Chapter 18 - Reproductive System Flashcards
1
Q
Amount of chromosomes in somatic cells
A
46
2
Q
Amount of homologous pairs in somatic cells
A
23
3
Q
Amount of chromosomes in gametes
A
23
-this is the haploid number
4
Q
Gametes contain only
A
One member of each homologous pair of chromosomes
5
Q
Gametes contain only one
A
Member of each homologous pair of chromosomes
6
Q
Gameoteongensis is accomplished by
A
Meiosis
7
Q
Autonomies
A
22 pairs which code for general human characteristics and specific traits such as eye colour
8
Q
Sex chromosomes
A
Remaining pair of chromosomes
-larger is X chromosome
-smaller is Y chromosome
9
Q
Meiosis vs mitosis
A
Mitosis—> produces identical daughter cells, growth
Meiosis—> produces four different daughter cells, reproduction
10
Q
Gameotigenesis
A
-nuclear division by meiosis
-half set of genetic information distributed to each of four new daughter cells
11
Q
Testes perform dual function, which is:
A
-production of sperm within seminiferous tubules
-secretion of testosterone, in leydig cells (between seminiferous tubules)
12
Q
Serotoli cells vs leydig cells
A
-support for sperm
-testosterone
13
Q
Testosterone is a ____ derived from _____
A
-steroid
-cholesterol
14
Q
Five categories of testosterone effects
A
-before birth (system)
-after birth (tissues)
-other effects
-secondary sexual characteristics
-non reproductive actions
15
Q
Spermatogeneiss results in
A
Many specialized, mobile sperm
Spermatogonia —> spermatozoa, haploid (at puberty)
16
Q
Amount of time from spermatogonia to sperm
A
64 days
17
Q
Amount of time from spermatotonia to sperm
A
64 days
18
Q
(Spermatogenesis) Mitosis proliferation
A
2 mitosis divisions to create —> 4 identical primary spermatocytes
19
Q
(Spermatogenesis) Meiosis
A
2 meiotic divisions
-16 spermatozoa from each spermatogonium
20
Q
(Spermatogenesis) packaging
A
Not built to last
-closely associated with sertoli cells throughout development
21
Q
Anatomy of a spermatozoan
A
Head: acrosome, nucleus
Midpiece: mitochondria
Tail or flagellum: microtubules
22
Q
Anatomy of a spermatozoan
A
Head: acrosome, nucleus
Midpiece: mitochondria
Tail or flagellum: microtubules
23
Q
Function of acrosome
A
-used to penetrate ovum
-formed by ER and golgi complex, before organelles are discarded
-enzyme filled
24
Q
Functions of Sertoli cells in seminiferous tubules
A
-Secretes fluid that flushes sperm into epididymis for storage and maturation
-secrete androgen binding protein
-controls spermatogenesis
25
How do Sertoli cells control spermatogenesis
-release inhibin
-negative feedback that regulates FSH
26
Testes are controlled by
2 gonadotropic hormones (anterior pituitary)
-LH
-FSH
27
What is essential to maintaining spermatogenesis
Testosterone
-directly controlled by LH
28
What is essential to maintaining spermatogenesis
Testosterone
-directly controlled by LH
29
FSH affects
Sertoli
30
LH affects
Leydig
31
Sertoli affects either
-inhibin
-spermatogenesis
32
Inhibin lessens
Gonadrop
33
Leydig affects
Testosterone
34
Inhibin inhibits
FSH release
35
FSH acts on
Sertoli cells to stimulate spermatogenesis
36
LH and FSH are too low to stimulate
Testosterone production pre puberty
37
Spermatogenesis travels via seminiferous tubules to
Epididymis to ductus vas deferens
38
Ovaries secrete two main female sex hormones
-estrogen
-progesterone
39
Estrogen function
-Essential for ova maturation + release
-female secondary sexual characteristics
-transport sperm for fertilization
-contribute to breast development
40
Progesterone function
-prepares suitable environment for fetus
-contribute to beasts ability to produce milk
41
Oogenosis is equivalent to
Spermatogenesis
-identical steps
-timing and end result very different
42
Oogonia stage
-undifferentiated primordial germ cells in fetal ovaries
-divide mitotically
43
Oogonia during last part of fetal life
Begin early steps of first meiotic division, do not compete
