A common disease of cattle and may also in dog, cat, sheep, goat, mare, Buffalo. The slides contain an introduction, causes of torsion, clinical signs and symptoms, torsion causes, treatment.
The mechanism of parturition, theories of initiation of parturition, and the stages of parturition are described for the domestic animal species. Useful for students in veterinary science, practitioners, and researchers.
This lecture describes the use of ultrasonography in animal reproduction. This lecture would be useful for veterinary students, practitioners, and researchers.
This is the first lecture in the series of lectures covering the complete syllabus of Veterinary Obstetrics for veterinary students, practitioners, and researchers. This lecture describes fertilization, maternal recognition of pregnancy, and implantation.
In this presentation oogenesis , folliculogenesis and ovulation is discussed briefly . You can find useful content for your college and school projects.
A common disease of cattle and may also in dog, cat, sheep, goat, mare, Buffalo. The slides contain an introduction, causes of torsion, clinical signs and symptoms, torsion causes, treatment.
The mechanism of parturition, theories of initiation of parturition, and the stages of parturition are described for the domestic animal species. Useful for students in veterinary science, practitioners, and researchers.
This lecture describes the use of ultrasonography in animal reproduction. This lecture would be useful for veterinary students, practitioners, and researchers.
This is the first lecture in the series of lectures covering the complete syllabus of Veterinary Obstetrics for veterinary students, practitioners, and researchers. This lecture describes fertilization, maternal recognition of pregnancy, and implantation.
In this presentation oogenesis , folliculogenesis and ovulation is discussed briefly . You can find useful content for your college and school projects.
Anatomy of male and female reproductive system, Functions of male and female
reproductive system, sex hormones, physiology of menstruation, fertilization,
spermatogenesis, oogenesis, pregnancy and parturition
Oogenesis and follicular development Part 1 I Endocrine Physiology IHM Learnings
Oogenesis and follicular development Part 1 I Endocrine Physiology I
The slides will talk about
1. Introduction
2. Stages of follicular development
3. Primordial follicle
4. Preantral follicle (primary and secondary follicle)
5. Antral follicle
You can also watch the same topic on HM Learnings Youtube channel.
You can also follow HM Learnings on facebook, instagram and twitter for daily updates
What role do the follicles in the ovary play in the endocrine system.pdfrushabhshah600
What role do the follicles in the ovary play in the endocrine system?
Solution
Ans:
· An ovarian follicle is a roughly spheroid cellular aggregation set found in the ovaries. It
secretes hormones that influence stages of the menstrual cycle. Women begin puberty with about
400,000 follicles, each with the potential to release an egg cell (ovum) at ovulation for
fertilization. These eggs are developed only once every menstrual cycle.
· The ovaries are the site of production and periodical release of egg cells, the female
gametes.When the oocyte finishes its maturation in the ovary, a surge of luteinizing ghormone
secreted by the pituitary gland stimulates the release of the oocyte through the rupture of the
follicle, a process called ovulation.
· Ovarian follicles are the basic units of female reproductive biology. Each of them contains
a single oocyte (immature ovum or egg cell). These structures are periodically initiated to grow
and develop, culminating in ovulation of usually a single competent oocyte in humans They also
consist of granulosa cells and theca of follicle.
· The ovarian follicles, sometimes called graafian follicles, are rounded enclosures for the
developing ova in the cortex near the surface of the ovary. At birth and in childhood they are
present as numerous primary or undeveloped ovarian follicles. Each contains a primitive ovum,
or oocyte, and each is covered by a single layer of flattened cells. As many as 700,000 primary
follicles are contained in the two ovaries of a young female. Most of these degenerate before or
after puberty.
· Means follicles play an important role in maintaining the puberty in females by secreting
several harmones (When there are no more follicles or eggs, the ovary no longer secretes the
hormones oestrogen and progesterone which regulate the menstrual cycle. As a result,
menstruation ceases).
· In the ovary, all eggs are initially enclosed in a single layer of cells known as a follicle
which supports the egg. Over time, these eggs begin to mature so that one is released from the
ovary in each menstrual cycle. As the eggs mature, the cells in the follicle rapidly divide and the
follicle becomes progressively larger..
The mechanism of action of reproductive hormones and their clinical use is explained as useful for students, practitioners, and aspirants of competitive exams.
