Reproductive Structures and All That Jazz Test Flashcards
1
Q
What is a description and the function of the bulbourethral (Cowper’s) gland?
A
- A pair of small glands that lie on either side of the urethra
- Secrete a clear mucous fluid prior to ejaculation that attempts to protect sperm from any acidic urine that might be present in the urethra.
2
Q
What is a description and the function of the seminal vesicles?
A
- A pair of glands that lie behind and slightly below the urinary bladder
- Secrete a fluid containing fructose (for energy) and prostaglandins (stimukates the smooth muscles of the female reproductive tract).
3
Q
What is a description and the function of the vas deferens?
A
- Tubes which run on either side of the abdomen
- Used to transport sperm.
4
Q
What is a description and the function of the testes?
A
- Male gonads which descend from the abdominal cavity during embryonic development
- Produce sperm and secrete testosterone.
5
Q
What is a description and the function of the urethra?
A
- Tube that runs through the penis
- Transports sperm and other secretions out of the body.
6
Q
What is a description and the function of the penis?
A
- Consists mainly of blood vessels and erectile tissue
- Allow for the deposit of sperm in the female reproductive system.
7
Q
What is the function of the seminiferous tubules?
A
Where sperm are produced.
8
Q
What is a description and the function of the prostate gland?
A
- Large gland which lies below the urinary bladder and surrounds the urethra
- Secretes an alkaline buffer which helps to neutralize the acidic nature of the vagina.
9
Q
What is a description and the function of the epididymis?
A
- Highly coiled structure lying on the outside of each testis
- Stores sperm until mature.
10
Q
What is a description and the function of the scrotum?
A
- Outward fold of the body wall
- Helps to store sperm at appropriate temperature (2 degrees less than body temp).
11
Q
What is a description and the function of the interstitial cells?
A
- Cells scattered around the seminiferous tubules
- Secrete testosterone.
12
Q
What is a description and the function of the ovaries?
A
- A pair of structures located in the abdominal cavity, enclosed in a tough protective covering, attached to the uterus
- Secrete hormones and produce a viable egg each month.
13
Q
What is a description and the function of the corpus luteum?
A
- Yellow body remaining in the ovary
- Secretes estrogen and progesterone
14
Q
What is a description and the function of the fimbrea?
A
- Finger-like extensions
- Help to ensure secondary oocyte enters oviduct.
15
Q
What is a description and the function of the follicles?
A
- Cells within the ovary
- Promote and support growth of the egg/secondary oocyte, secrete estrogen
16
Q
What is a description and the function of the uterus?
A
- Thick, muscular, pear shaped organ, consists of two layers
- Site of implantation as well as further prenatal development
17
Q
What is a description and the function of the cervix?
A
- Muscular ring at the base of the uterus, normally about the size of the head pin, closed over with mucus
- Prevents premature birth, holds the developing fetus in place.
18
Q
What is a description and the function of the vagina?
A
- Thin walled muscular tube
- Receives sperm and serves as the birth canal
19
Q
What is a description and the function of the fallopian tubes (oviducts)?
A
- Tubes running from the ovary to the uterus lined with cilia
- Allows for the transport of the egg/secondary oocyte
20
Q
What is a description and the function of the myometrium?
A
- Strong OUTER muscular layer, stimulated by oxytocin
- Contracts to allow the fetus to move through the birth canal
21
Q
What is a description and the function of the endometrium?
A
- INNER layer of the uterus that thickens and becomes more glandular and vascular
- Nourishes the zygote through early embryonic development
22
Q
How long after ovulation can an egg/secondary oocyte be fertilized for?
A
24 hours
23
Q
How long will sperm remain viable in the female reproductive tract for?
A
5 days
24
Q
Where does fertilization usually take place?
A
The fallopian tube/oviduct, in the outer third.
25
How does the sperm get to its location?
- Sperm swim up the female repoductive tract, aided by muscular contractions of the uterus stimulated by prostaglandins in the semen
- The oocyte (egg) also secretes a chemical that attracts sperm
- The first sperm attaches to receptors in the zona pellucida which activates the acrosome cap of the sperm
26
What does the acrosome activation cause?
- The acrosome activation causes the release of digestive enzymes which break down the zona and allows the sperm to enter.
- This stimulates the release of granules that cause changes in the zona pellucida to prevent entry of other sperm, which prevents more than one sperm from entering.
