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Biomed P2 > Week 10 > Flashcards

Week 10 Flashcards

1
Q

What is a key advantage of sexual reproduction?

A

Variability

Sexual reproduction increases genetic diversity among offspring.

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2
Q

What process leads to genetic recombination?

A

Meiosis

Meiosis is essential for the formation of gametes and genetic variation.

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3
Q

What are gonads?

A

Primary sex organs

Gonads include ovaries in females and testes in males.

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4
Q

What structures are involved in the male reproductive system?

A
  • Testes
  • Epididymis
  • Ductus deferens
  • Urethra
  • Penis

These structures work together for sperm production and transportation.

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5
Q

What is the function of the testes?

A

Sperm production and sex hormone secretion

Testes must be maintained at a temperature 3°C lower than body temperature for optimal sperm production.

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6
Q

What is the role of the epididymis?

A

Storage and maturation of sperm

The epididymis is a 6-meter coiled duct where sperm undergo maturation over about 20 days.

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7
Q

What are the accessory reproductive organs?

A
  • Ducts for gamete transport
  • Glands for fluid secretion
  • External genitalia
  • Organs for embryo nurture
  • Organs for newborn nurture

These structures support reproductive functions and processes.

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8
Q

What is the function of seminal vesicles?

A

Produce 70% of semen volume

Seminal vesicles contribute essential fluids to semen.

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9
Q

What does the prostate gland produce?

A

Approximately 30% of semen

Prostate fluid helps nourish and transport sperm.

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10
Q

What is the purpose of the bulbourethral glands?

A
  • Produce thick clear mucus
  • Provide lubrication
  • Neutralize residual urine in the urethra

These glands help prepare the urethra for sperm passage.

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11
Q

Fill in the blank: The _______ is a dual-purpose duct for urinary and reproductive systems.

A

Urethra

The urethra serves both urinary and reproductive functions in males.

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12
Q

What is the volume of ejaculate?

A

2-5 mL

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13
Q

What are the main components of ejaculate?

A
  • Sperm
  • Seminal fluid
  • Clotting factors
  • Enzymes
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14
Q

What are the ‘sperm factories’ located in the testis?

A

Seminiferous tubules

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15
Q

What cells in the testis produce androgens?

A

Leydig cells

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16
Q

What hormone is primarily produced by Leydig cells?

A

Testosterone

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17
Q

What does ‘2n’ indicate in terms of cell ploidy?

A

Diploid cell

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18
Q

What does ‘n’ indicate in terms of cell ploidy?

A

Haploid cell

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19
Q

How many chromosomes are present in a diploid cell?

A

23 pairs of chromosomes

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20
Q

How many chromosomes are present in a haploid cell?

A

23 individual chromosomes

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21
Q

What are the three main regions of a sperm structure?

A
  • Head
  • Mid piece
  • Tail
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22
Q

What is contained in the head of a sperm?

A
  • Genetic material
  • Acrosome contains enzymes required for penetration of oocyte
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23
Q

What is the function of the mid piece of a sperm?

A

Mitochondria

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24
Q

What does the tail of a sperm provide?

A

Motility

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25
Q

What is the volume of ejaculate?

A

2-5 mL

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26
Q

What are the main components of ejaculate?

A
  • Sperm
  • Seminal fluid
  • Clotting factors
  • Enzymes
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27
Q

What are the ‘sperm factories’ located in the testis?

A

Seminiferous tubules

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28
Q

What cells in the testis produce androgens?

A

Leydig cells

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29
Q

What hormone is primarily produced by Leydig cells?

A

Testosterone

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30
Q

What does ‘2n’ indicate in terms of cell ploidy?

A

Diploid cell

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31
Q

What does ‘n’ indicate in terms of cell ploidy?

A

Haploid cell

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32
Q

How many chromosomes are present in a diploid cell?

A

23 pairs of chromosomes

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33
Q

How many chromosomes are present in a haploid cell?

