REPRODUCTIVE SYSTEM

Question 1

What is the function of the uterus

Answer 1

to nurture the ovum as it develops into a fetus

Question 2

What is the function of the ovaries

Answer 2

produce reproductive hormones an oocytes

Question 3

What is the function of the cervix

Answer 3

allow flow of blood from uterus, directs sperm into uterus

Question 4

What is the function of the prostate

Answer 4

create prostate fluid for semen, muscle propel sperm in ejaculation

Question 5

What is the function of the corpus spongiosum

Answer 5

contains spongy erectile tissue for erection

Question 6

What is the function of the testes

Answer 6

produce sperm and reproductive hormones

Question 7

What is the function of the ejaculatory duct

Answer 7

connects ductus deferent to the urethra as a passage for semen ejaculation

Question 8

What is the function of the corpus cavernosum

Answer 8

prevents urethra from pinching shut during an erection

Question 9

Explain the transport of sperm through the testes and epididymis

Answer 9

Within testes are seminiferous tubules packed into tunic albuginea. Spermatogenesis occurs here

Sperm collected by rete testis and efferent ducts carry to epididymis

Epididymis stores sperm and is where motility is acquired

Question 10

What are the reasons behind the testes being outside of the body

Answer 10

Optimal temperature for spermatogenesis is 34ºC. Being outside of body lower temperature from body 37ºC.

Question 11

How is the testes thermogenesis controlled

Answer 11

Cremaster muscle: raises/lowers testes in sex or fear for thermoregulation and protection from damage

Dartos muscle: contracts and relaxes the wrinkled scrotal surface for thermoregulation.

Pampiniform plexus: Countercurrent blood heat exchange in testes.

Question 12

What is the spermatic cord

Answer 12

Thick walled tube from epididymis passing through abdominal body wall (inguinal canal).

Contains muscle and fascial layers, testicular artery and vein and ductus deferens.

Question 13

What are the accessory organs of the male reproductive system

Answer 13

Seminal vesicles
Prostate gland
Bulbourethral glands
Urethra

Question 14

Explain the seminal vesicles and prostate gland

Answer 14

Seminal vesicles: Behind bladder, join d. deferens to form ejaculatory duct. Secrete fructose and prostoglandins for sperm and dilation of cervix.

Prostate gland: Inferior to bladder, secretes citric acid (nutrients), seminal plasmin (antibiotic of UTI) and PSA (liquifies semen)

Question 15

Explain the bulbourethral glands and the urethra

Answer 15

Bulbourethral (Cowper’s glands: each side of membranous urethra. Secretes viscous mucin to protect urethra, lubricant in sex.

Urethra: Transports semen and urine. Pre-prostatic prostatic, membranous and spongy

Question 16

What is the penis

Answer 16

3 primary erectile tissue bodies (spongy masses of potential vascular space).

Corpus cavernosum (clitoris) paired masses on anterior side of penis

Corpus spongiosum single mass on posterior side of penis

Glans is the expanded distal end with the external urethral orifice

Question 17

What are the sexual functions of the Penis

Answer 17

Erection: parasympathetic cause dilation

Emission: Secretion of accessory glands an spermatozoa into urethra

Ejaculation: Release of semen by contraction of bulbospongiosus and ischiocavernosus muscles around the corpus.

Question 18

What are the functions of Sertoli cells

Answer 18

Sex determination by expressing SRY (drives development)

Development by secreting AMH, regression of female characteristics in foetal life

Hormonal regulations

Stem cell regulation by GDNF ensuring self-renewal

Form blood-testis barrier

Question 19

What is the syncytium

Answer 19

Cytoplasmic bridge between sperm to share products of X and Y genes

Question 20

How does a prostate cancer test work

Answer 20

Pca is a substance produced in the prostate. If a tumour occurs pca is found in the bloodstream

Question 21

Outline the steps of spermatogenesis

Answer 21

Spermatogonium
Primary spermatocyte

FIRST MEIOTIC DIVISION

Two secondary spermatocytes

SECOND MEIOTIC DIVISION

4 spermatids

SPERMIOGENESIS

4 spermatozoa

Question 22

Outline female external genitalia

Answer 22

Collectively called the vulva

Mons pubis: skin and tissue anterior to pubic bone

Labia majora and minora: paired folds of skin. minora vascularised, sebaceous glands

Clitoris: erectile body anterior to l. minora

Prepuce: Fold of l. minora covering clitoris

Vestibule: Space between l. minora. Urethral opening, vaginal orifice.

