Human Reproduction Flashcards Preview

A2 Biology > Human Reproduction > Flashcards

Flashcards in Human Reproduction Deck (62):
1

Give the function of the scrotum

Contains the testes

2

Give the function of the testes

Contains seminiferous tubules where spermatogenesis occurs

3

Give the function of the epididymis

Where the spermatozoa mature

4

Give the function of the vas deferens

Connects the epididymis to the urethra

5

Give the function of the seminal vesicle

Produces a secretion that aids the mobility of spermatozoa

6

Give the function of the prostate gland

Produces a secretion that neutralises the alkali of the urine

7

Give the function of the urethra

Tube that carries the urine and spermatozoa out of the body

8

Give the function of the penis

Intermittent organ used to insert spermatozoa into the reproductive system of the female

9

Give the function of the ovary

Oogenesis occurs here

10

Give the function of the oviduct (fallopian tube)

Site of fertilisation, where spermatozoa fuses with an oocyte. After fertilisation a zygote is formed which moves down the oviduct to the uterus

11

Give the function of the uterus

Embryo plants in the endometrium and develops in the uterus

12

Give the function of the vagina

During copulation, spermatozoa are deposited at the top of the vagina

13

What do gametes contain?

Haploid number of chromosomes
One chromosome from each homologous pair

14

What is gametogenesis?

Production of gametes

15

Where are sperm produced?

Seminiferous tubules

16

State the four stages of spermatogenesis

1- GERMINAL EPITHELIAL CELLS undergo MITOSIS to form SPERMATOGONIA

2- SPERMATOGONIA undergo MITOSIS to form PRIMARY SPERMATOCYTES

3- PRIMARY SPERMATOCYTES undergo MEIOSIS 1 to form haploid SECONDARY SPERMATOCYTES. They then complete MEIOSIS 2 to form SPERMATIDS

4- SPERMATIDS mature to form SPERM

17

What is a sperm cell comprised of?

Nucleus
Acrosome
Mitochondria
Flagellum

18

Give the function of the nucleus in a sperm cell

Contains the DNA

19

Give the function of the acrosome in the sperm cell

Release enzymes which digests the zona pellucida

20

Give the function of the mitochondria in sperm cells

Release energy (ATP) for the flagellum to propel the sperm

21

Give the function of sertoli cells

Nourish and protect sperm in the seminiferous tubules

22

Give the function of the interstitial cells

Secrete testosterone

23

What is testosterone?

Hormone involved in stimulating the process of spermatogenesis

24

When does the first stage of oogenesis occur?

Before birth

25

What is the first stage of oogenesis?

OOGONIA divide by MITOSIS to form PRIMARY OOCYTES ( begin meiosis 1 but stops at prophase 1)
GERMINAL EPITHELIAL CELLS divide to form FOLLICLE CELLS which surround the PRIMARY OOCYTE

26

When does the second stage of oogenesis occur?

Once a month once the girl reaches puberty

27

What is the second stage of oogenesis?

Follicles begin to develop, only one matures into a Graafian follicle
Primary oocyte completed meiosis 1 to form a haploid secondary oocyte and a polar body

28

Why does only one follicle develop into a graafian follicle?

In oogenesis there is an uneven splitting of cytoplasm.
The developed follicle has to have enough cytoplasm to provide nourishment for the developing embryo

29

What happens to the graafian follicle?

Moves to the surface of the ovary where it releases the secondary oocyte (ovulation)

30

What happens after ovulation in terms of oogenesis?

The secondary oocyte begins meiosis 2 but stops at metaphase 2

31

What happens at fertilisation? (Oogenesis)

Sperm cell enters the oocyte.
Secondary oocyte completes meiosis 2, forming an ovum and a second polar body

32

How are zygotes formed (oogenesis)?

Nucleus of the sperm fuses with the nucleus of the secondary oocyte to form the zygote

33

During copulation, where are spermatozoa ejaculated from?

The epididymis
They travel up the vas deferens and out through the urethra

34

Once spermatozoa is ejaculated, where does it travel?

Swim through the cervix, along the lining of the uterus and into the oviduct where they meet the secondary oocyte

35

What is capacitation?

Physiological changes to spermatozoa to complete fertilisation

36

What must occur before a sperm cell can fertilise an oocyte?

Capacitation

37

What are the two reactions which occur during capacitation?

Acrosome reaction
Corticle reaction

38

What is the acrosome reaction?

The acrosome membrane ruptures and hydrolase enzymes are released. Enzymes digest through the zona pellucida to allow sperm to enter the oocyte

39

What is the cortical reaction?

Contents of the cortical granules fuse with the cell memrane of the oocyte which causes to zona pellucida to modify
Fertilisation membrane forms, preventing polyspermy

40

What is polyspermy?

Entry of additional sperm into the oocyte

41

What happens to the zygote after fertilisation?

Stimulates the secondary oocyte to complete meiosis 2
Haploid nucleus from each gamete forms a diploid nucleus of the zygote
Zygote divides by mitosis to form a blastocyst

42

What is a blastocyst?

Hollow ball of cells

43

What does the rapid division of the zygote cause?

Cleavage

44

What is a trophoblast?

Outer layer of a blastocyst formed when it reaches the endometrium

45

What does the trophoblast consist of?

chorion- develops chorionic villi to absorb nutrients through the endometrium
Amnion- forms the amniotic sac

46

What are the female hormones involved during pregnancy?

Progesterone
LH (luteinising hormone)
FSH (follicle stimulating hormone)
Oestrogen

47

State when each of the hormones are at their peak levels

FSH- before ovulation
LH- during ovulation
Progesterone- after ovulation (if fertilisation occurs)
Oestrogen- during ovulation

48

What is the role of FSH?

Stimulates the maturation of a follicle in the ovary. Positive feedback on oestrogen

49

Where is FSH secreted?

Anterior pituitary gland

50

What is the role of oestrogen?

Inhibits FSH
Positive feedback on LH
Triggers the repair of the endometrium

51

Where is progesterone secreted from?

Corpus luteum

52

What is the role of progesterone?

Causes further development of the endometrium

53

What is the role of LH?

Cause ovulation to occur and the graafian follicle to develop into the corpus luteum

54

What happens to the hormones if implantation doesn’t occur?

FSH and LH levels fall, causing the corpus luteum to degenerate
Progesterone levels fall and the endometrium breaks down

55

What hormone is released when implantation occurs, and what is its role?

Human chorionic gonadotrophin
Maintains the corpus luteum for the first 16 weeks

56

What hormones do the placenta secrete?

Progesterone and oestrogen
Progesterone suppresses the uterine wall’s to contract
Oestrogen stimulates the growth of the uterus and the mammary glands

57

What happens to FSH and LH during pregnancy?

They are inhibited

58

What happens to oestrogen and progesterone at birth?

Oestrogen levels increase
Progesterone decreases to allow uterine walls to contract

59

What 2 other hormones occur at birth?

Oxytocin- stimulates contractions and allows milk to be released from the mammary glands
Prolactin- stimulates mammary glands to produce milk
Both released by the anterior pituitary gland

60

What os the placenta?

Organ which connects the developing foetus to the wall of the uterus via the umbilical cord

61

What are the 4 functions of the placenta?

•Exchange of gases and nutrients- countercurrent blood system between foetal and mother’s blood to allow for diffusion
•Provides a barrier to protect foetus from high BP from mother
•Protection from the mother’s immune system
•Secretion of horomones

62

What is the function of the amniotic fluid?

Acts as a shock absorber to protect the foetus from impacts