The menstrual cycle is regulated by hormones from the hypothalamus, pituitary gland, and ovaries. It involves both the ovarian cycle and uterine cycle. The ovarian cycle consists of the follicular phase leading up to ovulation on day 14, and the luteal phase after. The uterine cycle involves the menstrual, proliferative, and secretory phases. Hormones like FSH, LH, estrogen, and progesterone are involved in a feedback loop to regulate the cycle. Disorders of the menstrual cycle can cause problems like painful periods or abnormal bleeding.
Physiology Of Menstruation
By: Nur Afiqah Binti Jasmi (11-2013-031) & Luqman Hakim Bin Mohd Jais (11-2013-170)
Dokter Pembimbing: Dr. Harianto Wijaya Sp.OG
DEFINITION OR MEANING OF MENSTRUAL (REPRODUCTIVE) CYCLE:-
Menstruation (Greek word, men-month) is monthly uterine bleeding out flowing through vagina into vulva for 4-5 days every 28 days (24-35 days)during reproductive life of a woman from menarche to menopause.
The Menstrual cycle of 28 days starts on day of onset of menstruation and ends at day 28 on start of next mens.
The cycle consists of a series of changes taking place concurrently in the ovaries and uterine lining, stimulated by changes in blood concentration of hormones.
Physiology Of Menstruation
By: Nur Afiqah Binti Jasmi (11-2013-031) & Luqman Hakim Bin Mohd Jais (11-2013-170)
Dokter Pembimbing: Dr. Harianto Wijaya Sp.OG
DEFINITION OR MEANING OF MENSTRUAL (REPRODUCTIVE) CYCLE:-
Menstruation (Greek word, men-month) is monthly uterine bleeding out flowing through vagina into vulva for 4-5 days every 28 days (24-35 days)during reproductive life of a woman from menarche to menopause.
The Menstrual cycle of 28 days starts on day of onset of menstruation and ends at day 28 on start of next mens.
The cycle consists of a series of changes taking place concurrently in the ovaries and uterine lining, stimulated by changes in blood concentration of hormones.
Control mechanism of Female Reproductionsunitafeme
The menstrual cycle is the scientific term for the physiological changes that occur in fertile women for the purpose of sexual reproduction.The menstrual cycle is controlled by the endocrine system
AnswerThe hormones and structuresorgansPituitary glandFemal.pdfanandanand521251
Answer:
The hormones and structures/organs:
Pituitary gland
Female reproductive organs, fallopian tubes, ovaries and uterus
Anatomy & layout of pituitary:
In vertebrates, this is the endocrine gland with no ducts and looking like a small pea weighing
0.5 grams. It has anatomically protruded from hypothalamus & referred as “hypophysis” at the
base of brain. This gland is meticulously rests on hypophysial fossa & center to the middle
cranial fossa attaché to sphenoid bone & bony cavity i.e. sella tercica.
It composed of three main lobes:
Anterior pituitary (adenohypophysis): release stress hormones, growth hormones, FSH, LH
Intermediate lobe: cell synthesize melanocyte-stimulating hormone release into blood portal
system
Posterior pituitary (neurohypophysis): This is connected to hypothalamus as described below
with median eminence, releases vasopressin, oxytocin
Gonadotrophin releaseing hormone (GnRH) formally released from GnRH neurons located
within the hypothalamus. This hormone travels through hypophyseal portal system and
stimulates adenohypophysis of pituitary gland to release gonadotrophins such as, androgen
release (testosterone synthesis hormones) follicle stimulating hormone and leutinizing hormone
(LH).
Positive feedback mechanism is defined as the output response produced by the activity of input
signal trough a specific amount of stimulus on the organ during the process of homeostasis.
Positive feedback in isolation is not sufficient to maintain homeostasis because of set point
alterations triggered by the stimulus.
Positive feedback cycle in reproductive cycle: Female reproductive system controlled by the two
phases predominantly one follicular phase from day 1 to day 14 and in this phase, follicle growth
is going be observed controlled by follicle stimulating hormone. The predominant stages
involved here primordial ell become primary followed by secondary in which one will mature
one with structures such as zona pellucida, theca follicle along with estrogen formed at day 6.
Feedback mechanism involves the following events
Stimulus: It produced on effector cells and this variable be regulated
Receptor activity: The stimulus activates receptors such as nuclear receptors to trigger gene
expression
Input via afferent nerves: Information passes through afferent nerves to the control center
Output via efferent nerves: Output effect produce by the control center via efferent pathway
Response: Finally, response in the form of either positive or negative produced via cellular
organs
Ovulation takes place on day 14 due to the stimulus given by leutinizing hormone.
Higher levels of estrogen are during the last follicular phase produces a positive feedback
mechanism on leutinizing hormone and gonadotrophic hormone and further leading to formation
of corpus luteum.
Hormones such as gonadotrophins (FSH, LH) released from the anterior pituitary are responsible
for the regulation of ovarian and uterine menstruation cycle further leading to elev.
A natural decline in reproductive hormones when a woman reaches her 40s or 50s.
Menopause is signalled by 12 months since last menstruation.
Common symptoms include hot flashes and vaginal dryness. There may also be sleep disturbances. The combination of these symptoms can cause anxiety or depression.
Menopause is a natural process with treatments that focus on symptomatic relief. Vaginal dryness is treated with topical lubricants or oestrogen. Medications can reduce the severity and frequency of hot flushes. In special circumstances, oral hormone therapy may be used.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
2. Menstruation???
Natural changes that occur in the uterus and ovary as
an essential part of making sexual reproduction
possible.
