Reproductive system Flashcards
What are the main functions of human reproduction?
- to produce gametes (egg + sperm)
- release sex hormones
- to reproduce species
What are the benefits of sexual reproduction?
Male and female required, increases variability ( increased variability = increased survival)
What are main parts of the male reproductive system?
(in order)
- Testes
- Epididymis
- Vas deferens
- Ejaculatory duct
- Penis
- Urethra
What is the testes?
Where the sperm+testosterone is produced, inside scrotum
What is the epididymis?
The outer layer of testes, where sperm cells mature and are stored
What is the vas deferens?
Long tubes leading from epididymis to ejaculatory gland
What is the ejaculatory duct?
- Propels+regulates sperm and fluids into urethra
- Found at union of vas deferens and seminal vessicles
What is the penis?
- External sex organ
- compromised of erectile tissue surrounding urethra
What is the urethra?
- Tube leading through penis
- Exit for semen+urine
What are the 3 glands found in the male reproductive system?
(SPC)
Seminal vesicles
Prostate
Cowper’s gland
What is the seminal vesicle?
Gland that secretes fructose to provide energy for sperm cells
What is the prostate?
Gland that provides alkaline fluid that neutralizes acidic environment of vagina
What is the Cowper’s gland?
Gland that releases mucus to help sperm motility
What parts are used in the formation of sperm cells?
- Seminiferous tubules
- Sertoli cells
- Interstitial cells
What is the seminiferous tubules?
- Coiled tubes in testes
- Where immature sperm cells divide/differentiate
What is the sertoli cell?
- Found in between sperm cells in seminiferous tubules
- Provides nourishment+support
What are the interstitial cells?
Found in between seminiferous tubules, produces testosterone
What is the pathway of the sperm?
Testes–> epididymis—>vas deferens–> ejaculatory duct–> urthrea
Seminal, prostate, cowpers (join into ejaculatory duct)
What is the anatomy of the sperm?
Acrosome– head, has enzymes that break down egg barrier (leads to fertilization)
Midpiece- has mitochondria=energy
Tail/flagellum- motility
What are the hormones of the male reproduction system?
GnRH- From hypothalamus, regulates pituitary release of FSH and LH
FSH- from pituitary, stimulates production of sperm in seminiferous tubules
LH- from pituitary, stimulates testosterone production in interstitial cells
Testosterone- from interstitial cells, effects sperm production+secondary sex characteritics
What is the negative feed back loop for male reproduction hormones?
Hypothalamus–> Pituitary= FSH—> Seminiferous tubules+sertoli cells== sperm
Hypothalamus–> Pituitary= LH—> Interstitial cells=testosterone (turns off hypothalamus)
What are the main functions of the female reproductive system?
- Vagina
- cervix
- uterus
- fallopian tubes
- Ovaries
What is the vagina?
- Path for for menstrual flow+ baby
- Slightly acidic, for protection
What is the endometrial lining?
Lining of the uterus
Changes thickness through cycle
Where embryo implants OR
what is shed during flow phase
What is the cervix?
- At the bottom of uterus
- Dilates during labour
- Produces mucus
What is the uterus?
- Muscular organ
- supports fetal development
- Implantation of embryo occurs in endometrial lining
What are the fallopian tubes?
- Tubes to transport egg after ovulation
- Where fertilization occurs
What are the ovaries?
- Where egg+follicle are stored
- Secretes estrogen+progesterone
Which hormones are specific to the female reproduction system?
Estrogen+progesterone
Which hormones are used in the female reproduction system?
- GnRH
- FSH
- LH
- Estrogen
- Progesterone
What is GnRH responsible for in the FRS?
- from hypothalamus
- controls ptuitary
What is FSH responsible for in the FRS?
- Released from pituitary
- Targets ovaries= stimulates development of a follicle containing oocyte
What is LH responsible for in the FRS?
- from pituitary
- targets ovaries= stimulates egg to be released from follicle
What is Estrogen responsible for in the FRS?
-Secreted by developing follicle (w/ oocyte) and ovary
What is progesterone responsible for in the FRS?
- secreted by corpus luteum (follicle left over after ovulation)
- Functions: thickens+ maintains endometrium lining
-Inhibits ovulation (LH)
Inhibits uterine contraction (ooxytocin)
What are the steps to the ovarian cycle?
- FSH stimulates follicle to develop
- contains oocyte
- follicle creates estrogen (more development=more estrogen) - Estrogen released from follicle reaches its peak
- stimulates release of LH= OVULATION
- follicle ruptures, releases egg into fallopian tubes - Ruptured follicle becomes corpus luteum
- secretes progesterone - Corpus luteum breaks down
- progesterone lowers, cycle restarts
What is the feedback loop for the female reproductive system?
