reproductive system Flashcards
define reproduction
process by which new individuals of a species are produced and
genetic material is passed from generation to generation
describe somatic cells; number of chromosomes
◦ 23 pairs of chromosomes for a total of 46 chromosomes
◦ Paired homologous chromosomes since contain same genes in same
order
◦ One chromosome from Dad, one from Mom
also known as sister chromatid
22 autosomes & 1 pair of sex chromosomes
Sex chromosomes are either X or Y
what is a diploid chromosome in humans
A diploid cell (2n) has two sets of chromosomes.
◦ For humans, the diploid number is 46 (2n = 46).
what is a gamete
A gamete (sperm or egg) contains a single set of chromosomes and is haploid (n).
◦ For humans, the haploid number is 23 (n = 23)
at sexual maturity what do the ovaries and testes produce
At sexual maturity, the ovaries and testes produce haploid gametes.
◦ Secondary oocytes (female)
◦ Sperm cells (male
describe meiosis in humans
Gametes are the only types of human cells produced by meiosis, rather than
mitosis.
◦ Meiosis results in one set of chromosomes in each gamete
what does meiosis produce in humans
Meiosis results in the production
of haploid cells that contain only
23 chromosomes.
Which of the following is found at the beginning
of meiosis I?
a) 23 nonduplicated chromosomes
b) 46 nonduplicated chromosomes
c) 23 duplicated chromosomes
d) 46 duplicated chromosomes
D
Which of the following is found in a daughter
cell, at the end of telophase I?
a) 23 nonduplicated chromosomes
b) 46 nonduplicated chromosomes
c) 23 duplicated chromosomes
d) 46 duplicated chromosomes
C
Which of the following is found in a daughter
cell, at the end of telophase II?
a) 23 nonduplicated chromosomes
b) 46 nonduplicated chromosomes
c) 23 duplicated chromosomes
d) 46 duplicated chromosomes
A
what are the different organs of reproduction?
Gonads (produce gametes and secrete hormones),
◦ Ducts (transport, receive, and store gametes),
◦ Accessory sex glands (produce materials that support gametes).
◦ Supporting structures help in the delivery and joining of gametes
what structures are part of the female reproductive system
what do the ovaries, fallopian tubes, uterus and mammary glands do?
◦ Two ovaries (gonads)
◦ Produce oocytes and hormones
◦ Two uterine (Fallopian) tubes
◦ Transport fertilized ova
◦ Uterus
◦ Fetal development
◦ Vagina
◦ Vulva
◦ Mammary glands
◦ Produce milk
what are the two different repoductive ligaments in the female reproductive system and what do they support?
The broad ligament is a major
support for the uterus (provides
side-to-side and rotational support)
The ovarian ligaments provide
support for the ovaries
describe the structure of the ovaries
located on either side of the
uterus, ovaries are maintained
in position by a series of
ligaments
where are the ovarian follicles and what do they contain?
ovarian follicles lie in the
cortex and consist of oocytes
in various stages of
development
where does oogenesis occur
in the ovaries
what does oogenesis result in
the formation of dingle haploid oocyte -> the female gamete
what happens to the follicle cells surrounding the oocyte while oogenesis is occuring
While oogenesis is occurring, the follicle cells surrounding the oocyte are also
undergoing developmental changes
describe supporting cells and their function
Follicles consist of oocytes in various stages of development, and all
supporting cells known as follicular cells
or granulosa cells
(depending on
their stage) →nourish and secrete estrogens as the follicle grows
describe follicular development
how to eggs develop in a female
Germ cells from yolk sac migrate to ovary and become oogonia
◦ In the female fetus, oogonia divide to produce millions by mitosis but most
degenerate (atresia)
◦ Some develop into primary oocytes and stop in prophase stage of meiosis I
(prophase I)
◦ 200,000 to 2 million are present at birth
◦ 40,000 remain at puberty, but only 400 mature during a woman’s life
what happens to the egg of a female every moth. What needs to happen for meiosis to occur
Each month, hormones cause meiosis I to resume in several follicles so that
meiosis II is reached just before ovulation
Penetration by the sperm causes the final stages of meiosis to occur
describe the process of follicular development
describe follicular development and oogenesis
In oogenesis, what structures contain the
“extra” chromosomes?
