Reproductive Physiology Flashcards
1
Q
What are the 3 levels of sex differentiation?
A
Genetic Sex
Gonadal Sex
Anatomical Sex
2
Q
Genetic sex is predetermined by the configuration of the ___________
A
Sex chromosomes
3
Q
Gonadal sex is determined by the ___________. The ___ chromosome is necessary for testes production.
A
Sex chromosomes
Y
4
Q
Describe the process by which male gonadal sex develops
A
- Primitive gonads develop by the 6th week
- Due to the presence of the sex determining region on the Y chromosome (SRY) H-Y antigen is produced
- In the presence of H-Y antigen the testes form
- Androgen hormones are secreted
- Male anatomy forms
5
Q
Describe the process by which female gonadal sex develops
A
- Primitive gonads develop by the 6th week
- Due to the absence of the Y chromosome, no H-Y antigen is produced
- In the absence of H-Y antigen the ovaries form
- No hormones are secreted
- Female anatomy forms
6
Q
Define anatomical sex:
A
The apparent anatomical sex of a person depends on the genetically determined gonadal sex
7
Q
Embryonic Sertoli cells secrete ___________________
A
Anti-mullarian hormone (AMH)
8
Q
Embryonic Leydig cells secrete _____________
A
Testosterone
9
Q
Anti-mullarian hormone causes regression of the _____________
A
Mullarian ducts
10
Q
Testosterone causes growth of the ___________
A
Wolfian ducts
11
Q
Describe how male external genitalia form:
A
- Embryonic testes produce testosterone
- Some testosterone is converted via 5α-Reductase to dihydrotestosterone
- Both Testosterone and Dihydrotestosterone (Mainly) produce growth of the penis and scrotum
12
Q
Describe how female external genitalia form:
A
- Absence of embryonic testes
- No Testosterone or Dihydrotestosterone
- Female genitalia form
13
Q
The genital tubercle develops into the _______ in males and the _______ in females
A
Glans
Clitoris
14
Q
The urethral folds and labioscrotal swelling develop into the _______________ in males and _______________ in females
A
Urethra (Fusion of folds) and Scrotum
Labia minora and labia majora respectively
15
Q
The urogenital slit develops into the _________
A
Vagina
16
Q
The hypothalamus secretes _______ this causes the _______ pituitary to release LH and FSH.
A
GnRH
Anterior
17
Q
What is the role of LH?
A
Stimulates the production of gonadal hormones
18
Q
What is the role of FSH?
A
Stimulates growth and development of germ cells
19
Q
GnRH release is ________ which is essential and is caused by the firing of ______________
A
Pulsatile
Many Hypothalamic neurons
20
Q
Explain how GnRH secretion varies of development:
A
- High levels during neonatal period
- Period of quiescence in mid-childhood
- Sleep-entrained reactivation of GnRH at the onset of puberty
- Adult pattern of pulsatile release
21
Q
In males GnRH is secreted approximately every ________ while in females it ____________________
A
2 hours
Varies with the menstrual cycle
22
Q
In males LH causes ________________
A
Testosterone release
23
Q
The major male reproductive systems functions are:
A
- Production of sperm
- Production of sex hormones
- Transport of sperm from the male to female
24
Q
Spermatogenesis takes place within the ________________ that have a smooth muscles layer to provide _______
A
Seminiferous Tubules
Peristalsis
25
Seminiferous tubules contain:
Spermatogenic cells = the cells that divide and differentiate to for sperm
Sertoli/Nurse cells = provide mechanical and nutritional support for spermatogenic cells
26
Sertoli cells line the ____________ and are connected by __________. This separates ______ and ______ compartments and forms the ____________.
Seminiferous tubules
Tight junctions
Basal and central
Sertoli cell barrier
27
What is the function of the sertoli cell barrier?
Prevent chemicals and hormones in the blood entering the lumen of the seminiferous tubule
28
Sertoli cells synthesise and secrete ______________ which also contains ______________ and also secrete _______________________. Also they __________ defective sperm
Seminiferous tubular fluid
Androgen-Binding protein
Stimulatory and Inhibitory Hormones
Phagocytose
29
Outline the process of spermatogenesis:
1. Spermatogonia undergoes mitosis, one cell stays bhind and the other becomes a primary spermatocyte
2. Primary spermatocyte undergoes meiosis 1 and becomes secondary spermatocytes
3. Secondary spermatocytes undergo meiosis 2 and becomes spermatids
4. Spermatids are remodelled and become sperm
Takes 70-80 days
30
The acrosomal cap is filled with _______ needed for the _____________
Enzymes
| Penetration of the ova
31
The mid-piece of the sperm is filled with ______________
Mitochondrial residue
32
Sperm gain motility and the ability to fertile in the ___________
Epididymus
33
Sperm are stored in the ________
Vas deferens
34
Until maturation is complete, spermatocytes are connected by ____________. These allow exchange of essential _________ that can only be made in the presence of the __ chromosome
Cytoplasmic bridges
Proteins
X
35
If there is a FSH receptor defect testicular size _______ and there is an _______ sperm malformation
Decrease
| Increase
36
If there is a LH receptor defect on the leydig cells then the patient will be _________
infertile
37
Inhibin is produced by ________ in response to an increase in ____ stimulation. Inhibin feedbacks negatively on ____ secretion from the ___________.
