reproductive physiology Flashcards
1
Q
what are the primary reproductive organs
A
males gonads= testes
female gonads= ovaries
2
Q
successful reproduction needs
A
a union of male and female gametes ( reproductive cells)
3
Q
external genitalia
A
externally visible portions of reproductive systems
4
Q
what are the 2 roles of the male reproductive system
A
1) production of sperm ( gamete cells )which are made in testes
2) delivery of sperm to females
5
Q
Most important female reproductive functions are?
6 total
A
1) production of ova
2) reception of sperm ( occurs in the vagina )
3) transport of ovum and sperm to common site of fertilization
4) maintenance of the developing fetus
5) birth of baby
6) milk production to nourish baby
6
Q
embryonic development of both external genitalia and reproductive tract can be seen at what levels ?
A
genetic , gonadal and phenotypic
7
Q
Genetic embryonic development is characterize by
A
combination of sex chromosomes at conception
8
Q
how are gametes produced ?
A
through meiosis in which diploid parent cells will divide to make haploid gamete cells , half sperm carry x and half sperm carry y , while all ovum carry single x
9
Q
when 2 haploids combine
A
sperm+ovum = fertilized ovum
10
Q
gondola development is determined by :
A
the presence or absence of a Y chromosome
11
Q
what takes placate week 7 of gestation ?
A
sex determining region of Y chromosome(SRY) stimulates the production of H-Y antigen
12
Q
what happens when there is no H-Y antigen ?
A
ovaries will form because H-Y acts on gonads to form testes
13
Q
phenotypic development is determined by ?
A
dependent on the gonadal sex, is known as the apparent anatomical sex
14
Q
how will male reproductive system develop ?
A
androgens will be secreted by developing testes
15
Q
what are the 2 primitive duct systems in the undifferentiated embryo ?
A
the wolffian ducts and the mullerian ducts
16
Q
What happens in meiosis one ?
A
replicated chromosomes that contain identical pair of chromatids sort themselves into homogenous pairs before separating so each daughter cell receives single set of chromosome
17
Q
each 2 daughter cell contains ?
A
each contain a sister set of chromatids with a single set of chromosomes
18
Q
what happens in meiosis 2 ?
A
sister chromatids within the chromosomes of each of the daughter cells separate and distribute to 2 cells and creates 4 daughter cells each containing a single set of chromosomes and one chromatid each
19
Q
What is the wolffian duct ?
A
??
20
Q
Human chrorioic gonadotropin (hCG )
A
hCG will stimulate testes to produce testosterone, which will stimulate wollfian ducts to develop into male reproductive system.
21
Q
testosterone is also converted to :
A
dihydrotestosterone which is responsible for male genitalia
22
Q
testes will secrete ?
A
mullerian- inhibiting factor , which allows for degradation of mullerian ducts
23
Q
In the absence of testosterone
A
wolffian ducts will degrade and mullerian will develop which will create female reproductive tract and external genitalia
24
Q
males whose testes fail to develop or target tissues that lack testosterone receptors will result in :
A
a phenotypic female that is sterile due to lack of ovaries
25
A deficiency in the enzyme that converts testosterone to DHT
results in having a male reproductive tract with female external gentialia
26
genetic female with excessive adrenal secretions of DHEA in fetal development
reproductive tract and external genitalia are masculinized
27
the testes are :
outside the abdominal cavity and within the scrotal sac
28
descension of testes
descend in early childhood, however will sometimes remain in body cavity = cryptorchidism and sterility
29
why is location of testes important ?
temperature within the scrotum is several degrees less than body temperature because sperm production needs cooler temps
30
what is the role of the cremaster muscle and the dartos muscle?
testes too cold to make sperm, the muscles will contract to bring them closer , when too hot, they will relax and move them away from body
31
where are the sperm produced ?
in the seminiferous tubules in the testes
32
leydig cells
produce and secrete testosterone under control of luteinizing hormone , cells are found between the seminiferous tubules
33
what are the various effects of testosterone in the body ?