a) Primary oocyte
b) Polar bodies
c) Corona radiata
d) Follicle cells
B
In oogenesis, how many chromosomes do
polar bodies contain?
a) 23
b) 46
c) 46 in the first polar body, and 23 in the second polar body
d) 23 or 46, depending if first polar body divides again
A
What is required for meiosis II to be completed?
a) FSH
b) LH
c) Ovulation
d) Estrogen
e) Fertilization
E
what is the function of the fallopian (uterine) tubes
transport oocyte from the ovaries to the uterus
and are the normal sites of fertilization
function of fimbriae. (finger like things on top of ovaries)
sweep oocyte into the uterine tube
function of cilia in uterus
cilia (from ciliated columnar epithelium) &
peristalsis (from smooth muscle of muscularis
layer) move oocyte along
where does sperm reach oocyte and what happens after
*sperm reaches oocyte (generally in ampulla),
fertilization occurs within 24 hours after ovulation
*zygote reaches uterus about 7 days after
ovulation
function of uterus
Functions in
Transport of spermatozoa
Menstruation
Implantation of a fertilized ovum
Development of a fetus during pregnancy
Labour
describe the different tissue layers of the uterus
outer perimetrium (serosa)
◦ CT layer
middle myometrium
◦ smooth muscle layers, contract under
influence of oxytocin during labor
inner endometrium
◦ stratum functionalis (shed during
menstruation)
◦ stratum basalis (gives rise to a new stratum
functionalis after each menstruation
What primary tissue type is found in the
uterine myometrium?
a) Smooth muscle
b) Striated muscle
c) Simple columnar epithelium
d) Glandular epithelium
e) Collagenous connective tissue
A
Which of these is lost during menses?
a) Functional layer of endometrium
b) Functional layer of myometrium
c) Basal layer of endometrium
d) Uterine glands of endometrium
e) Entire endometrium
A
what do the secretory cells of the mucosaof the cervix produce. When are they less / more receptive to sperm
Secretory cells of the mucosa of the cervix produce a
cervical mucus (a mixture of water, glycoprotein, serum
type proteins, lipids, enzymes, and inorganic salts)
◦ when thin, is more receptive to sperm
◦ when thick, forms a cervical plug that physically
impedes sperm penetration
◦ mucus supplements the energy needs of the sperm.
describe the vagina and its 3 basic functions
The vagina is a fibromuscular canal lined with mucous membrane that extends
from the exterior of the body to the uterine cervix. It is composed of both
longitudinal and circular muscle, and has 3 basic functions:
◦ Serve as a passageway
◦ for menstrual flow
◦ Receive sperm
◦ Form the lower
◦ birth canal
what does the vulva refer to
The vulva (female external genitalia) refers to the:
◦ Mons pubis (created by adipose tissue)
◦ Erectile tissue of the clitoris
◦ Labia majora (outer limits of vulva)
and labia minora (cover the
vestibule)
◦ Vestibule, the area
between the labia minora
◦ Vaginal orifice (opening
what is the perineum. What happens to it during childbirth
Diamond-shaped area between the thighs and buttocks of both males and
females that contains the external genitals and anus
During childbirth, the emerging fetus may cause excessive stretching and tearing
of the perineum
describe the function of the mammary glands and how prolactin and oxytocin play a role
Responsible for milk production (lactation)
◦ Function in synthesis, secretion and ejection of milk
◦ Prolactin (along with estrogens and progesterone) stimulate milk production
◦ Contractions of myoepithelial cells surrounding alveoli help eject milk –
stimulated by oxytocin, in response to suckling
what are lactiferous ducts
Each breast has a pigmented projection nipple that has a series of openings that
are called lactiferous ducts where milk is expelled
what is the areola
the circular pigmented area of the brestes
what are suspensory (coopers) ligaments
Suspensory (Coopers) ligaments run between the skin and fascia to support the
breasts → become looser with age
describe the structure of the mammary glands
Within each mammary gland are modified sudoriferous (sweat) glands that
produce milk
There are 15-20 lobes that are separated by adipose tissue
Amount of adipose tissue
determines size of breast
Each lobe has several lobules
that are clusters of alveoli which
secrete milk into ducts
what is the female reproductive cycle controlled by and what 2 parts does it consist of?
