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Sex and reproduction Flashcards

The popularity of sex sex, disease and mammalian sex determination mammalian sex determination and the indifferent gonad, human reproductive systems mammalian development genetic and cellular principles

1
Q

asexual reproduction is common in what type of plants

A

angiosperms

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2
Q

asexual reproduction in plants is typically an extension of the capacity for …………………………….

A

intermediate growth

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3
Q

plant growth can be sustained or renewed indefinitely by what

A

meristems

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4
Q

what are meristems

A

regions of undifferentiated dividing cells

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5
Q

what are parenchyma cells

A

plant cells that can divide and differentiate into more specialised types of cells, enabling plants to regenerate lost parts

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6
Q

give an example of hoe a detached root or stem fragment can develop into whole new offspring

A

pieces of potato with a bud can generate a whole new plant

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7
Q

what is fragmentation

A

separation of a parent plant into parts that develop into whole plants by regeneration (one of the most common modes of asexual reproduction)

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8
Q

what is apomixis

A

produce seeds without pollination or fertilization by a male gamete
- a diploid egg in the ovule gives rise to an embryo and the ovules mature into sees

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9
Q

what are advantages of asexual reproduction

A
  • no need for a pollinator
  • allows a plant to pass all its genetic material onto its progeny
  • if the plant is well suited to its environment asexual reproduction is ideal because it doesn’t introduce any variation - good in a stable environment
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10
Q

what is asexual plant reproduction know as

A

vegetative reproduction

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11
Q

what are disadvantages of asexual reproduction

A
  • doesn’t produce any variation

- uniformity puts populations at risk of local extinction if there were to be a catastrophic environmental change

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12
Q

what are the advantages of sexual reproduction

A
  • introduces variation so advantageous in unstable environments
  • sexually produced seeds allow more widespread dispersal of offspring
  • seed dormancy allows growth to be suspended until the environmental conditions become more favourable
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13
Q

what are the disadvantages of sexual reproduction

A
  • requires a lot of resources and energy
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14
Q

are seeds produced in asexual reproduction

A

asexual reproduction new plants are obtained without production of seeds or spores
new plants are produced form roots, stems, leaves and buds

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15
Q

what is selfing

A

when plants self fertilize (sexual reproduction)

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16
Q

what is asexual reproduction

A

generation of offspring from a single parent that occurs without the fusion of gametes - in most cases offspring are genetically identical to the parent

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17
Q

what is sexual reproduction

A

reproduction rising from the fusion of 2 haploid gametes making a diploid zygote

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18
Q

what is parthenogenesis

A

a form of asexual reproduction in which females produce offspring from unfertilised eggs (offspring can be either haploid or diploid)

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19
Q

what is a hermaphrodite

A

an individual that functions as both a male and female in sexual reproduction by producing booth sperm and eggs (common in sessile animals)
this way any 2 individuals can mate or some can even self fertilize

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20
Q

what can prevent plants from self fertilizing and why does this happen

A
  • some plants lack carpels or stamens
  • some plants’ carpels and stamens mature at different times
  • carpel and stamens may be structurally arranged in a way that an animal pollinator is unlikely to transfer pollen from the anther to the stigma of the same flower
  • self incompatibility -plant rejects its own pollen

this all contributes to genetic variety by ensuring that sperm and egg come from different plants

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21
Q

what is fission

A

splitting and separation of a parent organisms into 2 individuals of approximately equal size

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22
Q

what is budding

A

when new individuals arise from outgrowths of existing ones

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23
Q

what is parthenogenesis thought to be a response to

A

low population density

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24
Q

what is sex reversal

A

changing sex e.g. when the one male of wrasse dies the largest female turns into a male - producing sperm instead of eggs
e.g. oyster change from male to female when they are at their greatest size to increase reproductive success as they can store more eggs

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25
Q

cycles in reproductive activity are often related to what

A

changing seasons - cycles are regulated by hormones which are in turn regulated by environmental cues

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26
Q

why do animals have reproductive cycles

A

it allows them to conserve resources, reproducing only when sufficient energy sources are available and when environmental conditions favour the survival of the offspring

