Unit B - Reproduction & Development Flashcards
1
Q
Which germ layer does the fetal digestive tract form from?
A
Endoderm
2
Q
Which female reproductive hormone stimulates prolactin secretion and inhibits the growth of facial hair?
A
Estrogen
3
Q
The process whereby a single cell divides twice to produce four cells containing half of the original genetic information is called?
A
Meiosis
4
Q
What is one thing that makes the reproductive system different than others?
A
It becomes functional at puberty.
5
Q
A gamete js a haploid cell made during _____ that participated in fertilization to create a _____.
A
Meiosis, zygote.
6
Q
The smallest cell in a human body is a _____ cell.
A
Sperm
7
Q
The male reproductive gamete is the _____, and the female reproductive gamete is the _____.
A
Sperm, egg.
8
Q
Each sperm cell contains how many chromosomes?
A
23
9
Q
Name the three parts of a sperm, and their functions.
A
- Oval head w/ across one covering container chromosomes.
- Cylindrical middle contains mitochondria to produce energy.
- Tail, to provide motility.
10
Q
Which hormone initiates the development of sperm cells?
A
FSH
11
Q
Where is sperm produced, specifically?
A
In the seminiferous tubules of the testes.
12
Q
Where do sperm cells reach maturity and finally become mobile?
A
Epididymus
13
Q
Through why structure do the speed leave the epidiymus and travel to the urethra?
A
Vas deferens
14
Q
What is added to the sperm in the vas deferens, and what is it called altogether, and what is its function?
A
Seminal fluid, semen.
It is alkaline to protect the sperm from acidic environments and contains food for survival.
15
Q
What are the three male accessory glands called?
A
- Seminal vesicles
- Prostate gland
- Cowper’s gland
16
Q
Name the gonads of the male and female reproductive system.
A
The testes and the ovaries.
17
Q
What are the components of primary sex characteristics?
A
Structures: glands, ducts and gonads.
18
Q
What hormone stimulates the production of testosterone?
A
LH
19
Q
What cells are responsible for the production and growth of sperm cells?
A
Sertoli cells
20
Q
Testosterone is secreted by the _____ cells in the seminiferous tubules.
A
Interstitial
21
Q
Gametogenesis is the _____ phase of germ cells.
A
Maturation.
22
Q
What are the specific names for gametogenesis in males and females?
A
Spermatogenesis, oogenesis.
23
Q
What kind of lifestyle conditions contribute negatively to sperm production?
A
Smoking, alcohol, stress, nutrition, exercise, and drug use.
24
Q
Name a few distinctively male secondary sec characteristics (six)?
A
- Facial hair
- Body hair
- Deeper voice
- Broader shoulders
- Narrower hips
- More obvious muscle development
25
Sertoli cells produce which hormone that prevents excessive sperm production?
Inhibit, inhibits GnRH.
26
Minimal body and facial hair, prominent breasts, a higher voice, more rounded shoulders and wider hips are indicative of what?
Female secondary sex characteristics.
27
What are the three main functions of the ovaries?
1. Produce and mature eggs.
2. Produce sex hormones.
3. Site of ovulation.
28
Where does fertilization of an oocyte occur?
The Fallopian tubes.
29
After producing and releasing an egg in ovulation, the follicular becomes the _____ _____.
Corpus luteum.
30
If implantation occurs, what is the function of the corpus luteum?
Produces sex hormones to maintain the uterus’ lining.
31
The lining of the uterus, the _____, is developed by the hormone _____ and maintained by the hormone _____.
Endometrium, estrogen, progesterone.
32
At puberty, the hypothalamus begins producing _____ which stimulates the pituitary gland to release both _____ and _____.
GnRH (gonadotropin releasing hormone), FSH and LH.
33
How long do ova survive after ovulation?
~24 hours
34
What is the female equivalent of the Sertoli cells in the female reproductive system?
Follicle cells
35
The oven is surrounded by a large amount of _____ and is encased in a thick membrane that is penetrated by the _____ of a sperm’s acrosome (cap).
Cytoplasm, enzymes.
36
Why can’t more than one sperm penetrate the egg’s corona radiata?