Question 23

Outline the female internal accessory organs

Answer 23

Fallopian tubes: Project from uterus with infundibulum at distal end.

Uterus: Muscular organ. Fundus = body, Cervix = opening

Linings: Perimetrium, myometrium, endometrium

Question 24

What are the body targets of estrogen

Answer 24

Brain: maintanence of body temp and memory

Heart/liver: cholesterol production

Bone: Preserves bone density

Breast/uterus/ovaries: Stimulates maturation and menstrual cycle

Question 25

Outline the steps of oogenesis

Answer 25

Before birth, primordial follicle forms and meiosis starts and halts. In puberty, FSH increases follicle growth and oocyte size. Each month, multiple follicles mature, one will dominant and become FSH-independent. Dominant follicle secretes inhibin to stop FSH production causing other follicles to degrade

Question 26

What are the similarities between spermatogenesis and oogenesis

Answer 26

surrounded by support cells (sertoli/granulosa) & hormone producing cells (leydig/theca) undergo maturation and meiosis Produce haploid germ cells

Question 27

What are the 3 principles sexual reproduction is governed by

Answer 27

Behavioural: Social structures, seduction/dominance pre and post copulation Physical: external physical attributes as reproductive signals Morphological: shape of penis, copulatory movement

Question 28

Explain the reasoning behind having many sexual mates

Answer 28

Gender that contributes most to infant care has lower gamete numbers and benefits by minimal mating with best mate Opposite gender benefits by additional mating to maximise fertilisation

Question 29

What are 3 types of competition tactics seen in animals

Answer 29

Sperm speed: important when multiple mates Sperm bundling: Sperm form cooperative groups to reach egg together Terminating previous fertilisation: Could physically block transfer of sperm of later mating, or release anti-aphrodisiac and enzymes that destroy previous sperm.

Question 30

When is sperm count high

Answer 30

In species where females copulate with multiple males

Question 31

What germ layer gives rise to the gonads, kidneys, reproductive and renal development

Answer 31

Mesoderm

Question 32

Explain the bipotential reproductive system

Answer 32

SRY gene carried on the Y chromosome causes production of testis if turned on.

Question 33

What are some of the syndrome due to issues with sex determination

Answer 33

Swyer syndrome: phenotypically female but XY. Issue with SRY gene. Ovaries non functional, no post-pubertal development of secondary sex characteristics, may become pregnant with donated egg Androgen insensitivity syndrome: Testosterone receptor issue, more female characteristics observed.

Question 34

What are the mullerian and wolffian tracts

Answer 34

Indeterminate genital ridge accompanied by twin set of ducts. Mullerian ducts = female, wolffian ducts = male. Mullerian ducts become fallopian tubes, uterus, vagina Wolffian ducts become d. deferens, prostate, seminal vesicles Opposite ducts degenerate

Question 35

Explain the steps of the primordial germ cell journey in mice

Answer 35

Specification: 6 cells in embryo express Blimp1 Commitment: After proliferation, some Blimp1+ cells express Stella and commit to germline Migration: PGCs migrate to gonads and proliferation occurs Colonisation: PGCs colonise gonad and undergo sex determination

Question 36

Explain the steps of the primordial germ cell journey in humans

Answer 36

Specification and commitment: Little is known Migration: 4th week of gestation, PGCs migrate from yolk sac into developing embryo, proliferation occurs Colonisation: PGCs enter gonads at 6-8 weeks of gestation