Unit 4: Reproductive Physio Flashcards
Define “growth”.
property of cell reproduction/division
Define “reproduction”.
2 types
Cell reproduction (divison)
Organism reproduction
Name and describe the stages of spermatogenesis.
“to make sperm”
Spermatagonia
Primary spermatocyte
Secondary spermatocyte
Spermatid
Spermatozoa
Spermatagonia cells [make sperm from puberty throughout life by regenerating themselves by mitosis]
> Produce 2 duplicate copies of themselves
> 1 becomes a primary spermatocyte > divides by meiosis 1
Meiosis 1 divides the primary spermatocyte into 2 23 chromosome cells [secondary spermatocytes]
the secondary spermatocytes go through Meiosis 2 (double divide) > spermatid
Spermatids mature and become the sperm cell (spermatozoa)
Describe the relationship between sertoli cells and developing sperm.
Nourishment: Sertoli cells provide food and support for developing sperm.
Protection: They create a barrier to shield developing sperm from the immune system.
Cleanup: Sertoli cells clean up excess stuff and debris produced during sperm development.
Hormonal Control: They respond to hormones to regulate the sperm-making process.
Transport: Sertoli cells help move sperm to where they need to be.
Maturation: They play a key role in turning immature sperm into fully functional sperm.
Describe the location and function of Leydig cells.
~found between seminiferous tubules
~production of sex hormone- testosterone
Name and describe the stages of oogenesis
Oogonium cell divides by mitosis>
Primary oocyte > meiosis 1 >
Polar body + secondary oocyte (the egg) >
if it comes into contact w/ sperm then :»_space;>
Meiosis 2 > 2nd polar body + Ootid
Differentiation > ovum
> > fertilization»_space; zygote
Describe the timing of oogenesis.
When does it start, at what point is it arrested, and what restarts arrested development?
eggs begin to develop before birth
After puberty, few eggs start to wake up
1 egg grows each month
Around the middle of the month, a mature egg is released in a process called ovulation.
If the egg meets a sperm and gets fertilized, it completes the second part of cell division (meiosis II) and becomes a fully mature egg.
If there’s no fertilization, the egg stays “paused” in the second part of cell division (metaphase II).
This monthly cycle continues until menopause, usually in the late 40s or early 50s, when the ovaries stop releasing eggs.
Name and describe the stages of follicular development.
How are follicular development and oogenesis related?
Primordial follicle>
primary follicle>
secondary follicle>
Graafian [mature] follicle wrapped around a secondary oocyte>
Graafian follicle swells, expands, ruptures, and ejects the center mass [the “egg” consisting of a secondary oocyte wrapped by zona pellucida with an outer layer of follicular cells AKA corona radiata]
Follicular structure transitions into Corpus luteum > degrades into remnant tissue called corpus albicans
Compare and contrast spermatogenesis and oogenesis.
Spermatogenesis
~starts at puberty and continues throughout entire life
~occurs in the seminiferous tubules of the testes
~results in four functional sperm cells from a single spermatogonium.
Oogenesis
~takes place in the ovaries.
~produces only one mature egg (ovum) from a single oogonium, with the remaining daughter cells becoming polar bodies
~finite process; only a limited number of eggs are produced, with a decline in quantity + quality over time
Describe the composition of the “egg”.
Center of egg: 23 chromosome nucleus of a secondary oocyte
thin layer- zona pellucida
surrounding cell layer: corona radiata
~secondary oocyte wrapped by zona pellucida with an outer layer of follicular cells AKA corona radiata
Describe the origin and function of FSH and LH.
Produced by the anterior pituitary
FSH- as it rises, follicle growth is stimulated
LH- triggers ovulation, the release of a mature egg (oocyte) from the ovary
Identify the three phases of the ovarian cycle.
What characterizes each phase?
Follicular Phase: days 1-13
begins on the 1st day of menstruation and lasts until ovulation.
FSH stimulates the growth of ovarian follicles, each containing an immature egg (oocyte).
As follicles develop, one becomes dominant and matures into the Graafian follicle.
Ovulatory Phase: day 14
short phase
LH surges, triggering the release of the mature egg (oocyte) from the Graafian follicle into the fallopian tube.
This phase marks the transition from follicular development to the release of the egg.
Luteal Phase: days 15-28
After ovulation, the ruptured Graafian follicle transforms into a structure called the corpus luteum.
The corpus luteum secretes progesterone and some estrogen, preparing the uterine lining for potential implantation of a fertilized egg.
If fertilization does not occur, the corpus luteum degenerates, leading to a decline in hormone levels and the onset of menstruation.
Describe the relationship between FSH and LH and the stages of follicular development.
FSH starts the growth of follicles, and when one is ready, LH helps release the mature egg
Describe the relationship between the stages of follicular development and the production of ovarian hormones.
as follicles develop, they produce increasing amounts of estrogen, especially the dominant follicle.
After ovulation, the corpus luteum contributes both estrogen and progesterone.
These hormones play crucial roles in preparing the uterus for potential pregnancy during the menstrual cycle.
Describe the relationship between estrogen and LH secretion.
estrogen, produced by growing follicles, influences LH secretion in a feedback loop.
Initially, it has a negative feedback effect on FSH, but as estrogen levels rise, it switches to positive feedback, leading to an LH surge, which triggers ovulation.
Describe the function of the ovarian hormones (estrogen and progesterone).
Estrogen- helps maintain the menstrual cycle and facilitates the preparation of the uterus for anticipated and actual pregnancy
Progesterone- Increased levels of progesterone signal the female body to thicken the lining of the uterus to accept a fertilized egg. If an egg is fertilized, the body continues to produce progesterone throughout pregnancy to support the developing fetus.
Progesterone is also necessary to prepare the breasts for milk production.
Why is progesterone sometimes referred to as the hormone of pregnancy?
it must be present to maintain the functional role/ anatomical integrity of the endometrial lining
Progesterone helps the fertilized egg be implanted in the uterus to establish a pregnancy and help maintain a healthy pregnancy.
Identify the three phases of the uterine [menstrual] cycle.
What characterizes each phase?
Menstrual Phase/ Menses: days 1-4
FSH levels rise; Estrogen and progesterone levels at their lowest
~the shedding of the uterine lining (endometrium).
Proliferative Phase: days 5-14
estrogen levels rise, stimulating endometrial growth
[proliferation of endometrial lining]
Secretory Phase: days 15-28
progesterone stimulates increased secretory activity of endometrial lining
What is the significance of hCG?
hormone- human Chorionic Gonadotropin produced by embryo
it is necessary to maintain progesterone levels [progesterone is required for pregnancy]
targets the corpus luteum, preventing it from regressing [stays intact so estrogen progesterone levels are elevated, and the endometrium lining stays intact, so pregnancy is possible]
Also prevents LH and FSH production so they don’t drive another cycle
What is unique to the reproductive system compared to all other body systems?
The only system unnecessary for an individual’s survival
In between the 3 segments of the seminiferous tubules, there is a population of cells known as:
Leydig cells
[interstitial cells of leydig]
The sperm is made of 3 parts:
head - [nucleus here with 23 chromosomes]
midpiece - made of mitochondria that serves as an engine (ATP generated to drive the flagellum tail)
tail - flagellum propels the sperm
