REPRODUCTIVE SYSTEM Flashcards
What is the function of the uterus
to nurture the ovum as it develops into a fetus
What is the function of the ovaries
produce reproductive hormones an oocytes
What is the function of the cervix
allow flow of blood from uterus, directs sperm into uterus
What is the function of the prostate
create prostate fluid for semen, muscle propel sperm in ejaculation
What is the function of the corpus spongiosum
contains spongy erectile tissue for erection
What is the function of the testes
produce sperm and reproductive hormones
What is the function of the ejaculatory duct
connects ductus deferent to the urethra as a passage for semen ejaculation
What is the function of the corpus cavernosum
prevents urethra from pinching shut during an erection
Explain the transport of sperm through the testes and epididymis
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
What are the reasons behind the testes being outside of the body
Optimal temperature for spermatogenesis is 34ºC. Being outside of body lower temperature from body 37ºC.
How is the testes thermogenesis controlled
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.
What is the spermatic cord
Thick walled tube from epididymis passing through abdominal body wall (inguinal canal).
Contains muscle and fascial layers, testicular artery and vein and ductus deferens.
What are the accessory organs of the male reproductive system
Seminal vesicles
Prostate gland
Bulbourethral glands
Urethra
Explain the seminal vesicles and prostate gland
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)
Explain the bulbourethral glands and the urethra
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
What is the penis
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
What are the sexual functions of the Penis
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.
What are the functions of Sertoli cells
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
What is the syncytium
Cytoplasmic bridge between sperm to share products of X and Y genes
How does a prostate cancer test work
Pca is a substance produced in the prostate. If a tumour occurs pca is found in the bloodstream
Outline the steps of spermatogenesis
Spermatogonium
Primary spermatocyte
FIRST MEIOTIC DIVISION
Two secondary spermatocytes
SECOND MEIOTIC DIVISION
4 spermatids
SPERMIOGENESIS
4 spermatozoa
Outline female external genitalia
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.
Outline the female internal accessory organs
Fallopian tubes: Project from uterus with infundibulum at distal end.
Uterus: Muscular organ. Fundus = body, Cervix = opening
Linings: Perimetrium, myometrium, endometrium
What are the body targets of estrogen
Brain: maintanence of body temp and memory
Heart/liver: cholesterol production
Bone: Preserves bone density
Breast/uterus/ovaries: Stimulates maturation and menstrual cycle
Outline the steps of oogenesis
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
What are the similarities between spermatogenesis and oogenesis
surrounded by support cells (sertoli/granulosa) & hormone producing cells (leydig/theca)
undergo maturation and meiosis
Produce haploid germ cells
What are the 3 principles sexual reproduction is governed by
Behavioural: Social structures, seduction/dominance pre and post copulation
Physical: external physical attributes as reproductive signals
Morphological: shape of penis, copulatory movement
Explain the reasoning behind having many sexual mates
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
What are 3 types of competition tactics seen in animals
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.
When is sperm count high
In species where females copulate with multiple males
What germ layer gives rise to the gonads, kidneys, reproductive and renal development
Mesoderm
Explain the bipotential reproductive system
SRY gene carried on the Y chromosome causes production of testis if turned on.
What are some of the syndrome due to issues with sex determination
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.
What are the mullerian and wolffian tracts
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
Explain the steps of the primordial germ cell journey in mice
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
Explain the steps of the primordial germ cell journey in humans
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
