Reproductive system Flashcards
Where are gametes produced?
Gonads
- Male = testes
- Female = ovaries
Pelvis location & structure
- Where is the pelvis located?
- What makes up the pelvis?
- What are the bones of the pelvis?
- What are the joints of the pelvis?
- Bony basin b/w lower limb & the trunk
- Hip bones + sacrum + coccyx
- ilium
- ischium
- sacrum
- coccyx
- pubis
- Sacroiliac joint
- Pubic symphysis (can widen)
Pelvic Inlet & outlet (holes)
- Which is open and which is closed by muscles?
- Which is bigger?
- Inlet is open, outlet is closed by muscles
- Inlet always bigger than outlet
What are the pelvic subdivisions?
- False/greater pelvis
- True/lesser pelvis
Features of the pelvic subdivisions
- Which is superior region?
- Which is inferior region
- Where is the false/greater pelvis located?
- Where is the true/lesser pelvis located?
- Which contains the GI tract?
- Which contains the reproductive organs?
True/lesser
- inferior region
- b/w inlet & outlet
- contains reproductive organs
False/greater
- superior region
- situated above pelvic inlet
- contains GI tract
Female vs Male pelvis
- Subpubic angle?
- Inlet shape?
- Coccyx shape?
Female
- Broader subpubic angle
- Oval inlet
- Straighter coccyx
Male
- Narrower subpubic angle
- Heart-shaped inlet
- Curved coccyx
- What closes over the pelvic outlet?
- What are the muscles involved?
- What are the openings in the pelvic floor?
- Pelvic floor
- Levator ani & cocygeus
- Urethra
- Anal canal
- Vagina (females)
Perineum
- What does it contain?
- What are the two triangle divisions?
- External genitalia & anus
- Anterior: urogenital triangle
- Posterior: anal canal & fat
Male reproductive tract
- What path is it?
- What does it include?
- Path that sperm travel along
- Testes
- Epididymis
- Ductus (vas) deferens
- Ejaculatory duct
- Urethra
What is makes up the scrotum?
- 2 testes
- 2 spermatic cord
Testes
- What do the produce?
- What are they surrounded by?
- Sperm
- Testosterone
- Inhibin
- Dense fibrous capsule - tunica albginea
Seminiferous tubules
- Where are they found?
- What do they join to form?
- Contained in the lobules of the testes
- Join to form rete testes; which
- Join to form ductules leading to epididymis
What are the cells of the seminiferous tubules?
- Leydig cells: testosterone
- Sertoli cells: inhibin
- Spermatogenic cells: spermatozoa
Epididymis
- What is it made up of?
- Whare does the sperm enter & leave?
- Head, body & tail
- Enters from seminiferous tubules
- Exits via ductus deferens
Ductus Deferens (‘vas deferens’)
- What is it in?
- What is covered by?
- What does run behind?
- What does it dilate to form?
- In spermatic cord
- Covered by smooth muscle
- Runs behind bladder
- Dilates to form the ampulla
The spermatic cord
- How many?
- Where does it run?
- What does it contain?
- One on each side
- Runs b/w abdomen & testes
Contains
- Ductus deferens
- Blood vessels (testicular arteries & veins)
- Nerves
- Lymphatics
Ejaculatory ducts
- What are they formed by?
- Where does i t open?
- Formed by the union of the duct from the seminal vesicle & the ampulla
- Opens in the prostatic urethra
Urinary/ urethral sphincters
- External
- Internal
External
- Skeletal muscle, voluntary control of urination
Internal
- Detrusor muscle - closes bladder thus ensures sperm ejaculated through the urethra; retrograde ejaculation - sphincter doesn’t close, therefore ends up in bladder
What is the path of sperm?
Testes (manufactured) → epididymis → ductus deferens → ejaculatory duct → urethra
The Penis
- What is the Dual function?
- What makes up the cylindrical organ?
- What are the 3 cylindrical erectile tissues?
- What are their features?
- Urination
- Copulation
- Root (bulb)
- Body
- Glans, covered by prepuce/foreskin
→ 2 corpora cavernosa - main erectile tissue - dorsal aspect → 1 corpus spongiosum - contains urethra - forms bulb & glans - ventral aspect
The scrotum
- Where does it house the testes? And why?
- Which muscle is it lined by?
- Which muscle contracts? And why?
- Houses testes away from the body to maintain temp @ ~34 °C
- Lined by dartos muscle
- Cremator muscle - contracts for heat conservation (thermoregulation)
Accessory glands
- What do they produce?
- What are the 3 glands associated w/ male RS
- Produce most seminal fluid (composition, volume)
- Seminal vesicles
- Prostate gland
- Bulbourethral glands
Seminal vesicles
- How many?
- Location?
- What does it merge with and become?
- What does it produce?
- What does it contain?
- What does alkaline pH protect?
- 2
- Posterior to bladder, lateral to ampulla of ductus deferens
- Merges w/ ampulla to form ejaculatory duct
→ Produce viscous secretion
- 60% of semen
- Contain fructose & other nutrients to nourish sperm
- Alkaline pH protects sperm against acidic environment in urethra & vagina
Prostate gland
- Location?
- What does it produce?
- pH? Why?
- What does it contain
- What is contribute to?
- Inferior to bladder, wraps around prostatic urethra
→ Produces secretion
- 30% of semen
- Slightly acidic, milky fluid containing enzymes & PSA (prostate specific antigen)
- Contains citrate to nourish sperm
- Contributes to sperm activation, viability & motility
Bulbourethral glands
- How many?
- Location?
- What does it open into?
- How much does it contribute to semen vol.
- What do the secretions do?