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27
Q

when in a reproductive cycle does ovulation occur

A

the midpoint

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28
Q

how can climate change decrease reproductive success

A

seasonal temperature is an important cue for reproduction so any fluctuations could confuse the cycle and make it less successful

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29
Q

what are the 2 types of eggs that a female daphnia can produce

A
  1. an egg that requires fertilization in order to develop

2. an egg that develops by parthenogenesis

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30
Q

when do daphnia reproduce asexually

A

when environmental conditions are favourable

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31
Q

when do daphnia reproduce sexually

A

when they are under environmental stress - the change from sexual to asexual is roughly linked with season

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32
Q

how do lizards still use sexual courtship even though they are all female

A

one female of each mating pair mimics a male and they switch roles several times
they take on the male role when levels of progesterone are high
they take on the female role when oestradiol levels are high
a female is more likely to ovulate when she is mounted at a critical point of the hormone cycle
these parthenogenic lizards evolved from species having 2 sexes and this is why they still require sexual stimuli

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33
Q

why is sexual reproduction maintained when asexual reproduction produces more offspring

A
  • in sexual reproduction the offspring show variation and offspring are more likely to survive environmental change
  • beneficial gene combinations might speed up adaptation
  • shuffling genes might allow a population to rid itself of harmful genes more readily
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34
Q

what is external fertilization

A

when the female releases eggs into the environment where the male then fertilises them

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35
Q

what is internal fertilization

A

sperm is deposited in or near the female reproductive tract fertilize eggs within the tract

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36
Q

what is spawning

A

when several females release their eggs at the same time in aquatic environments

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37
Q

if the release of gametes is not synchronised between individuals that fertilize externally then what can occur to ensure they release gametes at the same time

A

courtship behaviours

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38
Q

what are pheromones

A

small volatile water soluble molecules released by an organism that can influence the physiology and behaviour of other individuals of the same species
they may function as mate attractants

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39
Q

sexual reproduction relies on sets of cells that are …….… for eggs and sperm

A

precursors

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40
Q

what are gonads

A

organs that produce gametes

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41
Q

in many insect species the female reproductive system includes one or more spermathecae, what are these

A

sacs in which sperm may be kept alive for extended periods - the female releases the sperm in response to stimuli which allows offspring to be produced when conditions are well suited to survival

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42
Q

what is a cloaca

A

a common opening for the digestive, urinary, and reproductive tracts found in many non mammalian vertebrates but in few mammals - males can turn the cloaca inside out to release sperm if they lack a well developed penis

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43
Q

what is monogamy

A

sustained sexual partnership of 2 individuals

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44
Q

how can monogamy be sustained in some species

A

in fruit flies both the males and females can influence their partners mating success
males can diminish the chance of a female mating successfully with another partner

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45
Q

at what age do the anatomical signs of sex begin to emerge in an embryo

A

2 months

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46
Q

what is the SRY gene

A

the sex determining region of Y

  • In the presence of the gene the gonads develop into testes
  • in the absence of the gene the gonads develop into ovaries
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47
Q

what is a sex linked gene

A

a gene located on a sex chromosome

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48
Q

what are genes located on the X and Y chromosomes called

A

X linked genes and Y linked genes respectively

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49
Q

why are very few disorders transferred from father to son on the Y chromosome

A

because there are few Y linked genes

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50
Q

for the development of female gonads which gene is required

A

WNT4 found on chromosome 1

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51
Q

what does the gene WNT4 encode for

A

a protein that promotes ovary development

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52
Q

what happens if an XY embryo has extra copies of WNT4

A

it can develop rudimentary female gonads

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53
Q

which sex chromosome has more genes that are not related to sex

A

X

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54
Q

if an X linked trait is due to a recessive allele, a female will only express the phenotype if she is ……………. for the allele

A

homozygous

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55
Q

are males or females more likely to show an X linked recessive disease phenotype
explain

A

males are more likely to be affected because they only have one X chromosome so there is nothing to mask the recessive allele and so it will always be expressed
females have 2 X chromosome meaning that if they only inherit one copy of the recessive allele it will be masked by the other X chromosome and they will not express the diseased phenotype

