Reproductive Anatomy and Physiology Flashcards
T or F
The reproductive system is not essential for survival of an individual
T
The reproductive system has what two functions?
- Gametogenic function
- Support germ cells - Endocrine Function
- Secrete hormones
What are the three types of sex determination?
- Genetic sex (XX vs XY)
- Gonadal sex (ovaries vs testes)
- Phenotypic Sex (Feminine vs masculine)
Does the Y or X chromosome have the SRY gene?
Y
T or F
Females and males both develop the same type of gonad initially
T
Referred to as the indifferent gonad
What is meant by the phrase “female is the default”
A fetus will be female unless intervened by an SRY protein
What happens if the SRY protein on a Y chromosome isn’t produced at the right time?
The fetus will be a female with XY genetic sex.
The bipotential/indifferent gonad has what two ducts?
The Mullerian and Wolffian duct
If an SRY protein is present, what 3 hormones will be produced by the indifferent gonad to commence change to a male gonad?
- Anti-mullerian hormone (AMH)
- Testosterone
- Insl3 (cause testes to drop later in development)
If no SRY protein presents itself to the indifferent gonad, what changes will occur?
No male hormones (AMH, testosterone and Insl3) will be produced causing the wolffian duct dissapear. The mullerian duct will develop and form the cervix, uterus and oviduct.
If an SRI protein presents itself and the appropriate hormones are produced what changes will occur to the indifferent gonad?
The mullerian duct will disapear and the wolffian duct will develop and go onto form the epididymis, vas deferens and seminal vesicle.
T or F
The testes produce spermatozoa almost without limit
T
What is gametogenesis?
The process whereby diploid precursor cells undergo meiotic division to become haploid gametes (spermatozoa or ova)
What are the scientific terms for sperm and egg cells?
spermatozoa and ova
How many sperm cells does an adult male produce per second?
1500
What is an oocyte?
An immature ovum
T or F
Like spermatozoa’s, ovum don’t take much energy to make
F
They take a lot of energy to make
What does haploid mean?
A sperm and egg are both haploids (meaning they both carry one chromosome)
When a sperm and egg combine they form a single diploid cell called a…
zygote
What happens during meiosis stage 2?
Separation of sister chromatids
What happens during meiosis stage 1?
Separation of homologous chromosomes
What is the result of meiosis?
4 haploid cells
Which sex has stem cells as a part of their reproductive system?
Males
T or F
Before birth germ cells are not present in the testes
F
After the birth of a male, germ cells migrate to the … of the …. and become …
periphery
seminiferous tubules
spermatogonia
What happens when a stem cell divides? (in the male reproductive system)
One of the offspring differentiates into a primary spermatocyte while the other replaces the stem cell
(regarding males)
Meiosis is triggered by an increase in … during puberty
testosterone
Sperm are made within the ….
seminiferous tubules
What is the non-germ cell that’s located in the testes called?
Sertoli (nurse) cell
What cells produce testosterone in the male reproductive system?
Leydig/Interstitial cells
What is an acrosome?
An organelle that forms during spermiogenesis it contains enzymes that help the sperm penetrate the coating on the egg
What is spermiogenesis?
The differentiation of a spermatid into a spermatozoon. This process is completed in approximately 24 days.
T or F
Sperm have no organelles
F
They have an acrosome which is an organelle
What organelle is present in a sperm tail?
Mitochondria
T or F
Sperm are highly differentiated cells
T
What effect does follicular-stimulating-hormone have on the testes?
It stimulates Sertoli cells which then trigger the onset of spermatogenesis
What effect does luteinising hormone have on the testes?
It stimulates interstitial/leydig cells to make and release testosterone into the testes and the blood
At the commencement of puberty the hypothalamus secretes … which causes the …. to secrete FSH and LH
GnRn
anterior pituitary
T or F
Hormones control sperm production in a positive feedback system
F
negative
T or F
When spermatids leave the testes they are not yet capable of fertilising an ova
T
The male reproductive tract matures, nourishes, stores and transports sperm
Sperm are stored in the … prior to ejaculation
cauda epididymus
What role do stereocilia play in reproduction?
