REPRODUCTIVE SYSTEM Flashcards
1
Q
The reproductive system does not contribute to
A
Homeostasis
2
Q
Primary sex organs (gonads)
A
testes and ovaries
3
Q
Produce gametes (sex cells )
A
sperm & ova
4
Q
Secrete steroid sex hormones
Male
Female
A
Androgens (males)
Estrogens and progesterone (females)
5
Q
Sperm delivery pathway
A
Epididymis → ductus deferens → ejaculatory duct → urethra
6
Q
Accessory reproductive organs
A
ducts, glands,
and external genitalia 3
7
Q
THE SCROTUM
A
Sac of skin and superficial fascia Hangs outside abdominopelvic cavity
Contains paired testes
8
Q
What regularte temp in scrotum
A
Dartos muscle
Cremaster muscles
9
Q
Dartos muscle
A
smooth muscle; wrinkles scrotal skin;
pulls scrotum close to body
10
Q
Cremaster muscles
A
bands of skeletal muscle that
elevate testes
11
Q
THE TESTES surrounded by two tunics
A
Tunica vaginalis – outer layer
Tunica albuginea – inner layer;
fibrous capsule
12
Q
Septa
A
extensions of the capsule that extend
into the testis
Divide testes into lobules
13
Q
Each lobule contains
A
1-4
seminiferous tubules
14
Q
seminiferous tubules
A
Tightly coiled structures
Sperm-forming factories
Interstitial endocrine cells surrounding
seminiferous tubules produce androgens
15
Q
Ducts carry sperm from testes to body exterior
A
-Epididymis
-Ductus deferens
-Ejaculatory duct
-Urethra
16
Q
Duct of the epididymis
A
Microvilli absorb testicular fluid and pass
nutrients to stored sperm
17
Q
Duct of the epididymis Process
A
Nonmotile sperm enter
Pass slowly through
Become motile
Stored several months
18
Q
During ejaculation epididymis contracts,
expelling
A
sperm into ductus deferens
19
Q
DUCTUS DEFERENS
A
Carries sperm from the epididymis to the
ejaculatory duct
20
Q
DUCTUS DEFERENS Expands to form what and joins duct of
seminal vesicle to form…
A
ampulla; to form ejaculatory duct
21
Q
VASECTOMY
A
Cutting and ligating ductus deferens; nearly 100%
effective form of birth control
22
Q
URETHRA
A
Extends from the base of the urinary bladder to the tip of the penis
Carries both urine and sperm (different times)
Sperm enters from the ejaculatory duct
23
Q
Regions of the urethra
A
Prostatic urethra
Membranous urethra
Spongy (penile) urethra
24
Q
Prostatic urethra
A
—surrounded by prostate
25
Membranous urethra
—from prostatic urethra to penis
26
Spongy (penile) urethra
—runs the length of the penis
27
ACCESSORY GLANDS help
HELP PRODUCE SEMEN
28
Semen is a mixture of sperm and accessory gland secretions from
Seminal vesicles
Prostate
Bulbourethral glands
29
SEMEN
Milky-white mixture of sperm and accessory gland secretions
Contains fructose for ATP production
Suppresses female immune response
30
Alkaline
neutralizes acidity of male urethra and female
vagina
31
Prostaglandins
decrease viscosity of mucus in cervix;
stimulate reverse peristalsis in uterus
32
ACCESSORY -- SEMINAL VESICLES
Located at the base of the bladder
o Produces a thick, alkaline, yellowish secretion (60% of semen)
33
Prostaglandins promote
smooth muscle contraction
34
ACCESSORY -- PROSTATE
Encircles the upper part of the urethra
Secretes a milky fluid
Helps to activate sperm
35
ACCESSORY -- BULBOURETHRAL GLANDS
-Pea-sized gland inferior to the prostate
-Produces a thick, clear mucus known as pre-ejaculate
-Cleanses the urethra of acidic urine
-Serves as a lubricant during sexual intercourse
36
Genetic determination
XY for male, XX for female) @ conception
37
Gonadal differentiation:
SRY gene expression (on Y chromosome) encode testis determining Factor to make gonad to testes
produces testosterone and develop other male features
38
SPERMATOGENESIS 3 stages
Sperm (spermatozoa) production
⚫ Begins at puberty and continues
throughout life, declines with age
3 stages:
⚫ 1. Mitosis: always replenish stock of
spermatogonia
⚫ 2. Meiosis: Spermatogonia (diploid) →
spermatids (haploid)
⚫ 3. Spermiogenesis: morphological changes
of spermatid → spermatozoa
39
Spermatogonia (stem cells)
undergo rapid mitosis to produce more stem
cells before puberty
40
ANATOMY OF A MATURE SPERM CELL
The only human flagellated cell
Head
⚫ Contains DNA
⚫ Acrosome
41
Acrosome
breaks down and releases enzymes to help the sperm penetrate an egg
42
TESTOSTERONE