1 causes masculinization of the reproductive tract and external genitalia and descent of testes
2 maintains the reproductive tract throughout adult life and promotes sperm production and maturation of system at puberty
3develop of sex drive at puberty and controls the release of gonadotropin releasing hormones
4causes voice to deepen and body hair growth
34
non reproductive actions of testosterone
bone growth at puberty , closing of the epiphyseal plates as well as drives aggressive behaviour
35
spermatogenesis
diploid ( 46 chromosomes primordial germ cells are converted into motile sperm cells with haploid ( 23 chromosomes)
36
primordial germ cells
known as spermatogonia and are found in the outermost layer of the seminiferous tubules
37
Sperm forming daughter cells will undergo mitotic divisor how many times?
twice more to produce 4 identical primary spermatocytes that enter resting stage to prepare for meiosis 1
38
each primary spermatocyte forms :
2 secondary spermatocytes each with 23 double stranded chromosomes
39
what happens in meiosis 2
each secondary spermatocyte results in 2 spermatids, each with 23 chromosomes
40
each spermatogonia can produce
16 spermatids
41
what is the packaging process ?
maturation of spermatid into spermatozoa where the cells are stripped of all non essential organelles
42
what are the 4 parts of the spermatozoa
head, acrosome , mid-piece and tail
43
acrosome is
the enzyme packed vesicle at tip of head needed for penetrating ovum
44
mid piece contains
mitochondria
45
tail is needed
for movement and requires ATP
46
Sertoli cells are found ?
single layer of Sertoli cells make up walls seminiferous tubules
47
relationship between sperm cells and Sertoli cells
- developing sperm can get engulfed by the Sertoli cells as they move toward the lumen, where the sperm head will remain embedded until mature
48
what are the functions of the Sertoli cells ?
1 - create tight junctions and allows for the cells to control intra tubular environment which make it optimal for developing spermatozoa
2- nourish sperm cells
3- Absorb sperm cytoplasm and remove defective germ cells
4- secrete seminiferous tubule fluid into the lumen to flush released sperm to epididymis for storage
5- secrete androgen - binding protein that helps concentrate testosterone in lumen
6- site of action for testosterone an FSH to regulate sperm production
49
testes are under control of
LH and FSH
50
what is the role of GnRh ?
is secreted from hypothalamus and acts on anterior pituitary gland to secrete both FSH and LH
51
LH stimulates
leydig cells to secrete testosterone and FSH acts on Sertoli cells to stimulate spermatogenesis and secret inhibin ??
52
Testosterone has direct negative feedback pathway meaning
is able to decrease GnRh and anterior pituitary to decrease LH and FSH release
53
Inhibin is used as ?
feedback to anterior pituitary to decrease FSH release
54
where does sperm move from seminiferous tubules ?
swept to the epididymis a highly coiled tube , sperm however are not motel due to low Ph
55
epididymal ducts converge to form
ductus deferens which each tube empties to the urthrea
56
sperm can be stored in epididymis for how long ?
months
57
what are the male accessory glands ?
3 glands which make up the bulk of semen ( accessory gland secretion and sperm )
58
the accessory glands provide?
support for the continuing viability of sperm inside the female reproductive tract
59
seminal vesicles
there are 2 which each one will empty into the ductus deferens before the urethra
60
seminal vesicles provide
bulk of the semen and supply fructose as energy source for ejaculated sperm as well as secrete prostaglandins to cause smooth muscle contractions in male and female reproductive tract
- secrete fibrinogen
61
Prostate glands are ? what do they secrete ?
large gland that surrounds the ejaculatory ducts and the urethra , secretes alkaline fluid to neutralize the acidic environment of vagina
62
what clotting enzymes does the prostate secrete?
clotting enzymes which act on the fibrinogen from seminal vesicles to create fibrin which clots the semen and keeps it within female reproductive tract
63
bulbourethral gland
pair of glands that empty into the urethra , before urethra empties to penis
64
what does the bulbourethral gland secrete ?
a clear substance in sexual arousal which helps lubricate the urethra for sperm to pass
65
male accessory glands incude
seminal vesicles, prostate glands and bulbourethral glands
66
what happens at 5th month gestation ?
oogenia divide to give rise to 6 to 7 million primary oocytes
67
each ooycte is surrounded by ?
Granulosa cells
68
primary oocyte +granulosa cell =
primordial follicle
69
by birth how many primordial follicles ?
2 million ( potential ovum women have for lifetime
70
what happens when follicles begin to develop?
structure will turn into a primary follicle which will either release ova or undergo atresia ( turn into scar tissue )
71
before puberty all primary follicles ?
go through atresia
72
After puberty , only about how many follicles will mature ?
400 primary follicles will mature and release ova
73
what is menopause ?
pool of eggs is exhausted and womens reproductive capacity ceases
74
why will the primary follicle get larger ?
due to cytoplasmic materials that are necessary for early embryonic development
75
what happens prior to ovulation ?
primary oocyte undergoes first meiotic division to create 2 daughter cells each with 23 chromosomes
76
majority of cytoplasm will ?
go to one of the daughter cells which will become the secondary oocyte and other daughter cell will degenerate ( first polar body )
77
secondary oocyte is released when
in ovulation
78
what happens if sperm fertilizes egg ?
second meiotic division will take place in which 23 single stranded chromosomes form second polar body
23 remaining chromosomes combine with 23 from sperm ?
