Reproductive ageing Flashcards
What happens if the LH is not of sufficient magnitude?
If the preovulatory surge of LH is not of sufficient magnitude, ovulation will not occur and the cycle is said to be anovulatory
What happens to the menstrual cycle if the ovulation doesn’t occur?
The phases of the menstrual cyclo continue, but they are altered in the following ways:
1. Lack of ovulation causes failure of development of the corpus luteum, so there is almost no secretion of progesterone during the latter portion of the cycle
2. The cycle is shortened by several days, but the rhythm continues. Therefore, it is likely that progesterone is not required for maintenance of the cyvle itself, although it can alter the cycle’s rhythm
Why is the first few cycles after the onset of puberty usually anovulatory, as are the cycles occuring several months to years before menopause?
Presumably because the LH surge is not potent enough at these times to cause ovulation.
Define puberty
Puberty means the onset of adult sexual life
Define menarche
Menarche means the beginning of the cycle of menstruation
What causes the period of puberty?
The period of puberty is caused by a gradual increase in gonadotropic hormone secretion by the pituitary, beginning in about the eighth year of life, and usually culminating in the onset of puberty and menstruation between ages 11 and 16 years in girls (average, 13 years).
Are the pituitary gland and ovaries of full function when born?
In the female, as in the male, the infantile pituitary gland and ovaries are capable of full function if they are appropriately stimulated. However, as is also true in male, the hypothalamus does not secrete significant quantities of GnRH during childhood.
Why does the hypothalamus not secrete significant quantities of GnRH during childhood?
Experiments have shown that the hypothalamus is capable of secreting this hormone, but the appropriate signal from some other area of the brain to cause the secretion is lacking. Therefore, it is now believed that the onset of puberty is initiated by some maturation process that occurs elsewhere in the brain, perhaps somewhere in the limbic system.
What is menopause?
At age 40 to 50 years, the menstrual cycle usually becomes irregular and ovulation often fails to occur. After a few months to a few years, the cycle ceases altogether. The period during which the cycle ceases and the female sex hormones diminsh to almost none is called menopause.
What causes the menopause?
The cause of menopause is “burning out” of the ovaries. Throughout a woman’s reproductive life, about 400 of the primordial follicles grow into mature follicles and ovulate, and hundreds of thousands of ova degenerate. At about age 45 years, only a few primordial follicles remain to be stimulated by FSH and LH, and the production of estrogens by the ovaries decreases as the number of primordial follicles approaches zero.
When estrogen production falls below a critical value, the estrogens can no longer inhibit the production of the gonadotropins FSH and LH. Instead the gonadotropins FSH and LH are produced after menopause in large and continuous quantities, but as the remaining primordial follicles become atretic, the production of estrogens by ovaries falls virtually to zero.
Why must a women readjust her life at the time of menopause?
At the time of menopause, a woman must readjust her life from one that has been physiologically stimulated by estrogen and progesterone production to one devoid of these hormones.
How does the menopause cause physiological changes in the function of the body?
Menopause leads to the loss of estrogens which often causes marked physiological changes in the function of the body, including:
1. “Hot flushes” characterized by extreme flushing of the skin
2. Psychic sensations of dyspnea
3. Irritability
4. Fatigue
5. Anxiety
6. Decreased strength and calcification of bones throughout the body
How can you treat severe symptoms in post-menopausal women?
Daily administration of estrogen in small quantities usually reverses the symptoms, but large clinical trials have provided evidence that administration of estrogen after menopause may increase the risk for cardiovascular disease. As a result, hormone replacement therapy with estrogen is no longer routinely prescribed for postmenopausal women.
Some studies, however, suggest that estrogen therapy may actually reduce the risk for cardiovascular disease if it is begun early in the postmenopausal years.
Therefore, it is currently recommended that postmenopausal women who are considering hormone replacement therapy should discuss with their physicians whether the benefits outweigh the risks.
What are the characteristic symptoms of post-menopausal women?
- “Hot flushes” characterized by extreme flushing of the skin
- Psychic sensations of dyspnea
- Irritability
- Fatigue
- Anxiety
- Decreased strenght and calcification of bones throughout the body
What are the characteristic symptoms of post-menopausal women?
- “Hot flushes” characterized by extreme flushing of the skin
- Psychic sensations of dyspnea
- Irritability
- Fatigue
- Anxiety
- Decreased strenght and calcification of bones throughout the body
Hvad betegner klimakteriet?
Klimakteriet betegner den periode, hvor ovariernes funktion gradvist aftager.
Hvornår begynder klimakteriet normalt?
Normalt begynder klimakteriet i 40-50-årsalderen, og der går ca. fem år, inden ovariefunktionen er helt ophørt.
Definer menopausen
Menopausen defineret som det tidspunkt i kvindens liv, hvor ægløsning og menstruationsblødningen ophører.
Hvornår indtræffer menopausen normalt?
Menopausen indtræffer mellem 40-55 leveår; gennemsnittet er 51 år.
Hvor mange oocytter indeholder de to ovarier ved fødslen?
Ved fødslen indeholder de to ovarier næsten 1 million oocytter.
Hvor mange oocytter indeholder de to ovarier ved starten af puberteten?
I løbet af barndommen går et stort antal af dem til grunde, således at der ved pubertetens begyndelse er ca. 300.000 oocytter tilbage.
Hvad sker der i hypofysen, når estrogen og progesterone aftager?
Samtidig med at estrogen og progesteronproduktionen aftager, stiger hypofysens sekretion af LH og FSH. Stigningen skyldes, at kønshormonernes negative feedback-virkning på hypofysen og på hypothalamus aftager. Desuden producerer follikelcellerne inhibin, der hæmmer sekretionen af LH og i særlig høj grad FSH. Derfor ophører inhibinproduktionen også, når der ikke er flere follikler. Det forklarer, hvorfor produktionene af FSH øges mere end LH-produktionen i klimakteriet.
Hvorfor øges produktionen af LH og FSH i klimakteriet, og forsat resten af livet?
Den tiltagende LH- og FSH-produktion repræsenterer hypofysens forsøg på at stimulere ovarierne til fortsat funktion.
Hvorfor får en del kvinder øget hårvækst i klimakteriet?
Det høje LH-niveau i blodet stimulerer theca celler, der er tilbage i ovarierne, til at fortsætte produktionen af androstendion. I leveren og i fedtvævet omdannes androstention til østron, der er det vigtigste estrogen i klimakteriet. Da androstendionproduktionen fortsætter, vil der i klimakteriet være et relativt ovarskud af androgener i forhold til estrogener, og en del kvinder får derfor øget hårvæskt i denne periode.
Hvad sker der med knoglemetabolismen, når menopausen indtræffer?
Hos alle kvinder indtræffer der ved menopausen en ændring i knoglemetabolismen med øget knoglenedbrydning og reduceret nydannelse af knoglevæv. Det resulterer i en betragtelig stigning i knogletabet de første år efter menopausen.
What is perimenopause?
Perimenopause follows the period of declining fertility until it precedes menopause
What is perimenopause characterized by?
Irregularity in menstrual cycle and increasing symptoms