Enzymes of the acrosome depolarize the membrane where they’ve digested through, so other sperm can’t bind with it.
37
Why is pelvic inflammatory disease (PID) so serious for women?
PID can cause a build-up of scar tissue in the Fallopian tubes, and prevent sperm from meeting and fertilizing an egg (infertility).
38
What are the two major types of STIs?
Viral and bacterial.
39
What is the most common STI in the world?
Human papilloma virus (HPV).
40
What are the two most common bacterial STIs?
Chlamydia and gonorrhoea.
41
What makes viral STIs so dangerous?
The likelihood of death is much higher, and many are incurable.
42
Why are bacterial STIs dangerous?
Many go easily undetected, and can become resistant to antibiotics.
43
To develop as a male, the testes-determining factor (TDF) of the sex-determining region-Y part of a Y chromosome causes differentiation of supporting cells into _____ cells and _____ cells that begin to form testosterone around the 8th week of gestation, and begin differentiating into make structures.
Sertoli and interstitial cells.
44
In cells with two X chromosomes, one is inactivated and is called a _____ body, which appears as a dark stained structure in the nuclear envelope.
Barr
45
Which hormone stimulates the production of FSH and LH?
GnRH
46
What is the function of FSH in the male reproductive system?
Stimulates development of sex organs and gamete (sperm) production.
47
What is the function of LH in the male vs female reproductive systems?
Male: stimulates testosterone production.
Female: stimulates ovulation.
48
What are three functions of estrogen?
1. Stimulates production of female reproductive organs.
2. Stimulates secondary sex characteristics.
3. Develops the endometrium.
49
What are two functions of progesterone?
1. Causes uterine thickening.
| 2. Prevents uterine contractions.
50
What are the four phases of the female reproductive cycle (in order)?
1. Flow phase
2. Follicular phase
3. Ovulation
4. Literal phase
51
The increase of estrogen produced by the follicle in the follicular phase inhibits the release of _____ and triggers the release of _____, which causes LH to spike and _____ to occur.
FSH, GnRH, ovulation.
52
Once the ovum is released, in the _____ stage, LH causes the follicle to turn into the _____ _____, and the production of _____ increases.
Luteal, corpus luteum, progesterone.
53
If the egg is fertilized before implanting, it begins to produce _____ in order to maintain estrogen and progesterone production.
Human chorionic gonadotropin hormone (hCG).
54
The process between the fertilization of an egg and the beginning of childbirth is called?
Gestation
55
Weeks 1-8 after fertilization are known as which phase of gestation?
Embryonic development.
56
Weeks 9-38 are known as which period of gestation?
Fetal development.
57
Fertilization occurs when?
When the male and female gamete join to form a single cell with 46 chromosomes.
58
How long can sperm cells survive in the oviducts?
3-5 days
59
Why do so few sperm cells actually make it to the egg?
1. Only one ovary releases an egg per cycle, so some sperm go the wrong way (into the other Fallopian tube).
2. Some sperm aren’t as motile as others.
3. The vagina is an acidic environment.
60
When fertilization is complete, the resulting single cell becomes a?
Zygote
61
What happens to the zygote 2 days after fertilization?
The cell divides by mitosis for the first time = two cells.
62
When does a zygote become a morula?
About day 4, when the zygote has undergone cell division to the 16-cell stage.
63
When cells divide rapidly without enlargement or growth, the process is called?
Cleavage
64
What is the difference between a morula and a blastocyst?
A blastocyst is fluid filled, and begins to develop into two types of cells: those that nourish and those that become the embryo.
65
Are the cells in a morula totipotent (can become any cell in the body) or pluripotent (capable of becoming several different types of cells)?
Totipotent
66
What are the two types of cells in a blastocyst called?
Trophoblast cells and inner cell mass.
67
What are the primary functions of trophoblast cells (three important)?
1. Forms an outer protective layer that later becomes the placenta which nourishes the embryo/fetus.
2. Secretes enzymes that eat away endometrium tissue so blastocyst can implant.
3. Secretes hCG to maintain corpus luteum, and estrogen and progesterone production.
68
At what point is a woman known to be pregnant?
Day 10-14, when implantation is complete.
