reproductive system Flashcards
what is the primary role of the reproductive system?
produce offspring
what is the reproductive system made up of?
primary sex organs plus accessory reproductive organs (ducts, glands and external genitalia
what are the roles of the male reproductive system?
- manufacture sperm
- deliver sperm to the female reproductive system
what is the penis designed to do?
deliver sperm to the female reproductive tract
what are the 3 cylindrical columns of erectile tissue in the penis?
- dorsal: 2x corpus cavernosa
- ventral: 1x corpus spongiosum
how does an erection occur?
- blood vessels dilate
- increased blood flow to penis
- vascular channels become engorged with blood
- erection of penis occurs
what is the scrotum?
sac of skin housing the testes outside abdominal cavity of the body
what is the scrotum essential for?
temp regulation of testes
what are the two types of muscle that regulate temp in the scrotum?
- dartos muscle (smooth muscle)
- cremaster muscle (skeletal)
what does the dartos muscle do in the scrotum?
contracts to make scrotum wrinkled and thick, decreases heat loss
what does the cremaster muscle do in the scrotum?
contracts to bring scrotum and testes closer to body
what is the lobule in the testes the site of production for?
sperm production
what is the testes internally divided into?
into about 250 lobules
what are the functions of the epididymis in the male reproductive system?
- stores, nourishes and protects spermatozoa
- facilitates functional maturation
- recycles damaged sperm
- ejaculates sperm
what does the epididymus surround?
the posterior edge of the testes and is a series of coiled tubes (6m)
where are sperm stored?
tail of the epididymus
where are sperm ejaculated into from the epididymus?
ductus deferens
what tubes does sperm travel through from the testes to the outside of the body?
- epididymus
- ductus/vas deferens
- ejaculatory ducts
- urethra
what accessory glands create secretions while sperm is ejaculated?
- seminal vesicles
- bulbourethral gland
- prostate
what do seminal vesicles do?
release a viscous fluid which makes up 60-70% of semen volume and contains substances that enhance sperm mobility/ability to fertilise ovum
how much does the prostate gland fluid account for in the semen volume?
30%
is ejaculation a parasympathetic or sympathetic response?
sympathetic
what does the bulbospongiosum muscle do?
contracts to eject semen at a rate of 500cm/s
what is the process of producing sperm called?
spermatogenesis
where does the production of sperm occur?
seminiferous tubules of the testes
how long does each mature sperm take to produce?
about 10 weeks
how many pairs of chromosomes do most body cells contain?
23 pairs
what are the major structural regions of sperm?
- head
- midpiece
- tail
what is the head of the sperm responsible for?
genetic region; nucleus and vesicle containing enzymes that enable the sperm to penetrate an ovum
what is the midpiece of the sperm responsible for?
metabolic region; mitochondria, energy production
what is the tail of the sperm responsible for?
locomotor region; flagellum creates movement
what does semen consist of?
- 5% epidymal secretions
- 60% seminal vesicles
- 30% prostate secretions
- 5% bulbourethral secretions
what do the testes make?
sperm and hormones
what is the interaction of the production of sperm and hormones in the testes called?
hypothalamic-pituitary-gonadal (HGP) axis
in the HGP axis what hormone does the hypothalamus release?
gonadotrophin-releasing hormone (GnRH)
what does gonadotrophin-releasing hormone in the HGP axis signal?
release of FSH and LH from anterior pituitary
what does FSH stimulate in the male reproductive system (HGP axis)?
intestitial (leydig) cells in the seminiferous tubules to produce sperm
how does increased testosterone levels inhibit GnRH and FSH/LH release?
negatively feedback to inhibit
what occurs in the male reproductive system if the is an absence of GnRH, LH and FSH?
the testes will atrophy and sperm and testosterone production will cease
what are some things testosterone does after puberty?
- stimulates spermatogenesis
- increases size of penis
- enhance ability to maintain erection and ejaculate
what are some male secondary sex characteristics that are not directly involved in reproduction?
- enhanced hair growth
- deepened voice
- increased skeletal and muscle mass
- increased metabolism rate
what is the main role of the female reproductive system?
- produce and release gametes
- nurture a developing foetus
- give birth
what does the external structures of the vulva involve?
- labia majora
- labia minora
- vestibule
- clitoris
what is the labia majora?
two fatty skin folds
what is the labia minora?
two thin hair free skin folds the enclose the vestibule
what is the vestibule in the female reproductive system?
greater vestibular glands release mucus to lubricate intercourse
what is the clitoris?
erectile tissue, richly innervated, sexual arousal
what structures make up the female duct system?
- vagina
- uterus
- uterine/fallopian tubes
is the female duct system continuous?
no
is the male reproductive system continuous?
yes
what does the vagina provide a passageway for?
- eliminate menstrual fluids
- receive penis during intercourse
- expel foetus during child birth
what keeps vagina free from infection and hostile to sperm?
acidic enviro
what is the uterus?
hollow, thick muscular organ that receives, retains and nourishes offspring
what does the uterus consist of?
- body (major region)
- fundus (top region)
- cervix (joins to the vagina)
what do glands in the mucosa of the cervix secrete?
mucous that block the spread of bacteria into the uterus from the vagina, also blocks sperm expect at mid cycle
how come sperm is able to enter the uterus mid cycle?
mucous becomes less viscous
what are the three layers the uterine wall is composed of?