Stereocilia increase the surface area of the epididymus which increases how much luminal fluid can be absorbed
How long is the total transit time for sperm?
10-15 days
How is sperm transport achieved?
By rhythmic peristaltic contraction of smooth muscle layers (especially strong at the caudia)
How long is the vas deferens?
40-45cm long
How long can sperm be stored for?
up to 7 months
What 3 glands produce 95% of semen volume?
- Seminal glands (pair)
- Prostate gland
- Bulbourethral glands
Which gland/s of the male reproductive system secretes fructose which provides energy to the mitochondria in sperm tails?
The seminal glands
Where are the seminal glands located?
Located on the posterior side of the bladder
How long are the seminal glands?
15cm
During which part of the male reproductive tract do sperm flagella become mobile?
After contact with the seminal glands
Prostate fluid contains …, a protein with … properties that may help prevent urinary tract infections in males
seminalplasmin
antibiotic
The … gland contains a compound that coagulates sperm to help…
prostate
retain it in the female reproductive tract
Where are the bulbourethral glands located and what function do they perform?
Paired glands at the base of the penis, round and about 1cm in diameter.
They secrete thick alkaline mucous to neutralise any urinary acid that may remain in the urethra
What does non-obstructive azoospermia mean?
Male infertility because sperm are not produced
What does obstructive azoospermia mean?
Male infertility due to sperm not being able to exit the body
Why are the majority of men with cystic fibrosis infertile?
Mucus builds up prevent proper formation of the vas deferens.
What is cryptorchidism?
Testes fail to descend into the scrotum during the 7th month of pregnancy. Relatively common (4% of male births). More likely to have testicular cancer later in life.
What is hyperspadias?
A malformed penis wherein the urethra is not at the tip
What is testes germ cell cancer?
The most common cancer in young males - germ cells in the fetal testes do not develop properly and reactivate at puberty to form tumors
What is primary hypogonadism?
Low serum testosterone levels and high serum FSH and LH lvls
Sperm are … times smaller than an oocyte
10 000
T or F
An oocyte is the largest cell in the human body
T
(0.12 mm)
What is meant by the term “ovarian reserve”
The number of oocytes a female has at birth is called an ovarian reserve
One primary spermatocyte makes … haploid sperm
4
(regarding spermatogenesis)
The first meiotic division produces … secondary spermatocytes whilst the second meiotic division produces … haploid spermatids
2
4
Oogenesis begins during fetal life but then arrests in … of the first
meiotic division
prophase
…. triggers the onset of meiosis in all oogonia
Retinoic acid (RA)
At puberty, every month … triggers several
primary oocytes to finish the first meiotic division
LH
T or F
The division of primary oocytes is unequal
T
If a secondary oocyte is fertilized it completes … and a fertilized egg is
produced
meiosis II
T or F
From one primary oocyte, only one ovum is produced (other nuclei are in polar bodies and these degenerate)
T
By puberty a female has around … egg follicles left
300 000
By 37 years of age, how many egg follicles is a woman expected to have?
25 000
Why is early menopause/premature ovarian failure thought to happen?
If a woman has a lower ovarian reserve she is expected to start menopause earlier
At what age is a woman in “optimal fertility”?
30
What is atresia?
The degeneration of those ovarian follicles which do not ovulate during the menstrual cycle.
Ovarian follicles are specialised structures found in the … of the ovaries
cortex
T or F
Folliculogenesis is not continuous
F
What main follicle type is present in the ovary?
primordial follicles
Primordial follicles are surrounded by a thin layer of …
granulosa cells
What is the female version of a ledwig cell?
a theca cell
Name the stages of folliculogenesis
Primordial follicle
Primary follicle
Secondary follicle
Tertiary follicle
Ovulating follicle
Corpus luteum
After a girl hits puberty granulosa cells present on her follicles will transition from … to … and proliferate
flat
cuboidal
What differentiates a secondary follicle from a primary follicle?
