The Reproductive System

Question 1

What is the function of the reproductive system?

Answer 1

to produce, store, nourish and transport male and female gametes

Question 2

What are the testes made up of?

Answer 2

a series of lobules

Question 3

What is spermatogenesis and where does it take place?

Answer 3

Spermatogenesis is the process of forming sperm, this takes place in the testes.

Question 4

Describe the process of spermatogenesis

Answer 4

• The process begins in the outermost layer of cells and proceed towards the lumen
• Seminiferous tubules merge into straight tubules
• Merge to from rete testis which connect to the epididymis

Question 5

Describe the three processes of spermatogenesis in detail?

Answer 5

• Mitosis
  ○ Spermatogonium divides – one daughter cells remains in situ, the other moves towards the lumen of the ST
  ○ Differentiates into primary spermatocyte
  *Meiosis
  ○ Division of spermatocyte produces spermatids
• Spermiogenesis
  ○ Spermatids
  differentiate into physically mature spermatozoa

Question 6

Describe the structure of a sperm

Answer 6

• Head
  ○ Contains nucleus with densely packed chromosomes
  ○ Acrosome – contains enzymes essential to fertilisation
• Midpiece
  ○ Contains abundant mitochondria- what gives cells energy allowing themm to swim to the fallopian tube
• Tail
  ○ Flagellum- the only example of a flagellum in the human body

Question 7

What is the significance of acrosome in the head of the sperm?

Answer 7

it allows the sperm to break down the surface of the egg to allow the chromosomes to mix

Question 8

Why do sperm not have an ER, Golgi apparatus or lysosomes etc?

Answer 8

Reduces size and mass this means there are no stores of glucose etc so respiration cant occur.

Question 9

How do the sperm respire?

Answer 9

as they do not have any energy stores they must absorb fructose from fluid

Question 10

Name three accessory glands in the male reproductive system

Answer 10

• Seminal vesicle
  ○ 60% volume of semen
  ○ Fluid contains high conc. of fructose- food source
  ○ Slightly alkaline- Alkaline seminal fluid neutralises acid secretions of prostate and vagina
• Prostate gland
  ○ 20-30% volume of semen
  ○ Encircles urethra
  ○ Contains
  seminalplasmin- protein with antibiotic properties, prevents infection in males
• Bulbourethral gland
  ○ Produce thick, alkaline mucus
  ○ Neutralises any remaining urinary acids

Question 11

What is the purpose of testosterone in men?

Answer 11

○ Maintains libido
○ Stimulates osteogenesis and myogenesis- governs bone and muscle production helps increase their bone and muscle mass
○ Maintains male secondary sex characteristics- beards etc
○ Maintains male accessory glands

Question 12

What is the function of the female reproductive system?

Answer 12

• Produces sex hormones and gametes
• Also protects and supports developing foetus

Question 13

Where does Oogenesis occur?

Answer 13

In the ovaries

Question 14

Describe the structure of the ovaries

Answer 14

• Pair of small, lumpy, almond-shaped organs
  ○ Ovarian ligament stabilises their position relative to the uterus
• Produce oocytes (eggs)
  ○ Oogenesis

Question 15

What is the function of the ovaries?

Answer 15

To secrete female sex hormones

Question 16

What is the process of Oogenesis?

Answer 16

• Oogonium divides by mitosis to produce primary oocytes
• Primary oocytes prepare to undergo meiosis – proceed to meiosis 1
• Held in suspended development until puberty
• Rising levels of FSH at puberty trigger the ovarian cycle
• Some primary oocytes complete meiosis I to form secondary oocytes
• Secondary oocytes leave ovary suspended in metaphase of meiosis II
• Meiosis will not be completed until fertilisation occurs

Question 17

What happens to the cells after puberty?

Answer 17

They mature.
Cells are held in prophase of meiosis 1 until puberty – occurs between 3rd and 7th month of foetal development

Question 18

What is the follicular phase?

Answer 18

producing and releasing a viable egg

Question 19

what events take place during the follicular phase?

Answer 19

• Primary oocytes in outer portion of ovarian cortex in egg nests – forms primordial follicle with follicle cells
• Primary follicle develops – follicular cells divide to produce granulosa cells
• Layer of thecal cells develops around follicle
• Mature graafian follicle formed – LH levels rise and primary oocyte completes meiosis I
• At ovulation, secondary oocyte released from graafian follicle into fallopian tube
• Follicle cells divide to from several layers of cells surrounding the oocyte
• Thecal cells and granulosa cells produce oestrogen
• Mature graafian follicle or tertiary follicle formed after 10-14 days of the cycle

Question 20

What events take place during the luteal phase?

Answer 20

• Empty graafian follicle collapses and develops into corpus luteum (CL) – endocrine function
  ○ Cholesterol in CL used to synthesise progesterone
  ○ Prepares uterus for pregnancy
• CL degenerates if fertilisation doesn’t occur
  ○ Progesterone and oestrogen levels fall
• If fertilisation occurs, CL continues to produce progesterone which maintains uterine lining
• Placenta eventually takes over progesterone production and CL degrades
• CL degenerates about 12 days after ovulation unless fertilisation occurs

Question 21

What is the luteal phase?

Answer 21

preparing the uterus for fertiliasation

Question 22

What are the three phases of the uterine cycle?

Answer 22

-menses
-proliferative phase
-secretory phase

Question 22

What is an antrum?

Answer 22

the expanding central chamber of the follicle, fills with fluid

Question 23

What is the function of the uterus?

Answer 23

• Protects, nourishes and removes wastes from the developing foetus

Question 24

What is menses?

Answer 24

Menstruation
○ Degeneration of endometrium
○ Sloughing off of tissue

Question 25

What happens during the proliferative phase?

Answer 25

Oestrogens secreted by developing follicles stimulate growth

Question 26

What happens during the secretory phase?

Answer 26

Progesterone makes the endometrium receptive to implantation of the blastocyst

Question 27

What happens to the male reproductive system with age?

Answer 27

• Andropause
  this is where levels of circulating testosterone fall, also FSH and LH levels
  -However sperm production continues

Question 28

What happens to the female reproductive system with age?

Answer 28

• Menopause
  -Ovulation and menses cease
  -Levels of circulating oestrogen, progesterone, FSH and LH fall
  -Osteoporosis can develop