69
Which hormone does a home pregnancy test test for, and what produces it?
hCG, the trophoblast cells.
70
How are fraternal (dizygotic) twins produced?
More than one egg is released at the same time, and eggs are fertilized by different eggs, implanting around the same time.
71
How do identical (monozygotic) twins form?
Quickly dividing cell masses separate into two. Formed from the same cells with the same chromosomes, twins share the same genetic information and may share supporting structures (placenta, etc.).
72
The first thing that occurs in the embryonic development stage, in week 3, is the space that develops in between the inner cell mass and the trophoblast. It is called the _____ _____ and fills with fluid. This becomes the _____ _____.
Amniotic cavity, amniotic sac.
73
As the inner cell mass flattens it becomes a structure called the _____ _____ and has two layers: the _____ and the _____.
Embryonic disc, endoderm, ectoderm.
74
The third layer of the embryonic disc is called the?
Mesoderm
75
The formation of the three primary germ layers is called?
Gastrulation
76
Morphogenesis is the phase that begins after gastrulation, and it is a series of events that...?
Forms distinct structures of the organism.
77
When do organs begin to form in embryonic development?
About weeks 4-9, following gastrulation and differentiation of the three primary germ layers.
78
Which primary germ layer forms a structure called the notochord that becomes a framework for the spine and skeleton?
Mesoderm
79
The nervous system and sense organs are formed out of which primary germ layer?
Ectoderm
80
The pancreas, thyroid glands and bladder form from which primary germ layer?
Endoderm
81
Muscle and connective tissue form from which primary germ layer?
Mesoderm
82
Which primary germ layer forms the respiratory system?
Endoderm
83
The heart, kidney and spleen are formed from which primary germ layer?
Mesoderm
84
Eye lenses, tooth enamel, hair and nails are formed from which primary germ layer?
Ectoderm
85
Which primary germ layer forms the digestive system and bladder?
Endoderm
86
Which primary germ layer is responsible for the reproductive system?
Mesoderm
87
The circulatory system is formed from which primary germ layer?
Mesoderm
88
What happens during neurulation?
Cells of the ectoderm begin to thicken and folds develop around the notochord. Where they fold, they fuse to form the brain and spinal cord.
89
What are some identifiable changes during the fourth week of embryonic development (three)?
1. Head is distinctly visible with early evidence of ears, eyes and nose.
2. Blood vessels and first blood cells begin to form and fill.
3. Lungs and kidneys take shape.
90
What are some identifiable changes during the fifth week of embryonic development (two)?
1. Cells in brain are differentiating very quickly, head becomes very large.
2. Eyes are open but no eyelids.
91
What are some identifiable changes during the sixth week of embryonic development (two)?
1. Limbs begin to lengthen.
| 2. Gonads begin producing hormones to influence genitalia development.
92
What are some identifiable changes during the seventh and eighth weeks of embryonic development (four)?
Distinct human characteristics:
1. Organs are mostly formed.
2. Nervous system is beginning to coordinate body activity.
3. Skeleton of cartilage is formed.
4. Eyes are well developed but eyelids are closed.
93
When 90% of organs and structures have been formed by the end of the eighth week, what is the embryo now called?
Fetus
94
What are the four extra-embryonic membranes?
1. Amnion
2. Yolk sac
3. Allantois
4. Chorion
95
Which extra-embryonic membrane provides nutrients for the first two weeks after implantation?
The yolk sac.
96
Which extra-embryonic membrane forms part of the urinary bladder?
Allantois
97
Which extra-embryonic membrane forms the placenta?
Chorion
98
What is the function of the amniotic sac and fluid?
Cushions fetus from trauma and protects it from temperature changes.
99
Which extra-embryonic membrane forms the umbilical cord?
Allantois
100
Folic acid is a nutrient necessary for the success of which stage of embryonic development?
Neurulation
101
Which critical structure is complete by around the 10th week?
Placenta
102
What are the two components that form the placenta?
Chorionic tissue and mother’s endometrium tissue.
103
What are the five functions of the placenta (think about body systems)?
1. Nutritional
2. Excretory
3. Respiratory
4. Endocrine
5. Immune
104
The umbilical cord contains two _____ and one _____ vein. What are their functions?
