Endocrine system and female reproduction Flashcards
What is the function of endocrine glands
secrete products called hormones and release them into the adjacent tissue spaces
What are the three classes of hormones (give exampe)
- Proteins, polypeptides, and peptides (GnRH,FSH) 2. Amines (epinephrine) 3. Steroids (androgens like testosterone)
What class do androgens belong to
steroids
What is a ligand
A molecule that binds to a specific receptor on another molecule, often triggering a cellular response by delivering a signal.
True or False: Receptors for steroid hormones are located within the cytoplasm or nucleus of target cells
true
True or False: the half life of a peptide hormone is hours compared to a steroid hormone which is minutes
false
What is the function of a sex steroid binding globulin
it binds to sex hormones like testosterone and estrogen in the bloodstream, effectively regulating the amount of these hormones that are actively available to target tissues by controlling their access to cells
True or False: Each hormone has its unique receptor, resulting in equal numbers of hormone and receptor types
false
What is weak versus strong affinity of a hormone to a receptor? Give an example
of a hormone
A weak affinity means the hormone binds poorly while a strong binds well. Estradiol has a strong affinity while estrone and estriol are weak.
What is an agonist and antagonist
An agonist mimics while antagonist block
Which hormones would a GnRH Antagonist and a GnRH Inhibitory Agonist affect and why is it important in terms of fertility?
It lowers gonadal steroids (reduces estrogen). This is a potential contraceptive and prevents premature ovulation.
Which is medically useful for the ability to
shut down gonadotropins and, thus, lower gonadal steroids and inhibit egg and
sperm maturation
GnRH inhibitory agonists and GnRH antagonist
What is the function of the pituitary gland
It synthesizes and secretes hormones that travel in the bloodstream and influence many aspects of our body like other endocrine glands. If removed, reproductive system doesn’t function
What is the name of the two lobes in the pituitary gland
Adenohypophysis and Neurohypophysis
What kind of nerve cells secrete hormones and how does this differ from the most common one
Neurosecretory cells. It differs from neurons because it releases hormones directly in the bloodstream.
Neurohormones are secreted from neurons that originate from where
The hypothalamus
Which hormones do neurosecretory neurons secrete and what is the function of
each hormone?
Oxytocin and Vasopressin. Oxytocin causes contractions and facilitates milk. Vasopressin causes kidneys to retain water and and raises blood pressure
Where is the GnRH Pulse Generator located and why is its function important to
fertility?
In the hypothalamus. It controls the menstrual cycle
True or False: GnRH regulates the release of FSH and LH and these two hormones control
gamete production and hormone release from the gonads (testes/ovaries).
True
Would an increase in FSH and LH lead to a gain or loss in fertility and WHY?
It would lead a loss in fertility because it causes fewer eggs that are able to mature
What is happening with sex steroids in the Luteal Phase of the menstrual cycle
versus in a combination contraceptive pill? What is the ultimate result of the
activity of these sex steroids?
Both cause a negative feedback cycle. In the luteal phase, GnRH is inhibited and decreases FSH and LH which prevents ovulation. Combination pills do this too. The ultimate result is ovulation being stopped.
Releasing Hormone
Neurohormone that increases output of a particular adenohypophysial hormone
Growth Hormone
Stimulates tissue growth
LH
induces release of egg from ovary
FSH
Maturation of germ cells in ovaries
Example of negative feedback system
Moderate levels of estrogen decrease FSH and LH and thus decrease estrogen
What are the primary sexual characteristics that distinguish females from males
ovaries, female accessory ducts (oviducts,uterus, and vagina) ad external
What are the ovaries roll in reproduction
produce female gametes (oocytes and eggs). secretion of hormones like estrogen, progesterone, and inhibin
What is the zona pellicuda
thin transparent membrane between oocyte and follicular wall. It’s secreted by the oocyte.
Primordial Follicles
1st stage in follicular growth. It has small, non growing follicles. It consists of oocyte surrounded by a single layer of granulosa cells. Lies in periphery of ovarian cortex. Most die during this stage.
