Biology II > ch. 46 > Flashcards

ch. 46 Flashcards

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1
Q

external male organs

A

scrotum and penis

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2
Q

testes

A

male gonads that consist of tightly coiled tubes surrounded by connective tissue

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3
Q

purpose of scrotum

A

sperm cannot be produced at body temperatures, so hangs outside abdominal cavity in mammals where temperature is lower

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4
Q

how long is each seminiferous tubule

A

70cm, 750 in each testis

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5
Q

where does sperm go after the seminiferous tubules

A
  • coiled duct of epididymis
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6
Q

path of sperm in ejaculation

A
  • sperm propelled through muscular vas deferens
  • ejaculatory duct
  • exits penis through urethra
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7
Q

semen

A

composed of 5% sperm and secretions from 3 sets of accessory glands

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8
Q

3 male accessory glands

A
  1. seminal vesicles
  2. prostate gland
  3. bulbourethral glands
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9
Q

seminal vesicles

A

contribute fructose
- 60% of total volume of semen

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10
Q

prostate gland

A

secretes alkaline products directly into urethra through several small ducts

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11
Q

bulbourethral glands

A

secrete alkaline, clear mucus before ejaculation that neutralizes acidic urine remaining in the urethra

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12
Q

how many types of erectile tissue in penis

A

3 cylinders of spongy erectile tissue

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13
Q

sexual arousal and penis

A

erectile tissue fills with blood from arteries (causes erection)

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14
Q

glans

A

head of penis, has thinner skin covering shaft
- more sensitive to stimulation

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15
Q

prepuce/foreskin

A

fold of skin surrounded glans

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16
Q

sexual reproduction

A

creation of offspring by fusion of haploid gametes to create diploid zygote

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17
Q

asexual reproduction

A

creation of offspring without fusion of egg and sperm

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18
Q

budding

A

simple form of asexual reproduction only found among invertebrates
- new ind. arise from outgrowths of existing ones

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19
Q

difference between sex and coitus

A
  • sex - union of gametes
  • coitus - physical union of female and male genitalia accompanies by rhythmic movements
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20
Q

binary fission

A

separation of parent into 2+ ind. of about the same size
- invertebrates

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21
Q

types of asexual reproduction

A
  • budding
  • binary fission
  • fragmentation
  • parthenogenesis
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22
Q

fragmentation

A
  • breaking of body into pieces, some or all of which develop into adults
  • accompanies by regeneration
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23
Q

parthenogenesis

A

development of a new ind. from an unfertilized egg
- mostly invertebrates

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24
Q

is finding a partner easy or difficult?

