35 Flashcards
What prevents sperm ending up in the bladder during ejaculation?
Internal urethra
There are three regions of the epididymis. What are they known as?
Head body tail
What hormone do interstitial endocrine (Leydig) cells produce?
1. Inhibin
2. Testosterone
3. Both inhibin and testosterone.
4. Interstitial endocrine (Leydig) cells do not produce hormones
Testosterone
Where would you find a spermatogonia?
Semiferus tubule - found adjacent to the basement membrane
The scrotum contains….
- two testes (lined with thin facia)
- two epididymis
- two spermatic cords (with part of ductus deferens)
Why Dey on the outside?
To prevent them from over heating
Where does the scripture house the testers ? Why?
Away from the body to maintain temp at ~34 decrees
Why does the scrotum house testes away from the body
To maintain temp at around 34 degrees celcieus
Srutem is lined by the _____ muscle
Dartos
What dies the dartos muscle do? I DONT UNDERSTADN?
Pulls muscle tight to decrease the surface area and wrinkle the skin to keep warm when cold
What does the cremaster muscle do?
Contracts for heat conservation - pulls closer to body
How many spermatic cords?
2 - One in each teste
What does the spermatic cord contain
• ductus deferens
• blood vessels - testicular arteries and veins
• nerves
• lymphatics
Venous plexus or pampiniform plexus
Allows for …
Counter exchange of heat between arteries and veins
Dual function of the penis
- urination
- copulation
The penis is a _____ shaped organ and contains:
• Root (bulb)
• Body
• Glans covered by
prepuce/foreskin
The 3 cylindrical erectile tissues
Two corpora cavernosa (corpus cavernosum)
• Main erectile tissue
• Dorsal aspect
One corpus spongiosum
• Contains urethra
• Forms bulb and glans
• Ventral aspect
Corpus spongiosum is also erectile but not to the same extent, cos you dont want them to be blocked as they are the channel of the sperm
The _______ houses the testes ________ the body to maintain
temperature at ___________ °C.
The scotrum houses the testes outside the body to maintain
temperature at 34 °C.
The dartos and cremaster muscles are involved in
___________ regulation.
Temperature
What does the spermatic cords contain?
- ductus deferens and the testicular artery, Venus plexus and the lymphatic vessels and nerves that supple the testes
• The penis contains erectile tissues known as the corpora
___________ and the corpus ___________.
Corpora cavernosa and the corpus spongenosum
Accessory glands
What are spermatozoa carried to the female reporoductive tract in?
Seminal fluid
What is spermatazoa mixed with seminal fluid called?
semen
Seminal fluid is mostly produced by three types of accessory glands - what are these glands called?
• Seminal vesicles
• Prostate gland
• Bulbourethral glands
What is seminal fluid needed for?
- sperm activated by seminal fluid
- transport
- protection from acidic vagina
How many seminal vesicles are there?
Two
Where are the two seminal vesicles located?
- posterior to the bladder
- lateral to the ampulla
Seminal vesicles produce ____ secretion
Viscous
What percent of semen is made up from seminal vesicles secretion
60%
How does the viscous seminal vesicle secretion protect sperm?
• Alkaline pH protects sperm against acidic environment in urethra and vagina
Location of the prostate gland
- inferior to bladder
- wraps around prostatic urethra
What percent of semen is made up of prostate gland secretions
30%
Characteristic of prostrate gland secretions
• Slightly acidic, milky fluid
• Contains PSA: prostate-specific antigen
• Contributes to sperm activation, viability and motility
How many bulbourathral glands and where are they located
Two glands located in the urogenital diaphragm
Where do the bulbourethral glands open into?
Open into spongy/penile urethra
What percent of semen does the bulbourethral glands conrobute to semen volume
5%
What do the bulbourethral glands secretions do?
• Secretions lubricate and neutralise acidity in urethra prior to ejaculation
Components of semen
• ~60% from seminal vesicles
• ~30% from prostate
• ~5% from bulbourethral glands
- last 5% is spermatazoa
What is a vasectomy? What gets cut?