In secondary follicles there is a layer of theca cells. The
oocyte secretes a zona pellucida membrane (critical for fertilization) Fluid builds up surrounding the oocyte.
What is a follicular antrum?
The follicular antrum is the portion of an ovarian follicle filled with follicular fluid.
A tertiary follicle is also known as a…
Graafian follicle
The one tertiary follicle that does not die will continue to grow and develop until ovulation, when it will expel its ….
secondary oocyte
After an oocyte is released, the
remaining follicle cells develop into
the ….
corpus luteum
About 12 days
later, if there has been no
fertilization, the corpus luteum degenerates to a ….
corpus albicans (scar tissue)
During the Follicular phase, … builds up in the
follicles and this feeds back to the … to induce
… which instructs the
anterior pituitary to release a surge of …
estrogen
hypothalamus
GnRH
LH
LH is important for what 3 main things?
1) the oocyte to resume
meiosis (primary oocyte
becomes secondary oocyte)
2) triggers ovulation
3) Stimulates formation of CL
During the … phase, the corpus luteum produces
… which prepares the uterus for pregnancy (just in
case fertilization has occurred)
Luteal
progesterone
T or F
Most feedback to the hypothalamus and anterior pituitary is negative.
T
tertiary follicles secrete very high levels of … – this stimulates a fresh burst of GnRH and LH, triggering
…
Estrogen
ovulation
Progesterone, made by the …, stimulates growth of the … lining of the uterus (in preparation for pregnancy) and feeds back to … GnRH production by the hypothalamus and
LH and FSH production by the anterior pituitary
corpus luteum
endometrial
block
What are the 3 phases of the uterine cycle?
- menstrual phase (during follicular phase of ovarian cycle)
- proliferative phase (during follicular phase of ovarian cycle)
- secretory phase (during luteal phase of ovarian cycle)
Just prior to ovulation, a surge of … triggers the
resumption of meiosis in a primary oocyte.
luteinising hormone (LH)
Meiosis of a secondary oocyte is completed only if…
a sperm succeeds in
penetrating its barriers.
What causes the uterine endometrium to shed during the menstrual phase?
Arteries that feed the endometrium are
constricted and therefore the tissue of the
functional zone is deprived of oxygen and
nutrients
In menstruation only the … zone is affected because the deeper … zone still receives blood
through unconstricted arteries
functional
basilar
In the days following menstruation, … cells of the uterine glands multiply and spread across the endometrial surface, restoring the uterine …
epithelial
epithelium
Proliferative phase restoration takes place at the same time as the
… and … follicles enlarge in the ovary
primary and secondary
… secreted by the developing ovarian
follicles stimulates and sustains the proliferative
phase.
Estrogen
By the time ovulation occurs the functional zone is … mm thick and has reformed glands that
begin to secrete …., important for the survival of a fertilized ovum.
several
glycogen-rich mucus
… phase begins at ovulation and
continues while the corpus luteum remains
intact
Secretory
The secretory phase lasts about … days and ends
with …
14
menstruation
T or F
The ovarian and uterine cycles must operate in synchrony
T
Basal body temperature is about 0.3 degrees C lower during … phase.
follicular
The released secondary oocyte is caught by the … at the end of the Fallopian tube.
fimbriae
Fertilization usually occurs in the first 1/… of the fallopian tube.
3rd
T or F
During cleavage, the cells divide without an increase in mass
T
Implantation occurs when the … makes contact with the wall of the uterus and invades the uterus endometrium
zygote
Only about
… to …% of zygotes successfully implant
50 – 75
Maternal recognition of pregnancy is due to which hormone?
hCG = human chorionic gonadotrophin
HCG is produced about … days post-conception by cells surrounding the implanting embryo
6-7
The extreme muscular work of labour and delivery are the result of a … feedback system
positive
Toward the end of gestation, the number of oxytocin receptors in the uterus increases up to … fold
200