A

can be challenging

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25
hermaphroditism
each ind. has both male and female reproductive systems
26
2 types of hermaphrodites
1. synchronous 2. sequential
27
synchronous hermaphrodites
ind. simultaneously male and female
28
sequential hermaphrodites
sex change - protogynous and protandrous
29
protogynous hermaphrodites
egg products become sperm producers
30
protandrous hermaphrodites
sperm producers become egg producers
31
spotted hyena females
- bigger than males - have pseudopenis (pseudophalluses) - both sexes get erections when greeting each other - give birth through "penis"
32
what are reproductive cycles related to
- environmental cues (seasons) - hormones
33
ovulation
release of mature eggs at midpoint of female cycle
34
parthenogenesis of fish, amphibians, and lizards
- doubling of chromosomes after meisos
35
asexual whiptail lizards
- all females - still exhibit mating behaviors (pseudo-copulation) - parthenogenesis
36
twofold cost of sexual reproduction
sexual females have half as many daughters as asexual females
37
when is sexual reproduction beneficial
enhance reproductive success of parents when environmental factors change rapidly
38
when is asexual reproduction beneficial
in stable, favorable environments
39
fertilization
union of egg and sperm
40
external fertilization
eggs shed by female are fertilized by sperm in the external environment
41
favorable environment for external fertilization
moist habitat - sperm can swim to egg - prevents gametes from drying out
42
spawning
individual cluster in same area to release gametes into the water at the same time - chemical and environmental signals
43
internal fertilization
enables sperm to reach an egg despite dry external environment
44
what does internal fertilization require
behavioral interactions and compatible copulatory organs - often pheromones
45
characteristics of internal fertilization
- fewer gametes - higher survivorship of zygotes - protection of embryos - parental care of young
46
purpose of shells for eggs of birds and reptiles
- protect against water loss - protect against physical damage
47
where are gametes produced
precursor cells in: - gonads - undifferentiated tissue
48
what do elaborate gamete-producing systems include
sets of accessory tubes and glands that carry, nourish, and protect gametes/embryos
49
do insects have separate sexes
yes, each with complex reproductive systems
50
spermatheca
where sperm is stored in female insects during copulation
51
cloaca
common opening between external environment and the digestive, excretory, and reproductive systems - common in nonmammalian vertebrates
52
monogamy
having one mate - can decrease chance of mate mating w/ another ind. - females sometimes influence reproductive success of mates
53
male external organs
scrotum and penis
54
male internal organs
- gonads - produce sperm and hormones - accessory glands - secrete products needed for sperm movement - ducts - carry sperm and glandular secretions
55
male gonads
testes
56
testes
consist of highly coiled tubes (seminiferous tubules) surrounded by connective tissue
57
where does sperm form
seminiferous tubules
58
female echidnas
- cloaca - branches into different systems (2-branched reproductive tract)
59
female external reproductive structure
clitoris and two sets of labia
60
female internal organs
- pair of gonads - system of ducts and chambers that carry gametes and house embryo/fetus
61
major vestibular glands
produce mucoid secretion that aids in vaginal and vulvar lubrication
62
how long does it take for the fertilized egg to travel to the uterus
6-12 days
63
sperm capacitation
set of natural physical changes that a spermatozoon undergoes to be able to fertilize ovum - occurs in vivo following ejaculation when spermatozoa come into contact with different fluids of female genital tract
64
how long as sperm viable in the female reproductive system
5 to 6 days
65
how long are ovum viable after ovulation
6 hours
66
female gonads
ovaries - flank uterus in abdominal cavity
67
what does each ovary contain
follicles
68
follicles
consist of partially developed egg (oocyte) surrounded by support cells
69
path of egg from ovary to uterus
- leaves ovary - travels through oviduct/fallopian tube by cilia - enters uterus/womb
70
endometrium
uterus lining that contains many blood vessels
71
where does uterus narrow
cervix - opens into vagina
72
vagina
muscular but elastic chamber - repository for sperm during copulation - birth canal
73
vulva
where vagina opens to outside - consist of labia major, labia minor, hymen, and clitoris
74
clitoris composition
- head - glans - glans covered by prepuce - small hood of skin - many nerve endings
75
what do the vagina, labia minor, and clitoris all contain
blood vessels
76
mammary glands
contain small sacs of epithelial tissue that secrete milk
77
are mammary glands part of the reproductive system
no
78
gametogenesis
production of gametes
79
spermatogenesis
formation of sperm - continuous and prolific
80
how many sperm produced per day
75 to 100 million
81
how long does it take for each sperm to develop