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56
Q

what is meant by viruses being obligate intracellular parasites

A

they can replicate only within a host cell

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57
Q

what is the host range of a virus

A

the number of host species it can infect

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58
Q

how do viruses usually identify host cells

A

by a lock and key fit between viral surface proteins and specific receptor molecules on the outside of cells

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59
Q

when does a viral infection begin

A

when a virus binds to a host cell and the viral genome makes its way inside

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60
Q

how can the viral genome make its way into the host cell

A
  • it can be injected by T phages using their tail apparatus
  • viruses may be taken up by endocytosis, enveloped viruses may be taken up by fusion of the viral envelope with the host’s plasma membrane
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61
Q

how does entry of the viral genome into the host cell affect the host cell

A

the proteins encoded by the viral genome reprogram the cell to copy the viral genome and manufacture viral proteins

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62
Q

what resources do host cells supply for the virus

A 
nucleotides
enzymes 
ribosomes 
tRNAs 
amino acids 
ATP 
DNA polymerase
etc
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63
Q

how do viruses replicate their genome and make new genomes

A

replicate - they use virally encoded RNA polymerase that can use RNA as a template
new genomes - use host cell DNA pol to synthesise new genomes along the templates provided by the viral DNA

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64
Q

what are the 4 steps in the replicative cycle of a virus

A
  1. virus enters the cell and is uncoated releasing viral DNA and capsid into the cell
  2. host enzymes replicate the viral genome
  3. host enzymes transcribe and translate viral DNA to make more capsid proteins
  4. viral genomes and capsid proteins self assemble into new virus particles which exit the cell
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65
Q

what are plasmids

A

small circular DNA molecules that replicate independently of the bacterial chromosome and are occasionally transferred between cells

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66
Q

what are transposons

A

DNA segments that move from one location to another in a cells genome

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67
Q

what are emerging viruses

A

viruses that suddenly become apparent e.g. HIV, ebola, zika and the west nile virus

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68
Q

what is virulence

A

the degree of damage caused by a pathogen to its host

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69
Q

why do RNA viruses have a high mutation rate

A

they do not have a proofreading system - RNA pol does not check or correct errors in replication

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70
Q

what are the human males external and internal reproductive organs

A

external - scrotum and penis
internal:
- goads that produce sperm and reproductive hormone
- accessory glands that secrete products for sperm movement
- ducts that carry sperm and glandular secretions

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71
Q

what are the male gonads

A

the testes

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72
Q

testes produce sperm in highly coiled tubes called …….………

A

seminiferous tubules

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73
Q

most mammals produce sperm properly only when the testes are warmer/cooler than the rest of the body and what maintains this temperature

A

cooler - why they hang outside the body

testes temperature is maintained by the scrotum (a fold of the body wall)

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74
Q

where do the testes develop and what happens to them at birth

A

they develop in the abdominal cavity and then descend into the scrotum just before birth

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75
Q

what is a testis within a scrotum called

A

a testicle

76
Q

why are some mammals able to keep their testes within the abdominal cavity at all times

A

because their body temperature is low enough to allow sperm maturation

77
Q

between breeding seasons the testes of some rodents are drawn back into the …………………, interrupting sperm maturation

A

abdominal cavity

78
Q

where does the sperm pass from the seminiferous tubules to and what happens to the sperm during this journey from the seminiferous tubules

A

they travel to the coiled duct of an epididymis which take about 3 weeks and during this time the sperm complete maturation and become motile

79
Q

what happens to the sperm during ejaculation

A

the sperm are propelled from each epididymis through a muscular duct called the vas deferens

80
Q

how many vas deferens does a male have

A

2 - one from each epididymis

81
Q

how are the vas deferens arranged in the body

A

each one extends around and behind the urinary bladder where it joins a duct from the seminal vesicle, forming a short ejaculatory duct

82
Q

the ejaculatory ducts open into the ………….