- Stimulates reproductive organ development
(paracrine)
⚫ Underlies sex drive
⚫ Causes secondary sex characteristics
Deepening of voice
Increased hair growth
43
Erection
Spongy erectile tissue around the urethra
Erections → erectile tissue fills with blood
-Arterioles normally constricted
-Activation of parasympathetic neurons
44
Ejaculation
Propulsion of semen from male duct system
⚫ Sympathetic spinal reflex
45
Corpus spongiosum
ssurrounds urethra and
expands to form glans and bulb
46
Sympathetic spinal reflex
Internal urethral sphincter constricts
47
Erectile dysfunction
↓ Nitric Oxide (NO)
48
Ovaries - female gonads produce and secrete
Produce female gametes (ova)
Secrete female sex hormones, estrogen and progesterone
49
Accessory ducts include
Uterine tubes
Uterus
Vagina
50
erection viagra
NO → activates cGMP
- Viagra prevents breakdown
of cGMP (increases blood flow)
prolongs effect of cGMP aka latch phenomenon & [Ca 2+ ]ic
51
VAGINA
-From cervix to exterior of body
-Between bladder and rectum
-Receives the penis
-Birth canal
-Hymen
52
UTERUS
Receives, retains, nourishes the fertilized egg
53
Regions of the Uterus (inferior to superior)
-Cervix
-body
- Fundus - superior rounded region
above where uterine tube enters
54
Cervix
– that protrudes into the vagina
55
- Body
is the main portion
56
fundus
- superior rounded region
above where uterine tube enters
57
Semen prostaglandins → decrease
viscosity of mucus & trigger peristalsis
58
WALLS OF THE UTERUS
Endometrium
Myometrium
Perimetrium
59
Endometrium
inner layer
-Allows for implantation of a fertilized egg
-Sloughs off if no pregnancy occurs (menses)
60
Myometrium
middle layer of smooth muscle
61
Perimetrium
outermost serous layer of the
uterus
62
UTERINE TUBE
-Site of fertilization
-Receive the ovulated oocyte
-Attach to the uterus
-Little or no contact between ovaries and uterine tubes
63
Genetic determination
(XX for female) @ conception
64
female Gonadal differentiation:
SRY gene NOT expressed
Degeneration of
male organs → development of female gonads: ovaries
→ produce gametes & hormones, mature follicles
65
female Phenotypic differentiation:
strogen & progesterone promote
differentiation of internal and external genitalia
66
Estrogens
Produced by follicle cells
⚫ Cause secondary sex characteristics
Enlargement of accessory organs
Development of breasts
Appearance of axillary and pubic hair
Increase in fat beneath the skin, particularly in hips and breasts
Widening and lightening of the pelvis
Onset of menses (menstrual cycle
67
Progesterone
Produced by the corpus luteum
⚫ Production continues until LH diminishes in the blood
⚫ Major effects
Regulates uterine and ovarian cycle
Helps maintain pregnancy
Prepares the breasts for milk production
68
Mitosis (diploid to diploid
produces two daughter cells
⚫ maintains # chromosomes
(23 pairs of chromosomes = 46 chr)
⚫ identical chromosomes w/1 chromatid
69
Meiosis (diploid → haploid
formation of gametes
reduction of the chromosome number
23 pairs of chromosomes (2n) → 23 chromosomes (n)
haploid cells (n)
⚫ 4 daughter cells,
⚫ 23 chromosomes w/1 chromatid each
⚫ not identical to each other
10
70
Theca cells
Express LH receptor
⚫ when stimulated by LH → produce androgens
⚫ surround the follicle
71
Granulosa cells
Express FSH receptor
⚫ When stimulated by FSH → hyperplasia of granulosa cells
to protect and sustain oocyte
⚫ Produce aromatase enzyme:
androgens → estrogens
⚫ After ovulation: become granulosa
lutein cells that produce progesterone
72
Spermatogenesis:
Replenish spermatogonia stock
⚫ 4 identical cells (different DNA)
⚫ 4 viable sperm
⚫ error rate of 3-4%
73
Oogenesis
Limited number at birth → puberty → menopause
⚫ 1 viable gamete; 3 polar bodies
Unequal divisions ensure oocyte has ample nutrients for 6-7
day journey to uterus
Polar bodies degenerate and die
⚫ error rate of 20%
14
74
Ovarian cycle
Monthly series of events associated with
maturation of egg
75
Follicular phase
period of follicle growth
(days 1–14 or more)
can be highly variable
76
Ovulation
occurs mid cycle
1-2% more than 1 secondary oocyte
released
77
Luteal phase
period of corpus luteum activity
(days 14–28)
Progesterone and estrogen
little variation - 14 days
17
