Flashcards in Repro - 1 Deck (68):
What suspends the testis in the scrotum?
Where is the testis not covered by the visceral layer of the tunica vaginalis?
Where it attaches to the epididymis and spermatic cord.
What lies adjacent superficially to the parietal layer of the tunica vaginalis?
Internal spermatic fascia
What is the tough, fibrous outer surface, deep to the visceral layer of the tunica vaginalis, of the testis called?
The tunica albuginea thickens on its posterior aspect into a ridge. What is this ridge called?
Mediastinum of the testis
What is found in the mediastinum of the testis?
Rete testis = a network of canals
What extends inwards into the testis from the mediastinum of the testis?
Fibrous septums which create lobules full of long and highly coiled semifierous tubules.
What joins the seminiferous tubules to the rete testis?
Where are sertoli cells found? What is their role?
They are associated with the seminiferous tubules and are involved in spermatogenesis.
Where are Leydig cells found? What is their role?
They are cells found in the interstitial tissue, which secrete testosterone.
What separates the tubules from the surrounding interstitial tissue?
Blood testis barrier
What are the germ stem cells of males called?
What is the spermatogenic cycle?
The development of A1 spermatogonia through to 256 sperms. The amount of time it taker for reappearance of the same stage of the cycle within a given segment of tube.
What is the spermatogenic wave?
Different parts of the tube begin the spermatogenic cycle at different times, in a 'wave', so the production of sperm is constant. The distance on the tube between parts that are in the same stage is the spermatogenic wave.
What is the role of the rete testis?
A network of canals in the mediastinum of the testis that seminiferous tubules drain into.
What is the role of the epididymis?
A convuluted duct, in which sperm are stored and continue to mature.
What is the role of the vas deferens?
A continuation of the epididymis, the vas deferens has relatively thick muscular walls and a minute lumen. During copulation these muscular walls contract, forcing sperm along the tube to be mixed with other components of the ejaculate.
What is the role of the seminal vesicles?
They secrete a thick, alkaline fluid that is rich in fructose (energy source for the sperms), amino acids, citrate, prostaglandins and a coagulating agent. This fluid makes up ~60% of the volume of the semen.
What is the role of the prostate?
Prostatic fluid makes up ~20% of the volume of semen, and plays a role in activating sperm. It contains proteolytic enzymes and zinc.
What is the role of the bulbourethral glands?
Their mucus-like secretion enters the urethra during sexual arousal. Help lubricate and neutralise acidic urine in distal urethra (
Where do the bulbourethral glands lie?
They are two pea-sized glands which lie posterolateral to the membranous part of the urethra, largely embedded within the external urethral sphincter. The ducts open into the proximal part of the spongy urethra of the bulb of the penis.
What is the name of the mesentery (short peritoneal fold) which suspends the ovaries?
What is the name of the ligament, within the mesovarium, that tethers the ovary to the uterus?
What is the ovarian ligament an embryological remenant of?
The superior part of the ovarian gubernaculum.
What is the name of the connective tissue capsule of the ovary?
Tunica albuginea of the ovary
What covers the tunica albuginea of the ovary? What happens to this layer after puberty?
The smooth layer of the ovarian mesothelium. This has a dull, grayish appearance which becomes progressively scarred and distorted because of the repeated rupture of ovarian follicles and discharge of oocytes during ovulation.
The fallopian tubes conduct oocytes between which cavities?
Periovarian peritoneal cavity to the uterine cavity.
What is another name for mesonephric cells?
What causes the arrest of oocytes at diplotene (a stage of prophase) in meiosis I?
Oocyte maturation inhibitor (OMI) secreted by the follicular cells.
Why is there an increased risk of foetal chromosomal abnormalities in pregnancies of older woman?
Their oocytes have been arrested since birth and therefore have had a longer length of time in which they can be damaged.
What are the three stage of follicle maturation to produce mature gametes?
1. Pre-antral (primordial follicle)
2. Antral (secondary follicle)
3. Pre-ovulatory follicle
What is the female vestibule?
The space posterior to the glans clitoridis and between the labia minora, containing the openings of the vagina, urethra, and ducts of the greater vestibular glands.
When does structural sexual development occur?
In utero from an indifferent stage where both males and females have the same gonad and duct system (two pairs of ducts).
When does functional sexual development occur?