A

urethra

83
Q

what is the urethra

A

the outlet tube of both the excretory and the reproductive system (it runs through the penis and opens to the outside at the tip of the penis)

84
Q

what are the 3 sets of accessory glands in the male reproductive system

A

seminal vesicles
prostate gland
bulbourethral glands

85
Q

what is the role of the accessory glands

A

they produce secretions that combine with sperm to form semen - the fluid that is ejaculated

86
Q

two ……………… contribute about 60% of the volume of semen

A

seminal vesicles

87
Q

describe the fluid secreted from the seminal vesicles

A

thick, yellowish and alkaline

it contains mucous, fructose, a coagulating enzyme, ascorbic acid and local regulators called prostaglandins

88
Q

what is the role of the fructose in the secretions from the seminal vesicles

A

it provides most of the sperms energy

89
Q

where does the prostate gland secrete its product

A

directly into the urethra through small ducts

90
Q

describe the fluid secreted from the prostate gland

A

thin and milky

contains anticoagulant enzymes and citrate (sperm nutrient)

91
Q

where are the bulbourethral glands found

A

they are found along the urethra below the prostate

92
Q

what is the role of the bulbourethral glands

A

before ejaculation they secrete clear mucous that neutralises any acidic urine remaining in the urethra

93
Q

what is the evidence that correlates with the high failure rate of the withdrawal method

A

the bulbourethral fluid carries some sperm released before ejaculation

94
Q

where is the prostate gland located

A

beneath the bladder

95
Q

where is the seminal vesicle located

A

behind the bladder

96
Q

what does the penis contain

A

3 cylinders of spongy erectile tissue and the urethra

97
Q

what happens too the erectile tissue during sexual arousal

A
  • the erectile tissue fills with blood from the arteries
  • increasing pressure seals off the veins that drain the penis causing it to engorge with blood
  • the resulting erection enables the penis to be inserted into the vagina
98
Q

what can cause erectile dysfunction

A

alcohol consumption
some drugs
emotional issues
ageing

99
Q

what do drugs like Viagra do

A
  • they promote the vasodilating action of the local regulator Nitric Oxide
  • the smooth muscle in the blood vessels of the penis relax enhancing blood flow into the erectile tissues
    this allows those with long term erectile dysfunction to achieve an erection
100
Q

what is the baculum

A

the bone in some mammal penises that further stiffens the penis for mating

101
Q

what is the glans of the penis

A

the head

102
Q

what is the glans surrounded by

A

a fold of skin called the prepuce (foreskin)

103
Q

what are a human females external reproductive structures

A

the clitoris and two sets of labia

104
Q

what are the human females internal reproductive structures

A
  • gonads which produce eggs and reproductive hormones

- a system of ducts and chambers which receive and carry gametes and house the embryo and fetus

105
Q

what are the female gonads

A

a pair of ovaries that flanks the uterus and are held in place in the abdominal cavity by ligaments

106
Q

what is the outer layer of the ovaries packed with

A

follicles - each consisting of an oocyte (a partially developed egg) surrounded by support cells which nourish and protect the oocyte

107
Q

what is the oviduct and where is it located

A

it is the fallopian

it extends from the uterus toward an opening at each ovary

108
Q

what is the role of cilia that line the oviduct

A

upon ovulation the cilia of the epithelium lining of the oviduct help collect the egg by drawing fluid from the body cavity into the oviduct
oviduct contractions and the cilia convey the egg down the oviduct to the uterus (womb)

109
Q

what is the uterus

A

also known as the womb

it is a thick muscular organ that can expand during pregnancy

110
Q

what is the inner lining of the uterus called

A

the endometrium

111
Q

what is the neck of the uterus called

A

the cervix - it opens into the vagina

112
Q

what is the outside opening of the vagina

A

the vulva

113
Q

what encloses and protects the vulva

A

the labia majora

114
Q

the vaginal opening and the urethra are located in a cavity bordered by what

A

the labia minora

115
Q

what is the clitoris

A

it is found at the top of the labia minora and consists of erectile tissue supporting a rounded glans covered by the prepuce

116
Q

during sexual arousal what happens the labia minora, clitoris and vagina

A

they enlarge due to engorging blood

117
Q

during sexual arousal what do the vestibular glands do

A

they secrete lubricating mucous that facilitates intercourse

118
Q

what are mammary glands

A

they are present in both sexes
they produce milk in females
small sacs of epithelial tissue in the glands secrete milk
the milk then drains into a series of ducts that open at the nipple