78
OVARIAN FOLLICLE STAGES SUMMARY
Primary follicle contains an immature oocyte
Ovulation occurs when the egg is mature* (secondary oocyte)
The ruptured follicle is transformed into a corpus luteum
79
Meiosis I is completed
just before ovulation:
Primary oocyte
→ secondary oocyte +
polar body
80
Secondary oocyte
arrested
in Meiosis II
(until fertilization)
81
HORMONAL EVENTS LEADING UP
TO OVULATION
Hypothalamus releases gnrh which tell Anterior pituitary to Secrete FSH and LH, High LH triggers ovulation, from fsh tell ovary to release egg
as the follicle
grows → leads to
estrogen secretion
LOW levels of
estrogens encourage
the hypothalamus to
release more GnRH
→ more FSH and LH
82
HORMONAL EVENTS AT AND AFTER OVULATION
Ovulation: follicle
ruptures releases
secondary oocyte
Corpus luteum release Progesterone
and estrogen Negative
feedback on
hypothalamus
Less GnRh → less
FSH and LH
Corpus luteum
degenerates* (Does not happen if egg is fertilized
and implants)
decrease in Progesterone
and estrogen
83
As progesterone and estrogen levels decrease the
hypothalamus again releases GnRH
stimulates the pituitary
to secrete more FSH and LH → new cycle begins
84
UTERINE (MENSTRUAL) CYCLE
Cyclic changes of the endometrium are regulated by cyclic
production of hormones
85
Stages of the menstrual cycle
⚫ Menstrual phase
⚫ Proliferative stage
⚫ Secretory stage
86
Menstrual phase: Days “1–5”
⚫ Functional layer of the endometrium is sloughed
bleeding occurs for 3–5 days (varies)
87
Proliferative stage: Days “6–14”
⚫ Regeneration of functional layer of the endometrium
⚫ Estrogen levels rise → LH surge → ovulation
88
Secretory stage: Days “15–28”
⚫ Levels of progesterone rise → Increase the blood supply to the endometrium
→ Endometrium increases in size & prepares for implantation
89
Secretory stage: If fertilization occurs →
embryo produces human chorionic gonadotropin
→ causes the corpus luteum to continue producing its hormones
90
Secretory stage If fertilization does NOT occur
Corpus luteum degenerates
↘ levels of released hormones
New cycle starts
91
HOW DOES THE BIRTH CONTROL WORK?
The “pill” usually contains
both estrogen & progestin
(at low levels)
NO GnRH no
OVULATION.
⇒ No pregnancy
92
Synthetic progestin and estrogen (in pill) mimic
the negative
feedback loop at the hypothalamus
→ STOPS production GnRH → NO production of FSH and LH
o → NO ovulation → NO pregnancy
93
DEVELOPMENTAL ASPECTS OF
THE REPRODUCTIVE SYSTEM
Females
- Breast development signals puberty (often around age 11)
- Menarche is the first menstrual period
- Menopause occurs when a full year has passed without menstruation
-Ovaries stop functioning as endocrine organs
-childbearing ability ends
-There is no equivalent of menopause in males, but there is a steady decline in
testosterone
94
SPERM TRAVEL THROUGH THE FEMALE
REPRODUCTIVE TRACT
Testes → Epididymis → Ductus deferens →
Ejaculatory duct → Urethra (prostatic, membranous,
spongy) → out of male body → Vagina → Uterus
(cervix, body) → uterine tube
95
HUMAN LIFE CYCLE
Union of an egg (n, 23 chromosomes) with
a sperm (n, 23 chromosomes)
creates a zygote (2n or 23 pairs of chromosomes = 46 chromosomes)
96
ectopic pregnancy
an abnormal
implantation of a fertilized egg that occurs
outside the uterus, usually fallopian tube
(tubal pregnancy)
97
FERTILIZATION
The oocyte is viable for 12 to 24 hours after ovulation
Sperm are viable for 2 to 5 days after ejaculation
~3-5 day window for fertilization to occur
98
The Process of Fertilization
Sperm capacitation (7-10hs)
⚫ Sperm surface proteins bind to
egg receptor proteins:
sperm and egg plasma membranes
fuse & two nuclei unite
⚫ Changes in the egg membrane:
prevent entry of additional sperm
(polyspermy)
⚫ The fertilized egg (zygote):
develops into an embryo 8
99
THE PROCESS OF FERTILIZATION 7 steps
- The sperm
approaches
the egg
- Proteins on the
sperm head bind to
egg receptors
- The plasma
membranes of sperm
and egg fuse
- The sperm
nucleus
enters the egg
cytoplasm
- A fertilization
envelope forms
- The sperm’s
acrosomal enzymes
digest the egg’s jelly
coat
- The nuclei of
sperm and egg
fuse
100
PRE-EMBRYONIC STAGE: CLEAVAGE
From the zygote (1 cell) to hundred cells packed.