- permimetrium
- myometrium
- endometrium
what is the permimetrium layer of the uterine wall?
outermost layer
what is the myometrium layer of the uterine wall?
bulky, middle muscular layer
what layer of the uterine wall contracts to expel baby?
myometrium
what is the endometrium layer of the uterine wall?
inner, mucosal layer that allows for implantation of fertilised egg
what are the two layers of the endometrium layer of the uterine wall?
functional layer (stratum functionalis) and basal layer (stratum basalis)
what does the functional layer of the endometrium layer of the uterine wall undergo?
cyclic changes due to ovarian hormones and is shed during menstruation
what is the basal layer of the endometrium layer of the uterine wall unresponsive to?
ovarian hormones
what regenerates the functional layer of the endometrium layer of the uterine wall after menstruation?
basal layer
what do the ovaries do?
- produce gametes (oocytes)
- secrete female sex hormones(oestrogen and progesterone)
what are the female gametes called?
oocytes
what does each ovary consist of?
- medulla
- cortex
what is the medulla of the ovary?
inside region which is highly vascularised
what is the cortex of the ovary?
outside region where follicles are matured to release oocytes
where are oocytes produced?
ovaries
what are the oocytes a female has at birth called?
primary oocytes
what are the oocytes recruited each month called?
secondary oocytes
what are the two phases of the ovarian cycle?
- follicular phase (day 1-14)
- luteal phase (day 15-28)
what occurs in the luteal phase of the ovarian cycle?
periods of corpus luteal activity
what occurs in the follicular phase of the ovarian cycle?
follicle growth, ovulation occurs at the end of this stage
how long does the luteal phase normally last in the ovarian cycle?
14 days
what triggers ovulation?
increasing levels of oestrogen stimulate surge in LH
what triggers the release of FSH and LH during the follicluar phase of the ovarian cycle?
GnRH
what stimulates follicle maturation in the follicular phase?
FSH
what does the LH surge transform ruptured follicles in the luteal stage into?
corpus luteum
what does the corpus luteum produce?
oestrogen, progesterone and inhibin
what occurs in the luteal phase if fertilisation does not occur?
the corpus luteum degenerates, hormone levels decline and cycle begins again
what is the uterine (menstrual) cycle driven by?
oestrogen and progesterone released by the ovaries
what are the three phases of the uterine cycle?
- menstrual phase (menses)
- proliferative (pre-ovulatory) phase
- secretory (post-ovulatory) phase
what days does the menstrual phase of the uterine cycle occur?
1-5
what days does the proliferative phase of the uterine cycle occur?
6-14
what days does the secretory phase of the uterine cycle occur?
15-28
are progesterone and oestrogen levels high or low during the menstrual phase of the uterine cycle?
low
what occurs in the menstrual phase of the uterine cycle?
shedding of the functional layer of the endometrium, painful menstruation, dysmenorrhoea
what occurs in the proliferative (pre-ovulatory) phase of the uterine cycle?
- rebuilding of endometrium
- cervical mucous becomes less viscous
- ovulation occurs at the end of this phase
what occurs at the end of the proliferative phase of the uterine cycle?
ovulation
what stimulates and sustains the proliferative (pre-ovulatory) phase of the uterine cycle?
ovarian oestrogen
when does the secretory phase of the uterine cycle occur?
immediately after ovulation
what is the proliferative phase stimulated by?
progesterone and oestrogen from the corpus luteum
what occurs in the proliferative phase of the uterine cycle?
endometrium prepares for implantation
what is amenorrhoea?
cessation of menses
what does oestrogen do at puberty?
promote oogenesis and increase growth of vagina, uterus and uterine tubes
what do oestrogen and progesterone work together to do?
- regulate uterine cycles and changes in cervical mucus
- oestrogen repairs functional layer
- progesterone promotes blood vessels and gland growth/secretion
- maintain pregnancy and breast growth
what are female characteristics not involved in reproduction induced by female hormones?
- growth of hair in pubic and axilliary regions
- growth of breasts
- widening of pelvis
- increased subcutaneous fat (hips and breasts)
how are the mammary glands functional in females?
produces milk to nourish newborn
what part of the mammary gland produces milk?
lobules
how long can the secondary oocyte survive for?
12-24hrs
how long can sperm survive in the female reproductive tract?
up to 3 days
for fertilisation to occur when must intercourse occur?
on day of ovulation or few days prior
what does capacitation do to the sperm?
enhances sperm mobility and prepares sperm for penetration of the oocyte
what does capacitation do to the cap of the acrosome?
thins, in the readiness to release enzymes
how long does capacitation take to occur?
8-10hrs
once sperm reaches the ovum what must they weave through to reach the zona pellucina?
granulose cells of the corona radiata
what is the zona pellucida?
thick gylcoprotein coat surrounding oocyte
when sperm bind to the zona pellucida what does this cause?
rise in calcium levels resulting in breakdown of acrosomal membranes, that digest holes in layer
is a sperm that arrives earlier or later more likely to fertilise ovum?
later
when the sperm has digested through the zona pellucida what does it bind to?
special receptors on the oocyte membrane
after the sperm binds to the receptors what occurs?
the sperm and oocyte fuse and the sperm’s DNA is released into oocyte
what does DNA being released into the oocyte stimulate?
cortical reaction, where calcium levels increase causing destruction of sperm receptors and hardening zona pellucida
why does the zona pellucida harden after fertilisation?
prevents further entry of sperm
where does fertilisation usually occur?
distal end of the uterine tube