Arteries: transport oxygen depleted blood away from fetus.
Vein: transports oxygen rich blood to the fetus.
105
What structure connects the placenta to the fetus?
The umbilical cord.
106
Which extra-embryonic membrane is the outermost membrane?
Chorion
107
Nutrient supply to the embryo/fetus changes throughout gestation. What are the three main sources following implantation?
1. Endometrium
2. Placenta
3. Umbilical cord
108
In which order do the following four stages occur?
1. Neurulation
2. Placental development
3. Organ development
4. Gastrulation
4, 1, 2, 3
109
Nutrition is especially important in which trimester, and why?
The third. Poor nutrition damages the placenta.
110
How many days does the average pregnancy last?
266 days
111
In which trimester is avoidance of teratogens the most important, and why?
The first trimester, because that’s when all the organs are forming and are highly sensitive to environmental factors.
112
What are five types of teratogens?
1. Cigarette smoke
2. Alcohol
3. X-rays
4. Drugs (prescription/antibiotics)
5. Nutrients
113
Why is cigarette smoke dangerous to developing babies?
It constricts a baby’s blood vessels, preventing adequate oxygen supply.
114
Why is alcohol dangerous for developing babies?
It has a significant effect on the developing brain and nervous system.
115
Where is relaxin produced?
The corpus luteum and then the placenta.
116
Which hormone is responsible for signalling labour to begin?
A slight decrease in progesterone.
117
What is the function of relaxin?
Relaxing the ligaments and joints so the body can accommodate the growing fetus.
118
What are the three stages of parturition?
1. Dilation
2. Expulsion
3. Placental
119
What two events signal the start of labour?
1. Uterine contractors that occur every 15-20 minutes and last 40+ seconds.
2. Dilation of the cervix to 3+ cm.
120
The dilation of the cervix signals the release of which hormone?
Oxytocin
121
What is the function of oxytocin in childbirth?
Contracting the uterine muscles to push the fetus downward, further dilating the cervix.
122
What hormones are involved in the first stage of parturition?
1. Oxytocin
| 2. Prostaglandins
123
What event signals that the umbilical cord can be cut?
The baby has been delivered and is breathing independently.
124
If a vaginal birth isn’t possible, what is an alternative?
Caesarean section (c-section).
125
What is expelled from the uterus in the third stage of parturition, and what is it called?
The placenta and umbilical cord; the afterbirth.
126
In what stage of parturition does the amniotic sac break?
First: dilation.
127
Which hormones inhibit the production of prolactin?
Estrogen and progesterone.
128
Which gland released prolactin?
The anterior pituitary gland.
129
What hormone is released by the stimulation of a suckling baby?
Oxytocin
130
What role does oxytocin perform in breastfeeding and parturition (three)?
1. Causes uterine contractions during birth.
2. It causes smooth muscles in the breasts to contract and release milk.
3. It reduces blood loss by shrinking the uterus.
131
What methods can be used to reduce reproductive potential (six)?
1. Abstinence
2. Tubal litigation
3. Vasectomy
4. Physical barriers
5. Hormonal medications
6. Natural planning
132
What is the most effective form of birth control?
Abstinence
133
What is the least effective form of birth control?
Natural planning.
134
When is a woman most fertile?
Day 14 of an ovarian cycle; the 24 hours immediately following ovulation.
135
What hormone are women undergoing IVF given to stimulate the growth of oocytes?
FSH
136
What technology is used in IVF to identify healthy follicles?
Ultrasound
137
How long are eggs retrieved for IVF treatment incubated before being inserted into the uterus?
Until the zygote reaches the blastocyst stage.
138
For what reason would a couple rely on artificial insemination to conceive?
When a man is sterile or infertile, or does not produce enough sperm.
139
What is the difference between being infertile and being sterile?
Infertility is when men or women are having trouble conceiving.
Sterile means a man or woman is unable to have a child.
140
Chromosomal abnormalities of a fetus may be tested through the collection of what material?
Amniotic fluid, via amniocentesis.
141
Why are umbilical cords sometimes preserved?
They contain stem cells.
142
What is the best strategy to prevent pregnancy and STIs?
A combination of physical and chemical barriers.