101
Rapid cell cycles with no significant volume change = morula (solid ball)
→ Blastocyst (hollow ball with cell mass)
→ Gastrula (ball with invagination)
102
CLEAVAGE (D2-4)
Rapid cell cycles with
no significant overall
Vol change
morula
has the same size as
the original zygote
103
Cleavage ends with
zygotic transcription
104
in cleavage Blastomeres develop
distinct
cell-cell &
cell-medium
interactions.
105
in clevage Gap and tight junctions
form on
superficial
cells.
106
Na+/K+ pump expressed and Na+ (and water) are absorbed through
newly expressed channels. creating Blastocyst
107
Start off as a totipotent cell (morula)
Can form any cell in body AND placenta cells
⚫ Up to 8-cell stage, cells are totipotent
108
The blastocyst contains an inner cell layer mass of pluripotent cells
Can form any cell in body
109
Blastocyst is:
inner cell mass
(embryoblast) + trophoblast
110
Embryoblast becomes
Trophoblast becomes
the embryo
the chorion and
amnion (from where the embryo eats
[tropho-]
111
Trophoblast cells secrete
human Chorionic Gonadotropin hormone
112
human Chorionic Gonadotropin hormone maintain
maintains corpus luteum
113
Late Blastocyst hatches from zona pellucida and implant
→ implantation in
uterine wall
114
PRE-EMBRYONIC STAGE: IMPLANTATION
- Blastocyst adheres to endometrium
● at adherence, trophoblast cells differentiate
● hCG production continues and
stimulates the corpus luteum
→ ↗ estrogen & progesterone
115
● at adherence, trophoblast cells differentiate
:
○ superficial syncytiotrophoblast
(multinucleated mass)
○ Cytotrophoblast
116
PRE-EMBRYONIC STAGE: IMPLANTATION
Syncytiotrophoblast will cover the
blastocyst as it
digest endometrial
cells and penetrates the endometrium.
117
PRE-EMBRYONIC STAGE: IMPLANTATION
- Endometrium engulfs the blastocyst
● Amniotic cavity forms, separating
embryoblast from trophoblast
(amnion)
● Embryoblast flattens embryonic disc and cover amniotic and yolk sac
118
GASTRULATION
- Differentiation of cells forming
primitive streak → primitive groove
⇒ bilateral symmetry
● Trilaminar germ layers from epiblast (ectoderm, mesoderm, endoderm
)
119
TRIMESTERS: THE FIRST TRIMESTER weeks
First Trimester: Weeks 1-12
120
DEVELOPMENT AFTER IMPLANTATION:
EXTRA-EMBRYONIC STRUCTURES
- Chorionic villi (projections of the blastocyst)
& cells of the uterus form the placenta
- Amnion
-Umbilical cord
121
Amnion
⚫ fluid-filled sac that surrounds the embryo
122
Umbilical cord
⚫ Blood-vessel containing
stalk of tissue
⚫ Attaches the embryo to the
placenta
123
ORGANOGENESIS: embryonic stage
Within the first 8 weeks of fertilization,
appear rudimentary structures of all organs and
tissues
Neurulation (NS) & somites (muscles, skeleton,
dermis) @ 4th week
124
ORGANOGENESIS: embryonic stage
Heart begins beating
Limb movements
@ 4th week
@ 6th week
⚫ muscle contraction
⚫ neural connections
125
SEX DETERMINATION WEEKS
7-10 weeks
126
THE FETUS
(BEGINNING OF THE NINTH WEEK OF DEVELOPMENT
All organ systems are formed
Growth and organ specialization
Growth and change in appearance
127
SECOND TRIMESTER
Weeks 12-~26
- Growth and refinement of the human
features
128
THIRD TRIMESTER
- The third trimester ends in birth
“Full term” ranges from 37 to 42 weeks
- Full lung maturation
129
PREMATURE BIRTH
Before 37 weeks
at 26 weeks surfactant for lungs has not developed yet which is less likely to survive
130
FUNCTIONS OF THE PLACENTA
- Delivers nutrients and oxygen
- Removes waste from embryonic blood
- Becomes an endocrine organ and takes over
for the corpus luteum (by end of second
month) by producing
⚫ Estrogen
⚫ Progesterone
⚫ Other hormones that
maintain pregnancy
hCG
131
FUNCTIONS OF THE PLACENTA - Becomes an endocrine organ and takes over
for the corpus luteum (by end of second
month) by producing
⚫ Estrogen
⚫ Progesterone
⚫ Other hormones that
maintain pregnancy
hCG
132
How do pregnancy tests work?