119
Q

what do the breasts contain in addition to the mammary glands

A

adipose tissue

120
Q

what is gametogenesis

A

the production of gametes

121
Q

what is spermatogenesis

A

the formation and development of sperm

122
Q

what is oogenesis

A

the development of mature eggs

123
Q

where does cell division and maturation occur

A

in the seminiferous tubules coiled in the 2 testes

124
Q

in what 3 ways do spermatogenesis and oogenesis differ

A
  1. only in spermatogenesis do all 4 products of meiosis develop into mature gametes. (in oogenesis cytokinesis during meiosis is unequal with almost all the cytoplasm segregated to single daughter cell. The large cell is destined to become the egg and the smaller cells (polar bodies) become degenerate
  2. spermatogenesis occurs throughout adolescence and adulthood (mitotic divisions in oogenesis are complete before birth and production of mature gametes ceases at about 50)
  3. spermatogenesis produces mature sperm from precursor cells in a continuous sequence (in oogenesis there are long interruptions)
125
Q

where are stem cells (spermatogonial stem cells) that give rise to sperm found

A

near the outer edge of the seminiferous tubules

126
Q

how do the spermatogonial stem cells arise

A

from division and differentiation of primordial germ cells in the embryonic testes

127
Q

in mature testes upon mitosis what doo spermatogonial cells produce

A

spermatogonia

128
Q

upon mitosis what do spermatogonia generate

A

primary spermatocytes

129
Q

each primary spermatocyte gives rise to …….. spermatids through meiosis

A

4

130
Q

describe the structure of sperm

A

a head containing a nucleus which is tipped with the acrosome which contains enzymes that help sperm penetrate the egg
the sperm have a flagella tail powered by ATP for movement

131
Q

go through the spermatogenesis process

A 
primordial germ cell in embryo 
MITOSIS
spermaogonial stem cell
MITOSIS
spermatogonium 
MITOSIS
primary spermatocyte 
MEIOSIS I
secondary spermatocyte 
MEIOSIS II
early spermatid
DIFFERENTIATION 
sperm cell
132
Q

oogenesis begins in the female embryo with the production of …………….. from primordial germs cells by mitosis

A

oogonia

133
Q

the oogonia undergo mitosis to form what

A

primary oocyte

134
Q

what happens to the primary oocyte

A

embryo - it undergoes meiosis but is arrested at prophase I
puberty - meiosis I is completed and meiosis II is carried out and arrested at metaphase II. this produces a polar body (which may or may not divide again) and a secondary oocyte

135
Q

what does FSH stand for

A

follicle stimulating hormone

136
Q

what does FSH do in females

A

beginning at puberty it stimulates a small number of follicles to resume growth and development

137
Q

how many follicles fully mature each month

A

one with its primary oocyte completing meiosis I

138
Q

what happens when a follicle fully matures

A

its primary oocyte completes meiosis I and the second meiotic divisions begin but stop at metaphase
the secondary oocyte is released at ovulation when its follicle breaks open

139
Q

under what circumstances does meiosis II resume in the secondary oocyte

A

only if it is penetrated by a sperm

140
Q

what is the functional product of complete oogenesis

A

a single mature egg containing a sperm head

141
Q

what is the exact definition of fertilization

A

the fusion of the haploid nuclei of the sperm and secondary oocyte

142
Q

what does the ruptured follicle left behind after ovulation develop into

A

the corpus luteum

143
Q

what does the corpus luteum do

A

it secretes oestradiol and progesterone (hormone that helps maintain the uterine lining during pregnancy
if the egg isn’t fertilised the corpus luteum degenerates

144
Q

mammalian reproduction id governed by the coordinated actions of hormones from which 3 places

A

hypothalamus
anterior pituitary
gonads

145
Q

endocrine control begins with the hypothalamus which secretes what

A

gonadotropin releasing hormone (GnRH)

146
Q

what does GnRH do

A

it directs the anterior pituitary to secrete the gonadotropins follicle stimulating hormone (FSH) and luteinizing hormone (LH)