Primary Follicles
Second stage in follicular growth. Initial growth of follicle is due to increase in size of oocyte and granulosa. layer. Thin layer rich in glycoprotein, the zona pelicuda develops in space between oocyte and granulosa cells.
Secondary follicles
Third stage in follicular growth. Granulosa cells go through mitosis so it has multiple layers (2-6) of granulosa cells around oocyte. Fibroblast precursor cells recruited into peripheral layer and the theca. Blood vessels bring blood-borne nutrients to follicle. Lasts four months.
Tertiary follicle
Fourth stage in follicular growth. Takes 2-3 months. Granula secretes fluid that goes imbetween cells. This fluid space join. The follicle wall is permeable so proteins can diffuse into antral cavity.
Where are granulosa and theca located
the ovary
What is the largest, most mature follicle
Graafian follicle
What is follicular atresia
breakdown of ovarian follicles
About how many follicles does a woman around the age of 35 have in her ovaries
between 8 and 15
What is the precursor for steroid hormones?
cholesterol
What are the common steroid hormones that pertain to reproduction
estrogens, androgens, and progestagens
How many pathways are involved in steroidogenesis and how do they differ
Two different pathways. Delta four goes to progesterone. Delta five goes to ends at DHEA
Two cell model of steroidgenesis
Theca cells and granulosa cells coordinate to produce steroid hormones. If enzyme available can convert one steroid to another. Between secondary and teritary phases.
Which pathway of steroidogenesis is common in the corpus luteum?
delta four
The corpus luteum, through the Δ4 pathway produces and secretes
progesterone and testosterone.
False
The ovarian follicles, through the Δ5 pathway produce and secrete estradiol and
estrone. (T or F)
True
How many follicles are ovulated each month
1
What is the difference between diploid and haploid in meiosis.
Haploid 1n. Diploid is 2n.
oogenesis
Results in production of
mature female gametes (sex cells)
Which hormone triggers meiotic maturation in the oocyte?
LH
Explain primary oocyte versus secondary oocyte. Explain primary follicle versus
secondary follicle
A primary oocyte is an immature egg cell that has not yet completed the first meiotic division. A primary follicle is a developing ovarian follicle containing a primary oocyte surrounded by a single layer of granulosa cells, whereas a secondary follicle is a more developed follicle with multiple layers of granulosa cells and a fluid-filled antrum surrounding the secondary oocyte.
How does an oocyte escape from the follicle? Explain the process of ovulation
the mature follicle in the ovary ruptures, releasing the egg (oocyte) into the abdominal cavity, which is then captured by the fimbriae of the fallopian tube to be transported towards the uterus
What is the corpus luteum
Mass of cells that form in the ovary
Which hormones have control over follicular growth
FSH and LH
What is the function of the oviducts?
Transport eggs from ovary to uterus
How does estrogen affect the oviducts
Estrogen can help the movement and maturation of eggs, sperm, and embryos in the fallopian tube
Which layer of tissue (be specific) in the uterus sheds during menstruation
Stratum functionalis
What is the purpose of a mucus plug in the cervix
blocks the opening of your cervix during pregnancy. It forms a seal to prevent bacteria and infection from getting into your uterus and reaching the fetus
Which vaginal layer expands under the influence of estrogen?
Tunica mucosa
Are bacteria, fungi, and protozoa good or bad in the vaginal environment
Some are good because they help balance the ph
Bacteria in the vagina metabolize glycogen to make the vaginal environment
acidic, which allows all the sperm to survive. (T or F)
False
Why can taking an antibiotic affect the vaginal environment
It can get rid of beneficial bacteria.
Which structure in the female is homologous to the male scrotum?
labia majora
Which structure in the female is homologous to the prostate glands?
Skenes glands
Is the urethral orifice anterior or posterior to the vaginal introitus
Anterior
What is the part of the clitoris called that is externally visible?
glans
