BY5.2 - Human Reproduction

Question 1

What is the function of the testes?

Answer 1

Contains seminiferous tubules where spermatogenesis occurs

Question 2

What does hCG stand for?

Answer 2

Human Chorionic Gonadotropin

Question 3

What is the function of the epididymis?

Answer 3

Spermatozoa mature

Question 4

What is the function of the Vas Deferens?

Answer 4

Connects epididymis to the urethra

Question 5

What is the function of the Seminal vesicles?

Answer 5

Produces a secretion that aids spermatozoa motility

Question 6

What is the function of the Prostate Gland?

Answer 6

Produces a secretion that neutralises the acid conditions of the vagina

Question 7

What is the function of the urethra?

Answer 7

Carries urine and spermatozoa out of the body

Question 8

What is the function of the Ovary?

Answer 8

Oogenisis occurs in the ovary

Question 9

What is the function of the Oviduct?

Answer 9

Site of fertilisation,

carries the zygote down to the uterus

Question 10

What is the function of the uterus?

Answer 10

Embryo implants into the endometrium of the uterus and develops there in its thick, muscular walls

Question 11

What is the Endometrium?

Answer 11

a mucus membrane lining the uterus where embryo implantation occurs

shed during menstruation

Question 12

What is the name of the opening to the cervix

Answer 12

vagina

Question 13

What is spermatogenesis?

Answer 13

the process by which spermatozoa are produced

Question 14

Where does spermatogenesis occur?

Answer 14

Germinal epithelium of the seminiferous tubules

Question 15

Describe the process of Spermatogenesis

Answer 15

1) Diploid spermatogonia divide many times by mitosis - produces primary spermatocytes
2) First meiotic division - stops at metaphase 1
3) Haploid (n) secondary spermatocytes form
4) Second meiotic division
5) Spermatids form
6) Differentiation -> Mature spermatozoa
7) Sertoli cells secrete fluid which nourishes spermatozoa and protects them from the immune system

Question 16

What is the function of the mid piece of spermatozoa?

Answer 16

-Has many mitochondria to carry out aerobic respiration to produce ATP for flagellum contraction (movement)

Question 17

What is Oogenesis?

Answer 17

the process by which ova are produced in the ovaries

Question 18

Describe the processes of Oogenesis that occur before puberty

Answer 18

1) Oogonia (formed before birth) -mitosis-> Primary oocytes (2n)
2) Primary Oocytes undergo meiosis - stop at prophase I
4) Germinal epithelium divides = follicle cells
5) Follicle cell surrounds primary oocytes
6) result = primary follicles

Question 19

Describe the processes of oogenesis that occur at and after puberty

Answer 19

1) primary oocyte completes 1st meiotic division -> haploid secondary oocyte and small polar body form
2) hormones stimulate the follicles to develop
3) every month one follicle matures into a fully developed graafian follicle
4) Graafian follicle migrates to the surface of the ovary and bursts
5) Secondary oocyte is released into the oviduct - ovulation
6) remaining follicle cells form the Corpus luteum (endocrine gland which secretes hCG) - maintains endometrium if implantation is successful
7) secondary Oocyte begins second meiotic division - stops at metaphase - unless fertilisation takes place

Question 20

Describe the process of fertilisation:

Answer 20

1) Enzymes in the uterus cause the ovum to undergo capacitation - proteins and glycoproteins are removed
2) sperm contacts the corona radiata
3) the sperms acrosome ruptures and releases protease enzymes - digest oocyte’s zona pellucida
4) Inversion of one sperms acrosome - acrosome reaction - needle-like filament pierces softened oocyte membrane
5) head of same sperm penetrates secondary oocyte
6) Zona pellucida thickens -> fertilisation membrane - prevents polyspermy
7) entry of head stimulates completion of second meiotic division of oocyte nucleus
8) sperm and ovum nuclei fuse to form a diploid nucleus - zygote

Question 21

Describe the completion of Oogenesis upon fertilisation:

Answer 21

1) upon fertilisation, division is completed to form a large ovum and a second polar body
2) after division, the ovum nucleus fuses with a sperm nucleus to form a zygote
3) result = embryo

Question 22

What is A blastocyst?

Answer 22

A hollow ball of cells (3 day old)

Question 23

What is Implantation?

Answer 23

3 day old blastocyst embedding in the endometrium

Question 24

What is the function of the placenta?

Answer 24

Supplying blood to the embryo

Question 25

Describe the process of the formation of the placenta:

Answer 25

1) Trophoblast(outer blastocyst layer) develops into 2 membranes: -Amnion&Chorion
2) Chorion grows chorionic villi -> increase S.A. for absorption of Nutrients from the wall of the uterus
3) Chorion also secretes human chorionic gonadotrophin (hormone) -> prevents degeneration of corpus luteum, which secretes progesterone -> maintains endometrium
4) chorionic villi form part of the placenta which is attached to the foetus via the umbilical cord

Question 26

What is female infertility?

Answer 26

The complete inability to conceive a child

Question 27

What are the causes of female infertility?

Answer 27

1) failure to ovulate - no/irregular menstrual cycles - treated with clomiphene
2) blockage of Fallopian tubes -> prevents movement of ovum to uterus - can be caused by infection - treated with microsurgery

Question 28

What biological compound do most pregnancy testing kits use, and what do they detect?

Answer 28

Monoclonal Antibodies

• antibodies that bind to only one foreign antigen
• is specific
• binds to hCG

Question 29

How do pregnancy testing kits work?

Answer 29

1) hCG is produced in high quantities by the placenta in early pregnancy - present in mothers urine
2) Monoclonal antibodies are embedded in coloured latex beads (immobilised) at the end of a dipstick
3) dipstick is placed in urine - hCG binds to antibodies
4) hCG - antibody complexes form
5) thousands of hCG molecules bind together
6) colour change in beads, visible in test window