Reproductive system Flashcards
What are androgens?
male sex hormones
What are estrogens?
female sex hormones
What temperature is ideal for the testes production of sperm?
3 degrees lower than body temperature
What divides the scrotum into left and right?
a midline septum
What are the two sets of muscles and what do they do?
DARTOS - smooth muscle that wrinkles scrotal skin
CREMASTER - skeletal muscle that raises the scrotum
What is the pampiniform plexus?
it is a network of veins covering the testicular artery to cool the incoming blood
Each testicle is surrounded by two tunics. What are they called?
TUNICA VAGINALIS: derived from peritoneum (outer tunic)
TUNICA ALBUGINEA: the fibrous capsule (inner tunic)
how many lobules are the testes divided into?
250-300
What are the two structures do the lobules contain?
1-4 SEMINIFEROUS TUBULES: produce sperm cells
INTERSTITIAL CELLS: produce testosterone
Describe the pathway of sperm.
seminiferous tubules-> rete testes-> efferent ductules-> epididymis-> ductus (vas) deferens
What is the spermatic cord?
it is the connective tissue sheath that runs from testes up into the pelvic cavity
it encloses nerves, blood and lymphatic vessels
What are the three components of the penis?
ROOT
SHAFT
GLANS PENIS
What is another name for the foreskin?
prepuce
What is the crura and what is its purpose?
it is the proximal end of the penis that is surrounded by muscle. It anchors the penis to the pubic arch
Explain the internal structure of the penis.
contains the spongy urethra
and three cylinders of erectile tissue
What are the 3 cylinders of erectile tissue in the penis called?
CORPUS SPONGIOSUM: surrounds the urethra
CORPORA CAVINOSA: the paired dorsal erectile bodies
What is the epididymis? Describe its structure
the duct that receives sperm from the testes
head contains efferent tubules
the duct contains STERIOCILIA which pass nutrients to the sperm
How long does sperm stay in the epididymis?
20 days to mature and become motile.
can stay for several months
What happens to the epididymis during ejaculation?
the smooth muscle in its walls contract to expel sperm
What is the length of the uncoiled epididymis?
6m or 20 ft
how long is the ductus (vas) deferens?
45cm or 18 inches
What is the ampulla?
it is what the vas deferens becomes when it expands towards the end after wrapping around the urinary bladder and coming back down behind it.
What is the purpose of the ductus (vas) deferens?
to gather sperm after it leaves the epididymis and expel it into the ejaculatory tract.
does this by having a thick wall of smooth muscle that contracts to generate strong peristaltic (pressure waves created by wave contractions) waves
Describe what a vasectomy is and its rate of success.
It is the cutting and ligating (tying off) of the ductus (vas) deferens
nearly 100% effective
What are the three regions of the urethra?
PROSTATIC urethra: through the prostate gland
MEMBRANOUS urethra: between prostate and penis
SPONGY urethra: through penis
What does the seminal vesicle do?
produces viscous seminal fluid (60%) of the semen volume
What are the characteristics of the seminal fluid?
it is alkaline - to neutralize the acidity of the female tract
contains FRUCTOSE and ASCORBIC acid; nutrients for sperm
contains a coagulating enzyme to assist sperm by clumping them together.
contains PROSTAGLANDINS
What percent of the semen volume does the prostate secrete and what are the properties of its secretion?
produces 30% of the semen volume
milky, slightly acidic fluid that activates the sperm.
contains:
CITRATE - nutrient
ENZYMES - enhance motility
PROSTATE-SPECIFIC ANTIGEN (PSA) - levels will rise with enlargement of prostate
What are the bulbourethral glands and what do they do?
They are pea-sized glands inferior to the prostate
prior to ejaculation they produce a thick clear mucus into the spongy urethra that:
lubricates glans penis and neutralizes any acidic urine left in the urethra
What is semen, how much is secreted and how many sperm are in each secretion?
the mixture of sperm and accessory gland secretions
only 2-5mL are ejaculated containing 20-150 million sperm/mL
Explain the process of erection.
Initiated by sexual stimuli (can be induced or inhibited by higher brain centers)
PARASYMPATHETIC reflex promotes the release of NO which causes vasodilation
corpora cavernosa expands and fills with blood compressing drainage vessels
corpus spongiosun’s purpose is to keep the urethra open
Explain the process of ejaculation
SYMPATHETIC SPINAL REFLEX causes responses from the genital organs:
contraction of ducts and accessory glands
constriction of sphincter and bladder
rapid contractions of bulbospongiosum muscles (propel sperm along the urethra)
What is spermatogenesis?
the sequence of events that produces sperm in the seminiferous tubules of the testes.