147
Q

LH and FSH are tropic hormones - what does this mean

A

they regulate the activity of endocrine cells or glands

148
Q

how do LH and FSH support gametogenesis

A

by stimulating sex hormone production by the gonads

149
Q

what are the 3 major types of steroid sex hormones produced and secreted by the gonads

A

androgens - mainly testosterone
oestrogens - mainly oestradiol
progesterone

150
Q

although the gonads are the major source of sex hormones, the …………………….. also secrete sex hormones in small amounts

A

adrenal glands

151
Q

the androgens produced in male embryos direct the appearance of primary sex characteristics. what are primary sex characteristics

A

the structures involved directly in reproduction which include the seminal vesicles and associated ducts as well as external reproductive structures

152
Q

during sexual maturation sex hormones induce the formation of …………………..

A

secondary sex characteristics

153
Q

what are secondary sex characteristics

A

the physical and behavioural differences in males and females that are not directly related to the reproductive system - this often leads to sexual dimorphism

154
Q

in directing spermatogenesis which cells do FSH and LH act on in the testis

A

FSH stimulates Sertoli cells located in the seminiferous tubules to nourish developing sperm
LH causes leydig cells, scattered in the connective tissue between the tubules, to produce testosterone and other androgens which promote spermatogenesis in the tubules

155
Q

what are the two negative feedback mechanisms that control sex hormone production in males

A
  • testosterone regulates blood levels of GnRH, FSH and LH through inhibitory effects on the hypothalamus and anterior pituitary
  • inhibin (a hormone produced by Sertoli cells in males) acts on the anterior pituitary gland to reduce FSH secretion
    these circuits together maintain androgen levels in the normal range
156
Q

what are other roles of Leydig cells besides producing testosterone

A

they secrete small quantities of other hormones and local regulators, including oxytocin, renin, angiotensin, corticotropin-releasing factor, growth factors and prostaglandins
these signals coordinate the activity of reproduction with growth, metabolism, homeostasis and behaviour

157
Q

what are the two closely linked reproductive cycles in females

A

the ovarian cycle and the uterine cycle

158
Q

what is the ovarian cycle

A

cyclic events in the ovaries - once per cycle a follicle matures and an oocyte is released

159
Q

what is the uterine cycle

A

changes in the uterus - a menstrual cycle

160
Q

what happens in a menstrual cycle

A

the endometrium (lining of the uterus) thickens and develops a rich blood supply before being shed through the cervix and the vagina if pregnancy does not occur

161
Q

why is it important the ovarian and uterine cycles are linked

A

by them being linked hormone activity synchronises ovulation with the establishment of a uterine lining that can support embryo implantation and development

162
Q

what happens if an oocyte is not fertilized

A

the uterine lining is sloughed off and another pair of ovarian and uterine cycles begins

163
Q

what is menstruation

A

cyclic shedding of blood rich endometrium from the uterus through the cervix and the vagina

164
Q

what are the steps in the ovarian cycle

A
  1. hypothalamus secretes GnRH which stimulates the anterior pituitary to secrete small amounts of FSH and LH
  2. FSH stimulates follicle growth, aided by LH, and the follicles start to make oestradiol
  3. oestradiol concentration slowly rises during most of the follicular stage when follicles grow and oocytes mature
  4. when oestradiol secretion by the follicle begins to steeply rise and the FSH and LH levels increase markedly
  5. the maturing follicle enlarges to form a bulge at the surface of the ovary
  6. the follicular stage ends at ovulation about a day after the LH surge
  7. the luteal phase follows ovulation
  8. LH stimulates the remaining follicular tissue to form the corpus luteum which releases progesterone and oestradiol which exert negative feedback on the hypothalamus an the anterior pituitary
  9. negative feedback reduces the level of FSH and LH secretion preventing maturation of another egg when pregnancy may be under way
  10. if pregnancy doesn’t occur low gonadotropin (FSH and LH) levels cause the corpus luteum to disintegrate triggering a sharp decline in oestradiol and progesterone which stops the negative feedback
  11. the pituitary can then secrete enough FSH to stimulate the growth of new follicles, initiating the next ovarian cycle
165
Q

low levels of oestradiol ………. secretion of pituitary gonadotropins (LH and FSH)