Essential for the production of eggs, and for the
preparation of the uterus for pregnancy.
3. Average length= 28
days
Ages of 11 and 14
Controlled by
hormones
Interaction between
hypothalamus,
pituitary, ovaries &
uterus.
Each cycle divided into
phases
7. Ovarian Cycle
Ovulation occurs at 14th day of 28-days ovarian cycle.
14 days prior to ovulation are called follicular phase.
While 14 days after ovulation constitute luteal phase.
8. Uterine Cycle
Ovulation occurs at 14th day of 28-days uterine cycle.
14 days prior to ovulation are subdivided into menstrual phase
(day 1-5) and a proliferative phase (6 -14) .
While 14 days after ovulation constitute secretory phase.
9. In the first 5 days, GnRH stimulates anterior
pituitary to increase production of FSH and
LH.
Day 1-5: Primordial follicle matures to primary
follicles each containing a diploid primary
oocyte.
Day 6-13: Primary follicles form secondary
follicles.
After 16 hours: FSH & LH
Maturation of follicle called graafian follicle.
Just prior to ovulation, primary
oocyte complets meiosis
1 to form secondary
haploid oocyte.
Follicular Phase
10. Ovulation
• Release of secondary
oocyte from mature
follicle.
• Guided by high level of
LH.
Luteal Phase
•Days: 15-28
•Remaining ovarian follicular cells
form a yellowish structure called
corpus luteum.
•Production of progesterone and
estrogen by corpus luteum
11. Menstrual Phase
• Progesterone Shedding of endometrial
lining.
• Woman’s period.
Proliferative Phase
• Estrogen produced by follicular cells
endometrian begins to reform
12.
13. Secretory Phase
• Days: 15-28
• Progesterone and estrogen from corpus luteum
stimulates further thickening of the
endometrium.
In case of no fertilization:
• Corpus luteum becomes corpus albicans.
• Decreased level of progesterone and estrogen
• Leads to menstruation.
16. *Gonadotropin-releasing
hormone
Five hormones
involved in an
elaborate
scheme
involving both
positive and
negative
feedback
Cyclic secretion of GnRH* from the hypothalamus
And of FSH and LH from the anterior pituitary
orchestrates the female reproductive cycle
17. ROLE of GnRH IN THE MENSTRUAL CYCLE
• The hypothalamus secretes GnRH in a pulsatile fashion
• GnRH activity is first evident at puberty
• Follicular phase GnRH pulses occur hourly
• Luteal phase GnRH pulses occur every 90 minutes
• Loss of pulsatility down regulation of pituitary receptors
secretion of gonadotropins
• Release of GnRH is modulated by –ve feedback by:
steroids
gonadotropins
• Release of GnRH is modulated by external neural signals
18. 1. High levels of estrogens suppress the release of GnRH (bar) providing a negative-
feedback control of hormone levels.
2. Secretion of GnRH depends on certain neurons in the hypothalamus which
express a gene (KISS-1) encoding a protein of 145 amino acids. From this are cut
several short peptides collectively called kisspeptin. These are secreted and bind
to G-protein-coupled receptors on the surface of the GnRH neurons stimulating
them to release GnRH. However, high levels of estrogen inhibit the secretion of
kisspeptin and suppress further production of those hormones.
19. Follicle
Stimulating
Hormone
(FSH)
Site of Secretion
Pituitary gland
Target Organ
Ovary
Function
stimulates the
growth &
development of the
follicle
stimulates
secretion of
oestrogen
effect of LH in
stimulating
ovulation
Oestrogen
Ovary
Endometrium
(lining of the uterus)
stimulates repair of
uterine lining
at high conc.
inhibits FSH,
however during
'pituitary hormone
surge' it stimulates
further FSH
production
as conc. peaks
stimulates release
of LH
Lutenising
Hormone (LH)
Pituitary
Ovary
stimulates the final
development of the
follicle
stimulates
ovulation
stimulates the
development of the
corpus luteum
stimulates
production of
progesterone
Progestrone
Corpus luteum
Uterus
maintains uterine
lining
endometrium)
inhibits release of
FSH
inhibits release of
LH
fall in conc. results
in menstruation
fall in conc.
removes inhibition
of FSH and a new
cycle begins.
20. Found in follicular fluid
Stimulates FSH induced
estrogen production
gonadotropin receptors
androgen
No real stimulation of FSH
secretion in vivo (bound to
protein in serum)
Local peptide in the
follicular fluid
-ve feed back on
pituitary FSH secreation
Locally enhances LH-
induced
androstenedione
production
ACTIVINS
INHIBINS
24. Hormones of Placenta
The placenta forms large quantities of human chorionic gonadotropin,
estrogen, progesterone and human chorionic somatomammotropin,
which are all essential to a normal pregnancy
HUMAN CHORIONIC GONADOTROPIN (HCG)
HCG is a glycoprotein with a molecular weight of 39,000.
It is secreted by the syncytial trophoblast cells and can be measured in
the blood 8 to 9 days after ovulation.
The rate of secretion rises rapidly to reach maximum bout 10 to 12
weeks after ovulation and decreases to much lower value by 16 to 20
weeks after ovulation.
It continues at this level for the remainder of pregnancy.
25. • This hormone is identical to LH in its effect and
therefore is able to maintain the corpus luteum
past the time when it would otherwise regress.
• The secretion of estradiol and progesterone is
thus maintained and menstruation is normally
prevented.
• Diagnosis of the early pregnancy