A

23 individual chromosomes

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34
Q

What are the three main regions of a sperm structure?

A
  • Head
  • Mid piece
  • Tail
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35
Q

What is contained in the head of a sperm?

A
  • Genetic material
  • Acrosome contains enzymes required for penetration of oocyte
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36
Q

What is the function of the mid piece of a sperm?

A

Mitochondria

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37
Q

What does the tail of a sperm provide?

A

Motility

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38
Q

What is the primary function of the ovaries?

A

Store eggs, ovulate one egg per cycle, produce sex hormones

Ovaries are essential for female reproductive health and hormone regulation.

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39
Q

What are the oviducts also known as?

A

Uterine or fallopian tubes

They play a critical role in receiving the ovulated egg and are the site of fertilization.

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40
Q

What is the main role of the uterus?

A

Site of embryo implantation

The cervix projects into the vagina, serving as a passage for sperm and menstrual flow.

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41
Q

What is oogenesis?

A

The process of female gamete production

It differs from spermatogenesis, as it produces only one viable gamete.

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42
Q

How many viable gametes are produced during oogenesis compared to spermatogenesis?

A

One viable gamete in females, four in males

This highlights a significant difference in gamete production between genders.

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43
Q

What remains in the oocyte during oogenesis?

A

Most cytoplasm

The polar body contains a haploid set of chromosomes and minimal cytoplasm.

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44
Q

What are the three layers of the uterus?

A
  • Perimetrium or serosa
  • Myometrium
  • Endometrium

Each layer has distinct structural and functional roles in the reproductive process.

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45
Q

What type of tissue makes up the perimetrium?

A

Simple squamous epithelium and areolar connective tissue

This outer layer provides protection and support to the uterus.

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46
Q

What is the myometrium composed of?

A

Longitudinal, circular, and oblique layers of smooth muscle

It constitutes about 90% of the uterine mass, facilitating contractions.

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47
Q

What are the two layers of the endometrium?

A
  • Stratum functionalis
  • Stratum basalis

The functional layer changes during the menstrual cycle while the basal layer remains permanent.

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48
Q

What happens to the stratum functionalis during the menstrual cycle?

A

Thickness changes

It is shed during menstruation and rebuilt after each cycle.

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49
Q

What is the role of the stratum basalis?

A

Permanent layer that gives rise to new stratum functionalis after each menstruation

It is crucial for the regeneration of the functional layer.

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50
Q

What is the endometrial thickness during menstruation?

A

2-4MM

This thickness is characteristic of the menstrual phase in the menstrual cycle.

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51
Q

What is the endometrial thickness one week after menstruation?

A

5-7MM

This reflects the proliferative phase of the menstrual cycle.

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52
Q

What is the maximum endometrial thickness reached three weeks after menstruation?

A

Up to 16MM

This thickness is typically observed during the secretory phase.

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53
Q

What causes variation in endometrial thickness?

A

Changes in stratum functionalis

The stratum functionalis is the functional layer of the endometrium that undergoes cyclical changes.

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54
Q

How many lobes are present in mammary glands?

A

15-20 lobes

These lobes are surrounded by connective tissue and fat.

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55
Q

What are lobules in the context of mammary glands?

A

Smaller units within lobes

Lobules consist of compound alveolar glands that produce milk.

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56
Q

What is the function of lactiferous ducts?

A

Pass milk into the nipple

These ducts are essential for the delivery of milk during lactation.

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57
Q

What is the lactiferous sinus?

A

Dilated region of lactiferous ducts

It accumulates milk during nursing.

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58
Q

How many rounds of cell division occur in meiosis?

A

Two rounds of cell division

Meiosis is essential for the production of gametes.

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59
Q

What is the significance of hormones in reproduction?

A

Hormones are responsible for the development of sex-specific traits and characteristics.

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60
Q

What are the primary sex organs developed during embryonic and fetal development?

A

Primary sex organs are developed during embryonic and fetal development.