Hypothalamus— GnRH—> Ptuitary— > FSH= stimualtes follicle development= estrogen (turns off hypothalamus, in order to stop more follicles from developing)
Pituitary—>LH (once peak estrogen levels reached= OVULATION–> turns into corpus luteum= progesterone+little estrogen ===Turns off LH pathway (to stop eggs from being released anymore)
What is the uterine cycle?
- Flow phase (days 1-5)
- Follicular phase (days 6-13)
- Ovulation (day 14)
- Luteal phase (day 15-28)
What is the flow phase?
Days 1-5,
low progesterone + estrogen, causes endometrium to shed, FSH may satrt to be released during this time
What is the follicular phase ?
Day 6-13
Follicle develops= estrogen released
endometirum builds, FSH levels decrease
What is ovulation phase?
Day 14,
ovum released from follicle into fallopian tubes (due to LH surge from high estrogen levels)
What is the luteal phase?
Day 15-28
Follicle becomes corpus luteum= progesterone+estrogen
thickens+ maintains endometrium
What happens if no fertilization occurs after the luteal phase?
corpus luteum breaks down, progesterone levels decrease, uterine lining sheds,
What is fertilization?
In fallopian tubes, 4-6 hours after intercourse,
egg+sperm=zygote, (46 chromosomes)
What occurs after zygote forms?
Zygote begins to divide, does not increase in size, cells get smaller
What occurs after zygote differentiate?
Cilia+peristaltic motion moves zygote towards uterus
What occurs after zygote moves towards uterus?
Differentiation of cells begin (cells decide what type they will be)
becomes blastocyst
What is the blastocyst?
Cells divide into outer ring (extraembryonic structures ie: cherion, amnion, umibolical cord)
and the inner clump (embryo/baby)
What occurs after the blastocyst is formed?
Blastocyst imbeds/ implants into endometrium lining in uterus (to grow)
- secretes hCG
What is the hCG?
Maintains corpus luteum, to secrete progesterone+estrogen, maintains endometrium lining, (3 months) placenta then takes over
What is gastrulation?
Blastocyst imbedded in endometrium folds up, becomes GASTRULA
What are the layers of the gastrula?
- ectoderm (outer layer)- skin, hair, nails
+ nervous system - mesoderm (middle)- bones, muscles,
- circulatory system,
blood
- excretory system
- reproductive system 3. endoderm(inner) - respiratory, digestive systems
What are the main extraembryonic structures?
- chorion
- amnion
-yolk sac - allantois
Placenta (formed of chorion and endometirum)
What is the Chorion?
Outer layer of embryo sac
- secretes hCG (for maintaining corpus luteum)
- Forms part of placenta
What is the amnion?
Second layer, AKA amniotic sac, is filled with amniotic fluid for protection of baby
protection= cushioning, temp regulation, prevents dehydration, prevents infection
What is the Yolk sac?
Responsible for blood cell development, know on diagram
What is the allantois?
Becomes the umbilical cord (know on diagram)
What is the umbilical cord?
Allows for nutrients, gasses and wastes to be exchanged,
connects fetus to placenta
What is the placenta?
- Spongy mass of tissue
- Built from chorion+endometrium
- Allows for exchnage of nutreitns, gases, wastes, hormones, antibodies, etc
- Secretes progesterone + estrogen after 3 months (takes over for hCG)
- Blood cells do not pass through placenta
- placenta does not filter out teratogens (substances that impact development ie: alcohol)
What are the 3 stages of pregnancy?
- 1st trimester - conception to 3 months
2nd trimester - end of 3/beginnign of 4 to 6 months
3rd trimester- end of 6/beginning of 7 to birth
What happens during the 1st trimester?
- All organ systems from (rapid development)
- Most susceptible to teratogens
What happens during the 2nd trimester?
- Growth
- organs continue developing
What occurs during the 3rd trimester?
- rapid growth
- increased weight
- full maturation of organs
What is the process of giving birth called?
Parturition
What are the steps to labour?
- after 3rd trimester, the placenta ages and stops producing progesterone + estrogen
- decreased progesterone levels stops inhibiting oxytocin and prostaglandins, which both stimulate uterine contractions
- Relaxin is also released when the baby head pushes against the cervix, dilates cervix
What is the positive feedback loop for labour intensity?
baby head pushes against cervix->relaxin release, cervix dilates-> release of oxcytocin+progesterone stimulates uterine contraction -> pushes baby against cervix (restarts)
How does the body prepare for breast milk production during pregnancy?
- Two hormones, that were inhibited by rogesterone, are released
Oxytocin- stimulates muscles contraction in breasts to release milk
Prolactin - stimulates milk production
What is the order of steps to release milk when breastfeeding?
- Sensory neurons stimulated @ nipple (suckling)
- Nerve impulse travels to hypothalamus, to pituitary
- Pituitary releases oxytocin
- Oxytocin stimulates breast muscle contraction to release breast milk
