Repro Physl 1.2 Flashcards
1
Q
What is the benefit of having internal fertilization?
A
Motile flagellated sperm can remain in an aqueous environment
2
Q
What is sexual dimorphism?
A
The physical distinction between males and females
3
Q
What is reproduction?
A
The perpetuation of a species with the purpose of producing a robust offspring that are able to cope with the changing environment
4
Q
What can allow for Biological Variation?
A
Integration of parental chromosomes
5
Q
What does the combination of gametes give rise to?
A
The zygote
6
Q
What does the zygote develop into?
A
The embryo and then the fetus
7
Q
What are the gametes produced by?
A
The gonads
8
Q
What does the HPG axis involve?
A
The hypothalamus, the pituitary and the gonads working together so the drive reproduction
9
Q
What is the homeostatic flow of information?
A
Coordination and cooperation between different cells, tissues and organs in order to bring about a successful reproduction
10
Q
What is gametogenesis?
A
The development of mature sperm and ova to form a zygote and then an embryo
11
Q
What is the product of conception referred to from 0-8 weeks?
A
An embryo
12
Q
What do we refer to the product of conception after 8 weeks?
A
A fetus
13
Q
What three structures do male and female sex organs comprise of?
A
- Gonads
- Internal genitalia
- External genitalia
14
Q
What are Gonads?
A
- Organs that produce gametes
- Testes produce sperm
- Ovaries produce eggs/ova
15
Q
What are the internal genetalia?
A
- Accessory glands and ducts
* Connect gonads with the outside environment
16
Q
What are external genitalia?
A
All external reproductive structures
17
Q
What is the dual function of the gonads?
A
- Gametogenesis
* Secretion of steroid hormones
18
Q
What steroid hormones do the gonads produces?
A
- Androgens - Testosterone, DHT
- Estrogens - Estradiol
- Progesterone
19
Q
What hormones do males tend to have in excess?
A
Androgens
20
Q
What hormones do females tend to have in excess?
A
They tend to have estrogens in excess
21
Q
What are Germ cells?
A
Developing gametes that eventually give rise to mature sperm of mature ova
22
Q
How many chromosomes do the gametes have?
A
The are haploid so they have 23 chromosomes
23
Q
What is the difference in the timing mitosis in germ cells between males and females?
A
Males: Primary spermatocytes are present at birth and are generated by mitosis in embryonic testes
Females: Germ cell mitosis to create primary oocytes occurs during fetal development
24
Q
When does germ cell mitosis occur in males?
A
At puberty
25
Why can men remain fertile their entire life span?
Because they can continually add to the pool of primary spermatocytes because mitosis of germ cells never ends
26
When does germ cell mitosis occur in females?
During fetal development
27
What is a female born with in the gonads?
Her complete set of primary oocytes
28
What is germ cell mitosis like in females after birth?
Females no longer have mitosis after birth so once a female is born she has all her primary oocytes for her lifetime
29
What is the first stage of gametogenesis?
Mitosis of primordial germ cells that can go on to the subsequent stages of gametogenesis
30
What is the process of gametogenesis in males?
* During embryo development the germ cell undergo mitosis so they remain diploid. The product of this is called spermatogonia that remain until puberty
* At puberty the spermatogonia can undergo meiosis so it replicates DNA to be 4N (primary spermatocyte)
* Secondary spermatocytes are diploid and occur after the primary spermatocyte divides
* They then go on to produce spermatids
* Which go on to develop into mature sperm cells
31
What are spermatogonium?
The diploid products germ cell mitosis in males
32
What is a primary spermatocyte?
The 4N product of the spermatogonium duplicating its genetic material but not dividing yet
33
What are secondary spermatocytes?
The diploid products of the division of the 4N spermatocytes
34
What are spermatids?
The haploid products of the division of secondary spermatocytes
35
What do spermatids develop into?
Mature sperm cells
36
What is the germ cell called in females?
Oogonium
37
What is the process of gametogenesis in females?
•In the embryo the oogonium/germ cell undergoes mitosis to proliferate the diploid cells
•Meiosis then begins and produces a primary oocyte that is 4N
•At puberty, the primary oocyte then divides to become a 2N secondary oocyte
•
37
What is the process of gametogenesis in females?
* In the embryo the oogonium/germ cell undergoes mitosis to proliferate the diploid cells
* Meiosis then begins and produces a primary oocyte that is 4N
* At puberty, the primary oocyte then divides to become a 2N secondary oocyte and extruding a polar body
* If the secondary oocyte is selected for maturation before it leaves the follicle it undergoes its second meiotic division to become haploid
38
When does meiosis begin in males vs females?
Meiosis in males begins after puberty and meiosis in females begins before puberty
39
What is the only case that there is completion of the second meiotic division in females?
The second polar body is fertilized by a mature sperm cells
40
What happens if the secondary oocyte is not fertilized?
It will degenerate without completing a second meiotic division to become haploid
41
What is a primary oocyte?
The 4N product of the duplication of germ cells before undergoing division
42
What is the secondary oocyte?
The 2N product of division of a 4N primary oocyte which also give rise to a polar body
43
What process begins at the reproductive adult phase in females?
The primary oocyte (4N) undergoes its first meiotic division
44
What process begins at the reproductive adult phase in males?
Meiosis of spermatogonia
45
How many pairs of sex chromosomes do humans have?
1 pair of sex chromosomes 22 pairs of autosomes
46
What do sex chromosomes contain the genes for?
Directing development of internal and external sex organs
47
Which sex chromosome is larger?
The X chromosome
48
What is a genotype?
The genetic composition of an individual
49
What gamete determines the genetic sex of a baby?
