Reproductive System Flashcards
what does the reproductive system do?
produce male and female gametes
enhances fertilisation of an oocyte by a sperm
female: nurtures new individual until birth
produces reproductive hormones
what are the organs present in the male reproductive system?
testes
penis
what are the ducts present in the male reproductive system?
epididymis
ductus deferens
urethra
what are the glands present in the male reproductive system?
seminal vesicles
prostate
what is the anatomy of the testes?
Testes covered in
* Fibrous connective tissue
* (under skin- scrotum)
Each testis contains
* Connective tissue forms lobes
* Seminiferous tubules (produce sperm)
* Rete testis
* (Efferent ductules)
* Epididymis
* Ductus deferens
* Leydig cells (outside seminiferous tubule)
* (Produce testosterone)
what is gameotogenesis?
formation of the male and female gametes
what is the female gametogenesis?
oogenesis
what is the male gametogenesis?
spermatogenesis
what happens in the seminiferous tubule?
where sperm is formed (mature in lumen, immature on outside)
leydig cells (testosterone)
sertoli cells (nourish the germ cells and produce hormones)
what is the process of spermatogenesis?
Spermatagonia
(mitosis)
Spermatocytes
(meiosis)
Spermatids
(differentiation)
Spermatozoa
what is the function of the testes?
- Exocrine – produce sperm
- Endocrine – produce hormone
- Spermatogenesis
- Process of sperm maturation
- Involves both mitosis & meiosis
- Takes ~ 74 days to complete (incl
maturation)
what is the journey of the spermatozoa in the male reproductive system?
Seminal vesicles in testis
Epididymis
Ductus deferens (vas deferens)
* loops behind the urinary bladder
* peristaltic waves to propel the sperm to approach the prostate gland
* Seminal vesicles (semen)
* Prostate (semen – surrounds urethra)
Urethra
Semen secretion
* Nutrients (inc fructose)
* pH regulators
* Coagulation proteins (prolong time in vagina)
* Proteolytic enzymes – release sperm – swim to oocyte
what is contained within the female reproductive system?
Ovary
Uterine tube / fallopian tube/oviduct
Uterus
Vagina
* Distendable smooth muscle
tube, 10cm long
* Small glands secrete lubricant
* Related to rectum posteriorly
and bladder/urethra
anteriorly
female reproductive and urinary tracts open separately to the exterior
what are the uterine tissue layers?
endometrium
myometrium
perimetrium
what is the endometrium?
vascular and glandular
stratum compactum- cuboidal ciliated epithelium
stratum spongiosum- loose connective tissue
stratum basale- slough during menstruation
what is the myometrium?
3 layers of smooth muscle
what is the perimetrium made of?
peritoneum
what are the three major components of the fallopian tubes?
isthmus- narrowing
ampulla- swelling-fertilisation usually occurs here
infundibulum- collecting area with fimbrae
what is contained within the outer and centre area of the ovary?
outer: connective tissue (ovarian follices( oocyte))
centre: blood vessels nervous tissue
what is the process of follicular development in the ovary?
primordial follicles (present at birth)
puberty:
primary follicles (oocyte enlarges, develops granulosa cells)
secondary follicle (fluid filled vesicles, thecal cells)
grafian follicle (ruptures and secondary oocyte surrounded by cells released during ovulation)
what is the development of oocytes?
Primitive germ cells
(differentiation)
Oogonia
(mitosis)
Primary oocyte
(early meiosis)
Secondary oocyte
(late meiosis)
Ovum
what are hormones?
a chemical substance produced by ductless glands within the endocrine system
what are the three classes of hormones?
hormones derived from amino acids
proteins and peptides
hormones derived from lipids
what hormone is cholesterol a precursor for?
-steroid hormones
adrenal steroid
glucocorticoids
mineralcorticoids
(sex hormones/ steroids)
oestrogens
progesterons
androgens
what are the three classes of reproductive hormones?
- Oestrogens
- Androgens
- Progestogens
what are the three types of oestrogens?
oestradiol
oestrone
oestriol
what are the four types of androgens?
testosterone
5a-dihydrotestosterone (DHT)
androstenedione
dehydroepiandrosterone (DHEA)
what is the primary role of the reproductive hormones?
maturation of reproductive organs, fertility and pregnancy
what is the secondary role of reproductive hormones?
development of physical characteristics
where is the site of testosterone production?
testes in the leydig cells
where is the site of steroid hormone production in the female reproductive system?
ovarian granulosa cells (oestrogen)
ovarian theca cells (androgens)
corpus luteum (progesterone)
placenta- placental syncytiotrophoblasts (progesterone)
what is the mechanisms of action that reproductive hormones go through?