hCG found in urine at high concentrations and
The test works by mixing the urine sample with antibodies that bind to hCG. If hCG is present, the antibodies bind to it, and the test will show a positive result.
133
Leydig cells secrete and are stimulated by
testosterone
Luteinizing Hormone (LH)
134
The normal diploid number of human chromosomes is
46
135
the structures that draw an ovulated oocyte into the female duct system are
fimbriae
136
The hormone that most directly influences the secretory phase of the menstrual cycle, with or without pregnancy, is ____ .
progesterone
137
During the luteal phase, progesterone level is low or high
high
138
The layer of cells closest to a mature secondary oocyte is the ____ .
corona radiata
139
Before secreting milk, the mammary glands excrete
colostrum
140
Few women become pregnant while nursing because _______ inhibits GnRH secretion.
prolactin
141
As sperm first reach the oocyte, they will contact the ______ .
corona radiata
142
Cleavage produces daughter cells called
blastomeres
143
The inner cell mass of the blastocyst is destined to become the _____.
embryo
144
Labor occurs in three stages
Dilation
Expulsion
Delivery of the placenta
144
Dilation
- Uterine contractions begin
and increase
⚫ Cervix becomes dilated
Full dilation is 10 cm
⚫ Cervix softens and effaces
(thins)
⚫ Often amnion ruptures
(“breaking the water”)
145
Expulsion
- Infant passes through the cervix and vagina
⚫ Can last as long as 2 hours, but typically is 50 minutes in the first birth
and 20 minutes in subsequent births
⚫ Normal delivery is head first (vertex position)
⚫ Breech presentation is buttocks-first
146
Placental stage
- Delivery of the placenta
Afterbirth—placenta and attached fetal membranes
⚫ Usually accomplished within 15 minutes after birth of infant
⚫ All placental fragments should be removed to avoid postpartum
bleeding
147
MAMMARY GLANDS
- in Both sexes
- Areola
Contain glandular
alveoli that
produce milk
148
lactiferous ducts
to
lactiferous
sinuses → open to
outside at nipple
149
LACTATION
Toward end of pregnancy
- Placental estrogens,
progesterone, and human
placental lactogen
→ hypothalamus to release
prolactin-releasing factors (PRFs)
→ Anterior pituitary releases
prolactin
150
Early milk =
Colostrum
Less lactose but more protein,
151
Prolactin builds up towards
end
of pregnancy
152
Prolactin release decrease or in crease after birth
decrease after birth
153
Lactation sustained by
mechanical
stimulation of
nipples - suckling
154
Suckling causes afferent
impulses to
hypothalamus
1. prolactin → stimulates milk
production for next feeding
2. oxytocin from posterior pituitary
cause Milk ejection
155
BENEFITS OF LACTATION TO CHILD
Immune benefits
Brain development
Lowers risk of child and adult
diseases
156
BENEFITS OF LACTATION TO MOTHER
- Decreased risk of osteoporosis
- Decreased risk of weight-gain
& faster loss of excess weight
gained through pregnancy
- Mother-child bonding
- Reduction of risk of postpartum
depression
- Decreased risk of cancer
157
JAUNDICE
yellow discoloration in a skin and eyes
excess of bilirubin in blood
158
If the child has type A or B blood and the mother has
type O blood there is an increased risk of jaundice
ABO incompatibility,
where the mother's antibodies can attack the baby's red blood cells, causing the baby to develop jaundice
; this is because a type O mother naturally produces antibodies against both A and B antigens present in a baby with type A or B blood
destroying thir blood cells and lead to increased bilirubin levels, causing jaundice