What is a diploid and what is a haploid?
a diploid is a 2n cell. This is what most body cells are. they contain 23 pairs of chromosomes. (46 chromosomes total)
gametes are haploid (n) and contain only 23 chromosomes which allows for genetic variation
What are the 3 processes in spermatogenesis?
MITOSIS - diploid spermatogonia divide to produce more spermatogonia
MEIOSIS - diploid spermatogonia produce haploid gametes (early spermatids)
SPERMIOGENESIS - early spermatids develop into mature spermatozoa
What are the 3 important cells in the testes as relating to spermatogenesis?
SPERMATOGONIA: become gametes
SUSTENTACULAR (sertoli) cells: nurse cells that enclose and assist sperm cell in development
INTERSTITIAL cells: located outside seminiferous tubules that secrete testosterone
Explain the process of the portion of spermatogenesis that involves mitosis.
spermatogonia (stem cells) in contact with the epithelial basal wall undergo mitosis producing 2 cells:
Type A: purpose is to maintain the germ cell line at the basal lamina.
Type B: move toward the lumen and develop into primary spermatocytes
Explain the process of the portion of spermatogenesis that involves meiosis.
this goes from spermatocytes to spermatids
MEIOSIS I : primary spermatocyte (2n) -> two secondary spermatocytes (n)
MEIOSIS II : each secondary spermatocyte (n) -> 2 spermatids (n)
Explain the process of the portion of spermatogenesis that involves spermiogenesis.
this goes from spermatids to sperm
spermatids lose excess cytoplasm and form a tail becoming spermatozoa (sperm)
What are sustentacular cells?
they are the large supporting cells that extend from the wall of the tubule and surround the developing cells.
assist in sperm cell development by:
providing nutrients and signals and removing excess cytoplasm sloughed off during spermiogenesis.
secrete fluid for sperm transport
form the blood-testis barrier
What is the blood-testis barrier?
it is formed by the nurse cells in the testes and prevents the sperm antigens from escaping into the blood where they would activate the immune system.
tight junctions between nurse cells form two compartments:
BASAL compartment: spermatogonia and primary spermatocytes
ADLUMINAL compartment: meiotically active cells and the tubule lumen
What produces androgen binding protein (ABP)?
the sustentacular cells
Why would the sperm antigens activate the immune system of the body if they escaped into the blood?
because spermatogenesis does not begin until puberty. This means that because the immune system develops early in life, it will not recognize these cells as “self”
explain the HPG axis (the relationship between the hypothalamus, pituitary and gonads in hormonal control of reproduction.
Hypothalamus releases GnRH
GnRH stimulates pituitary to release LH and FSH
LH stimulates the interstitial cells to release testosterone
FSH stimulates sustentacular cells to release ABP and inhibin
ABP increases spermatogenic cell’s susceptibility to testosterone. Testosterone causes the cells to proceed with spermatogenesis
rising testosterone and inhibin levels cause the hypothalamus to stop releasing GnRH
What is testosterone synthesized from?
cholesterol
How does testosterone exert its effects?
by being converted to:
DIHYDROTESTERONE in the prostate
ESTRADRIOL in the neurons of the brain
What does testosterone do?
- stimulates spermatogenesis
- maintains accessory organs
- produces sex drive
Secondary characteristics:
hair growth, voice deepening, skin thickening, bone growth and density, and enhances development of skeletal muscles
What is the purpose of the ovaries?
to produce haploid gametes and hormones
What are the three ligaments that hold the ovaries in place?
OVARIAN LIGAMENT: anchors ovary to the uterus
SUSPENSORY LIGAMENT: anchors ovary to the pelvic wall
MESOVARIUM: suspends the ovary in between the uterus and pelvic wall
What is the broad ligament?
it supports the uterine tubes, uterus, and vagina.
it also contains the suspensory ligament and the mesovarium
what is the layer that surrounds the ovaries?
a fibrous tunica albuginea
What are the two regions of the ovaries?
OUTER CORTEX: contains ovarian follicles
INNER MEDULLA: large blood vessels and nerves
What is a follicle in the ovary?
it is an immature egg (oocyte) surrounded by:
- follicle cells (one layer thick)
- granulosa cells (when more than one layer is present)
Go through the 8 stages of development of an egg.
PRIMORDIAL follicle: squamous follicle cells + oocyte
PRIMARY follicle: cuboidal or columnar follicle cells + oocyte
SECONDARY follicle: 2+ layers of granulosa cells + oocyte
LATE SECONDARY follicle: fluid filled cavities begin to form. CT (theca folliculi) and granulosa cells cooperate to produce estrogens. Zona pellucida forms around the oocyte.
