation

Question 26

Placenta

Answer 26

A temporary organ that allows the blood systems of the fetus and the mother to come in close contact without actually mixing.

Question 27

Fetus

Answer 27

What the embryo and placenta are called after fertilization

Question 28

Substances diffusing from mother to fetus

Answer 28

Oxygen, minerals, vitamins, glucose, amino acids

Question 29

Substances diffusing from fetus to mother

Answer 29

Carbon dioxide, urea

Question 30

Why are maternal and fetal circulations separated?

Answer 30

1) So the baby can rely on its own systems when born, not completely reliant on mother 2) Possibly different blood types 3) Blood pressure

Question 31

Umbilical cord

Answer 31

Carries blood back to the placenta from the fetus

Question 32

Amniotic fluid

Answer 32

Protects developing baby by cushioning against blows to the mother's abdomen. Allows for easier fetal movement and promoting muscular/skeletal development

Question 33

Length of pregancy

Answer 33

28-40 weeks

Question 34

3 Stages of labor

Answer 34

1) Amnion ruptures and the cervix widens to diameter of 10 cm 2) Strong contractions of uterine muscle push baby out of uterus, through cervix and vagina 3) Placenta and umbilical cord expelled after baby born

Question 35

Advantages of baby born headfirst

Answer 35

Prevent baby suffering brain damage when skull moves outwards

Question 36

Oxytocin

Answer 36

Hormone produced right after birth that causes lactation and allows woman to breastfeed

Question 37

HIV

Answer 37

Virus that damages immune system by infecting/destroying white blood cells.

Question 38

AIDS

Answer 38

The final, life threatening stage of infection of HIV.

Question 39

How is HIV transmitted?

Answer 39

Bodily fluids (blood, semen, breast milk), sexual intercourse, sharing needles

Question 40

Testis function

Answer 40

Produces sperm. Are located outside of the body as sperm cannot be produced in too hot a temperature

Question 41

Sperm duct function

Answer 41

Carries sperm from testes to urethra

Question 42

Scrotum function

Answer 42

Pouch of skin containing the testes

Question 43

Epididymis function

Answer 43

Coiled tube where sperm is stored

Question 44

Urethra function

Answer 44

The duct that carries urine/sperm

Question 45

Penis function

Answer 45

Transfers sperm into vagina

Question 46

Seminal vesicle function

Answer 46

Produces fluid containing nutrients for sperm, makes up semen

Question 47

Ureter function

Answer 47

Connects bladder to kidney

Question 48

Prostate gland function

Answer 48

Produces alkaline fluid (to neutralize acidity of vagina) to add to sperm to make semen

Question 49

Route taken by ejaculated sperm to oviduct of female

Answer 49

1) Testis 2) Epididymis 3) Sperm duct 4) Urethra 5) Vagina

Question 50

How are sperm adapted to their function?

Answer 50

Pointed head to penetrate egg, long tail to help it swim faster, stream-like shape to decrease resistance