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61
Q

What are secondary sex characteristics and when do they develop?

A

Secondary sex characteristics develop at puberty.

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62
Q

Where are major sex hormones secreted from?

A

Major sex hormones are secreted by the gonads.

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63
Q

Name two types of androgens.

A
  • Testosterone
  • Dihydrotestosterone
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64
Q

What are the main types of estrogens?

A
  • Estradiol
  • Estrone
  • Estriol
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65
Q

What is the role of progesterone in reproductive physiology?

A

Progesterone is involved in the regulation of the menstrual cycle and pregnancy.

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66
Q

How are sex hormones regulated?

A

Sex hormones are controlled via the hypothalamus and anterior pituitary.

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67
Q

What is the hypothalamic-pituitary-gonadal axis also known as?

A

HPO axis

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68
Q

What hormone does the hypothalamus secrete to regulate sex hormones?

A

Gonadotropin releasing hormone (GnRH)

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69
Q

What are the key gonadotropic hormones secreted by the anterior pituitary?

A
  • FSH (Follicle Stimulating Hormone)
  • LH (Luteinizing Hormone)
70
Q

What are the functions of FSH in females?

A
  • Growth of ovarian follicles
  • Ovulation
  • Menstruation
71
Q

What are the functions of FSH in males?

A
  • Promotes development of secondary spermatocytes from primary spermatocytes
  • Increases androgen binding protein for binding of androgens
72
Q

What are the functions of LH in females?

A
  • Promotes follicle maturation
  • Surge in mid-cycle helps ovulation
  • Production by corpus luteum promotes maturation of the endometrium for implantation
73
Q

What is the primary function of LH in males?

A

Stimulates testosterone production.

74
Q

What does the hypothalamus secrete to regulate male reproductive function?

A

Gonadotropin-releasing hormone (GnRH)

GnRH stimulates the secretion of FSH and LH.

75
Q

What hormones are stimulated by GnRH in males?

A
  • FSH
  • LH

FSH stimulates spermatogenesis, while LH stimulates testosterone secretion.

76
Q

What is the role of FSH in male reproductive function?

A

Stimulates spermatogenesis via secretion of androgen binding protein (ABP)

ABP helps in the transport and concentration of testosterone.

77
Q

What does LH stimulate in male reproductive function?

A

Testosterone secretion from interstitial cells

Interstitial cells are also known as Leydig cells.

78
Q

What are the two distinct cycles controlled in female reproductive function?

A
  • Ovarian cycle
  • Uterine cycle

The ovarian cycle produces one ovulated oocyte per cycle, while the uterine cycle prepares the uterus for implantation.

79
Q

What stimulates the secretion of FSH and LH in females?

A

Gonadotropin-releasing hormone (GnRH)

GnRH is crucial for the regulation of the menstrual cycle.

80
Q

What is the primary action of FSH in the ovarian cycle?

A

Acts on growing follicles and stimulates estrogen secretion

Estrogen is vital for the development of oocytes and the regulation of the menstrual cycle.

81
Q

How does LH affect estrogen concentration in females?

A

Increases estrogen concentration via conversion of androgens

This process occurs in the ovaries.

82
Q

What happens to the dominant follicle during the ovarian cycle?

A

Continues development for ovulation

Negative feedback from estrogen reduces the development of other follicles.

83
Q

What marks the beginning of the menstrual phase in the ovarian cycle?

A

First day of menstruation

This phase is characterized by the shedding of the stratum functionalis.

84
Q

What role does FSH play during the menstrual phase?

A

Promotes primordial follicles to develop into primary and then secondary follicles

This growth is essential for future ovulation.

85
Q

What occurs to the stratum functionalis during the menstrual phase?

A

It is shed due to low concentrations of progesterone and estrogens

This shedding leads to menstrual bleeding.

86
Q

What causes an increase in prostaglandins during the menstrual phase?