-primary oocytes
44
Oogonia—> primary locates
Contain diploid number of 46 replicated hormones
-remain in meiotic arrest for years until prepared for ovulation
45
Primary oocyte is surrounded by
Single layer of granulosa cells
46
Oocyte + granulosa cells =
Primordial follicle
47
Primordial follicle
After development starts there are 2 possible fates
-reach maturity and ovulate
-dgenerate to form scar tissue
48
Oogenosis happens between
Puberty and menopause
49
Just before ovulation
Primary oocyte completes first meiotic division
-first polar body
-secondary oocyte
50
Just after fertilization
Sperm entry triggers second meiotic division
-secondary polar body
-mature haploid ovum unties with haploid sperm cell during fertilization
51
Timing of spermatogenesis versus oogenesis
-accomplished within two months
-take anywhere from 12 to 50 years to complete on cyclic basis from onset of puberty until menopause
52
Productive of spermatogenesis versus oogenesis
-postpubertal male can produce several hundred million sperm each day
-female born with limited, largely non renewable supply of germ cells
53
Primary yeilds…. Spermatogenesis versus oogenesis
-four equally viable spermatozoa
-only one cytoplasm rich ovum and three cytoplasm poor polar bodies that disintegrate
54
Follicular phase
Dominated by presence of maturing follicles
55
Lateral phase
Characterized by presence of corpus luteum
56
First stage (diagram)
Primary oocyte
-primary follicles
-single layer of granulosa cells
57
Stage 2/3 (diagram)
Follicular cells, made up of granulosa and thecal
-zona pellucida
Preantral follicle
Primary oocyte
58
Stage four (diagram)
Beginning of formation of antrum
59
Stage 5 (diagram)
Ovum or primary oocyte
60
When is development of natural (secondary) follicle
Stage 4-5
61
Stage 6 (diagram)
Mature follicle
-ovum 2nd oocyte
62
Stage 7 (diagram)
Follicular remnant
-ovulated ovum
63
Stage 8 (diagram)
Developing corpus luteum
64
Stage 9 (diagram)
Corpus luteum
65
Stage 10 (diagram)
Degenerating corpus luteum
66
When does follicular phase take place
First half of cycle
67
Oocyte during follicular phase
Oocyte inside follicle enlarges
68
Granulosa cells in follicle secrete (during follicular phase)
Increased amounts of estrogen
69
Rapid follicular growth continues during
follicular phase
70
Process of ovulation
-one follicle grows more rapidly
-follicle ruptures and releases oocyte from ovary
-enters oviduct where it may or may not be fertilized
71
Literal phase lasts
14 days of ovarian cycle
72
Old follicular cells form
Corpus luteum
73
Becomes function within
Four days after ovulation
-thanks to progesterone and estrogen secretion
74
If released ovum is not fertilized and does not implant
Corpus luteum degenerates within 14 days after formation
75
FSH is high when
Beginning of menstrual stage, ovulation
76
LH is high during
Ovulation
77
Estrogen is high during
Right before ovulation, then briefly before menstruation
78
Progesterone is high before
Menstruation
79
During follicular phase there is a rise in ___ to signal
-FSH
Signals ovarian follicle to secrete more estrogen
80
Rise in estrogen feeds back to
Inhibit FSH secretion, which declines as follicular phase proceeds
81
LH rises in
follicular phase
82
What triggers ovulation
LH
83
What hormone triggers a mature follicle to convert into a corpus luteum
Estrogen
84
Corpus luteum secretes
Progesterone and estrogen
-during luteal phase
85
Progesterone output inhibits
Release of FSH and LH
86
Corpus luteum degenerates due to
Low LH
87
When corpus luteum has degenerates what declines
Progesterone levels
88
What initiates a new cycle
FSH rises again
89
What primarily inhibits FSH from anterior pituitary
estrogen
90
LH rise continues during
Follicular phase
91
Estrogen cannot inhibit what alone?
LH secretion
92
Ovulation is triggered by
LH surge
93
The LH surge is a positive feedback by..
Estrogen
94
LH surge mid cycle does what?
