Structure and function of the male and female reproductive tract

Question 1

What does the male reproductive system consist of?

Answer 1

• Seminal vesicle
• Prostate gland
• Penis
• Vas deferens
• Testis
• Scrotum
• Urethra

Question 2

What is the process of spermatogenesis?

Answer 2

• Primordial Germ cell
• Spermatogonium (2n)
• Primary spermatocyte (2n)
• Secondary spermatocyte ( n x n = 2n)
• Spermatids (2xn, 2xn)
• Sperm cells (4 x n)

Question 3

How is sperm produced?

Answer 3

• Produced in the testes which also produces testosterone
• Seminiferous tubules = site of spem production
• Sertoli cell - nourish and support sperm production
• Rete testis contain microvilli that aid to the transport to the effecernt ducts
• Transported to epididymis by contractions for storage and to acquire motility
• Spermiogenesis

Question 4

What is the epididymis?

Answer 4

• Epididymis - post spermiogenesis for storage and maturation of sperm (motility)
• Convoluted tube (6m) consisting of head,body and tail, lined with stereocilia
• Muscular wall for ejecting sperm

Question 5

What is the vas (ductus) deferens?

Answer 5

• Long (30 cm), muscular tube
• Transports sperm from epididymis to ejaculatory ducts
• Sperm may be stored in vas for several months ready for ejaculation
• Site of vasectomy

Question 6

What are ejaculatory ducts?

Answer 6

-Two ducts (one for each testes)
- Formed from dilated portion (ampulla) of the vas duct of each seminal vesicle
- Delivers sperm from testes, seminal fluid and alkaline prostate secretion into the urethra

Question 7

What is the male urethra?

Answer 7

• Part of the urinary and reproductive system
• transports urine and sperm to the exterior of a person
• Structure through which semen is ejaculated

Question 8

What is semen (Seminal fluid)?

Answer 8

• Bodily fluid containing salts, carbohydrates, weak organic acids (citric acid), lipids, nutrients including fructose, some cells and sperm
• Alkaline pH of (7.2-7.8) ; 20 million/ml
• Function is to carry and deposit sperm with the female reproductive tract through coitus
• Produced by glands , with over 50% produced by the seminal vesicles, followed by the prostatem testes,epididymis and the bulbourethal gland

Question 9

What are seminal vesicles?

Answer 9

• Glandular tissue with pseudostratified epithelium
• No sperm present
• Secretes alkaline fluid containing fructose and vitamin C
• Muscular wall for ejaculation

Question 11

What are bulbourethral glands?

Answer 11

• Produces a lubricant for urethral opening
• Clears urethra of urine residue

Question 12

What is the prostate gland?

Answer 12

• surrounds the bladder neck and urethra and ejaculatory ducts
• Compound glands surrounded by muscular stroma
• Secretes citric acid and enzymes (fibrinolysin) to nourish sperm and liquefy ejaculate

Question 13

What are the stages of spermiogenesis (pt II)?

Answer 13

• Last stage of spermatogenesis, sperm still attached to the Sertoli (sustentacular) cells, which maintain the blood-testis barrier (tight junctions, prevent contact of sperm specific antigens and components of the immune system)
• Maintain high concentration of androgens, oestrogens, K + in tubular fluid
  -Androgen binding protein (ABP) —binds testosterone/DHT- concentrated- to
  enable spermatogenesis and maturation
  -Spermatids embedded in Sertoli cell
  cytoplasm

Question 14

How does differentiation occur in spermiogenesis?

Answer 14

Spermiogenesis (differentiation)
* Golgi vesicles combine to form the acrosomal vesicle
containing lytic enzymes
Centrosomes organise microtubules in the
developing flagellum
* Mitochondria accumulate in the midpiece
* Nucleus condenses and is stabilised by protamines
(replace histones) for denser packing of most (-96%
of genome)
* Excess cytoplasm is pinched off as a residual body
* Any abnormalities in head, tail, midpiece may cause male infertility

Question 15

What are the structures of the FRT?

Answer 15

• Vulva
  External structures comprising clitoris and labia
  Vagina
  — Orifice leading to the uterus via the cervix (lower Uterus; fundus is the upper part of the uterus)
  — Exit route for menstrual efflux and fetus
  — Facilitates coitus and childbirth via a smooth muscle cell located in vaginal wall
  — Bartholin’s gland secrete mucus to ensure vagina remains moist
  Vaginal microbiome abundant in Lactobacilli keeping py acidic and helps prevent infection
  — Vaginal dysbiosis
  Uterus
  — Muscular organ
  — Lined by endometrium which is shed monthly (see ‘Menstrual cycle’ lecture to review endometrial
  structure and function); shed monthly
  Myometrium-smooth muscle of the uterus — undergoes proliferation and growth during pregnancy

Question 16

What is the fallopian tube (Salpinx)?

Answer 16

• Pair of tubes which ova are transported through following ovulation
• Infundibulum with fimbriae is closest to the ovary - has an ampulla and isthmus that links to the uterus
• Ampulla is most likely the site of fertilisation
• Lined by cillia to assist ovum transport

Question 17

What is the myometrium?

Answer 17

• Smooth muscle of the uterus
• Longitudinal and circular smooth muscle interdigitating
• Imparts strength and directionality of contractions
• During pregnancy- develops gap junctions between cells
• During pregnancy - cells undergo hypertrophy and hyperplasia

Question 18

Histology of FRT

Answer 18

Ovary
1.) Outer covering of cuboidal
epithelium continuous with pelvic peritoneum (cilia and microvilli)
2.) Stroma: support and hormones
3.) Gamete producing structures
**Cervix **
1.) Endocervix - mucus secreting
columnar epithelium
2.) Ectocervix - stratified squamous
epithelium
Fallopian tube (uterine tube/ oviduct)
1.) Epithelium
2.) Smooth muscle wall
3.) Serosa

**Uterus: **
1.)Endometrium—Columnar
epithelium arranged in glands
upported by stroma

2.)Myometrium: smooth muscle

Question 19

What are some pathologies of the uterus?

Answer 19

• Endometrium:
• Cancer
• Emndometriosis; ectopic endometrial material that is under the influence of cyclic hormones
• Myometrium:
• Fibroids : benign smooth muscle tumour
• Often multiple
• Recede after menopause
• Can make it difficult for an embryo to implant/cause spontaneous abortion