10 weeks
82
length of entire sperm production cycle
70-75 days
83
how long can motile sperm survive int he female reproductive tract
5 days
84
how many sperm are released per ejaculation
40-500 million
85
where does spermatogenesis take place
seminiferous tubule wall
86
order of spermatogenesis
- primordial germ cell in embryo - mitosis - spermatogonial stem cell - diploid - mitosis - spermatogonium - diploid - mitosis - primary spermatocyte - diploid - meiosis I - secondary spermatocyte - haploid - meiosis II - spermatids - haploid - differentiation - sperm cell - haploid
87
oogenesis
development of a mature egg - prolonged process
88
where do immature eggs form
in female, but don't complete development until years/decades later
89
how many eggs in each ovary at puberty
200,000
90
order of oogenesis
- primordial germ cell - mitosis - oogonium - mitosis - primary oocytes (present at birth, arrested in prophase of meiosis I) - at puberty, completion of meiosis I and onset of meiosis II - secondary oocyte - arrested at metaphase of meiosis II - ovulation, sperm entry - completion of meiosis II - fertilized egg
91
when is first polar body produced
after puberty starts, completion of meiosis I and onset of meiosis II to create secondary oocytes
92
when is second polar body created
after ovulation and sperm entry
93
how is spermatogenesis different from oogenesis
1. all 4 products of meiosis develop into sperm, only 1 of four becomes an egg 2. spermatogenesis occurs throughout adolescence and adulthood 3. sperm produced continuously w/o prolonged interruptions in oogenesis
94
what control mammalian reproduction
hormones from hypothalamus, anterior pituitary, and gonads - hypothalamus - gonadotropin-releasing hormone - anterior pituitary - release FSH and LH to act on - gonads - release steroid hormones
95
main sex hormones are what?
steroid hormones
96
main androgen
testosterone
97
what do estrogens mainly consist of
estradiol and progesterone
98
what do sex hormones function in
- gamete production - sexual behavior - development of secondary sex characteristics
99
what does FSH stimulate in males
Sertoli cells to nourish developing sperm
100
what does LH stimulate in males
Leydig cells to produce testosterone and other androgens, which promotes spermatogenesis
101
what does testosterone regulate production of
1. GnRH 2. FSH 3. LH through negative feedback mechanisms
102
Sertoli cells
- secrete hormone inhibin - reduce FSH secretion from anterior pituitary
103
what do changes in the ovaries define
ovarian cycle
104
what do changes in the uterus define
menstrual cycle (uterine cycle)
105
what happens in each menstrual cycle
- endometrium thickens w/ blood vessels in preparation for embryo implantation - if no embryo implanted, endometrium shed
106
menstruation
shedding of endometrium when no implantation of embryo
107
when does the ovarian cycle begin
when hypothalamus released GnRH
108
ovarian cycle steps
- hypothalamus releases GnRH - anterior pituitary secretes FSH and LH (stimulate follicle growth) - follicles start to make estradiol - increase in estradiol increases FSH and LH - follicle enlarges to form bulge at surface of ovary - follicular phase ends at ovulation, secondary oocyte released - luteal phase follow ovulation - LH stimulus remaining follicular tissue to form corpus luteum - corps luteum secretes progesterone and estradiol - reduced LH and FSH secretion
109
what follows ovulation
luteal phase
110
what does LH stimulate remaining follicular tissue to form
corpus luteum
111
what does corpus lute secrete
progesterone and estradiol
112
purpose of progesterone and estradiol secreted by corpus luteum
exerts negative feedback on hypothalamus and pituitary to reduce LH/FSH secretion - prevents maturation of another egg
113
phases of menstrual cycle
- menstrual flow phase - proliferative phase - secretory phase
114
proliferative phase of menstrual cycle
thickening of endometrium - coordinates with follicular phase
115
secretory phase of menstrual cycle
glands develop that secrete nutritive substances to sustain embryo for first 2 weeks
116
menstrual flow phase
shedding of endometrium - coordinates with growth of new ovarian follicles
117
what happens if no embryo implants in endometrium
new menstrual cycle begins
118
ectopic
cells of uterine lining can sometimes migrate to this abnormal location
119
endometriosis
swelling of cells in uterine lining in response to hormone stimulation
120
how many cycles before menopause
about 500
121
menopause
cessation of ovulation and menstruation
122
is menopause common in animals
no - very unusual
123
what type of organisms experience menstrual cycles
only humans and some other primates - sexual receptivity not limited to time frame
124
estrous cycles
- endometrium reabsorbed by uterus - sexual receptivity limited to estrus - most mammals
125
estrus
"heat" period of sexual receptivity - length/frequency varies among species
126
2 sexual reactions in both sexes
1. vasocongestion 2. myotonia
127
vasocongestion
filling of tissue with blood
128
myotonia
increase muscle tension
129