A

inhibits

166
Q

high levels of oestradiol …………. gonadotropin (LH and FSH) secretion from the pituitary by

A

stimulate

167
Q

how do high levels of oestradiol stimulate LH and FSH

A

oestradiol causes the hypothalamus to increase output of GnRH and also causes increased sensitivity of LH releasing cells to GnRH

168
Q

what are the steps in the uterine cycle

A
  1. prior to ovulation, ovarian steroid hormones stimulate the uterus to prepare to support an embryo
  2. oestradiol signals the endometrium to thicken
  3. after ovulation the oestradiol and progesterone secreted by the corpus luteum stimulate further development of the uterine lining including enlargement of arteries and growth of endometrial glands
  4. if an embryo is not implanted in the endometrium by the end of the secretory phase the corpus luteum disintegrates
  5. the drop in ovarian hormone (oestradiol and progesterone) levels causes the arteries in the endometrium to constrict
  6. the uterine lining disintegrates and menstrual floe begins and a new set of follicles begin to grow
169
Q

what is endometriosis

A

disorder in which some cells of the uterine lining migrate to an abdominal location that is abnormal (ectopic)
the ectopic tissue swells and breaks down during each ovarian cycle resulting in pelvic pain

170
Q

what is menopause

A

the cessation of ovulation and menstruation

ovaries lose their responsiveness to LH and FSH resulting in a decline in oestradiol production

171
Q

what is the estrous cycle

A

where the uterus reabsorbs the endometrium instead of releasing it in menstrual flow

172
Q

what is vasocongestion

A

the filling of a tissue with blood

173
Q

what is myotonia

A

increased muscle tension

174
Q

what are the sexual response cycle stages

A

excitement
plateau
orgasm
resolution

175
Q

how are the functions of FSH and LH similar in males and females

A

in both males and females FSH encourages the growth of cells that support and nourish gametes (follicle cells in females and Sertoli cells in males)
in both males and females LH stimulates the production of sex hormones that promote gametogenesis (oestrogens (mainly oestradiol) in females and androgens (manly testosterone) in males)

176
Q

what are the 5 steps in formation of a human zygote and its early postzygotic events

A
  1. ovulation releases a secondary oocyte which enters the oviduct
  2. a sperm enters the oocyte; meiosis of the oocyte is completed and the nuclei of the sperm and oocyte fuse - producing a zygote
  3. cell division begins in the oviduct as the embryo is moved towards the uterus by peristalsis and cilia movement
  4. the embryo is nourished by endometrial secretions in the uterus and becomes a blastocyst
  5. the blastocyst implants in the endometrium
177
Q

where are the Sertoli cells found in males

A

in the seminiferous tubules

178
Q

between which 2 phases of the menstrual cycle do the concentrations of FSH and LH peak

A

between the proliferative phase and the secretory phase (this is also when oestradiol peaks - oestradiol causes the influx of FSH and LH) - at ovulation

179
Q

in what phase of the ovarian cycle do FSH and LH peak

A

at the end of the follicular phase before going into the luteal phase - this crosses over with the proliferative and secretory phases of the uterine/ovarian cycle - at ovulation

180
Q

what are the steps in oogenesis

A 
primordial germ cell 
MITOSIS
oogonium 
MITOSIS
primary oocyte 
MEIOSIS I
secondary oocyte 
OVULATION/SPERM ENTRY
COMPLETION OF MEIOSIS II
fertilized egg
181
Q

once the sperm enters the secondary oocyte what is produced

A

a fertilized egg and a second polar body

182
Q

where does the hypothalamus release GnRH to

A

the anterior pituitary

183
Q

what does GnRH stimulate

A

secretion of LH and FSH from the pituitary

184
Q

what do FSH and LH stimulate in females

A

follicle growth

185
Q

what does the LH surge trigger in females

A

ovulation

186
Q

what do progesterone and oestradiol promote

A

thickening of the endometrium

187
Q

what is secreted by the corpus luteum

A

progesterone and oestradiol

B (19 decks)

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