module 9 Flashcards
what does the parasympathetic devision control in the penis
- blood vessels dilate
- Increased blood flow to penis
- Vascular channels become engorged with blood
- Erection of penis
what does the sympathetic nervous system control in the penis
ejaculation
what does the scrotum do
- houses the testies
- composed of the darts and cremaster muscele which maintain optimal temperature (34) for the production of sperm
whats the functions of the epididymis
- stores, nourishes and protects spermatozoa
- Facilitates functional maturation
- Recycles damaged sperm
- Ejaculates the sperm to vas deferens
the travel of sperm
Epididymis ductus/vas deferens Ejactulatory ducts Urethra (total 66 meters) Secretions are added the sperm by seminal vesicles, prostate
whats the ductus deferens
transport sperm from the epididymis to the ejaculatory duct.
whats the seminal vesicle
produces seminal fluid which makes up 60-70% of semen volume and contains substances that enhance sperm mobility and their ability to fertilise an ovum.
whats the ejaculatotry duct
transports sperm through the prostate gland to the urethra.
prostate gland
doughnut shaped gland, surrounded by urethra and produces 30% of semen volume
whats the bulbourethral glands
produces a thick mucous that lubicates the glans of the penis
whats the testes contain
interstitial cells which produce and secrete testostorne
seminiferous tubules which produce sperm
whats the process of production of sperm
Spermatogenesis
occurs in the seminiferous tables of the testse
Begins at approximately 14 years of age
Results in 400 million new sperm per day
Sperm take 10 weeks to make
Meiosis
Gametes contain 23 chromosomes (one of each pari)
whats the structure of sperm
Head: genetic region, nucleus and a vesicle containing enzymes that enable the sperm to penetrate an ovum
Midpiece: metabolic region, mitochondria= energy production
Tail: locomotor region, flagellum= movement
what does semen consist of
Epididymal secretions (fluid and sperm) 5%
Seminal vesicle secretions 60%
Prostate secretions 30%
Bulbourethral secretions 5%
whats the HPG hypothalamic pituitary gonadal axis steps
The hypothalamus releases gonadotropin-releasing hormone (GnRH)
GnRH signals the release of follicle stimulating hormone (FSH) and
luteinizing hormone (LH) from the anterior pituitary
FSH stimulates sustenocytes (Sertoli cells) in the seminiferous tubules to produce androgen-binding protein (ABP) which concentrates testosterone
LH stimulates interstitial (Leydig) cells in the seminiferous tubules to produce testosterone
Concentrated testosterone drives spermatogenesis
Increased testosterone levels negatively feed back to inhibit GnRH and FSH/LH release
Inhibin is also produced during spermatogenesis and has negative feedback effects on FSH and GnRH
what does testosterone do
stimulates spermatogenesis
Increases growth of reproductive glands and cuts
Increases size of penis
Enhances ability to maintain erection
Stimulates male secondary sex characteristics
whats male secondary sex characteristic include
Pubic, axillary and facial hair – Enhanced hair growth on chest and other areas – Deepening of voice – Increased skeletal and muscle mass – Increases metabolism rate – Influences behaviour
what would low GnRH levels affect spermogenizsis
low levels of FSH and LH=not enough testosterone=decrease sperm=decreased fertility
function of the vagina
is often called the birth canal
provide passageway for menstral fluids
receives pensi during intercousrse
Acidic environment helps keep the veggie free of infection but makes it hostile to sperm (teenagers have not yet developed an acidic environment making them more susceptible to STD.)
whats the function of the uters
is the site of implantation
contracts doing child birth
contains the functional layer which is shed during menses
whats the three layers of the uterus
- Perimetruim outmost layer
- Myometrium middle later (contracts to expel, baby)- has smooth muscle
- Endometrium inner later -allows implication of fertilised egg and made of two layers
Functional Layer (stratum functionalis) - sheds during mutations and changes due to hormones
Basal layer (stratum basalts) - doesn’t repsond to hormones
whats the function of the uterine tube
site of fertilisation
whats the function of the frimbriae
has ciliated finger like projections. these assist the coccyges journey into the uterine tube
whats the ovaries
2 small almond shaped organs produce female gametes (oocytes), secrete female sex hormones (oestrogen and progesterone)
whats oogenesis
occurs in the ovaries
A small number of primary oocytes are recruited each moth to go through process of meiosis to form the mature ovum.
whats the two phases of the ovarian cycle called
Follicular phases (day 1-14) follicle growth, ovulation occurs at the end of this stage Luteal phase (days 15-28) period of corpus lute activity
what occurs during the follicular phase
follicle cell develops
menses occurs at the start where the destruction of the functional layer (period), then proliferate occurs where the functional layer is repaired and regenerated.
