Chapter 17 Reproduction Flashcards
(108 cards)
1
Q
Occurs in testes
Results in four sperm for each starting cell.
A
Spermatogenesis
2
Q
Occurs in ovaries
Forms a single egg (ovum).
A
Oogenesis
3
Q
Genetic Determination of Sex
A
Gender is determined by genetic inheritance of two chromosomes known as the sex chromosomes (X and Y)
4
Q
The Y chromosome carries
A
SRY gene- controls development of testes in the male
5
Q
Male reproductive organs form from
Development stimulated by…
A
Wolffian ducts
testosterone
6
Q
Female reproductive organs form from
Develop when…
A
Müllerian ducts
testosterone is absent.
7
Q
External organs begin to develop differently in each sex at about
A
8 weeks
8
Q
two sexes can be distinguished on sonograms.
A
By 10-12 weeks
9
Q
released by the hypothalamus
A
Gonadotropin-releasing hormone (GnRH
10
Q
anterior pituitary
A
release of FSH and LH
11
Q
the formation of male sex gametes (spermatids) from spermatogonia
A
Spermatogenesis
12
Q
long coiled tubes where sperm are produced.
A
Seminiferous tubules
13
Q
cells located in the spaces between the tubules that produce testosterone.
A
Leydig cells
14
Q
stem cells formed during embryonic development. About 1000-2000 stem cells migrate from the yolk sac into the seminiferous tubules, then remain dormant until puberty.
A
Spermatogonia
15
Q
support and nurture the growth of spermatogonia are interspersed between them in the seminiferous tubules.
A
Sertoli cells
16
Q
undergoes the first meiotic division (meiosis I) to form two secondary spermatocytes.
A
primary spermatocyte
17
Q
The two secondary spermatocytes undergo a second meiotic division (meiosis II)
A
to form a total of four spermatids
18
Q
not yet fully functional spermatozoa
A
Spermatids
19
Q
required for maturation of the spermatids
A
Sertoli cells
20
Q
contains the nucleus; it is covered by the acrosome
A
a head
21
Q
has enzymes to penetrate the ovum
A
the acrosome
22
Q
contains mitochondria
A
a midpiece
23
Q
allows it to swim
A
a flagellum (or tail)
24
Q
During sexual excitation parasympathetic fibers release…..causing small arteries in the erectile tissue of the penis to dilate.
A
Nitrous Oxide
25
the penis becomes rigid
erection
26
the discharge of semen from the penis.
Ejaculation
27
Ejaculation
- Spinal reflux mediated by afferent pathways from penile mechanoreceptors.
28
This leads to contraction of smooth muscle in the epididymis, vas deferens, ejaculatory ducts, prostate, seminal vesicles, and urethra
orgasm
29
FSH acts only on the
Sertoli cells.
- These produce inhibin which feeds back to decrease further FSH secretion.
30
LH acts primarily on the
Leydig cells- which produce testosterone.
31
Testosterone effects
- Stimulates spermatogenesis
- Controls male secondary sex characteristics.
- Feeds back to inhibit LH secretion.
32
the steady decrease in testosterone secretion beginning at about 40 years of age
Andropause
May include a decrease in libido and depression
33
the process by which ova are formed from the oogonia in the ovaries
Oogenesis
34
Before birth – stem cells form oogonia by mitosis, and these mature into
primaryoocytes
35
These begin the.....but stop in prophase I and remain at thisstage until puberty (in meiotic arrest)
first meiotic division
36
oogenesis begins to occur cyclically
At puberty
37
a few primary oocytes complete the first meiotic division
Each month
This forms a secondary oocyte (which receives most of the cytoplasm and organelles) and the first polar body (which contains half the DNA).
38
The secondary oocytesbeg in the.....in the ovaries, but stop at.....
second meiotic division; metaphase II
39
the ovulated secondary oocyte may become fertilized by a sperm
In the Fallopian tube
40
the second meiotic division is completed and the cell becomes an ovum
If fertilized
41
Oogenesis takes place in......, which undergo their own monthly cycle.
ovarian follicles
42
present before birth; consists of a primary oocyte surrounded by a single layer of granulosa cells
Primordial follicle
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consists of a primary oocyte surrounded by the zona pellucida (clear layer of glycoproteins) and granulosa cells
Primary follicle
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secreted by granulosa cells of the maturing follicles.
Estrogen
45
has a primary oocyte surrounded by a zona pellucida, multiple layers of granulosa cells and an outer theca
Preantral follicle
46
a fluid-filled space (antrum) begins to form within the granulosa layer
Early antral follicle
47
one dominant follicle continues to enlarge
Mature follicle (Graafian follicle)
48
The oocyte completes the first meiotic division and begins the second, but stops in....
metaphase II
49
the release of the secondary oocyte with the zona pellucida and layers of granulosa cells from the ovary in response to a surge of LH (luteinizing hormone)
Ovulation
50
Ovulation occurs on about.... of a woman’s cycle.
Day 14
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under the influence of luteinizing hormone the remnant of the follicle becomes the....
Corpus luteum
- Secretes estrogen, progesterone, and inhibin
- continues to secrete progesterone which maintains pregnancy (if fertile)
52
The degeneration of the corpus luteum triggers
menstruation
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period when the follicles mature, Resulting in one dominant follicle. Spans day 1 – 13
Follicular phase
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release of a secondary oocyte on day 14
Ovulation
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period of development and regression of the corpus luteum. Spans day 15-28.
Luteal phase
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FSH stimulates growth of follicles which make increasing levels of estrogen.