Andrology lecture 16 Semen collection from male animals and its evaluationDrGovindNarayanPuroh
This lecture describes the techniques of semen collection and its evaluation. The lecture is useful for veterinary students, practitioners, semen labs, and aspirants of IAS
In this lecture, the approaches for breeding soundness evaluation of bulls are explained for veterinary students, practitioners, and aspirants of IAS, RAS, and other examinations.
Andrology lecture 14 semen and its composition in male animals (1)DrGovindNarayanPuroh
This lecture explains the semen and its components in domestic animals useful for veterinary graduates, clinicians and aspirants of IAS, RAS and other examinations.
Puberty and sexual maturity in male animals is explained in this lecture useful for veterinary students, practitioners and all those interested in male reproduction in domestic animals
The mechanism of puberty and age of puberty in domestic animals is explained in this lecture useful for students, practitioners and aspirants of examinations
The functional physiology of the female genital organs of domestic animals are explained in this lecture useful for students, practitioners and aspirants of examinations.
0x01 - Newton's Third Law: Static vs. Dynamic AbusersOWASP Beja
f you offer a service on the web, odds are that someone will abuse it. Be it an API, a SaaS, a PaaS, or even a static website, someone somewhere will try to figure out a way to use it to their own needs. In this talk we'll compare measures that are effective against static attackers and how to battle a dynamic attacker who adapts to your counter-measures.
About the Speaker
===============
Diogo Sousa, Engineering Manager @ Canonical
An opinionated individual with an interest in cryptography and its intersection with secure software development.
Acorn Recovery: Restore IT infra within minutesIP ServerOne
Introducing Acorn Recovery as a Service, a simple, fast, and secure managed disaster recovery (DRaaS) by IP ServerOne. A DR solution that helps restore your IT infra within minutes.
This presentation by Morris Kleiner (University of Minnesota), was made during the discussion “Competition and Regulation in Professions and Occupations” held at the Working Party No. 2 on Competition and Regulation on 10 June 2024. More papers and presentations on the topic can be found out at oe.cd/crps.
This presentation was uploaded with the author’s consent.
Sharpen existing tools or get a new toolbox? Contemporary cluster initiatives...Orkestra
UIIN Conference, Madrid, 27-29 May 2024
James Wilson, Orkestra and Deusto Business School
Emily Wise, Lund University
Madeline Smith, The Glasgow School of Art
Have you ever wondered how search works while visiting an e-commerce site, internal website, or searching through other types of online resources? Look no further than this informative session on the ways that taxonomies help end-users navigate the internet! Hear from taxonomists and other information professionals who have first-hand experience creating and working with taxonomies that aid in navigation, search, and discovery across a range of disciplines.
Eureka, I found it! - Special Libraries Association 2021 Presentation
Lecture 5 follicular dynamics in domestic animals
1. Ovarian Follicular dynamics in
domestic animals
• The Female gamete the oocyte originate and
develop from the ovarian follicles. The ovarian
follicles develop from the primordial germ
cells during fetal period and are called
primordial follicles.
• Follicle is the primary functional unit of ovary
that releases the oocyte and produces the
steroid hormones.
3. Fate of follicles and oocytes.
Total number of follicles
At birth 100,000
12 months 75,000
4-6 years 21,000
Aged cow 2,500
Follicles grow to tertiary characteristic and degenerate.
Maximum number of oocytes ovulated for a cow
10 cycles/year x 12 year = 120 oocytes ovulated/lifespan
100 Days of Gestation
2.9 million
It has been estimated that no more than about 300 oocytes are ever likely to
reach the ovulatory stage during the normal reproductive lifespan of the cow.
4. • Follicular growth can be classified into three
phases according to their developmental stage
and gonadotropin dependence : (1) follicular
growth through primordial, primary, and
secondary stages gonadotropin-independent
phase), (2) transition from preantral to early
antral stage (gonadotropin-responsive phase),
and (3) continual growth beyond the early
antral stage (gonadotropin-dependent phase),
which includes follicle recruitment, selection,
and ovulation.
5. • Ovaries of cattle contain two different pools of
follicles, the non-growing pool and the
growing pool. The non-growing pool contains
the primordial follicles, whereas the growing
pool contains the primary, secondary and
tertiary follicles. Entry of primordial follicles
into the growth phase occurs throughout the
reproductive life. The primordial follicles
continuously leave the arrested pool and
undergo the primordial to primary follicle
transition.