27
What happens once the sperm penetrates the secondary oocyte/egg?
- Once the sperm penetrates the secondary oocyte/egg, it then goes through meiosis II so that a haploid nucleus is formed.
- After meiosis II is complete, the ootid (ovum) pronucleus (23 chromosomes) and the sperm pronucleus (23 chromosomes) will unite. Fertilization occurs when the 2 nuclei unite forming a diploid zygote.
28
What happens to the zygote following fertilization?
The zygote undergoes rapid mitotic cell division, called cleavage divisions
29
What does cleavage produce?
Cleavage produces a solid sphere of cells still surrounded by a zona pellucida, now called a morula.
30
What happens at 4.5-5 days after fertilization?
- Cells have developed into a hollow ball of cells called a blastocyst: a rapidly dividing ball of cells.
- It is at this stage that it enters the uterus
31
What happens at about 6-7 days after fertilization?
- The blastocyst implants, it secretes enzymes that allow it to penetrate/digest the endometrial wall
- This nourishes the blastocyst for about a week after implantation
32
What is the blastocyst composed of?
An outer layer of cells called the trophoblast, an inner cell mass, and a fluid filled cavity called the blastocoel.
33
What will the trophoblast and part of the inner cell mass form?
The membrane of the fetal portion of the placenta.
34
What forms the embryo?
The rest of the inner cell mass.
35
After 8-12 days what does the chorion secrete and what does it do?
Human chorionic gonadotropin (hCG). It keeps the corpus luteum intact for the first three months of pregnancy.
36
What structure secretes estrogen and progesterone after the third month/the corpus luteum stops?
The placenta.
37
What is the ectoderm?
A germ layer in the embryo responsible for tissues such as nervous system (including brain, eyes, skin, ears) also nails, hair, teeth.
38
What is the mesoderm?
A germ layer in the embryo responsible for tissues such as muscles and bones, circulatory system, kidneys, and reproductive structures.
39
What is the endoderm?
A germ layer in the embryo responsible for organs of the digestive system, along with the lungs.
40
What is the chorion?
-Secretes human chorionic gonadotropin hormone (hCG). This hormone ensures that the corpus luteum will remain intact and not degrade into the corpus albicans. The corpus luteum remains for a period of 3 months secreting estrogen and progesterone.
41
What is the amnion?
This membrane forms the amniotic sac and fluid. These help to protect, insulate and hydrate the developing fetus.
42
What is the allantois?
Blood vessels in the umbilical cord are formed from this layer.
43
What is the yolk sac?
This provides nourishment to the embryo in the very early stages.
44
What does the chorion develop into?
The fetal part of the placenta
45
What is the placenta?
Composed of both fetal and maternal tissues formed by chorionic villi and endometrium, it is the connection between mother and developing embryo.
46
What does the umbilical cord to?
The umbilical cord connects the fetus to the placenta. Contains large blood vessels that transport blood between the embryo and the placenta. The allantois is the embryonic membrane that produces these blood vessels.
47
What are the functions of the placenta?
- Transfer gasses
- Transfer nutrients
- Excretion of wastes
- Hormone production (temporary endocrine organ for estrogen and progesterone)
- Formation of a barrier – incomplete and non-selective since some substances can cross the placenta (alcohol, steroids, narcotics, anesthetics, some antibiotics)
48
How long does the gestational period last?
40 weeks from the last period of menstruation. Closer to 38 weeks from the time of fertilization.
49
During which trimester are the first 2-4 weeks nutrition provided by the endometrium by diffusion?
First
50
During which trimester are the germ layers present?
First
51
During which trimester does the placenta soon take over the responsibility of exchanging gas, nutrients, and wastes?
First
52
During which trimester do internal organs and body structures begin to develop?
First
53
During which trimester are limb buds, eyes, heart, liver and anterior brain present?
First
54
During which trimester is exposure to toxins particularly dangerous?
First
55
During which trimester is cartilage being replaced by bone (skull and long bones)
Second
56
During which trimester is wrinkled skin thin and transparent?
Second
57
During which trimester are all organs developed and continuing to mature?
Second
58
During which trimester is the fetus becoming more active?
Second
59
During which trimester are the vagina and uterus forming? What week?
Second, week 19
60
During which trimester are the testes beginning to descend?