Sertoli
FSH
FSH
Ant. Pit.
38
Testosterone provides _______ feedback for the ________ and ________. It is absorbed by _____ which break it down into ________ which brings about the effect
Negative
Hypothalamus and Ant. Pit.
Neurons
Oestradiol
39
The testes produce small amounts of ________ and testosterone gets broken down into ________. It has an important function in the closing of ________ at the end of puberty
Oestrogen
Oestradiol
Epiphysis
40
What factors affect the Hypothalamic-Pituitary-Gonadal axis?
Xeno-oestrogens - foreign oestrogen like substances
Phyto-oestrogens - oestrogen like substances found in plants i.e. soya
Performance enhancing drugs
Heavy alcohol consumption (β- endorphins)
41
What are the 2 main female hormones?
Oestrogen - promotes Oestrous (gets the egg ready)
| Progesterone - prepares the uterus for pregnancy
42
Oestrogen and Progesteron are released on __ to __ hour intervals. They circulate bound to ____________, but unbound hormones are the _______ ones.
1-3 hours
Plasma proteins
Active
43
Females get their low levels of androgens from the __________ in the adrenal gland in the form of ____________, it can be converted to ________.
Zona Reticularis
Dehydroepiandrosterone (DHEA)
Testosterone
44
Before puberty fat reserves _______, this causes leptin levels to _______. This results in GnRH secretion to _______ and thus ______ puberty
Increase
Increase
Increase
Start
45
β-endrophins feedback ________ on GnRH secretion
Negatively
46
The menstrual and ovarian cycle lasts ___ days
28 days
47
The ovarian cycle has 2 phases, the 1st being the ____________ and the 2nd being the ___________
Follicular Phase
| Luteal Phase
48
The follicular phase is characterised by the presence of _____________ that operate to produce a ___________
Maturing follicles
| Egg
49
The luteal phase is when the _________ is present. It prepares the ______________ for pregnancy
Corpus luteum
| Reproductive tract
50
How do androgen-binding hormones regulate testosterone levels?
They bind to testosterone when levels are too high and release it when levels are too low
51
Outline the production of an ovum:
1. Primary follicles granulosa cells proliferate and a zona pellucida forms, Thecal cells form the thecal layer
2. Now called secondary follicles they develop a fuild filled space called an antrum contains mucopolysacchirides for nutrition
3. One follicle is chosen, known as Graafian cell, other become apoptotic
4. Graafian cell moves towards the outer portion of the ovary ready for ovulation
52
Outline the production of the corpus luteum:
1. After ovulation the cells of the follicle collapse inwards
2. They undergo hypertrophy and vascularisation
3. If no implantation then it degenerates
53
Describe the hormonal changes in the Follicular phase:
- FSH is initially high to stimulate follicle growth and antrum formation
- LH gradually rise and has a surge of activity around 12-16 days
- FSH also peaks during that time
- LH and FSH cause oestrogen production by the follicle to occur so it gradually increases
- Oestrogen peaks at the same time as LH
54
Describe the hormonal changes in the Luteal phase:
- Oestrogen levels quickly drop and then rise again but not as high
- Progesterone levels increase, peak and then decrease if implantation doesn't occur
55
LH causes thecal cells to convert _______ to _______
Cholesterol to androgens
56
FSH causes granulosa cells to convert _________ to __________. This product gives ______ feedback to the granulosa cells
Androgens to Oestrogen
| Positive
57
Increase in Oestrogen and ________ causes a _________ in GnRH and a _______ FSH. During this stage ____ secreting cells are not affected by GnRH therefore don't change
Inhibin B
Decrease
Decrease
LH
58
What causes the LH surge?
- High oestrogen levels provide positive feedback to the hypothalamus and Ant.Pit. and increases GnRH and LH
- The small increase in FSH is due to GnRH increase
59
The LH surges activates _______ and the gamete is formed. This halts ________ secretion and induces ________ production
Meiosis
Oestrogen
Prostaglandin
60
An increase in progesterone in some women may cause a _______ in serotonin levels. This causes PMS
Decrease
61
During the luteal phase, Oestrogen and Progesterone feedback _______ on GnRH, LH and FSH. This causes their levels to ________.
Negatively
| Decrease
62
What happens if LH drops low enough?
The corpus luteum can't be sustained and so it degenerates
63
When the corpus luteum degenerates, the levels of _________ and ________ decrease removing the negative feedback mechanism on GnRH and allows a new ___________ to begin
Oestrogen and progesterone
| Follicular phase
64
Describe the changes in the endometrium over the ovarian cycle:
Follicular phase: Oestrogen stimulates growth and proliferation of endometrium
Luteal Phase: Progesterone stimulates endometrial glands to secrete nutrient rich mucous and grow further
65
Outline the events that cause menstruation:
1. Corpus Luteum degenerates
2. Progesterone and Oestrogen levels drop
3. Endometrium becomes necrotic and blood filled
4. Endometrium separates from the uterus
5. Uterine prostoglandin release is initiated and uterine smooth muscle contracts
6. Menstruation occurs
66
Embryos secrete __________________, this maintains the corpus luteum and sex hormone production until the _______ takes control
Human Chorionic Gonadotrophin
| Placenta
