Reproductive system

Question 1

What are the Gonads (2)

Answer 1

1. The primary sex organs (testes in males and ovaries in females)
2. produce the gametes (sex cells) and secrete hormones

Question 2

Male Reproductive System (5)

Answer 2

1. Testes: Produce sperm and testosterone.
2. Epididymis: Sperm maturation and storage.
3. Vas deferens: Transports sperm to the ejaculatory duct.
4. Seminal vesicles & prostate gland: Add fluids to form semen.
5. Penis: Delivers semen during intercourse

Question 3

Female Reproductive System (5)

Answer 3

1. Ovaries: Produce eggs and hormones (oestrogen & progesterone).
2. Fallopian tubes: Fertilisation
3. Uterus: Supports embryo/fetal development.
4. Cervix: Lower uterus, opens to vagina.
5. Vagina: Receives sperm; birth canal

Question 4

Hormonal Regulation (4)

Answer 4

1. Controlled by the hypothalamic-pituitary-gonadal axis.
2. GnRH from hypothalamus → stimulates LH & FSH from pituitary.
3. In males: stimulates sperm and testosterone production.
4. In females: regulates ovarian cycle.

Question 5

What is the process of spermatogenesis (4)

Answer 5

1. Mitosis of a spermatogonium -primary spermatocyte (diploid, 2n)
2. Meiosis i - DNA replication, primary spermatocyte, synapsis and tetrad formation, secondary spermatocytes
3. Meiosis ii - spermatids (haploid, n)
4. Spermiogenesis (physical mutation) - sperm (haploid, n)

Question 6

What is the structure of a sperm (5)

Answer 6

1. Acrosome – membranous compartment, contains enzymes essential to fertilisation
2. Head – contains a nucleus (DNA) with densely packed chromosomes.
3. Neck – contains both centrioles of the original spermatid.
4. Middle piece – contains mitochondria to provide ATP for tail movement)
5. Tail (flagellum) – whiplike, moves sperm

Question 7

How is testosterone produced (2)

Answer 7

1. In the interstitial cells of Leydig (in the testes)
2. It is converted to dihydrotestosterone (DHT) in some tissues

Question 8

What are the peripheral effects of testosterone (6)

Answer 8

1. CNS effects
2. Bone and muscle growth stimulation
3. Establishment and maintenance of male secondary sex characteristics
4. Maintenance of accessory glands and organs of the male reproductive system
5. Controlling the local environment around spermatocytes and spermatids
6. Androgen-binding protein (ABP) binds androgens and stimulates the physical maturation of spermatids.

Question 9

What are the functions of the Luteinising hormone (LH) in males (2)

Answer 9

1. Targets the interstitial cells of the testes, which secrete testosterone and other androgens
2. Testosterone levels are regulated by negative feedback - high testosterone level inhibits the release of GnRH.

Question 10

What are the functions of the ovaries (6)

Answer 10

1. Two almond-shaped structures on either side of the uterus, near the lateral wall of the pelvic cavity
2. Produce immature female gametes (oocytes)
3. Are composed of ovarian follicles (sac-like structures – oocyte and follicular cells)
4. Secrete inhibin, which inhibits FSH production in the anterior pituitary gland)
5. Support for ovaries: suspensory, ovarian and broad ligaments
6. Layers: germinal epithelium, tunica albuginea, interior (cortex and medulla)

Question 11

What are the ovarian follicle stages (3)

Answer 11

1. Primary follicle – contains an immature oocyte.
2. Graafian (vesicular) follicle – growing follicle with a maturing oocyte
3. Ovulation – when the egg matures, the follicle ruptures (occurs approximately every 28 days), and the ruptured follicle is transformed into a corpus luteum

Question 12

What are the functions of the uterine (Fallopian) tubes (6)

Answer 12

1. The expanded funnel opens into the pelvic cavity along the surface of the ovary; the other end opens into the uterine cavity.
2. Supported by broad ligament
3. Receives the ovulated oocyte
4. Is the site for fertilisation?
5. Fimbriae: finger-like projections at the distal end that receive the ovulated oocyte and sweep it into the tube towards the uterus
6. Cilia inside uterine tubes move the oocyte slowly towards the uterus.