Second, week 22
61
During which trimester does system development continue?
Third
62
During which trimester do red blood cells form in bone marrow?
Third
63
During which trimester does the fetus grow in weight and length?
Third
64
During which trimester do bones harden (skull remains soft)?
Third
65
During which trimester is fat being deposited?
Third
66
During which trimester are lungs capable of functioning? What week?
Third, 36 weeks.
67
What are the three stages of labour?
Dilation, expulsion, and afterbirth
68
What happens during dilation?
- Labour is marked by uterine contractions that occur regularly every 15-20 minutes and last for 40 seconds or more.
- Mucous plug may be expelled from the cervical canal
- The uterine contractions cause the cervix to dilate to 10cm and the aminiotic sac may rupture.
69
What happens during expulsion?
- Contractions become more intense and frequent
- The amniotic sac breaks and lubricates the canal
- The baby's head descends into the birth canal and the baby is delivered
- Lasts minutes to an hour
- Relaxin is released to help relax and loosen the pelvic ligaments
70
What happens during afterbirth?
- The expulsion of the placenta and umbilical cord
- Usually occurs within 5-10 minutes after the birth of the baby, but can range from 5 to 60 minutes.
71
What is the role of prolactin in pregnancy?
Throughout the pregnancy prolactin is suppressed due to an increase in estrogen and progesterone. Sudden drop in estrogen and progesterone after delivery of the placenta stimulates the release of prolactin which will begin to stimulate the mammary glands to produce milk.
72
What are the three phases of interphase?
G1 (gap/growth 1), S (synthesis), and G2 (gap/growth 2)
73
What is G1?
Period of cell growth before DNA is replicated
74
What is S?
Period when the DNA is duplicated (i.e when chromosomes duplicate)
75
What is G2?
Period after DNA has replicated, cell prepares for division (proteins needed for formation of spindle fibers are produced)
76
What is paused/quiescent phase? (G0)
A phase where some cells in adult organisms will not divide for a period of time or at all, such as nerve cells or striated muscle cells.
77
Why is mitosis so important?
Continues to allow growth, repair of damaged or replacement of dying cells, and to ensure proper functioning of cells and tissues.
78
What happens during prophase?
- Nuclear membrane starts to dissolve
- Chromosomes shorten and thicken
- Spindle fibers begin to form
- Centrioles begin to move to the opposite poles
- Nuclear membrane continues to dissolve
- Chromosomes form double stranded chromosomes
- Centrioles reach the opposite poles
-Chromosomes attach to the spindle fibers at a region known as the kinetochore
79
What happens during metaphase?
- Chromosomes are attached to spindle fibers
- Chromosomes made up of sister chromatids move toward the center of the cell
- Stage is characterized by chromosomes aligning at the equatorial plate.
80
What happens during anaphase?
- Centromeres split and the sister chromatids move to the opposite poles
- The cell begins to elongate
- Cleavage furrow becomes evident as membrane stretches
81
What happens during telophase?
- Individual chromosomes have reached opposite poles
- Nuclear membrane begins to reform
-Chromosomes will lengthen and become a tangled mess of chromatin
82
What happens during cytokenesis?
- Nuclear membrane fully intact
- Chromatin present
- Cytoplasm splits
- One pair of centrioles present in each cell
- Two new identical cells are formed
83
How are mitosis and cancer related?
Cancer is caused by unregulated rapid cell division
84
How do cancerous cell differ from regular cells?
- Cells do not heed normal signals that regulate cell cycles
- Cells do not show “contact” inhibition
- Cells are abnormally shaped
- Do not carry out normal cell functions
- Can divide in isolation
- Can travel to other places in the body—metastasis.
- Divide more quickly
85
What are homologous chromosomes?
Pairs of chromosomes which are similar in size, shape, and gene sequence.
86
What are tetrads?
A pair of homologous chromosomes.
87
What is synapsis?
The event of homologous chromosomes coming together.
88
What are autosomes?
The 22 pairs of chromosomes unrelated to determining gender.
89
What are sex chromosomes?
The X and Y chromosomes, responsible for determining gender.
90
When does synapsis take place?
Prophase I, homologous chromosomes pair up and crossing over occurs.
91
What causes variation in gametes?
- Crossing over
- Random independent assortment of maternal and paternal chromosomes during metaphase I. The number of possible combinations are equal to 2^n.