79
what is the ovarian cycle ?
occurs in the ovaries and prepares for ova to release
80
what is the uterine cycle ?
prepares the uterus for implantation
81
at the onset of puberty ovarian cycle will alternate between 2 phases ?
the follicular phase ( preps mature egg),
luteal phase (prepares the reproductive tract for possible implantation)
cycle will last 28 days
82
follicular phase takes place when ?
in the first 14 days of the ovarian cycle
83
stage 1 in follicular phase
proliferation of granulose cells in primary follicle , which will divide to form several layers around the oocyte
84
Stage 2 follicular phase
granulosa cells secrete glycoproteins which form thick extracellular matrix which surrounds oocyte and separates it from granulosa cells
85
ovarian connective tissues cells surround ?
granulosa cells with layer of thecal cells
86
thecal cells+ granulosa cells =
follicular cells
87
development of primary follicle is due to ?
influence of FSH and estrogen
88
stage 3 follicular phase
follicle enlarges and becomes a secondary follicle which an now secrete estrogens ( mostly estradiol )
89
secondary follicle develops from?
FSH and estrogen
90
stage 4 follicular phase
fluid filled cavity ( Antrum ) is formed within the granulosa cells - expansion of Antrum increases size of the follicle as it matures and estrogens secretion increases
91
stage 5 follicular phase
one follicle will develop faster than others into mature follicle by 14 days of cycle
mature follicle , oocyte has undergone its first meiotic division to become secondary oocyte
92
stage 6 follicular cycle
ovulation will occur around day 14 under the influence of LH and FSH
93
what happens when ovum is released
ovarian follicle will rupture to release ovum in abdominal cavity and adoral fluid will push ovum into oviduct
94
end of follicular phase =
when ovum is released
95
Luteal phase takes place ?
during the last 14 days of the ovarian cycle
96
stage 1 luteal phase
ovum has been released , remaining follicular cells go through luteinization to form corpus luteum which produces estrogen and progesterone
97
stage 2 luteal phase
If in the 14 days the ovum is not fertilized and implanted , the corpus luteum will degenerate into the corpus albicans ( scar tissue ) which signals the end of the ovarian cycle and follicular phase will begin again
98
FSH and estrogen are needed because ?
early stimulation of follicular development and the formation of the secondary follicle
99
LH is needed for ?
estrogen production
100
actions of the LH surge
1) stops estrogen synthesis by follicular cells
2) reinitiates meiosis in oocyte
3) triggers release of local factors that increase swelling of follicle ,weakens wall
4) differentiates the follicular cells into luteal cells
101
in follicular phase , anterior pituitary releases LH as?
circulating estrogen inhibits actions of GnRH on FSH secreting cells of the anterior pituitary
102
estrogen will ?
continue to rise and will exert a positive feedback action on anterior pituitary to cause a surge LH secretion
103
in luteal phase
Lh will continue to maintain the corpus luteum
104
corpus luteum will begin secreting ?
large amounts of progesterone to prepare to for possible pregnancy
105
what does progesterone do ?
causes changes in the uterine lining to prepare for potential implantation of embryo to establish pregnancy
106
what happens if no implantation ?
rapid degeneration of the corpus luteum and results in rapid drop of circulating progesterone
107
Uterine/ menstrual cycle lasts ?
28 days in which the uterus is being prepared for possible implantation of fertilized ovum
108
the 2 layers of the uterus are :
myometrium ( outer layer and smooth muscle )
| endometrium ( inner lining that is highly vascularized and have many glands )
109
how will estrogen effect the 2 layers ?
stimulates the growth of both endometrium and myometrium
| - causes expression of progesterone receptors in the endometrium
110
how will progesterone act on endometrium ?
transforms lining to be suitable for implantation of fertilized ovum
- reduces the contractibility of uterus to further enhance implantation and embryo development
111
menstrual phase of the uterine cycle
endometrial growth ceases with end of luteal phase
| -decrease in estrogen and progesterone results in local release of prostaglandins
112
what is the role of prostaglandins ?
constrict blood supply to the endometrium and cause the myometrium to rythmically contract
- endometrial lining will shed and is excreted from vagina
113
proliferative phase of menstrual cycle
menstrual flow ceases and coincides with later stages of the ovarian follicular phase , cells of the endometrium being to proliferate with the help of estrogen where there is growth of glands until lining is 3-5 mm thick
114
where does ovulation occur ?