The sperm
50
What happens to one of the X chromosomes in females?
One condenses to form a barr body
51
Where can Barr bodies be detected?
In cheek mucosa cells/WBCs
52
How is karyotyping usually done?
Through tissue cell culture
53
What does a Y chromosome always indicate?
A male
54
What XO?
A female with turner's syndrome
55
Which chromosomes are required for normal reproductive function in females?
XX
56
What is XXY?
Male
57
Why is an individual with only a Y chromosome not viable?
Because the X chromosome contains genes that are not present on the Y chromosome
58
What is Sex Differentiation?
The multiple steps involved in fetal reproductive system development
59
What can cause atypical sex differentiation?
Atypical chromosome combinations
60
What is intersex?
Where you cannot tell the sex based on the general appearance of the genitalia
61
What directs sex differentiation and gives rise to the female phenotype?
The absence of testes
62
When do gonads differentiate in uterine life?
The 6th week
63
In what week do testes develop?
In week 7
64
What is the Bipotential phase?
The sexually indifferent phase at 6 weeks gestation
65
What structures are seen in the bipotential stage?
There are two sets of duct systems and primitive gonads
66
What are the two sets of gonads in the Bipotential stage known as?
The Wolffian duct system and the Mullerian duct system
67
What is the SRY gene?
A gene on the Y chromosome that causes the development of testes
68
Where is the SRY gene expressed?
In the urogenital ridge cells
69
What does the SRY gene encode for?
The Testis determining factor protein (TDF) or SRY protein
70
What does the SRY protein do?
Triggers the development of the testes in the genetic male
71
What two key cell types are present as a result of the SRY protein?
Leydig cells and sertoli cells
72
What happens if you don't have a y chromosome like in females?
Then no SRY gene is present and there is no development of the testes
73
What derives from the Gonadal ridge?
Both the testes and the ovaries
74
After the gonads develop what does sex differentiation do?
The internal and external genitalia can develop
75
What is the Cloaca?
The common opening of the ducts in the bipotential stage
76
What structures are going to give rise to most of the reproductive tract in the bipotential phase?
The wolffian and the mullerian ducts
77
What do the testes secrete after the bipotential phase?
Testosterone and Mullerian inhibiting substance or MIS
78
Which gene does the SRY protein induce?
The MIS gene
79
What does the MIS gene induced by the SRY protein do?
Triggers the degeneration of the mullerian duct system
80
What does the testosterone produced in the bipotential phase do?
Binds to androgen receptors in the wolffian duct system
81
How does the testosterone affect the Wolffian duct system?
It prompts it to differentiate into the internal duct system of the phenotypic male
82
What parts does the Phenotypic male have?
* Epididymis
* Vas deferens
* Ejaculatory duct
83
Which duct system persists and which duct system persists?
The Wolffian duct system persits and the mullerian duct system degenerates
84
What don't the duct systems give rise to?
The external genitalia structures
85
Which genetalia does the duct system give rise to?
The internal genitalia
86
What is the development of the male internal structures dependant on?
The presence of the fetal testes
87
What do Leydig cells secrete?
Testosterone
88
What do the Sertoli cells secrete?
Mullerian inhibiting substance (MIS)
89
What can testosterone be metabolized into?
DHT
90
What is DHT?
A more potent form of testosterone
91
What is DHT required for?
Forming the male external genitalia
92
What external genitalia does DHT produce?
* Penis
| * Scrotum
93
What happens if a person doesn't have DHT?
It can cause a different appearance of the external genitalia and there won't be proper development and give rise to the intersex phenotype
94
What stimulates the testes to move into the scrotum?
Testosterone
95
What is Cryptochidism?
The failure of the testes to descend into the scrotum
96
Why does Cryptorchidism need to be addressed early on?
To preserve the fertility of an individual
97
How can Cryptorchidism be treated?
Exogenous testosterone or surgery
98
What is the result of having no testes like in females?
There is no secretion of mullerian inhibiting hormone or testosterone which triggers the degeneration of wolffian ducts
99
Which duct system persits in females?
The Mullerian duct system
100
What does the Mullerian duct system give rise to?
The female internal genitalia
•Fallopian tubes
•Body of uterus and upper portion of the vagina
101
What is development of the external female genitalia due to?
The absence of testes which would've produced testosterone and DHT
102
What is the default situation of genetalia?
The female
103
Do embryonic ovaries secrete hormones?
No
104
What will androgen exposure in females after the 13th week of gestation do
Enlarges size of the clitoris with the appearance of a penis prior to 13 weeks. After, this will just cause an increase in size of the female anatomy
105
What happens if there is testosterone but an individual is unable to produce DHT?
There will not be development of male external genitalia giving the appearance of female external genitalia even though the male internal duct system is present
106
What is Androgen insensitivity syndrome or testicular feminization?
When an individual is a genetic male which drives the generation of the testes but they have the female phenotype of external genitalia
107
What causes Androgen insensitivity syndrome or testicular feminization?
A mutation in the androgen receptor gene so testosterone cannot bind in the fetal tissues
108
What is missing in people with Androgen insensitivity syndrome or testicular feminization?
The mullerian and wolffian ducts because they both degenerate
109
When is Androgen insensitivity syndrome or testicular feminization detected?
At puberty when menstrual cycle fails to initiate
110
What is Congenital adrenal hyperplasia?
The overproduction of androgens in the fetus due to a mutation in an enzyme that is required for the formation of cortisol so there is no negative feedback for pituitary production of ACTH so it acts on the adrenal gland and increases androgens. Resulting in virilization of the individual who is XX causing ambiguous genitalia
111
What is the treatment for Congenital Adrenal Hyperplasia?
Cortisol replacement