Functional development and maturation occurs after birth. Babies are born immature and sexual maturation occurs at puberty when secondary sexual characteristics develop.
What region of mesoderm gives rise to the primordial gonads?
A region of intermediate mesoderm called the urogenital ridge - it also gives rise to the embryonic kidney.
Where do primordial germ cells arise from?
Where do primordial germ cells migrate once they have arisen shortly after fertilisation?
They migrate from the yolk sac, up the retroperitoneum, along the dorsal mesentery and into the indifferent gonads.
What genes drive development of the male gonad, internal genitalia (duct system) and external genitalia?
SRY (sex-determining region Y) genes.
What do all primordial germ cells in a male conceptus carry?
A Y chromosome.
What is the main factor that differentiates between the indifferent gonad developing into an ovary or testis?
Presence or absence of a Y chromosome.
Where do both the mesonephric and paramesonephric ducts end at?
What is the function of the mesonephric tubules and duct?
They form the embryological kidney
What is another name for the mesonephric duct?
What is the cloaca
A shared outlet into which the urinary and GI tracts open.
What is the urogenital sinus?
The ventral part of the cloaca once it has been divided off from the GI tract by the urorectal septum. It is continuous with the umbilicus.
What is the urachus?
The urachus (or median umbilical ligament) is a fibrous remnant of the allantois, a canal that drains the urinary bladder of the fetus that joins and runs within the umbilical cord. The
What is the difference between the male and female development of the mesonephric ducts and the ureteric buds?
In males the mesonephic ducts do not regress and both the ureteric buds and mesonephric ducts make independent opening into the urogenital sinus. Around the opening go the mesonephric duct the prostate and prostatic urethra develop. In females the mesonephric ducts regress and only the ureteric bud opens into the urogenital sinus. This results in the mixing of male urinary and reproductive systems but not the females.
How do the paramesonephric ducts first appear?
As invaginations of the epithelium of the urogenital ridge.
What do the paramesonephric ducts make contact with cranially and caudally?
Cranially - open into the abdominal cavity
Caudally - open into the cloaca (urogenital sinus)
Fusion of the paramesonephric ducts in females forms which structures?
Uterus, cervix and fornix
What does the sinovaginal bulb (a portion of the urogentiary sinus) develop into?
Vagina and hymen.
Why does the mesonephric duct regress in the female but not the male?
Androgen secretions support the mesonephric duct
Why does the Paramesonephric duct degenerate in males but not females?
The testis secretes Mullerian inhibiting substance which causes the degeneration.
What are the three basic components of the indifferent stage of external genitalia?
What happens to the basic components of the external genitalia in a male as it develops from the indifferent stage?
1. Genital tubercle elongates
2. Genital folds fuse to form the spongy urethra
3. Genital swellings fuse to form scrotum and scrotal raphe.
What happens to the basic components of the external genitalia in a femal as it develops from the indifferent stage?
No fusion occurs with the genital folds or swellings, therefore the urethra opens into the vestibule.
What causes the development of male external genitalia?
What is the gubernaculum attached to in females?
Attaches ovary to the labio-scrotal folds
What is the gubernaculum attached to in males?
Attaches testis to the labio-scrotal folds
What is the difference in the descent of the testis and ovaries?
The ovaries does not pass through the inguinal canal but the round ligament of the uterus remains in the inguinal canal. The testis passes through the inguinal canal.
What are some congenital defects of the reproductive tract?
1. Genotype-phenotype mismatches
2. Structural defects:
(i) Cloacal partitioning defects
(ii) Hypospadias - where urinary opening in males is not in the usual place at the head of the penis
(iii) Uterine structural defect - e.g. bicornuate uterus
How many sperm do males produce a day?
What three events in meiosis cause genetic variation?
2. Random segregation
3. Independent assortment
What is the difference between random segregation and independent assortment?
Independent assortment is when the two copies of each GENE are distributed to the germ cells independently of the distribution of other genes.
Random segregation is when each pair of a homologous CHROMOSOMES are sorted independently durring the 2nd division in meosis to each other pair.
What happens to the medullary cords in the male at puberty?
They hollow out and become the seminiferous tubules where sperms are produced.
What is the average length of a spermatogenic cycle in a human?
What is spermiogenesis?
The remodelling of spermatids as they pass down the seminiferous tubules, through the rete testis and ductuli efferentes and into the epididymis, to finally produce speramtozoa and therefore gain motility.