what occurs at the end of the follicular phase
ovulation
building follicle eventually ruptures the wall of the ovary and the oocyte is released
Fluid helps to flush the oocyte out of the follicle
Increases in LH trigger ovulation
oestrogen also peeks
FSH stimulates follicle maturation
FSH stimulus the thecal cells and granulose cells to secrete oestrogen
what occurs in the luteal phase
Lh levels dramatically decrease
ruptured follicle takes on new role of corpus luteum
cl secretes progesterones
cl degenerates without fertilisation therefore progesterone and oestrogen decrease reultingin follicular stage again
stages of the menstral cycle
Day 1-5 Menstral phases (menses
shedding of the function later of the endometrium (oestrongen and progesterone are low)
Dysmenorrhea= painful menstration
Day 6-14: Poliferation (pre ovulatory) phase
rebuilding of the functional layer
Cervical mucous becomes less viscous and sticky to allow entry of sperm
Phase is stimulated and sustained by ovarian oestrogen
Ovulation occurs at the end of this phase
Day 15-28: Secretion (post ovulatory) phase
begins immediately after ovulation
Endometrium prepares for implantation
Stimulated by progestoerone and oestrogen form corpus lutes
If fertilisation does not occur the CL degenerates= low progesterone= breakdown of the endometrium=menses begins again.
what does oestrogen do
promotes oogenesis
Increase growth of the vagina, uterus and uterine tubes
what does oestrogen and progesterone do to work together
regulate uterine cycle and changes in cervical must
Oestrogen promotes repair and regeneration of the functional layer
Progesterone promotes blood vessel and gland growth plus gland secretion
Maintain pregnancy and stimulate breast growth.
the mammary glands
produces milk to nourish newborn
Part of integumentary system (modified sweat glands)
Areola (pigment skin)
Nipple (opening of multiple lactiferous ducts)
Mammary glands, 15-25 lobes open to nipple, each lobe has units called lobules, lobules produce milk
risks with fertilisation
many sperm leaks from the vagina immediately
Many killed by vaginal acid
Many get trapped in the thick mucous at the cervix
Many are phagocytksed by uterine macrophages
Even if sperm reaches the oocyte it needs to wait fro capacitation to occur.
what does fertilisation require
Capacitation: requires exposure to secretions of female reproductive tract, takes 8-10 hours.
whats the steps of fertilisation
Sperm weave through granulosa cells of the corona radiata
Sperm bind to zona pellucida cuscino increased calcium levels in the sperm- this leads to the complete breakdown of the plasma and acrosomal membranes (acrosomal reaction)
Acrosomal enzymes are released and digest holes in the zona pellucida
The sperm binds to special receptors on the oocyte membrane
The sperm and oocyte membranes fuse, releasing sperm DNA into the oocyte
Entry of sperm DNA causes increased calcium levels in the oocyteàtriggers the cortical reaction which destroys sperm receptors and hardens the zona pellucida
- This blocks polyspermy
what happens with identical twins
one fertilised zygote divides into two embryos
what happens with fraternal twins
two oocytes are released and fertilised individually
whats the embryonic development
zygote to blastocyst
fertilisation usually occurs in the distal uterine tube
When the oocyte is fertilised it becomes a zygote
The zygote undergoes cell division (2 cells, 4 cells, 8 cells) occurs in the absence of growth termed “clevage”
As cell division continues a fluid filled cavity forms and the zona pelludica starts to break down- structure is now termed Blastocyst
The blastocyst consists of:
1. The inner cell mass- becomes the embryo
2. A fluid filled cavity
3. A layer of trophoblast cells- becomes the placenta (nourishes the developing embryo/fetus, removes wastes, produces hormones)
whats the blastocyst implant
he zygote/ blastocyst is free floating and travels down the uterine tube into the uterus, nourished by glycogen rich mucus produced by uterine glands
Implantation of blastocyst occurs about 6-7 days after fertilisation, half way through the secretory phase when the endometrium is most receptive (good blood supply, lots of nutrient rich mucus)
Special proteins on the trophablast cells allow the blastocyst to attach to receptors on the receptive endometrium.
The blastocyst buries itself within the endometrium, the endometrial cells cover the blastocyst
what happens if implantation is successful
takes about 5 days- usually complete by the 12th day after ovulation
Usually just before menstration would normally occur
The embryo signals to the corpus lutes in the ovary to continue to produce progesterone and oestrogen this prevents sloughing of function layer of the endometrium.
Signaling occurs via the hormone human chorionic gonadotrophin (hCG) produced by the trophoblasts.
hCG bypasses hypothalamic and pituitary control of the ovarian cycle.
why is hCG important
maintains the corpus luteum so it continues to produce progesterone and oestrogen.
These hormones especiall progesterone, prevent sloughing of endometrium.
Endometrium is essential for the nourishment of the embryo
Loss of the endometrium would mean loss of the implanted embryo eg miscarriage.
Progesteron production must be maintained throughout the pregnancy
Embryonic hCG performs this function until 8-12 weeks
When the placenta is mature enough to take over hormone production (hCG also promotes placenta development)
what occurs during pregnancy testing
hCG levels are present in the mothers blood one week after fertilisation and continue to rise until the end of the second month
hCG can be detected in the urine using a home pregnancy test 7-12 days following conception (2-7 days before restoration would normally occur)