• Surgical method of sterilisation in males
• Cut the ductus deferens (cut ends tied or cauterised)
- volume of semen will decrease but doesn’t change the seminal fluid volume
Gametogenesis - what is it?
• Formation of the gametes (sex cells)
Gametogenesis in males
• Spermatogenesis
Gametogenesis in females
• Oogenesis
Gametogenesis is under ____ control
Hormonal
How does Gametogenesis occur?
via mitosis and meiosis
• Cells need to be haploid (23 chromosomes)
A very brief overview of Meiosis
• Original cell has 46 chromosomes (diploid/2n)
• Two cycles of cell division to produce gametes (23 chromosomes = haploid/n)
Meiosis 1:
–2 haploid cells produced from 1 original diploid cell
Meiosis 2:
- each cell produced from meiosis 1 devides to produce two haploid cells with 23 chromosome cells
What is Spermatogenesis
• Formation of the male gamete
• The process by which spermatogonia are transformed to mature spermatozoa (sperm)
When does Spermatogenesis occur?
• Occurs continuously from puberty onwards
Where does Spermatogenesis occur?
• Occurs in the seminiferous tubules
Process of Spermatogenesis
• Spermatogonia divide by mitosis into 2 daughter cells (diploid - 46 chromosomes)
• One spermatogonium (type A) stays at the basement membrane of the seminiferous tubule
• The second spermatogonia (type B) differentiates into a
primary spermatocyte (diploid), which undergoes meiosis I
• Forms 2 secondary spermatocytes (haploid - 23 chromosomes)
• These undergo meiosis II to form spermatids (haploid)
• Spermatids differentiate into spermatozoa with a head, body and tail via spermiogenesis
• Spermatozoa released into lumen
Spermatid → Spermatozoon
- on top of the nucleaus you get the formation of an acrosome
- bag of enzymes
- important for fertilisation
- you get formation of the flagellum, head and tail
- lots of mitochondria form then sit around the mid piece
- gets rid of cytoplasm and tissue they dont need
- can’t swim
YAP
Reproductive Hormones - FEMALE AND MALE
GnRH stimulates the release of two gonadotropin hormones
Hormones in males
Where is Inhibin from
• from nurse (Sertoli) cells
Gonadotropin =
Gonadotropin = hormone that acts on the gonads
Testosterone is produced by?
Interstitial endocrine cells
Testosterone is a type of_____
Androgen
What are androgens
- group of steroid hormones
What is the androgen group responsible for?
Male characteristics (maturation of sex organs, spermatogenesis, secondary sex characteristics, libido)
- synthetic androgens (steroids) have therapeutic purposes
Negative feed back loop - male - yappage edition
- production of GnRH in the hypothalamus
- this is then transported to the anterior pituitary
- this results in the production of LH and FSH (two ganototrpins)
- LH acts on interstitial endocrine cells and stimulates the production of testosterone
- FSH acts on the nurse cells and stimulates inhibin production
- inhibit and testosterone both act to regulate spermatogeneiis
- inhibin and testosterone as well as acting locally, they enter the systemic blood stream and are important for negative feedback
- inhibin provides negative feedback up to the anterior pituitary gland
- testosterone provides negative feed back up to the hypothalamus AND the putitartey gland
- slow down and speed up regulation not stop and start
Male Negative feedback loop
• LH stimulates production of testosterone (interstitial endocrine [Leydig] cells)
• FSH and testosterone control spermatogenesis & FSH
• FSH stimulates Inhibin production (nurse [Sertoli] cells)
Negative feedback:
• Inhibin suppresses FSH
• Testosterone suppresses LH & GnRH
Spermatogenesis is the formation of ___________ from
spermatogonia.
Sperm
Spermatogenesis Requires both mitosis and ___________.
Meiosis
Spermiogenesis is the maturaton of ___________ into
spermatozoa (head, midpiece, tail).
Spermatogonia
Spermatogenesis is regulated by a negative feedback loop
with hormones produced by the hypothalamus and anterior
___________, and the interstitial endocrine and ___________
cells in the testes.
Idk