92
What is gametogenesis?
The process by which diploid cells undergo meiotic division to become haploid gametes.
93
What is spermatogenesis?
The production of spermatazoa (sperm) in the seminiferous tubules of the testes.
94
When does the process of spermatogenesis begin?
At puberty, when cells in the seminiferous tubules divide by mitosis. These cells (spermatogonial cells) then undergo a period of cell growth, becoming primary spermatocytes.
95
What happens to the primary spermatocytes?
They undergo two meiotic divisions to form four haploid daughter cells (spermatids)
96
What do spermatids become?
Sperm cells
97
What is the starting cell of spermatogenesis? Diploid or haploid?
Spermatogonial cell, diploid
98
What does the spermatogonial cell result in after its divisions? Diploid or haploid?
Primary spermatocytes, diploid
99
What does the primary spermatocyte cell result in after its division? Diploid or haploid?
Secondary spermatocyte, haploid
100
What does the secondary spermatocyte cell result in after its division? Diploid or haploid?
Spermatids, haploid
101
What is oogenesis?
The production of female gametes (ova) within the ovaries
102
When does the process of oogenesis begin?
During fetal development
103
What happens to the oogonial cells?
They undergo cell growth until they begin meiosis (becoming primary oocytes)
104
What happens to the primary oocytes?
- The primary oocytes are arrested/paused in prophase I.
- They remain here until puberty when the menstrual cycle begins.
- These cells will complete the first meiotic division to form two cells of unequal size.
- One cell retains the majority of the cytoplasm to form a secondary oocyte, while the other cell forms a polar body.
105
What happens to the polar body?
The polar body remains trapped within the follicle until it eventually degenerates
106
What happens to the secondary oocyte?
The secondary oocyte is released from the ovary at ovulation and enters the oviduct.
107
What is the starting cell of oogenesis? Diploid or haploid?
Oogonial cell, diploid
108
What does the oogonial cell result in? Diploid or haploid?
Primary oocyte, diploid
109
What does the primary oocyte result in? Diploid or haploid?
Secondary oocyte and polar body, both haploid
110
What does the secondary oocyte result in? Diploid or haploid?
Ootid and second polar body, haploid
111
What are some differences between mitosis and meiosis?
Meiosis: results in haploid cells, sex cells, crossing over, has two divisions, homologous pairs, produces 4 cells
Mitosis: results in diploid cells, body cells, one division, single chromosomes, produces 2 cells
112
What is nondisjunction?
- The failure of homologous chromosomes or sister chromatids to separate. Happens in meiosis (anaphase I or II) but can happen in mitosis.
- A chromosomal mutation which may occur during meiosis. Results when the chromosomes fail to separate during meiosis. Can occur during anaphase I or anaphase II.
113
What are the results of nondisjunction? Meiosis I vs Meiosis II?
- Nondisjunction results in cells that do not function properly, since they lack the proper genetic material.
- In meiosis I, all of the cells are affected by nondisjunction. Two cells have an extra chromosome and two cells are missing a chromosome.
- In meiosis II, only two cells are affected. Therefore, two normal cells, one cell with an extra and one cell with a deficiency.
114
What is a monosomy?
A monosomy is a condition where there is one homologous chromosome where two should be. An organism with this condition would have one less chromosome.
115
What is a trisomy?
A trisomy is a condition where there are three homologous chromosomes where a homologous pair should be. An organism with this condition would have an extra chromosome.
116
What is a karyotype?
A karyotype chart demonstrates the arrangement of chromosomes presented as homologous pairs. This can help identify disorders caused by nondisjunction because it shows trends of where there is an abnormality. For instance, with down syndrome, if there’s three chromosomes on the 21st “pair”, then it makes it identifiable.
117
What causes down syndrome? What are some signs and symptoms?
- Trisomy on the 21st pair due to nondisjunction
- Round, full face, enlarged and creased tongue, short height, large forehead.
118
What causes Klinefelter's syndrome? What are some signs and symptoms?
- A trisomy where a male has an XXY condition
- Appears male, but produces high levels of female sex hormones, sterile.
119
What causes Turner syndrome? What are some signs and symptoms?
- A female has a single X chromosome instead of two
- Appear female but do not develop sexually, short height, thick, widened neck.