-stops estrogen synthesis
-reinitiates meiosis
-follicular cells —> luteal cells
95
LH ultimately causes high levels of
Estrogen and progesterone
-ovulation
96
What maintains the corpus luteum
LH
97
What is more abundant from the corpus luteum?
Progesterone
98
The start of new cycle is categorized by
First day of menstruation
99
Menstrual phase releases
Uterine prostaglandin
-death of endometrium
-contractions of uterine —> expel blood
100
Proliferative phase
-begins in last portion of follicular phase
-endometrium repairs itself with estrogen from new follicles growing
101
Peak estrogen levels during proliferation phase triggers
LH surge, responsible for ovulation
102
Proliferative phase is _____ dominant
Estrogen
103
Secretory or progestiational phase
-after ovulation, new corpus luteum is formed
-large amounts of P and E
-progesterone causes endometrium to become highly vasculariaed
104
If fertilization and implantation do not occur
-corpus luteum degenerates
-new follicular phase and menstrual phase begin once again
105
What is the site of fertilization
Oviduct
-upper third or ampulla
106
Fertilization must occur
24 hours after ovulation
107
First sperm to reach ovum triggers
Chemical change in ovums surrounding membrane
-impermeable entry for other sperm
108
Head of fused sperm …
Gradually pulled into ovums cytoplasm
-within hour sperm and egg nuclei fuse
109
What triggers completion of meiosis
First sperm to reach ovum
110
Fertilized ovum divides
MITOTICALLY
111
Fertilized ovum differentiates into
Blastocysts
-capable of implantation
112
Blastocyst implants in
Endometrial lining
-using enzymes released by trophoblasts
113
Fertilized ovum turns into
Cleavage
114
Cleavage turns into
Morula
115
Morula turns into
Blastocyst
116
After implantation, what develops
Placenta
117
Umbilical vein carries
Oxygen and nutrient rich blood from placenta to fetus
118
Umbilical arteries carry
Waste products and low oxygen conten to placenta
119
Placenta acts as a
Endocrine organ
-secretes essential pregnancy hormones
120
What hormones does the placenta secrete
-human chorionic gonadotropin
-estrogen
-progesterone
121
human chorionic donadotropin
Maintains corpus luteum of pregnancy
-secretion of testosterone in developing testes in XY embryos
122
Estrogen (pregnancy)
Stimulate growth of myometrium
-inc uterine strength
-prepare mammary glands
123
Progesterone (in pregnancy)
Suppress uterine contractions for quiet environment for the fetus
124
Low amounts of progesterone causes…
Uterine contractions
125
Relaxin (pregnancy)
-prepare mammary glands
-softens cervix to prep for dilation
-loosens tissues between pelvic bones
Preparation for parturition
126
what is the pregnancy test hormone
Human chorionic gonadotropin
127
HCG is secreted by
Trophoblast
128
If there is no hCG
There is not pregnancy
129
What month does hCG peak
1 or 2 months
130
When do estrogen and progesterone peak (pregnancy)
At birth/right before
131
When does placenta produce estrogen and progesterone
Third and fourth trimester
-since corpus luteum of pregnancy has degenerated
132
Pressure of fetus against cervix reflexly increases
Oxytocin secretion
133
Oxytocin
-stronger contractions
-positive feedback that increases until cervial dilation and delivery are complete
-stimulate milk ejection during breast feeding
134
Cervical dilation
Longest stage
-several hours to 24 hours
135
Delivery of baby
Beings when cervical dilation is complete
-30 to 90 minutes
136
Delivery of placenta
Second series of uterine contractions, to separate placenta from myometrium
-shortest stage (15 to 30)
137
Involution
Uterus shrinks after delivery to pregestatinoal size
138
During gestation estrogen and progesterone promote and inhibit …
Promote development of mammary glands, inhibit prolactin action on mammmary glands
139
prolactin
Stimulates milk production in alveolar cells
140
What stimulates prolactin to produce milk?
withdrawal of placental steroids at parturition initiates lactation
141
What releases oxytocin and prolactin
Suckling
142
Oxytocin -mammary glands
Squeeze secreted milk out through ducts
143
Prolactin -mammary glands
Secretion of more milk to replace milk ejected
144
Blastocyst reaches endometrium during
Literal phase
