Reproductive system

Question 1

Describe the events in spermatogenesis

Answer 1

• Spermatogonium 2n (diploid) -> some spermatogonia remain as stem cells
  Some are pushed away from basement membrane (mitosis)
  Differentiation occurs
• Primary spermatocyte 2n - DNA replication
  Meiosis 1
• Secondary spermatocytes (divides into 2) both are haploid (n)
  meiosis 2
• Divides again into haploid spermatids (4 of them) (start of spermiogenesis)
• Turn into spermatozoa (haploid with tails)

Question 2

Describe the structure of a sperm cell

Answer 2

Larger chunks - Head and Tail

More detail
Acrosome - tip
Nucleus 
Neck 
Middle piece (mitochondria)
Principle piece
End piece

Question 3

Describe oogenesis and follicular development from puberty to menopause each month

Answer 3

• Still a primary oocyte (still in prophase 1) -> primary follicle -> secondary follicle
  Meiosis 1 is completed by one primary oocyte each month
• First polar body, Secondary oocyte (haploid (n) 23 chromosomes) (in metaphase 2) -> mature follicle
  Meiosis 2 of first polar body may or may not occur (goes into 2), is completed if fertilization occurs
• Haploid oocyte combines with haploid sperm cell -> ovulated secondary oocyte

Left with polar bodies (degenerate) and a diploid ovum or zygote

Question 4

Describe oogenesis and follicular development at a foetal period

Answer 4

- A diploid 2n (46 chromosomes) oogonium 
Mitosis occurs 
2n Primary oocyte 
Meiosis in progress 
Remains as primary oocyte (prophase 1)

Question 5

Describe male and female fertility across the lifespan

Answer 5

Foetal - eggs are produced
Aren’t activated til puberty (oocyte)
Declining number in menopause - late 40 onwards
- Menstruation ceases
- Decline in hormone level
- Uterus lining does not thicken
- Less oestrogen, hypothalamus stimulates FSH and LH, no response, keeps producing more, results in hot flushes

Question 6

With reference to the uterine cycle describe some of the phases

Answer 6

Days 1-6 - menstruation
Days 7-13 - proliferative phase
Days 15-28 - secretory phase

Question 7

Describe the main phases of the reproductive cycle

Answer 7

Days 1-5 are the menstrual phase
Days 6-13 are the preovulatory phase
Day 14 is ovulation
Days 15-28 are the postovulatory phase

Question 8

With reference to the ovarian cycle days 1-13 and 15-28 are known as what in the reproductive cycle

Answer 8

1-13 is the follicular phase

15-28 is the luteal phase

Question 9

Describe the mammary glands

Answer 9

Dense irregular connective tissue
Produces breast milk (essential nutrients for infants)
Synthesis, secretion and ejection of milk

Question 10

Describe the vulva

Answer 10

Hormone production and protection of pathways
Involved in the excretion of urine
Involved in sexual activity

Question 11

Describe the vagina

Answer 11

Receptacle for the penis during sexual intercourse
Outlet for menstrual flow
Passageway for childbirth
Nonkeratinized stratified squamous and areolar connective tissue
Acidic to repel infections

Question 12

Describe the uterus

Answer 12

A path for sperm deposited into the vagina to reach the uterine tubes
Site of implantation of a fertilised ovum
Source of menstrual flow when implantation does not occur

Endometrium -> myometrium and perimetrium

Question 13

Describe the uterine tube

Answer 13

Provides a route for sperm to reach an ovum
Transports fertilized ovum from the ovaries to the uterus
Contains cilia and microvilli and fimbriae

Question 14

Describe ovaries

Answer 14

Produce gametes which develop into mature ova (eggs) after fertilization
Hormones (progesterone and Oestrogen) - inhibin and relaxin

Question 15

What are the organs of the female reproductive system

Answer 15

Ovaries, uterine tube, uterus, vagina, vulva, mammary glands

Question 16

Describe the penis

Answer 16

Provides a means of urination and sexual function

Question 17

Describe the scrotum

Answer 17

Supports the testes
Regulates the sperm of testes
If cold - it can move the testes closer to the body (absorbs more heat)
Smooth muscle fibres

Question 18

Define the bulbourethral gland

Answer 18

During sex arousal they secrete an alkaline fluid into the urethra that protects passing sperm
Secretes mucous which lubricates the end of the penis

Question 19

Describe the prostate

Answer 19

Secretes a milky, slightly acidic fluid
Is used by sperm for ATP production
Nourishes and transports sperm
Connective tissue and muscle fibres

Question 20

Describe the seminal vesicles

Answer 20

Secrete alkaline, viscous fluid and clotting proteins

Provide sperm with a source of energy to help them move

Question 21

Describe the urethra

Answer 21

This channel is the part of the urinary tract that transports urine from the bladder and the part of the reproductive system through which semen is ejaculated.

Question 22

Describe the ejaculatory ducts

Answer 22

Semen flows through each ejaculator duct during ejaculation, travelling through the penis to exit the body

Question 23

Describe the ductus deferens

Answer 23

Transport sperm cells from epididymis, where the sperm are stored prior to ejaculation

Question 24

Describe the epididymis

Answer 24

Pseudostratified columnar epithelium encircled by smooth muscle
Long branching microvilli
Site of sperm maturation
Stores sperm

Question 25

Describe the testes

Answer 25

Dense irregular connective tissue
Sperm is produces (spermatogenesis)
Contains SPERMATOGENIC CELLS (sperm forming) and SUSTENTACULAR CELLS (supports spermatogenesis and nourishes spermatocytes, spermatids and sperm)
Produces testosterone

Question 26

Describe the basic components of the male reproductive system

Answer 26

The bladder, 
ductus deferens (sperm duct), 
epididymis, 
ejaculatory duct, 
urethra, 
seminal vesicles, 
prostate, 
bulbourethral gland (Cowper's gland),
scrotum 
penis