Controlled by monthly hormone cycle of anterior pituitary, hypothalamus &
ovary
Ovarian cycle
◦ changes in ovary during & after maturation of oocyte
The uterine (menstrual) cycle
◦ involves changes in the endometrium
◦ preparation of uterus to receive fertilized ovum
◦ if implantation does not occur, the stratum functionalis is shed during
menstruation
What hormone is secreted ONLY by the
corpus luteum?
a) Progesterone
b) Estrogen
c) FSH
d) Luteinizing hormone
A
3 steps of ovulation
- high levels of estrogen from almost mature follicle stimulate release of more GnRH and LH
- GnRH promote and release FSH and more LH
3.LH surge brings about ovulation
what happens when the mature follicle has become a corpus luteum
the ovary, the mature follicle has become a corpus luteum, a temporary
structure essential for establishing and maintaining pregnancy in females
◦ It secretes estrogens and progesterone, which are responsible for the
thickening and maintenance of the endometrium, respectively
◦ After approx. 14 days, if the oocyte II is not fertilized, the corpus luteum stops
secreting progesterone and degenerates into a corpus albicans (a mass of
fibrous scar tissue
what happens is fertilization occurs and corpus luteum is “rescued”
If, on the other hand, fertilization occurs, the corpus luteum is “rescued” from
degeneration by a hormone called human chorionic gonadotrophin (hCG –
produced by the developing embryo). With hCG support, the corpus luteum
goes on to produce hormones well into the 1st trimester until the placenta can
take over
On what day in a typical ovarian cycle is
luteinizing hormone secreted?
a) Days 1 – 3
b) Days 13 – 14
c) Days 20 – 22
d) Day 28
b) 13-14
What event marks the beginning of the
ovary’s luteal phase?
a) Fertilization
b) Menstruation
c) Implantation
d) Ovulation
D
The secretory phase of the uterine cycle is
associated with
a) Increased secretion of progesterone and formation of the
corpus albicans.
b) Increased secretion of progesterone and formation of the
corpus luteum.
c) Increased secretion of luteinizing hormone and rupture of the
mature follicle.
d) Increased secretion of estrogen and maturation of the
secondary follicle.
B
describe the window or opportunity for fertilization
The window of opportunity for fertilization
to happen is approximately 2 days before
ovulation to 1 day after ovulation (the
sperm can survive 48-72 hrs in the uterine
tube)
what happens at the moment of conception
At the moment of conception, the
successful sperm penetrates the plasma
membrane of the 2o oocyte and the
nuclear material of the two cells unite to
reconstitute the normal number of
chromosomes (2n)
◦ The new diploid cell is called a zygote
describe the role of estrogen in the body
is responsible for the thickening of the endometrium, and for the regulation
of follicle development
◦ is responsible for the presence of secondary sex characteristics (adipose
tissue in the breasts, mons pubis, abdomen, and hips, voice pitch, and broad
pelvis)
◦ it also lowers blood cholesterol and assists with fluid and electrolyte balance
and protein anabolism
describe the role of progesterone in the female body
Progesterone is the principal hormone responsible for maturation of the uterine
endometrium, as well as an important player in stimulating breast development
◦ It inhibits GnRH and LH through a negative feedback loop
describe relaxin
Relaxin is released by the corpus luteum;
◦ it relaxes the myometrium and the pubic
symphysis at the end of pregnancy
describe inhibin
Inhibin is released by granulosa cells, and then
