Reproductive Systems (Chapter 11)

Question 1

Vas deferens

Answer 1

carries sperm from testes to the urethra

Question 2

Seminal vesicle

Answer 2

secretes a fluid that is rich in sugars and is the main component of semen

Question 3

Urethra (male)

Answer 3

carries semen and urine out of the body

Question 4

Testes

Answer 4

location of sperm and production. covered in scrotum and contains 200-300 lobules

Question 5

Scrotum

Answer 5

skin covered pouch that supports and protects the testes

Question 6

Epididymis

Answer 6

stores sperm while they finish maturing

Question 7

Erectile tissue

Answer 7

made up of 3 column-like chambers, all vascularised with a lot of spongy like sacs that become filled with blood during an erection.

Question 8

Bulbo-urethral glands

Answer 8

Small yellow glands that secrete a clear mucous to provide lubrication and alkalises the urethra to help flush it out and provide a healthier environment for sperm.

Question 9

Prostate gland

Answer 9

produces an alkaline, milky fluid that is injected into the semen, plays a role in coagulating and then de-coagulating sperm.

Question 10

Uterus

Answer 10

Sits between bladder and rectum. Location of embryo development after fertilisation. Surrounded by smooth muscle walls and a mucous membrane lining called the endometrium.

Question 11

Fimbriae

Answer 11

Finger-like projections that guide the ova into the uterine tubes

Question 12

Fallopian tube

Answer 12

Guides the ova to the cervix by the movement of beating cilia and smooth muscles contractions.

Question 13

Ovaries

Answer 13

One on each side of the body, the location for ova (egg) development and release. Also release sex hormones and are held in place by ligaments.

Question 14

Cervix

Answer 14

located at the lower end of the uterus. Around 10cm long and may also receive the penis during sexual intercourse. Stretches to form the birth canal with the vagina

Question 15

Vagina

Answer 15

end of the cervix that connects with external environment. Receives the penis during sexual intercourse, provides passageway for semen and menstrual fluid

Question 16

Labia Majora

Answer 16

large fleshy folds of skin made of fat and fibrous tissue that protect external reproductive organs. Contain sweat and oil-secreting glands.

Question 17

Labia Minora

Answer 17

Sit beneath and between labia majora

Question 18

Clitoris

Answer 18

Structural equivalent to male penis, contains a lot of nerves, blood vessels and erectile tissue. Becomes engorged when stimulated in a similar manner to the penis.

Question 18

What is spermatogenesis and where does it occur?

Answer 18

It is the process of creating male gametes, the formation of spermatozoa in the testes.
It occurs in the seminiferous tubules of the testes and takes about 72 days.

Question 19

Spermatogenesis process + Flow chart

Answer 19

After puberty, the presence of testosterone triggers the differentiation of one of each spermatogonia into type B spermatogonia.
These type B spermatogonia will go on to create four sperm cells.
The type B cells will travel further down the lumen and differentiate to become primary spermatocytes (diploid).
The primary spermatocytes then enter meiosis 1 to become two secondary spermatocytes.
Secondary spermatocytes then go through meiosis 2 and become 4 spermatids (haploid).
However, they aren’t fully matured sperm yet until they have undergone further differentiation in a process called spermiogenesis

Spermatogonia -> Primary spermocytes -> secondary spermocytes -> spermatids -> sperm (spermatozoa)

Question 20

3 major regions of sperm and what they contain

Answer 20

• The head: contains the nucleus and acrosome (the enzyme filled vesicle cap)
• The middle piece: contains mitochondria to power the sperm, relies on sugars in the seminal fluids
• The tail: provides movement, however no independent movement happens until after the sperm is ejaculated.

Question 21

What is oogenesis and where does it occur?

Answer 21

The process of creating female gametes, the formation of ova in the ovaries.
Occurs in the ovaries and takes years to complete one cycle

Question 22

Process of Oogenesis + Flow chart

Answer 22

The oogonia, unlike spermatogonia all differentiate and grow into primary oocytes (diploid).
These primary oocytes undergo prophase I but then stop at birth
Primary oocytes are surrounded by a single layer of cells to nourish the primary oocyte. The whole combination is called a primary follicle.
At puberty, follicle development and maturation begins, one by one, every month.

A single primary oocyte will finish meiosis I and produce one secondary oocyte with half the chromosomes but most of the cytoplasm. It also produces one polar body; which contains the other half of chromosomes but only a small portion of cytoplasm. Polar bodies are eventually reabsorbed.

The secondary oocyte immediately begins meiosis II but is arrested in metaphase II until ovulation.

When ovulation occurs, the follicle bursts releasing the secondary oocyte and polar body.
Only if fertilisation happens does meiosis II complete, this happens within minutes of fertilisation.

After fertilisation and completion of meiosis II an ootid (haploid) and another polar body is created which quickly matures into an ovum within minutes.
The first polar body may also divide into two more polar bodies.

oogonia -> primary oocytes -> secondary oocyte (+polar body) ->ootid (+/- 3 polar bodies) ->1 mature ovum

Question 23

What is the effect and target organ of the Follicle Stimulating Hormone (FSH)?

Answer 23

Target organ:
- Seminiferous tubules of testes
- Follicles of ovaries
Effect:
- Produces sperm
- Maturation of ovarian follicles

Question 24

What is the effect and target organ of the Luteinizing Hormone (LH)?

Answer 24

Target organ:
- Interstitual cells of the testes
- Cells of the ovaries
Effect:
- Stimulates secretion of testosterone
- Stimulates secretion of oestrogen and progesterone

Question 25

What is the effect and target organ of progesterone?

Answer 25

Target organ and effect:
- Uterus, maintenance of endometrium
- Placenta, development and maintenance of placenta
- Breasts, development of milk-secreting glands

Question 26

What is the effect and target organ of oestrogen?

Answer 26

Target organ and effect:
- Various organs, development of female reproductive system and development of secondary sexual characteristics

Question 27

What is the ovarian cycle, average length and what it includes?

Answer 27

The ovarian cycle is the series of events that take place in the ovaries during one cycle.
- this includes the maturation of the ovum and it’s release into the uterine tube.
- also associated is the development of the follicles in the ovary and the formation of the corpus luteum

The average length of one cycle is 20-40 days with the average being 28 days.

Question 28

Stages of menstrual cycle

Answer 28

• Menstruation (day 1-4) - the endometrium is shed
• Preovulation (day 5-12) - endometrial repair begins, development of ovarian follicle
• Ovulation (day 13-15) - rupture of mature follicle releases egg
• Secretion (day 16-20) - secretion of watery mucous by glands of endometrium,cervix and uterine tubes. Movement and breakdwon of unfertilised egg. Development of corpus luteum.
• ## Premenstruation - (day 21-28) - degeneration of corpus luteum, deterioration of endometrium

Question 29

Menarche

Answer 29

When menstruation first begins in a female. Marks the onset of puberty