Follicular phase
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triggered by the LH surge on day 14.
Ovulation
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LH stimulates growth of thecorpus luteum which secretes both estrogen and progesterone. These levels fall as the luteum regresses.
Luteal phase
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events that occur in the endometrium of the uterus.
Uterine Cycle
60
Day 1-5.
| The endometrial layer is shed from the uterus.
Menstrual phase
61
Day 6-13.
Occurs in response to increasing levels of estrogen released by the maturing follicles.
Endometrial lining begins to regrow and thicken.
Proliferative phase
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Day 14-28
| Occurs in response to increasing levels of progesterone released by the corpus luteum.
Secretory phase
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As progesterone increases the endometrium becomes thicker, spongier, and more vascular.
Day 14-24
64
As progesterone decreases, blood vessels constrict, cutting off blood flow and causing the endometrium to begin to break down.
Day 25-27
65
Cells of the endometrial lining die.
Day 28
66
a female's first menstrual cycle.
Menarche
67
the period during which the reproductive organs mature and reproduction becomes possible.
Puberty
- Usually occurs between 12 and 16 years of age in the male.
- Generally occurs between 10 and 12 years of age in the female.
68
Erectile tissue in the clitoris and vestibular bulbs, as well as the areola of the breasts, becomes engorged with blood as a result of
parasympathetic impulses.
69
Rhythmic contraction of the muscles of the perineum and the muscular walls of the vagina, uterus and uterine tubes occurs as a result of
sympathetic impulses
70
during passage through the acidic female tract, sperm gain the ability to fertilize a secondary oocyte, possibly due to alterations in the sperm’s cell membrane.
Capacitation
71
If fertilization takes place, the secondary oocyte usually encounters the sperm in the
first 1/3 of the uterine tube
72
occurs when the pronuclei of the sperm and ovum fuse to form one diploid cell with 46 chromosomes.
Fertilization
73
the first cell of the new individual.
zygote
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first 2 weeks
Pre-embryonic
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week 3 to week 8 (lasts for 6 weeks)
Embryonic
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week 9 to birth (lasts for 7 months)
Fetal
77
a series of mitotic divisions in which the cell number increases but the mass does not.
Cleavage
- Occurs as it travels downFallopian tube.
78
prevents the corpus luteum from regressing so it keeps secreting progesterone.
human chorionic gonadotropin (hCG).
- Pregnancy tests look for the presence of hCG since it will only be made if fertilization has occurred.
79
Around day 6 the developing blastocyst contacts the uterine wall
Implantation
80
Cells of the trophoblast secrete......that digest a small depression in the endometrium, which the blastocyst nestles into.
proteolytic enzymes
81
The endometrium under the blastocyst thickens
decidua basalis
82
The trophoblast produces finger-like projections, which grow into the endometrium.
chorionic villi
83
The rest of the trophoblast will develop into the
chorion
84
a combination of interlocking fetal and maternal tissues, which serves as the organ of exchange between mother and fetus for the remainder of the pregnancy.
placenta
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The placenta is formed from the...... of the mother and the...... of the developing embryo.
decidua basalis; chorionic villi
86
GI tract, liver, pancreas, lung alveoli, bladder and urethra.
Endoderm
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muscle, connective tissue, dermis, epithelium of blood vessels, kidneys and ureters.
Mesoderm
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epidermis and nervous tissue.
Ectoderm
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The embryo receives nutrients and oxygen from the mother through the
umbilical cord
90
formation of the organ systems.
Organogenesis
91
the amnion, yolk sac, and chorion
Formation of extraembryonic membranes
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the fetus is suspended in a fluid filled sac
Amniotic sac
- Cushion the developing embryo.
- Provide a constant pressure and temperature.
- Permit freedom of movement.
93
stimulates the growth of the uterine muscle, needed to deliver the fetus.
Estrogen
94
inhibits uterine contractility so that the fetus is not expelled prematurely.
Progesterone
95
266 days or 280 days from the beginning of the last menstrual cycle.
gestation period
96
birth of the baby
parturition
97
begins with rhythmic, forceful contractions of the myometrium of the uterus.
Labor
98
released by the posterior pituitary.
Oxytocin
99
produced in the uterus in response to oxytocin.
Prostaglandins
100
the cervix dilates to 10 cm over a period of 8 to 24 hours, and the amniotic sac ruptures.
Dilation
101
forceful uterine contractions expel the fetus from the uterus through the vagina. This requires about 30 minutes during a first pregnancy, and less time in subsequent pregnancies. This is actual parturition.
Expulsion
102
within 10 to 15 minutes, the placenta is separated from the uterine wall and expelled as the afterbirth.
Placental
103
presentation if it is positioned with its buttocks towards the vagina.
breech
104
Breast Development
1. Prior to pregnancy ducts with few alveoli exist
2. In early pregnancy alveoli grow.
3. In midpregnancy alveoli enlarge and acquire lumen.
4. During lactation alveoli dilate.
5. After weaning the gland regresses.
105
secreted by the anterior pituitary.
Stimulates breast development during pregnancy.
Stimulates production of milk after parturition.
Prolactin
106
secreted from the posterior pituitary in response to suckling by the baby.
- Stimulates milk ejection (contraction of myoepithelial cells around the alveoli).
Oxytocin
107
the cessation of menstrual cycles at the end of a woman’s reproductive years.
Menopause
occurs as a result of declining ovarian function.
108
the time when menstrual cycles become less regular, but have not yet come to an end.
Perimenopause
