Unit 14: Reproductive System Flashcards
Reproductive System
Combined functions of both male and female reproduction systems pass on the genes of the individuals+maintain the species
Sex Chromosomes
X and Y sex Chromosomes
Eggs carry X
Sperm carry Y or X
Female: XX
Male: XY
Development Timing
During the first 6 weeks of development male and female embryos contain common gonads
Two sets of premature reproductive tracts
Mullerian Duct: paramesonphric
Wolffian Duct: mesonephric
Male Embryo
After 6-7 weeks the presence of the Y chromosome causes the indifferent gonads to develop into testes
At 7 weeks testicular cells produce MIH
At 9 Weeks testicular cells begin to produce testosterone
Surge of Testosterone in Male embryos
Stimulates the wolffian duct to develop into the:
epidydimus
vas deferens
seminal vesicles
urethra
Female Embryo
After 9 weeks of development the XX chromosome are activated + overies develop
No hormonal control
no MIH
Mullerian duct develops into the
uterus
cervix
fallopian tubes
parts of the vagina
Lack of testosterones in female embryos
Wolffian duct degrades
Female genetalia develops
Three Principle Functions of the Male reproductive
To produce the sex steroid testosterone
Produce sperm (spermatogenesis)
Trigger effects on the whole body
Three Principle Functions of the Female Reproductive Systems
Produces sex steroids: estrogen + progesterone
Produces eggs + receives the sperm
Provides optimal conditions for the development of the fetus
Male External Genetalia
Penis: Corpus spongiosum + Corpus caveriosum + erectile tisse
Scrotum: Testes
Sperm + testosterone
sperm is stored in the epididymis
Ejaculation
Sperm from the epididymis travels through the vas deferens to the seminal vesicles to pick up fluid, then they travel to the prostate to pick up fluid from the bulbourethal gland and passes through the urethra and out of the penis
Testes
1000s of coiled tubes
Seminiferous tubules
After formation in the ______ _____ the sperm move into the _______.
seminifeorus tubules
epididymis
______ drains into the _____ ______.
epididymis drains into the vas deferens
_______ _____ contain ______ cells and developing sperm.
seminiferous tubules contain sertoli cells and developing sperm
______ cells are located outside the S.tubules
Leydig
Seminiferous tubules are the site of
Spermatogenesis
Sertoli Cells regulate (4 functions)
Blood Testes Barrier
Secretes a fluid the pushes premature sperm into the epipidymis
Secretes the hormone Inhibin
Spermatogenesis/Maintaining Developing Sperm Cells
Leydig Cells (1 Function)
Located in the interstitial space between the seminiferous tubules
Secretes Testosterone
Epididymis
Stores immature sperm and supports its maturation
Ductus/Vas deferens
Tubes that transport the sperm to the ejaculatory duct
Ejaculatory Duct
Drains into the urethra
Seminal Vesicles
Contribute a large amound of fluid to the semen during ejaculation.
Fluid is rich in fructose + enzymes that helps to maintain and nourish the sperm
Prostate Gland
Secretes enzymes + fluid that help to neutralize the acidic environment of the urethra and vagina
Bulbourethral Gland
Secretes a fluid that helps neutralize the pH and lubricate the urethra and vagina to make an optimal environement for the sperm
Urethra
Transports the sperm during ejaculation + drains the bladder during urination
Spermatogenesis begins during…
Begins during puberty
Spermatogonia (Location + components)
Germ cells
Contains the chromosomes
Located at the outer edges of the seminiferous tubules
Spermatogonia Division
Divide by mitosis into two cells
Asymmetrical division: one continues as the spermatogonia while the other divides into a primary spermatocyte
Primary Spermatocyte
Contains 46 chromosomes
Divides by meiosis into two secondary spermatocytes into two secondary spermatocytes and then into four spermatids (2nd mitotic division)
During the process of division the cells are surrounded + nourished by _____ _______ as they begin to work their way to the center of the ______ ______.
sertoli cells
seminiferous tubules
Spermatids develop into ____ _____ where they are released by the ______ ______ into the ____ of the _____ ______
Mature sperm
sertoli cells
lumen
seminiferous tubules
How long does Spermatogenesis take
64 days
Results in _ _____ _____ with __ chromosomes
4 sperm cells
23
Sperm Cell Structure
Contains a head with an acrosome and a nucleus
Midpeice with a mitochondria
Long tail/flagellum
Function of the testes is controlled by
FSH and LH
FSH acts on
Sertoli cells to promote spermatogenesis while also producing the hormone inhibin
Hormone Feedback Loop
Testosterone feeds back to the anterior pituitary which decreases the release of LH and FSH
Testosterone is essential for
Spermatogenesis
Testosterone (production+storage)
Steroid Hormone produced in the leydig cells in the testes.
Synthesized from cholesterol intermediate
Progesterone intermediate
Rise and Fall of testosterone levels during ______ ______.
Fetal development
Rise is necessary for the development of the male reproductive tract + external genitalia in the fetus
After _____ there is an increase in testosterone
Birth
No one knows why
Levels of testosterone remain low after ______.