Question 13

What are the uterine wall (layer) (6)

Answer 13

1. Endometrium: the inner layer that allows for implantation of a fertilised egg; sloughs off if no pregnancy occurs (menses)
2. Myometrium: the middle layer of smooth muscle
   Serous layer (perimetrium): outer visceral peritoneum
3. Uterine cavity, or uterine lumen - Large, superior cavity continuous with isthmus of uterine tube
4. Internal os: (os, opening or mouth)- opening connecting the uterine cavity to the cervical canal
5. Cervical canal: Constricted passageway at the inferior end of the uterine cavity; begins at internal os; ends at external os
6. External os: Curving vaginal opening into the uterus

Question 14

What are the stages of the ovarian cycle (7)

Answer 14

1. Primordial ovarian follicles in egg nest
2. Formation of primary ovarian follicle
3. Formation of secondary ovarian follicle
4. Formation of a tertiary ovarian follicle
5. Ovulation
6. Formation of corpus luteum
7. Formation of corpus Albicans

Question 15

What is the menstrual (uterine cycle) (5)

Answer 15

3. Menses stage – functional layer of endometrium sloughed
4. Proliferative stage: regeneration of functional layer
5. Secretory stage: endometrium increases in size and readies for implantation

Question 16

What are the endometrial changes during the uterine cycle (3)

Answer 16

1. Menstrual phase - the destruction of the functional layer (days 1-7)
2. Proliferative phase - repair and regeneration of functional layer (days 7-14)
3. Secretory phase - secretion by uterine glands (days 14-28)

Question 17

What happens to the hormone levels during the ovarian and uterine cycles (5)

Answer 17

1. FSH, LH & GnRH peak during ovulation day 14
2. Estrogen peaks around ovulation, with a smaller peak during the secretory phase
3. Progesterone peaks during the secretory phase
4. Inhibin peaks during the secretory phase, with a smaller peak around ovulation
5. Basal body temperature drops during ovulation and peaks during the secretory phase

Question 18

What hormones are produced by the ovaries (4)

Answer 18

1. Oestrogens: Produced by follicle cells
2. Oestrogens causes secondary sex characteristics (accessory organs enlargement, development of breasts, appearance of pubic hair, increase in fat beneath the skin, widening and lightening of the pelvis, onset of menses)
3. Progesterone: Produced by the corpus luteum
4. Progesterone production continues until LH diminishes in the blood and helps maintain pregnancy

Question 19

What is the anatomy of the mammary glands (5)

Answer 19

1. Areola: central pigmented areas
2. Nipple: protruding central area of areola
3. Lobes: internal structures that radiate around nipple
4. Alveolar glands: clusters of milk-producing glands within lobules
5. Lactiferous ducts: connect alveolar glands to nipple

Question 20

What are the stages of embryonic development (5)

Answer 20

1. Developmental stage from the start of cleavage until the ninth week
2. The embryo first undergoes division without growth
3. The embryo enters the uterus at the 16-cell state
4. The embryo floats free in the uterus temporarily
5. Uterine secretions are used for nourishment

Question 21

What are the initial stages of pregnancy (6)

Answer 21

1. Blastocysts - Ball-like circle of cells
2. Begins at about the 100 cell stage
3. Secretes human chorionic gonadotropin (hCG) to produce the corpus luteum to continue producing hormones
4. Contains trophoblast (large, fluid-filled sphere) and inner cell mass
5. Primary germ layers formed – ectoderm, mesoderm, endoderm
6. Late blastocyst implants in the wall of the uterus by day 14

Question 22

What are the stages of development after implantation (3)

Answer 22

1. Chorionic villi (projections of the blastocyst) develop
2. The embryo is surrounded by the amnion (a fluid-filled sac)
3. An umbilical cord forms to attach the embryo to the placenta (placenta forms a barrier between mother and embryo, delivers nutrients and oxygen, removes wastes from embryonic blood, becomes an endocrine organ (produces hormones – oestrogen, progesterone, other hormones that maintain pregnancy))

Question 23

What are the stages of development of the foetus (beginning of the ninth week) (3)

Answer 23

1. All organ systems are formed by the end of the eighth (8th) week
2. Activities of the foetus are growth and organ specialisation
3. A stage of tremendous growth and change in appearance

Question 24

What happens to the body from conception to birth (7)

Answer 24

1. Enlargement of the uterus
2. Relaxation of the pelvic ligaments and pubic symphysis due to production of relaxin
3. An umbilical cord forms to attach the embryo to the placenta
4. Kidneys have additional burden and produce more urine
5. The uterus compresses the bladder
6. Vital capacity and respiratory rate increase
7. Body water rises, blood volume increases by 25-40%, blood pressure and pulse increase, varicose veins are common

Question 25

What are the stages of labour (9)

Answer 25

1. oestrogen levels rise 2. uterine contractions begin 3. placenta releases prostaglandins 4. oxytocin is released by the pituitary, combination of the hormones produces contractions 5. Cervix becomes dilated 6. Uterine contractions begin and increase 7. The amnion ruptures 8. Expulsion - Infant passes through the cervix and vagina 9. Placental stage: delivery of the placenta

Question 26

How is positive feedback used in labour (7)

Answer 26

1. baby moves deeper into the mothers birth canal 2. Pressoreceptors in cervix of uterus excited 3. Afferent impulses to hypothalamus 4. Hypothalamus sends efferent impulses to prosterior pituitary where oxytocin is stored 5. Prosterior pituitary releases oxytocin targets mothers uterine muscle 6. Uterus responds by contracting more vigourously 7. Positive feedback mechanism continues to cycle until interrupted by birth of baby.