in the proliferative phase in which the ovum leaves ovary and travels to the uterus
115
Secretory Phase of menstrual cycle :
begins as the corpus luteum begins to form and the beginning of the ovarian luteal phase
116
What happens in the secretory phase ?
large amounts of progesterone and estrogen convert the The endometrium into highly vascularized and glycogen filled tissues needed to support early embryo ---> ovum is in the uterus
117
what happens if no implantation ?
corpus luteum degrades and triggers next menstrual cycle
118
endometriosis
when the endometrium grows outside of the uterus and grows over the ovaries , Fallopian tubes and connective tissues
119
what is the problem with endometriosis ?
bleeding can't escape, cysts often develop endometriomas near ovaries and develop scar tissues
120
what happens at menopause ?
no more viable primary follicles in ovaries and follicular growth stops where the ovarian and uterine cycles cease, will see a dramatic decrease in estrogen secretion , this will impact cardiovascular and skeletal systems
121
estrogen is linked to?
building strong bones through the inhibition of osteoclast activity ----> after menopause could develop osteoporosis because osteoclast activity increases
122
Male sex act:
involves erection and ejaculation
123
erection is when :
penile tissues fill with blood allowing penis to become rigid and entry to vagina
124
erectile tissue is made of :
3 columns of sponge -like vascular spaces known as corpora cavernosa
125
what is the erection reflex ?
initiated through thought about sex / stimulation of mechanoreceptors in the glans of penis ( head) and is a spinal reflex in lower spinal cord
126
what are the 3 actions of erection reflex
1- inhibiting the sympathetic supply to the penile arterioles ( removes the tonic vasoconstrictor actions of sympathetic nervous system )
2- activates the parasympathetic supply to the penile arterioles to cause vasodilation
3- activates parasympathetic supply to the bulbourtehral gland to secrete mucous for lubrication
127
erectile dysfunction :
the inability to main erection rigid enough for sex
128
ejaculation is:
a spinal reflex, mediated by the same stimuli for erection
129
2 stages of ejaculation
1 emission and 2 expulsion
130
step 1 emission in ejaculation :
increased sympathetic activity causes smooth muscle to contract in the prostate , reproductive ducts and seminal vesicles
131
order of fluids delivered to urethra
1 prostatic fluid , 2 sperm , 3 seminal vesicle fluid ( sphincter contracts to stoop urine from coming out)
all 3 together make semen
132
step 2 ejaculation : expulsion
filling of the urethra with semen triggers the skeletal muscles at the base of the penis , which increases the pressure and forcibly expels semen
133
male sexual response cycle consists of :
excitement phase, plateau phase, orgasmic phase, and resolution phase
134
1) excitement phase of sexual response cycle
heightened sexual awareness and erection
135
2)plateau phase of sexual response cycle
generalized response of increased heart rate , blood pressure and respiratory rate
136
3)orgasmic phase of sexual response cycle
includes ejaculation and physical and emotional response
137
4) resolution phase
return of the body to pre arousal phase
138
refractory period after sex
sexual stimulation can't trigger erection
139
female sexual response cycle : 1 excitement
stimulation of clitoris , activates spinal reflex which activates spinal reflex that activates parasympathetic system to dilate arterioles of vagina - clitoris becomes erect ,
140
dilation of arterioles in vaginal wall cause :
vasoconstriction of capillaries ---> forces fluid out of vagina
fluid from bartholins gland acts as lubricant for intercourse
141
plateau phase female sexual response cycle
uterus raises upward lifting cervix and enlarging upper portion of vagina ( creating space for ejaculated semen , heart rate and blood pressure increase
142
orgasm phase female sexual response cycle
sexual response culminates in orgasm , sympathetic impulses lead to rhythmic contractions of the pelvic musculature ( no female ejaculation )
143
resolution female sexual response cycle
heart rate , blood pressure and breathing go back to normal
144
what is fertilization ?
the joining of a female egg and a male sperm which takes place in the ampulla of the Fallopian tube
145
the stages of fertilization :
ovum transport to the oviduct, sperm transport to oviduct fertilization
146
1) ovum transport to oviduct
end of follicular phase , ovum is released into abdominal cavity fimbrae guide ovum into oviduct
- ovum gets to the ampulla through peristaltic contractions
147
2) sperm transport to oviduct
sperm must pass through cervical canal which contains large amounts of mucous
148
large amounts of estrogen at ovulation will :
cause the mucous the be thin enough that sperm can pass ( only a few days a month )
149
what are the role of contractions?