in large amount by the corpus luteum;
◦ it inhibits FSH and LH
name of GnRH
Gonadotropin-Releasing Hormone (GnRH)
describe the different structures that make up the male reproductive system
The testes make sperm and secrete hormones
Ducts transport and store sperm, assist in
their maturation, and convey them to the
exterior
Semen contains sperm plus the secretions of
sex glands
The penis delivers sperm to the female
reproductive tract
what is the scrotum and what does it do
The scrotum is a cutaneous outpouching of the abdomen that supports the
testes (male gonads)
Location of scrotum and contraction of its smooth muscles regulate the
temperature of the testes
◦ sperm survival requires ~3 degrees lower temperature than core body
temperature
◦ contraction of muscles
◦ elevates testes on exposure to cold (can absorb body heat)
◦ warmth reverses the process
function of dartos and cremaster muscles
move testes closer to the body which causes scrotum to become tighter / have less surface area
describe the lobules in the seminiferous tubules
Each lobule is filled with
2 or 3 seminiferous
tubules where sperm
are formed
(spermatogenesis)
200-300 compartments called lobules
what are the two types of cells that seminiferous tubules have?
Spermatogonia (stem cells - 2n) – single layer against basement membrane,
develop into sperm cells toward the lumen
* Sertoli cells (supporting cells) – internal to basement membrane and to
spermatogonia, form blood-testis barrier which means that substances from
blood must first pass through Sertoli cells before they reach the developing sperm
functions of sertoli cells
- Nourish spermatocytes, spermatids and sperm
- Produce fluid for sperm transport
- Control movement of spermatogenic cells and release of sperm into lumen
- Phagocytize excess spermatid cytoplasm
- Mediate effects of testosterone and FSH
- Secrete inhibin
- Secrete androgen-binding protein
- Form blood-testis barrier
describe interstitial cells (Leydig)
Interstital cells (Leydig) are found in between the tubules, and secrete
testosterone
how long does spermatogenesis take? describe the process
65-75 days
Spermatogonia (2n) undergo mitosis – some stay as stem cells, some
differentiate into primary
spermatocytes (2n)
Primary spermatocytes (2n) undergo
meiosis I → secondary
spermatocytes (n)
Secondary spermatocytes (n)
undergo meiosis II ➔ spermatids (n)
Spermatids turn into spermatozoon
(sperm cell; n)
result of spermatogenesis
one primary spermatocyte (2n) gives rise to
4 spermatids (n
Which of the following cells is diploid?
a) Secondary spermatocyte
b) Spermatogonium
c) Spermatid
d) Spermatozoon
B
Which of these represent the first haploid
stage of spermatogenesis?
a) Spermatogonia
b) Primary spermatocytes
c) Secondary spermatocytes
d) Spermatids
C
describe the sperm cell
Acrosome contains enzymes that help
penetrate/fertilize a secondary oocyte
* Nucleus contains 23 chromosomes
* Tail – microtubules for motility– mitochondria f
how does testosterone control spermatogenesis
before birth, stimulates development of male reproductive system ducts and
descents of testes
◦ at puberty, controls the growth, development and functioning of sex organs
and male secondary sex characteristics
◦ regulates male sexual behavior and sex drive, as well as spermatogenesis
describe control of testosterone production
In hot weather, the testes are protected by:
a) Contraction of the cremaster muscle.
b) Relaxation of the dartos muscle.
c) Contraction of the cremaster muscle and relaxation of the dartos muscle.