A

Low concentrations of progesterone and estrogens

Prostaglandins cause constriction of blood flow to uterine arterioles.

87
Q

What is the duration of the preovulatory (proliferative) phase?

A

6 - 13 days

88
Q

What happens to secondary ovarian follicles during the preovulatory phase?

A

Some continue to grow and secrete oestrogens

89
Q

What occurs to the dominant follicle during the preovulatory phase?

A

It becomes the mature or Graafian follicle, around 20mm in diameter

90
Q

What is the effect of the dominant follicle on other follicles?

A

Oestrogen concentration decreases, reducing activation of other follicles

91
Q

What triggers ovulation?

A

High oestrogen secretion causes the secretion of FSH and LH from the anterior pituitary

92
Q

What happens to the mature follicle during ovulation?

A

It ruptures and releases the secondary oocyte

93
Q

Where does the secondary oocyte go after ovulation?

A

It enters the uterine tube

94
Q

What does the corpus luteum secrete during the secretory phase?

A

Large concentrations of progesterone

95
Q

What happens to oestrogen concentrations during the secretory phase?

A

They drop

96
Q

What happens to FSH and LH concentrations during the secretory phase?

A

They reduce

97
Q

What are the hormone levels during the menstrual phase?

A

Oestrogen and progesterone are at their lowest levels

98
Q

What occurs in the uterus during the menstrual phase?

A

Stratum functionalis sheds

99
Q

What happens to FSH and LH concentrations during the menstrual phase?

A

They begin to rise

100
Q

What triggers the proliferation of the functional layer in the proliferative phase?

A

Increasing oestrogen levels

101
Q

What changes occur in the endometrium during the proliferative phase?

A

Increased synthesis of progesterone receptors and enlargement of glands

102
Q

What happens to spiral arteries during the proliferative phase?

A

They increase in number

103
Q

What prompts further development of the endometrium during the secretary phase?

A

Progesterone levels

Progesterone is crucial for maintaining the uterine lining for potential implantation.

104
Q

What are the three key processes prompted by progesterone during the secretary phase?

A
  • Further development of endometrium
  • Glandular secretion of glycogen
  • Formation of the cervical mucus plug

These processes support implantation and nourishment of a potential embryo.

105
Q

What are oogonia?

A

Stem cells that divide by mitosis before birth to form primary oocytes

Oogonia are the precursors to oocytes in female reproductive development.

106
Q

What stage do primary oocytes enter before birth?

A

Meiosis, but are arrested in prophase I

This arrest lasts until puberty when further development resumes.

107
Q

What happens to the first meiotic division of oocytes?

A

It is unequal, producing a very small first polar body

The first polar body does not participate in further development.

108
Q

At what stage are oocytes arrested before birth?

A

Prophase I of meiosis

This arrest ensures that oocytes are not fully developed until ovulation occurs.

109
Q

When is the first meiotic division completed?

A

After puberty

This completion occurs during the menstrual cycle.

110
Q

When is the second meiotic division completed?

A

Only if fertilization occurs

This division is critical for the maturation of the oocyte into a viable egg.

111
Q

What is the outcome of the second meiotic division?

A

It is also unequal, producing a small second polar body

Similar to the first polar body, the second polar body does not contribute to development.

112
Q

What must sperm do after entering the uterus?

A

Undergo capacitation

Capacitation prepares sperm for successful fertilization of the oocyte.

113
Q

What changes occur during capacitation of sperm?

A
  • Sperm flagella beat more vigorously
  • Cell membrane prepares for contact with secondary oocyte

These changes enhance the sperm’s ability to fertilize the egg.

114
Q

What barriers must sperm penetrate to fertilize an egg?

A
  • Corona radiata
  • Zona pellucida

These layers protect the oocyte and must be breached for fertilization to occur.

115
Q

True or False: The first polar body plays a role in subsequent development.

A

False

The first polar body is a byproduct of meiosis and does not contribute to embryo formation.

116
Q

What is the role of sperm acrosomal enzymes?