VESICULAR follicle: fluid filled cavities are now one large cavity called antrum. follicle now bulges the wall of the ovary
OVULATION oocyte ejected. some claim to feel pain.
CORPUS LUTEUM: develops from remaining follicle. secretes progesterone and estrogen.(if pregnancy happens will fill this role until 3 months when placenta takes over)
CORPUS ALBICANS: scar tissue develops if impregnation does not occur within 10 days
What are the three organs in the female duct system?
uterine (fallopian) tubes or oviducts
uterus
vagina
What do the fallopian tubes do?
receive the ovulated oocyte and provide a site for fertilization
Describe the structure of the fallopian tubes.
Not directly connected to the ovaries
smooth muscle in walls create peristalsis
non-ciliated cells: nourish the oocyte and sperm
supported by the mesosalpinx ligament
What is the ampulla?
the outer 1/3 of the fallopian tubes and the site of usual fertilization
What are the fimbriae?
they are the finger-like projections of the infundibulum
What is the infundibulum?
it is the distal end of the ampulla. It is a cone like structure that rests near the ovary
What are the three sections of the uterus?
fundus: top of the uterus
body: midsection
Isthmus: the narrow bottom part of the uterus superior to the cervix
What is the cervix?
the narrow outlet into the vagina from the uterus
opening on each end called:
internal and external os
Where are the cervical glands located and what is there purpose?
they are located in the cervical canal.
they secrete mucus to block of the cervix and the external os to protect bacteria from entering the uterus
during mid cycle it becomes less viscous to allow sperm in.
What supports the uterus?
laterally by the mesometrium (portion of the broad ligament)
lateral cervical ligaments to walls of pelvis
uterosacral ligaments secure uterus to the sacrum
round ligaments bind to the anterior wall
What are the three layers of the uterine wall?
Perimetrium: serous later
Myometrium: thick layers of smooth muscle
Endometrium: mucosal lining of simple columnar epithelium of CT
What are the two layers of the endometrium?
stratum functionalis: shed at menstruation
stratum basale: the basement layer that forms a new functionalis after menstruation
Describe the vascular supply of the endometrium.
straight arteries in the stratum basale
spiralling arteries in the stratum functionalis
How is the stratum functionalis shed during menstruation?
through spasms of the spiral arteries
What are the three layers of the wall of the vagina?
outer fibro elastic
middle smooth muscle
inner mucosa releases glycogen (this is then converted to lactic acid and gives the vagina its acidic properties)
What is the mons pubis?
fatty area overlying the pubic symphysis
What are the labia majora and minora?
majora is the outer hair covered fatty skin folds
minora: inner skin folds lying within the majora
What is the vestibule?
the recess between labia minora
What are the greater vestibular glands?
just posterior of the vaginal opening
purpose is to secrete lubricant for the vagina during intercourse.
What is the clitoris made of?
erectile tissue hooded by prepuce
glans clitoris: exposed portion
Describe the mammary glands and there structure.
they are modified sweat glands of 15-25 lobes
AREOLA: pigmented skin surrounding the nipple
SUSPENSORY ligaments: attach the breast to the underlying muscle
Lobules within the lobes contain glandular alveoli that produce milk
Describe the path of milk.
milk -> lactiferous ducts -> lactiferous sinuses -> open to the outside of the nipple
List the traits of breast cancer including how it arises, its risk factors, and treatment.
usually arises from the epithelial cells of small ducts.
RISK FACTORS: early onset of menstruation and late menopause, no pregnancies or late first pregnancy, family history
10% are due to heredity defects
70% of women have no risk factors
Treatment: depends on severity
radical mastectomy - removing the whole breast
lumpectomy - removing the lump
simple mastectomy - removing breast tissue only
Describe the overall hormonal control in the female reproductive system.
HYPOTHALAMUS (day 1)
I
GnRH
I
anterior pituitary
I
FSH and LH
I
ovaries
I
growth of several follicles and releasing of estrogen. estrogen stimulates synthesis and storage of FSH and LH and further stimulates release of estrogen.
I
High estrogen levels at day 14 trigger pituitary to release a surge of LH which triggers ovulation and corpus luteum development
I
Corpus luteum releases progesterone and estrogen and inhibits FSH and LH. Dropping FSH and LH ends luteal activity
I
Days 26-28 corpus luteum degenerates and ovarian hormone levels drop. Cycle restarts.