- Hormones enter cells
- Hormones bind to intracellular receptor
- Conformation change and translocation
- DNA binding (HRE’s)
- Gene expression (or repression)
what is gonadal steroidogenesis regulated by?
HPG axis
which is the hypothalamus, pituitary and gonads
what are the characteristics of the hypothalamus?
- Small structure at base of forebrain
- Hypothalamus releases GnRH
(Gonadotrophin Releasing Hormone) - Peptide hormone
- Released into blood
- Reach pituitary
what are the characteristics of the pituitary?
- Pea-sized gland located at the base of the
skull ventral to the hypothalamus
Comprised of two elements - Posterior and anterior lobes
- Anterior pituitary contains specialised cells
(gonadotropes)
GnRH stimulates gonadotropes to - Produce gonadotrophins
- glycoproteins
- FSH (follicular stimulating hormone)
- LH (Lutenising hormone)
- hCG (human chorionic gonadotrophin)
what are the characteristics of the gonadotrophins?
LH main functions
* ♀ acts on ovarian follicle inducing
ovulation
* ♂ acts on testes producing testosterone
FSH main functions
* ♀ promotes ovarian follicle development
& oestrogen production
* ♂ stimulates spermatogenesis in testes
what is the negative feedback of reproductive hormones?
decreases level of signal and maintains homeostasis
what is the direct negative feedback of reproductive hormones?
steroid hormones decrease secretion of gonadotrophins
what is the indirect negative feedback of reproductive hormones?
Steroid hormones inhibit their own production indirectly by inhibiting hypothalamus GnRH
* decreased pituitary gonadotrophin secretion
* reduced steroid hormone production
what is the positive feedback of reproductive hormones?
leads to an increase in hormone level
occurs within follicular phase of uterine (menstrual) cecle
oestrogen-induced LH to trigger ovulation
what are the steps for the regulation of the reproductive hormones in the male reproductive system?
- GnRH stimulates secretion of LH and FSH from anterior pituitary
- LH stimulates testosterone secretion from Leydig Cells
- FSH stimulates Sertoli cells to increase spermatogenesis
- Testosterone1. Stimulates Sertoli cells
- Development of reproductive organs
- Testosterone: negative effect on Hypothalamus and Pituitay
- Sertoli cells secrete inhibin – negative feedback
what are the three phases of the ovarian cycle?
follicular phase
ovulatory phase
luteal phase
what happens during the follicular phase?
development of graffian follicle
* secondary follicles mature
* Granulosa cells secrete oestrogens
* Oestrogen: causes the epithelial cells of the endometrium to divide rapidly.
* endometrium thickens
what happens during the ovulatory phase?
release of mature follicle
what happens during the luteal phase?
formation of corpus luteum
* the corpus luteum begins to secrete progesterone and smaller amounts of oestrogen.
* Progesterone: causes the cells of the endometrium to become larger and to secrete a small amount of fluid.
* Fullest development of endometrium
* If no fertilisation – corpus luteum degenerates – progesterone drops
what are all the hormones that take part in the female reproductive system?
Gonadotropin releasing hormone (GnRH) ( Hypothalamus)
* Stimulates secretion of LH and FSH from Anterior pituitary
Luteinizing hormone (LH)
* Causes follicles to complete maturation; causes ovulation; causes the
ovulated follicle to become the corpus luteum
Follicle-stimulating hormone (FSH)
* Causes follicles to begin development
Oestrogen (from follicles and corpus luteum)
* Proliferation of endometrial cells
Progesterone (from corpus luteum
* Enlargement of endometrial cells / maintenance of pregnant state
what is the feedback mechanisms of oestrogen?
- Postive feedback before ovulation,
- resulting in increased LH and FSH secretion;
- Negative feedback (with progesterone) on the hypothalamus and anterior
pituitary after ovulation, resulting in decreased LH and FSH secretion
what are the feedback mechanisms of progesterone?
- Negative feedback (with oestrogen) on the hypothalamus and anterior pituitary after ovulation, resulting in decreased LH and FSH secretion
what happens during the menses phase?
- Oestrogen and progesterone
secretion is low - In response to declining
progesterone levels, the
endometrial lining of the uterus
sloughs off, resulting in menses - The rate of LH remains low, and
- the rate of FSH secretion
increases as progesterone levels
decline (negative feedback
released) - Stimulates development of
follicles - Start to release oestrogen
what happens during fertilisation?
- hCG from pituitary and later placenta maintains corpus luteum
- Oestrogen and progesterone levels maintained
- Endometrium doesn’t break down
- Subsequently Placenta takes over progesterone and oestrogen production