myometrial contractions help propel sperm to the oviducts and peristaltic contractions move sperm to ampulla
150
3) fertilization
sperm have to penetrate the corona radiata( enzyme on sperm head ) and the zone pellucida ( bind to it )
151
plasma membrane of sperm contain
protein called fertilin which binds to ZP3 glycoprotein on outer layer of zone pellucida --> binding causes the release of acrosomal enzymes that digest the zone pellucida
152
First sperm reaches the ovum
will fuse with ovum membrane and the head will enter and tail is left behind and triggers release of intracellular Ca+
153
actions of Ca+
1 causes inactivation of ZP3 so no further sperm can bind
2) hardens the zone pellucida so no more sperm can penetrate
3) triggers second meiotic division in ovum
154
sperm and and ovum nuclei fuse to form
zygote 1 hour after fertilization
155
zygote will transform into
morula ( solid ball of cells ) in which progesterone allows it to move to uterus and will be nourished by the endometrial secretions
156
within week of ovulation,
endometrium is suitable for implantation and morula has transformed to blastocyst where the fetus will arise
157
implantation is finished when
entire blastocyst is completely buried in endometrium
158
identical twins occur when
single egg is fertilized with sperm cell and forms q zygote which divides into 2 separate embryos
159
Fraternal twins occur when
after 2 eggs are released from the ovary , both eggs are fertilized by 2 different sperm cells which are implanted in uterine wall at same time
160
monozygotic =
| dizygotic=
identical , fraternal
161
ecotopic pregnancy
fertilized egg implants outside main uterine cavity ( usually in fallopian tubes but can happen in cervix or abdominal cavity
162
Placenta
specialized organ which will sustain embryo for duration of pregnancy - endometrial glycogen are only sufficient for a few weeks for nutrients
163
4 weeks into pregnancy embryo is
embryo is completely embedded in endometrial tissues at implantation site and tissue will contribute to placenta forming
164
at 8 weeks pregnant , placenta is
not fully developed but well established and operational by week 5 after implantation
165
at 12 weeks , placenta is ?
completely developed to support embryo
166
at 40 weeks placenta is ?
will continue to grow in pregnancy and acts as digestive, respiratory and kidneys for the fetus , exchange of nutrients and blood takes place in placenta
167
what is unique about the placenta
does not need any external control to secrete hormones
168
hCG is the ?
first hormone that placenta secretes as it develops and is similar to LH structurally and functionally ( can bind to LH )
169
role of hCG ?
maintains the corpus luteum which allows it to get larger and become the primary source of estrogen and progesterone until the placenta is able to take over at 10 weeks
170
hCG will decrease when
the placenta secretes sufficient estrogen and progesterone and hCG will stay at a low stable level
171
hCG and male fetuses ?
stimulates the precursor leading cells to secrete testosterone needed for masculinization of reproductive tract
172
hCG is associated with
morning sickness and can be used as marker for pregnancy tests ( found in urine )
173
fetal adrenal cortex secretes DHEA into fetal blood which,
placenta takes it and converts it to estrogen which secretes into maternal blood ----> mainly estradiol
174
estrogen secreted by ovaries is primarily
estradiol
175
why is the corpus Luteum the primary source of estrogen in the first trimester ?
takes time for the fetal adrenal glands to secrete sufficient DHEA
176
what is estrogens role in pregnancy ?
increase the size of the myometrium as the uterus expands and to make sure the muscle mass is sufficient for child birth
177
estradiol promotes
the ducts development in the mammary glands
178
how long does intake for the placenta to take over progesterone production from the corpus leuteum ?
10 weeks
179
circulating levels of progesterone will increase as
placenta continues to grow throughout entire pregnancy
180
what is progesterones role in pregnancy
maintains the cervical mucous plug, stimulates milk , suppresses uterine contraction
181
parturition
requires dilation of cervical canal where fetus will passs
182
when baby is getting ready to come out
there is an increase in estrogen , to prepare cerix and uterus for delivery
183
first role of estrogen in birth
late surge allows for myometrium smooth muscle cells to synthesize connections and form gap junctions sp myometrium can contract smoothly
184
second role of estrogen in birth
increases the synthesis of oxytocin receptors in myometrium
185
positive feedback of oxytocin
estrogen-stimulated increase in oxytocin receptors , high levels of estrogen increase uterine responsiveness to oxytocin , to the point where uterine contractions will begin and initiates the positive feedback cycle ***