When does oogenesis and spermatogenesis begin?
spermatogenesis: at puberty
oogenesis: in fetal development
describe the process of oogenesis.
initial cell called the oogonium (2n)
-undergoes mitosis to produce the primary oocyte (housed in the primordial follicle)
Primary oocyte begins meiosis, but halts at prophase I
Each month a few cells are activated, one undergoes meiosis
ejects 1st polar body and new cell is called the secondary oocyte
secondary oocyte arrests in meiosis II and is ovulated. if penetrated by sperm, meiosis continues
ejecting 2nd polar body and resulting in an ovum
What are the differences between oogenesis and spermatogenesis?
gamete production: in males starts at puberty and continues for life. In females it is in fetal development and have about 400k left at puberty
each primary spermatocyte yields 4 functional sperm cells. Each primary oocyte yields only one functional egg cell.
all spermatocytes complete meiosis II, only oocytes penetrated by a sperm cell will complete meiosis II.
Describe the phases of the ovulation cycle
it is a 28 day cycle
FOLLICULAR phase: days 1-14 (follicle growth)
OVULATION day: 14
Luteal phase: days 14-28 (corpus luteum activity)
What prevents ovulation before puberty?
the ovaries secreting small amounts of estrogens that inhibit the hypothalamic release of GnRH
What are the three phases of the uterine (menstrual) cycle
MENSTRUAL phase: days 1-5
PROLIFERATIVE phase: days 6-14
SECRATORY phase: days 15-28
What happens during the menstrual phase of the uterine cycle?
ovarian hormones (estrogen and progesterone) are at their lowest level
FSH (gonadotropins) are beginning to rise
Stratum functionalis sheds
What happens during the proliferative phase of the uterine cycle?
Developing follicles secrete estrogen
ESTROGEN: prompts generation of new functional layer and increased synthesis of progesterone receptors in the endometrium
glands ENLARGE and spiral arteries inc in number
What happens during the secretory phase?
Corpus luteum secretes estrogen and Progesterone triggers further development of endometrium.
glandular secretion of GLYCOGEN
formation of CERVICAL PLUG
What happens during the menstrual cycle if fertilization does not occur?
corpus luteum degenerates resulting in falling progesterone
spiral arteries kink and spasm
endometrial cells begin to die
spiral arteries constrict again and then relax and flood blood in which causes capillaries to fragment and the stratum functionalis to shed
What are some of the effects of estrogen apart from the cycle?
rising levels at puberty:
- promote oogenesis and follicle growth
- exert anabolic affects on the female repro tract
- causes a short growth spurt because it also causes epiphyses of bones to close off
- induce secondary sex characteristics: breasts, fat, widening of pelvis
- metabolic changes (reduced cholesterol and facilitates Ca2+ uptake)
Why does it make sense that more older woman suffer from osteoporosis than men?
because estrogen contributes to the uptake of calcium and its levels drop after menopause.
What are the effects of progesterone during pregnancy?
during pregnancy inhibits uterine contractions and prepares breasts for lactation
Explain what gonorrhea is and give its characteristics.
bacterial infection
SYMPTOMS: males: urethritis, painful urination, discharge of pus.
females: 20% asymptomatic, abdominal discomfort, vaginal discharge or abnormal uterine bleeding
can result in sterility and pelvic inflammatory diseases
TREATMENT: antibiotics, but becoming resistant
list the characteristics of syphilis.
it is a bacterial infection transmitted sexually or congenitally
infants are born stillborn or die shortly after death
no symptoms 2-3 weeks after infection
painless sore appears but lasts a few weeks
secondary signs will appear 3-12 weeks later then disappear: pink skin rash, fever, joint pain
may progress to tertiary stage characterized by lesions of CNS, blood vessels, bone and skin
TREATMENT: penicillin
list the characteristics of chlamydia
most common bacterial STI and cause of infertility among women
causes 25-50% of pelvic inflammatory disease
SYMPTOMS: urethritis, discharges, abdominal, rectal, and testicular pain, painful intercourse, irregular menses
can cause arthritis and UTI in males
TREATMENT: tetracycline
list the characteristics of trichomoniases.
caused by a parasitic protest
most common curable STI among sexually active
SYMPTOMS: many have none, yellow-green vaginal discharge with a strong odor.
Easily treated
List the characteristics of genital warts.
second most common STI. (caused by HPV) viral
increases the risk of cancers in infected body regions (ex cervical)
treatment is difficult and controversial (what sex should be vaccinated)
List the characteristics of genital herpes.
viral infection. very difficult to treat, has latent periods with flare ups.
spread by direct skin contact when virus is active or with infectious secretions.
TREATMENT: acyclovir and other antiviral drugs