A

Digest an area of the zona pellucida

The zona pellucida is the protective glycoprotein layer surrounding the oocyte.

117
Q

What happens after sperm entry into the oocyte?

A

The secondary oocyte completes meiosis

This process results in the formation of a mature ovum.

118
Q

What are male and female pronuclei formed from?

A

The nuclei of the sperm and secondary oocyte

These pronuclei contain the genetic material from both parents.

119
Q

What is syngamy?

A

The fusion of pronuclei to form a single nucleus

This results in the formation of a diploid zygote.

120
Q

What is cleavage in the context of pre-implantation development?

A

Rapid post-fertilisation cell division

This process begins shortly after fertilization.

121
Q

When does the first division of the zygote occur?

A

After 24 hours

This marks the beginning of the cleavage stage.

122
Q

What are the cells produced during cleavage called?

A

Blastomeres

These cells are the result of the division of the zygote.

123
Q

What is formed by days 3-4 of development?

A

The Morula

The morula is a solid ball of cells resulting from cleavage.

124
Q

What enters the morula from the endometrium?

A

Uterine milk

Uterine milk provides nutrients to the developing embryo.

125
Q

What forms in the center of the morula by day 10?

A

The blastocyst

The blastocyst is a hollow structure that will implant into the uterine wall.

126
Q

What are the two distinct regions of the blastocyst?

A
  • Inner cell mass (embryoblast)
  • Outer cell ring (trophoblast)

The inner cell mass will develop into the embryo, while the trophoblast will contribute to the placenta.

127
Q

When does the blastocyst attach to the uterine wall?

A

Around 6 days post-fertilization

This is known as the implantation stage.

128
Q

What happens to the endometrium after implantation?

A

It is known as the decidua

This change supports the developing embryo.

129
Q

What increases as the blastocyst attaches firmly to the endometrium at 7 days?

A

Endometrial vascularization

This increase in blood vessels supports the nutrient and gas exchange for the embryo.

130
Q

What does the blastocyst secrete to aid in implantation?

A

Enzymes

These enzymes allow the blastocyst to invade the endometrium.

131
Q

What surrounds the developing embryo and provides nutrients?

A

Decidua basalis

It will form the Maternal placenta.

132
Q

What are the two layers formed by the cells of the embryoblast?

A
  • Hypoblast
  • Epiblast

Collectively known as the bilaminar embryonic disk.

133
Q

What cavity forms in the epiblast?

A

Amniotic cavity

It eventually surrounds the whole embryo.

134
Q

What does the yolk sac supply until the placenta is formed?

A

Nutrients

It is also an early source of blood cells and eventually forms gametes and part of the gut.

135
Q

What forms around the outside of the embryo?

A

Chorion

Later forms the embryonic part of the placenta.

136
Q

The bilaminar disk becomes what type of disk in the third week?

A

Trilaminar disk of primary germ layers

This includes endoderm, mesoderm, and ectoderm.

137
Q

What does the endoderm develop into?

A

Epithelial lining of GI tract, respiratory tract, and other organs

It is one of the three primary germ layers.

138
Q

What does the mesoderm develop into?

A

Muscles, bones, and other connective tissues

It is one of the three primary germ layers.

139
Q

What does the ectoderm develop into?

A

Epidermis and nervous system

It is one of the three primary germ layers.

140
Q

What is the function of chorionic villi in the placenta?

A

They permit the transfer of nutrients, waste, and respiratory gases between maternal blood and embryonic blood

Chorionic villi are finger-like projections from the chorion that extend into maternal lacunae.

141
Q

What occurs during the first trimester of prenatal development?

A

Conception to 12 weeks, embryological to early fetal development, rudiments of major organ systems appear

This phase is critical for the initial formation of the embryo.

142
Q

What are the key developments during the second trimester?

A

12 to 24 weeks, nearly complete development of organ systems

This phase focuses on refining and completing the development of organs.