- 2 glands
- Located in the urogenital diaphragm
- Open into spongy/penile urethra
- Contributes to 5% of semen vol.
- Secretions lubricate & neutralise acidity in urethra prior to ejaculation
Vasectomy
- What is it?
- Contraception; cut/tie ductus deferens
- Doesnt change seminal fluid vol.; bc accessory glands still functioning
- What is Gametogenesis?
- Males?
- Females?
- What type of control is it?
- How does it occur?
- Formation of the sex cells
- Males: spermatogenesis
- Females: oogenesis
- Under hormonal control
- Occurs via meiosis
- What is spermatogenesis?
- What type of cell division occurs?
- What are the 3 main stages of this cell division?
- Cell type
- Number of chromosomes
- Spermatogonia → mature spermatozoa (sperm)
- Occurs via meiosis
- Process:
1. Primary spermatocyte (diploid: 2n = 46)
Meiosis I
2. Secondary spermatocyte (n = 23)
Meiosis II
3. Spermatid/spermatozoa (haploid: n = 23)
Spermatogenesis during development
Spermatogonia migrate from yolk sac to testes & remain dormant until puberty
Spermatogenesis during puberty
- What does spermatogonia divide by?
- What does type B spermatogonia differentiate into?
What does it undergo to do this? - What is formed after this step?
- What do these undergo next?
- What do spermatids differentiate into?
- Where are spermatozoa released?
- How many spermatozoa are formed from 1 type B spermatogium?
- Spermatogonia divide by mitosis into type A&B spermatogonia (diploid - 46 chrom.)
- Type B spermatogonia differentiate into 1* sex cell/ 1* spermatocyte (diploid) which undergoes meiosis I
- Forms 2* spermatocytes (haploid)
- These undergo meiosis II to form spermatids (haploid)
- Spermatids differentiate into spermatozoa w/ a head, body & tail via spermiogenesis
- Spermatozoa released into lumen
- 1 type B spermatogium forms 4 spermatozoa
- How often does spermatogenesis take place?
- Where does sperm develop mobility?
- Where does sperm mature?
- Spermatogenesis takes place continuously daily after puberty
- Sperm develop mobility in epididymis
- Sperm mature in the epididymis
What is spermiogenesis?
Spermatid → Spermatozoon (change shape)
What is the spermiogenesis process?
1) Appearance of acromosomal vesicle & flagellum in spermatid
2) Growth of acrosome & flagellum
3) Shedding of excess cytoplasm (more streamline)
4) Mature sperm
- What hormone acts on the gonads?
- What is GnRH & where is it released from?
- What is LH & where is it released from?
- What is FSH & where is it released from?
- gonadotropin
- GnRH - gonadotropin releasing hormone
- released from hypothalamus (released in pulsatile fashion)
- LH - Luteinising hormone (a gonadotropin)
- from anterior pituitary
- FSH - Follicle stimulating hormone (a gonadotropin)
- from anterior pituitary
What are the reproductive hormones?
1) GnRH - gonadotropin releasing hormone
2) LH - Luteinising hormone (a gonadotropin)
3) FSH - Follicle stimulating hormone (a gonadotropin)
- What are the hormones in males?
- Where are they from?
Inhibin
- from sertoli cells
Testosterone
- from leydig cells
- Androgen
What is androgen?
- Hormones which develop male characteristics (eg gonads → testes; spermatogenesis, aggression & libido)
- Synthetic androgens (steroids) - therapeutic purposes
Endocrine controls of the testes
- What does LH stimulate the production of?
- What controls spermatogenesis?
- What does inhibin inhibit?
- What does the negative feedback of testosterine suppress?
- LH stimulates the production of testosterone
- FSH & testosterone control spermatogenesis
- Inhibin inhibits FSH
- Negative feedback of testosterone suppresses LH & GnRH
Oogenesis
- What is it the formation of?
- What does it require?
- When is it initiated? and when does it continue?
- Where do oocytes develop?
- Formation & development of the oocyte from oogonia
- Requires mitosis & meiosis
- Initiated before birth, continues b/w puberty & menopause
- Oocytes develop w/in ovarian follicles (one per follicle)
Generating the ovum - before birth
1) Oogonium (diploid) migrate to developing gonad
2) Population of oogonia ↑ by mitosis
3) Oogonia differentiate to form 1* oocytes (diploid)
- Encased in primordial follicle
- Many 1* oocytes undergo cell death (atresia)
4) 1* oocytes start meiosis
- Halts at prophase 1 until puberty begins
Generating the ovum - from menarche till menopause
1) Under GnRH influence, small number of follicles recruited each ovarian/mestrual cycle
2) Only one oocyte will complete development & ovulate
3) 1* oocyte completes meiosis I
- forms a 2* oocyte & first polar body (both haploid)
4) 2* oocyte starts meiosis II
- Halts at metaphase II until fertilisation
5) Meiosis II resumes when the sperm penetrates plasma membrane of the ovum at fertilisation
- If not fertilised, will die (atresia)
Oogenesis w/in developing follicle
- What develops in the developing follicle?
- Are follicles multilayered?
- What are the cells of the developing follicle?
- During ovulation what is released into the peritoneal cavity?
- Oocyte develops w/in developing follicle
- Follicles are multilayered
- Granulosa cells - produce estradiol
- Theca cells
- Ovulation: oocyte & corona radiata released into peritoneal cavity
Hypothalamus Hormones
- What is found and released in the hypothalamus?
- What does this stimulate?
- GnRH (gonadotropin releasing hormone)
- Release of FSH & LH
What are the Anterior Pituitary Hormones?
- FSH (follicle stimulating hormone)
- LH (luteinising hormone)
- Prolactin