d) Movement to the outside of the pelvic cavity
B
describe the pathway of sperm through the ducts od the testes
describe the epiididymis
Comma-shaped organ that lies along
the posterior border of each testis
Really long (6m), tightly-coiled tube
*Site of sperm maturation (14 days)
* Acquire motility and ability to
fertilize oocyte
*Sperm may remain in storage here for
several months, after which they are
either expelled or they degenerate
and are reabsorbed
desctrivbe the ductus (vas) deferens
Loops around ureter and posterior to bladder
Stores sperm and propels them from the
epididymis toward the prostatic urethra during
ejaculation by PERISTALSIS → 3 layers of
smooth muscle
*45 cm long duct
*Ascends along posterior border of the
epididymis
*Passes over the pubic symphysis and enters
the pelvic cavity
describe the ejaculatory ducts
Formed by union of duct from seminal
vesicle and ampulla of ductus (vas)
deferens (posterior to urinary bladder)
Terminate in prostatic urethra
Eject sperm and secretions from seminal
vesicles into urethra before ejaculation
describe the male urethra
20 cm long passageway for urine & semen
Prostatic urethra (passes through
prostate)
Membranous urethra (passes through
deep muscles of perineum)
Spongy urethra (through penis)
describe the accesory sex glands
While the ducts of the male reproductive system store and transport sperm
cells, the accessory sex glands secrete most of the liquid portion of semen
3 accessory sex glands:
◦ The seminal vesicles
◦ The prostate gland)
◦ The bulbourethral glands
describe the fluid from seminal vescicles
Pair of pouch-like organs found posterior to the base of bladder
Secrete an alkaline, viscous fluid that contains fructose and other substances
(about 60% of semen volume)
* Alkaline nature of the fluid helps
neutralize acid in the male urethra and
from female reproductive tract (acidity
would kill sperm)
* Fructose is for ATP production by sperm
* Prostaglandins contribute to sperm
motility and viability
describe the prostate
Donut-shaped gland about the size of a golf ball which is inferior to the urinary
bladder and surrounds the prostatic urethra
The prostate secretes a milky, slightly acidic fluid (pH 6.5) into the prostatic
urethra, that contains:
Citric acid, which can be used by
sperm for ATP production
Several proteolytic enzymes which
liquefy coagulated semen and act as
antibacterial agents
describe the bulbourethral glands
Paired glands located inferior to the prostate on either side of the membranous
urethra, within deep muscles of perineum
* Size of a pea
* Ducts open into spongy urethra
* Secrete an alkaline fluid into the
urethra that protects the passing
sperm by neutralizing acids from
urine
* Secrete mucus (lubricant
Which of these is NOT part of the pathway for
sperm?
a) Seminal glands
b) Urethra
c) Ductus deferens
d) Epididymis
A
describe semen
A mixture of sperm and seminal fluid
◦ secretions from seminiferous tubules (sperm), seminal vesicles (alkaline pH,
sticky), prostate (milky) and bulbourethral glands (sticky)
volume ~ 2.5-5 mL
50-150 million sperm / mL
◦ If < 20 million sperm / mL, likely infertile
Slightly alkaline pH (7.2-7.7)
Coagulates after ~5min and reliquefies after ~10-20 min.
Reliquefaction important to allow sperm motility through cervix of uterus
corpora cavernosa penis
HE HARD AF
spongy structures composed of numerous blood sinuses (vascular
spaces) lined by endothelial cells, smooth muscle and elastic CT. They fill with blood during
erection
corpus spongiosum penis
◦ Corpus spongiosum penis: contains the spongy urethra and keeps it open during ejaculation
describe erection
parasympathetic reflex causes erection
sexual stimulation ➔ dilation of arteries supplying the penis (nitric oxide mediates
local vasodilation)
Expansion of blood sinuses compresses the veins - blood is trapped
describe ejaculation
Ejaculation is a sympathetic reflex
peristalsis in epididymis, vas deferens, seminal vesicles, ejaculatory ducts and prostate
propel semen into spongy urethra
urination is prevented during ejaculation
The ___________ is/are the longest of the male
reproductive system ducts.
a) Rete testes
b) Ductus epididymis
c) Ductus deferens
d) Ejaculatory duct
B
The structure that contributes the most to
semen volume is:
a) Epididymis
b) Urethra
c) Seminal vesicles
d) Prostate
e) Bulbourethral glands
C