143
Q

What significant growth occurs during the third trimester?

A

Rapid fetal growth, most organ systems become fully functional, deposition of adipose tissue

This stage prepares the fetus for life outside the womb.

144
Q

What is organogenesis?

A

The process of organ development during embryonic development from weeks 3 to 8

Weeks 4 to 8 are particularly crucial for the development of main organs.

145
Q

What happens to the embryo starting from week 4?

A

The embryo becomes 3D, undergoes rapid growth, extensive vascularization, and neural tube development

These changes are essential for the proper formation of the embryo.

146
Q

Fill in the blank: Maternal blood vessels are broken down, creating blood-filled spaces called _______.

A

lacunae

147
Q

True or False: The chorionic villi are connected to the embryonic heart via umbilical blood vessels.

A

True

148
Q

What is the duration of the first trimester in prenatal development?

A

Conception to 12 weeks

149
Q

What is the time frame for the second trimester?

A

12 to 24 weeks

150
Q

What are the three integrated trimesters of prenatal development?

A
  • First Trimester
  • Second Trimester
  • Third Trimester

Each trimester has distinct developmental milestones and focuses.

151
Q

What is the initial shape of the embryo?

A

Flat plate

The embryo undergoes folding to form a tube at both ends.

152
Q

What is formed from endodermal folding during embryonic development?

A

Primitive gut

It forms the epithelial lining of the gastrointestinal tract.

153
Q

At what week of gestation are all organ systems recognizable?

A

Week 8

This marks a significant milestone in embryonic development.

154
Q

Which hormone levels are maintained by hCG during the first trimester of pregnancy?

A

Estrogen and progesterone

These hormones are secreted by the corpus luteum.

155
Q

How long do hCG levels last during early pregnancy?

A

3-4 months

After this period, the placenta takes over hormone production.

156
Q

When do estrogen and progesterone start being produced by the placenta?

A

After 3-4 months of pregnancy

This transition is crucial for maintaining pregnancy.

157
Q

What happens to hCG concentration during pregnancy?

A

Peaks at quiescence

It is present in maternal urine and used in home pregnancy tests.

158
Q

What triggers the initiation of labor?

A

Rising estrogen levels

This occurs in the final weeks of pregnancy due to placental cortisol secretion.

159
Q

What effect does rising estrogen have on progesterone?

A

Reduces the effects of progesterone

This change helps prepare the body for labor.

160
Q

What increases in response to rising estrogen levels before labor?

A

Oxytocin receptors

This prepares the uterus for contractions during labor.

161
Q

What is the fetus totally dependent on during gestation?

A

The mother

This includes delivery of oxygen and nutrients, removal of wastes, and exchange of some antibodies.

162
Q

What happens to the fetal lungs during gestation?

A

They are either compressed or contain amniotic fluid

This influences the development of the respiratory system.

163
Q

When does surfactant production begin in the fetus?

A

Between 6-7 months

Surfactant is crucial for lung function at birth.

164
Q

What triggers the respiratory muscles at birth?

A

Rising CO2 levels

This activates the respiratory center in the CNS.

165
Q

What occurs during the first breaths of a newborn?

A

Large initial inspiration inflates lungs

This is followed by a rapid breathing rate.

166
Q

What closes at birth to stop blood passage between atria?

A

Foramen ovale

This ensures proper circulation post-birth.

167
Q

What does the ductus arteriosus become after it closes?

A

Ligamentum arteriosum

This change prevents blood flow from bypassing the lungs.

168
Q

How long may it take for the ductus arteriosus to close?

A

Up to 3 months

This is part of normal cardiovascular adjustment after birth.

169
Q

What happens to fetal umbilical vessels after birth?

A

They remodel

This is part of the transition from fetal to postnatal circulation.

170
Q

Fill in the blank: During gestation, the fetus exchanges some _______ with the mother.

A

Antibodies

This provides the newborn with some immunity.

Biomed P2 (11 decks)

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