Puberty
Puberty (Male)
Childhood to Adulthood
Between about 9 and 14 yoa levels of GnRH begin to increase
Final maturation fo the male reproductive system is the point where mature sperm can be produced
Sexual maturation + peak testosterone levels occur at 16-18 yoa
From 50 yoa onwards testosterone levels decrease
Andropause: Leydig cells which produce testosterone no longer respond fully to LH
Testosterone Functions
- Development of male reporductive tract + external genetalia in the embryo
- growth and development of all male reproductive organs at puberty
- development of the male secondary secxcharacteristics at puberty (muscle growth; hair growth on face and genitalia + deep voice)
- sex drive at puberty
- spermatogenesis
- bone and skeletal muscle growth
- increased aggressiveness
Female Reproductive System Structure
Vulva
Female internal Genetalia
Vulva
Clitoris: erectile tissue
Labium majus: surrouds the labia minus
Folds of skin are derived from the same embryonic tissues as the: scrotum and shaft of the penis
Labia minora: encloses the vaginal shaft (opening of the vagina)
Female internal genetalia
Vagina
Cervix
Uterus
Vagina
Is the canal that receives the penis during intercourse + sperm is received
Allows for discharge of fluid during menstruation + after the birth of the baby
Sperms travels from the _____ into the _____.
Cervix
Uterus
Uterus
Muscular walled hollow organ
Sperm continues to the ____ ____.
Falliopian tubes: roughly 20cm long and end in the fimbria
Eggs produced in the ______ is released + travels through the ______ to the _____ _____ to reach the sperm.
Overies
Fimbrae
Fallopian Tubes
Cervix
Secretes mucus that varies during the menstrual cycle from thin (to facilitate sperm entry) to thick (to prevent sperm entry)
Uterus (3)
The site of implantation of the fertilized egg
Where the developing embryo is nourished and maintained
During the menstrual cycle the uterine lining undergoes several phases under hormonal control
Fallopian tubes (2)
Site of fertilization of the egg
They contain cilia that pass the egg from the fimbria to the uterus
Fimbriae capture the egg after it is expelled from the ovarues ad funnel it into the infundibulum
Ovaries (2)
Produces eggs
Produces estrogen + progesterone
Oogenesis: ______ stages of development.
Several
Egg is contained in a
Follicle
First stage begins w/ the production of
Several million oogonia in the developing female embryo
Oogonia
Develop into a primary follicle that consists of a single outer layer of granulosa cells that contain the primary oocyte
Granulosa Cells
Secretes a fluid into the interior of the follicle which forms into the antrum
Primary oocyte and follicle remains in this form until
Puberty
At ______ ovaries are activated by _ _ _ _, _ _ _ and _ _.
Puberty
GnRH
FSH
LH
Only several ____ _____ primary oocytes have survived.
Hundred thousand
The female begins her menstrual cycle during which
a few primary follicles begin to grow
Primary follicle develops another _____ of _____ called _____ ____, which form ______ the granulosa cell.
layer
cells
theca cells
outside
The primary follicle will slowly ______ as it develops into the mature follicle.
Enlarge
Oocyte will
Seperate from the granulosa cells and will float around freely in the antrum immediately before ovulation
Oogenesis produces
Only 1 viable oocyte
The production of ____ from the _____ begins to increase dramatically as the follicle grows.
Estrogen
Ovaries
This triggers _____ _____ to grow and produce more _______.
Granulosa cells
estrogen
Estrogen is involved in a (+)ve feedback mechanism
Does not feedback to the hypothalamus or pituitary to inhibit the secretion of LH or FSH
Levels of LH and FSH increase
LH surge causes granulosa cells to secrete ______ ______ of _______ into the ______ causing it to _____ and rupture releasing the egg.
large amounts
fluid
antrum
swell
Egg is gathered by the ____ into the _____ _____.
fimbriae
fallopian tubes
Mature follicle then degenerates into the hormone releasing ____ _____.
corpus luteum
_____ ____ desintegrates into the _____ _____ if pregnancy does not occur
Corpus luteum
Corpus albicans
LH + FSH (Females)
Involved in the development of the follicle
estrogen production
Estrogen refers to a group of hormones
17B-estradiol
esterone
estrial
______ is secreted in humans and is more potent.
estradiol
Estrogen synthesis
Cholesterol is tranformed into a series of intermediates
Continuation of testosterone formation
Formed from androstenedione
Progesterone
Produced in small quantities by both granulosa cells and theca cells before ovulation
stimulated by LH
After ovulation of the oocyte the follicle degenerated into the corpus luteum
Continues to secrete estrogen and progesterone
this prepares the ____ of the _____ for the _____ of the ______ egg.
lining
uterus
implantation
fertilized
Should the egg cell fail to be fertilized the corpus luteum will develop into the
corpus albicans
Estrogen Levels
Low until puberty 8-13
Dramatic rise in estrogen levels due to increased secretion of gnRH from the hypothalamus
Pulsatile nature of estrogen levels due to
(+)ve feedback
Ovulation/menstruation cycle becomes irregular + cycle stops around
40-50 yoa
50 (menopause)
Menopause is caused by the
Decrease in teh number of primary follicles in the ovaries
fewer follicles = less estrogen
Little (_)ve feedback allowing for
-
LH+FSH levels to rise dramatically
ovaries are less responsive to the surge causing estrogen levels to drop
Proliferation Phase (3)
7-14 days
follicle increases the production of estrogen causing LH to surge
follicle ruptures + egg is expelled
estrogen and progesterone stimulate the growth of the uterine lining
Secretory Phase
14-28 days
follicle develops into a corpus luteum and increases the production of progesterone that propares the uterus for implantation
if fertilization and implantation does not occur the corpus luteum degenerates into scar tissue
progesterone levels drop
Menses
1-7 days
FSH, estrogen and progesterone levels are low
lining of the uterus cannot be maintained and uterus lining is lost
FSH Stimulates (Males)
Sertoli cells
promotes spermatogenesis
LH Stimulates (Males)
Leydig cells promoting secretion of testosterone
FSH Stimulates (Females)
Maturation of the primary follicles
Estrogen is secreted + synthesized by
Granolulosa + theca cells making up follicles found in the ovaries
LH Stimulates (Females)
LH surge causes ovulation
Progesterone Role
Maintining the lining of the uterus