4 phases of sexual response cycle
1. excitement 2. plateau 3. orgasm 4. resolution
130
excitement
prepares penis and vagina for coitus (sexual intercourse)
131
plateau phase
direction stimulation of genitalia, prepares vagina for receipt of sperm
132
orgasm
characterized by rhythmic contractions of reproductive structures
133
orgasm in males
semen first released into urethra and then ejaculated from urethra
134
orgasm in females
uterus and outer vagine contract
135
resolution phase
organs return to normal state and muscles relax
136
conception
fertilization of an egg by a sperm
137
where does fertilization occur
oviduct
138
process by which zygote begins to divide by mitosis
cleavage
139
blastocyst
ball of cells with central cavity that results form division of zygote cells
140
what happens after blastocyst formation
embryo implants into endometrium
141
pregnancy/gestation
condition of carrying one or more embryos in the uterus
142
what does the duration of pregnancy correlate with
body size and maturity of young at birth
143
how many months of human gestation
9 - divided into 3 trimesters
144
what does the embryo secrete
hormones that signal its presence and regulate mother's reproductive system
145
human chorionic gonadotropin (HCG)
maintains secretion of progesterone and estrogens during early pregnancy
146
examples where embryos don't complete development
- spontaneously stop due to chromosomal/developmental abnormalities - ectopic pregnancy
147
ectopic pregnancy
fertilized egg lodges in fallopian tube
148
where does embryo obtain nutrients during the first 2-4 weeks
directly from endometrium
149
outer later of blastocyst
trophoblast
150
what does the trophoblast form
mingles with endometrium to form placenta
151
how does blood travel to and from the fetus
- blood from embryo travels to placenta through umbilical arteries - blood returns through umbilical veins
152
monozygotic twins
- genetically identical - splitting of embryo during first month of development
153
dizygotic twins
- fraternal and genetically distinct twins - release and fertilization of two eggs
154
first trimester
main period of organogenesis
155
organogenesis
development of body organs
156
steps of embryo development
1. cleavage 2. gastrulation 3. neurulation 4. organogenesis
157
when are all major structures present in an embryo
8 weeks
158
fetus
when all major structures are present at 8 weeks
159
changes in mother during pregnancy
- mucus plug in cervix to protect against infection - growth of placenta/uterus - cessation of ovulation/menstrual cycle - breast enlargement - nausea
160
second trimester
- fetus grows and is active - fetal movements - hormones levels stabilize - placenta takes over production of progesterone
161
what hormone maintains pregnancy
progesterone
162
third trimester
- fetus grows and fills space within embryonic membranes
163
labor
series of strong, rhythmic uterine contractions that push fetus and placenta out of body
164
what is labor regulated by
prostaglandins and hormones like estradiol and oxytocin
165
3 stages of labor
1. dilation - thinning and opening of cervix 2. expulsion - delivery of baby 3. delivery of placenta
166
lactation
production of mother's milk
167
how can a woman acceptance her "foreign" offspring?
- may be due to suppression of immune response - symptoms of rheumatoid arthritis (autoimmune disease) becomes less severe during pregnancy
168
contraception
deliberate prevention of pregnancy
169
3 categories of contraceptive methods
1. preventing release of eggs and sperm 2. keeping sperm and egg apart 3. preventing implantation of an embryo
170
methods of contraception for males
- vasectomy - abstinence - condom - coitus interruptus
171
methods of contraception for females
- birth control - abstinence - female condom - tubal ligation - spermicides, diaphragm, progestin - morning-after pill, intrauterine device
172
rhythm method
- natural family planning - refrain from intercourse when conception most likely - pregnancy rate of 10-20%
173
coitus interruptus
withdrawal of penis before ejaculation - unreliable
174
barrier methods
blocks fertilization - pregnancy rate of less than 10% - condom, diaphragm
175
intrauterine devices
inserted into uterus and interfere with fertilization and implantation - pregnancy rate: less than 1%
176
female birth control pills
hormonal contraceptives with a pregnancy rate of less than 1%
177
only contraceptive effective preventing spread of STDs
latex condoms
178
sterilization
permanent, prevents release of gametes - tubal ligation - vasectomy
179
tubal ligation
ties off oviducts
180
vasectomy
ties off vas deferens
181
rate of spontaneous abortion/miscarriage
1/3 of all pregnancies
182
ultrasound imaging
detects fetal condiiton
183
amniocentesis and chorionic villus sampling
use needle to obtain fetal cells for genetic analysis
184
genetic testing of fetus
poses ethical questions and difficult decisions
185
most significant cause of infertility
STDs
186
in vitro fertilization (IVF)
mixes eggs with sperm in culture dishes and returns embryo to uterus at 8-cell stage
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