Reproductive System Flashcards
What are the male gonads?
Testes
What is the role of the testes?
To produce sperm and secrete hormones (including androgens, most importantly testosterone)
What are the main parts of the male reproductive system?
Testes, ducts, accessory glands, penis and scrotum
What is the role of the ducts in the male reproductive system?
To transport sperm (internally and externally) and to store sperm
What are the three accessory glands of the male reproductive system?
Seminal vesicles, bulbourethral glands, prostate gland
What is the role of the penis in the male reproductive system?
Delivering sperm to female reproductive tract
What is the role of the scrotum in the male reproductive system?
Support for testes and temperature regulation for optimal sperm production conditions
What temperature difference is typical between the abdominaopelvic cavity and the scrotum?
~3 degree celcius cooler than body temperature in the scrotum.
Where in the testes is sperm produced?
In the seminiferous tubules
Describe the anatomy within the testes.
Septa divide testes into 250-300 lobules, each containing 1-4 seminiferous tubues.
How does the spermatic cord regulate temperature?
Pampiniform plexus (veins and arteries are close together within the spermatic cord, arterial blood cooled by venous blood and vice versa.
What are the three types of cells found in the seminiferous tubules?
Sertoli, spermatogonia (stem cells), myoid cells
What is the role of the sertoli cells?
They provide nutrients and signals to the dividing cells, secrete testicular fluid, dispose of excess cytoplasm during spermiogenesis
What is the role of Leydig cells (aka interstitial endorcrine cells)?
They prompt spermatogenesis and produce androgens (most importantly testosterone)
Describe the process of spermatogenesis.
- Mitosis (spermatogonia -> spermatocytes @ puberty)
- Meiosis (spermatocytes -> spermatids)
- Spermiogenesis (spermatids lose excess cytoplasm and gain tail)
In the mitotic division of spermatogonia, what daughter cells are produced?
1 type A daughter cell (stem cells remaining at basal lamina) and 1 type B daughter cells (develops into primary spermatocyte)
Approximately how many sperm are produced daily in the average adult male?
~90+ million produced per day
What are some ways that the morphology of spermatogenesis can be adversely affected?
Environmental toxins, certain antibiotics, radiation, excess alcohol consumption, hormonal imbalances, thermo-related activities (hot spa, tight underwear keeping testis close to body)
What are the three main parts of a sperm cell?
Head (nucleus and acrosome containing enzymes)
Midpiece (metabolic)
Tail (locomotion)
Approximately how many days does it take from spermatogonium to sperm release?
~64-72 days
Approximately how many days does it take sperm to gain motility and mature in the epididymis?
~12+ days
Describe hormonal regulation in males via the HPG axis
Hypothalamus stimulates anterior pituitary to secrete FSH and LH. FSH produces cell products for spermatocytes. LH produces testosterone for sertoli cells. Negative feeback given back to anterior pituitary and hypothalamus.
What are the four main ducts in the male reproductive system?
- Epididymis (sperm gain motility and testicular fluid absorbed)
- Ductus (vas) deferens (epididymis -> urethra)
- Ejaculatory duct
- Urethra
What are the three main accessory glands in the male reproductive system?
- Seminal vesicles
- Prostate
- Bulbourethral (Cowper’s) Gland
What are the seminal vesicles responsible for in semen?
Produces viscous alakine seminal fluid (~70% of semen volume)
What is the prostate responsible for in semen?
Produces milky, slightly acidic fluid that plays a role in activating sperm (~30% of semen volume)
What is the bulbourethral gland responsible for?
Produces a thick, clear mucus prior to ejaculation that lubricates the glans penis and neutralises traces of urine (acidic) in the urethra
What are the three cylindrical bodies of erectile tissue in the penis?
Corpus spongiosum that surrounds the urethra and two corpora cavernosa
What is the difference between the corpus spongiosum and the corpora cavernosa?
The corpus spongiosum surrounds the urethra therefore it cannot be filled with as much blood to prevent compressing the urethra. The corpora cavernosa provides the ‘bulk’ of an erection
Why is semen slightly alkaline?
To counter the hostile female reproductive tract which is acidic
How does an erection retain blood?
Erectile tissue filling with blood compresses penile veins which results in engorgement
About how many sperm are there in a mL of ejaculate?
~20-150 million sperm/mL of ejaculate
What is the role of the ovaries?
Produce ova and secrete hormones
What hormones are secreted by the ovaries?
Progesterone, oestrogens, inhibin, relaxin
What are the accessory ducts of the female reproductive system?
Fallopian tubes (fertilisation)
Uterus (implantation/fetal development)
Vagina (birth canal and copulation organ)
What are the three types of ligaments found in the female reproductive system?
- Ovarian (anchors ovaries to the uterus)
- Suspensory (anchors ovaries to pelvic wall)
- Broad (supports uterus, uterine tubes and vagina)
What are the two sections of the ovary and what are they responsible for?
- Medulla - contains large BVs and nerves
2. Cortex - contains ovarian follicles in different stages of development, each follicle contains an oocyte
What is the role of the corpus luteum in the ovary?
It produces progesterone until the placenta takes over production in pregnancy
What is oogenesis?
The production of female gametes. Begins in the fetal period and each month after puberty a few primary oocytes are activated.
What are the four major sections of the fallopian tubes?
- Fimbriae - cilliated and moved ovum into fallopian tube
- Infundibulum - funnel shaped opening of fallopian tube
- Ampulla - wide section, usual site of fertilisation
- Isthmus - Narrow section of fallopian tube leading into uterus
As the oocyte has no motility, how is it propelled through the fallopian tube?
Peristalsis (smooth muscle contraction) and cilliary action
What are the four major parts of the uterus?
- Body - major part
- Fundus - rounded superior region
- Isthmus - narrowed inferior region
- Cervix - narrow neck projecting into vagina
Why do cervical glands secrete mucus?
To block sperm entry except during mid-cycle
What are the three layers of the uterine wall?
- Perimetrium - serous layer
- Myometrium - interlacing layers of smooth muscle
- Endometrium - mucosal lining with many glands
What are the two layers of the endometrium and what are their functions?
- Stratum functionalis (spiral arteries and the functional layer that sheds during menstration)
- Stratum basalis (straight arteries and the developing next functional layer)
What are mammary glands?
Modified sweat glands with between 15 to 25 lobes. Each lobule has glandular alveoli for milk production
How does milk travel through the mammary glands to the nipple?
Milk -> lactiferous ducts -> lactiferous sinuses -> nipple
What metabolic effect would you expect if someone developed an autoimmune disease in which the person’s interstitual cells were destroyed?
Testosterone production would plummet
What is the majr difference between spermatogenesis and oogenesis?
Oogenesis results in the formation of one viable oocyte