6. After the preovulatory LH surge in the early hours of estrus in the cow,
the follicle is known as the preovulatory follicle.
7.
8. • The growth of follicles from the primordial to
ovulatory follicles is complex and requires a
couple of days to months.
• The sequence of events involves the growth of
primordial follicles into preantral and then antral
follicles (follicles with a central fluid filled cavity-
the antrum). This transformation involves the
proliferation of granulosa cells and reorganization
of cells forming the follicle.
9. • The growth of the primordial follicles is
resumed at puberty subsequent to which the
follicles grow in a cyclic fashion that is
repeated at defined intervals regularly
throughout the year in non seasonal breeding
species.
10. • During this transition the oocytes increase in size
and the surrounding squamous pre-granulosa
cells become cuboidal and proliferate to form a
layer of cuboidal cells around the growing oocyte.
The follicle is now called the primary follicle. The
mechanisms responsible for the initiation of
follicular growth during this phase are poorly
understood although some molecules such as
growth factors and gonadotrophins have been
discussed.
11. Puberty
Primordial follicle activated Primary and Sec follicle
• Preantral Antral follicles
• Early antral Follicle recruitment, selection,
and ovulation-Follicular waves
Gonadotropin-independent phase
Gonadotropin-dependent phase
Gonadotropin-dependent phase
14. It is now known that the antral follicles
are selected to grow and this growth
occurs in a wave like fashion in most
domestic mammalian species. The
follicular growth waves lead to growth in
the size and fluid secretions within the
follicle, expression of estrus, and
ovulation with release of mature oocyte.
15. • Normally three to six follicles with a diameter
of 4 to 5 mm occur after recruitment of follicle
into a follicular wave.
• From the cohort of the growing follicles one
follicle is selected for continued growth and
becomes dominant. If luteolysis occurs during
the growth phase of the dominant follicles,
final maturation and ovulation occurs. If
luteolysis does not occur during the growing
and maintenance phase of follicles, the fate is
atresia
16.
17. • Follicle recruitment
• The concept recruitment is used for the entrance
of follicles in the growing pool, but also for the
processes associated with the entrance of
follicles in a wave like growth. FSH appears to
be the key hormone for the initiation of the
follicular wave. The surges in FSH precede the
emergence of a wave. The FSH surges begin 2-
4 days before the detectable (ultrasound)
emergence of a follicular wave (follicles of 4
and 5 mm), peaked 1 or 2 days and started
declining nearly when the follicles of a wave
begin to diverge into a dominant follicle and
subordinate follicles (follicles 6 to 8 mm).
18. • Recruitment of the cohort containing the
future preovulatory follicle occurs during a
recruitment window which lasts 1, 2 or 3 days
in sheep, cattle or horses respectively. Only
gonadotrophin dependent healthy follicles
are recruited. The number of recruited
follicles growing in the cohort appears to be
highly variable between species. It ranges
from over 50 in pigs, to 5 to 10 in cattle and
1 to 4 in horses. All follicles of the cohort are
capable of ovulating, since selective ablation
of all except one will not postpone ovulation
in sheep and cattle.
19. • Selection
• Selection means that the number of
growing follicles is brought into line with the
species-specific ovulation number. After
recruitment fewer and fewer recruited
follicles continue in growth and one follicle
is selected to become dominant while the
remaining members of the recruited
follicles become static and eventually
undergo atresia via apoptosis.
20. • Dominance
• Follicles are functionally dominant (capable of
ovulating after luteal regression) while they are still
growing. Follicles acquired ovulatory capacity at
about 10 mm, corresponding to about 1 day after the
start of follicular deviation.
• Dominance negative feedback effects of products of
the dominant follicle on circulating FSH.
• Dominance progressive increases in the ability of
theca cells to produce androgen and granulosa cells
to aromatize androgen to estradiol.
• Dominant follicles grow to a much larger size (from
8.5 mm at the end of selection to 12-20 mm) in 3 to 4
days.
• Dominant follicle . Progesterone LH Ovulation
• Dominant follicle No follicular wave
28. Preovulatory LH Surge
Ovulation
Increased Blood
Flow to Ovary and
Follicle
Vascular
Permeability
Plasminogen
Cumulus
Expansion
Oocyte
Separates
From
Follicular
Wall
Contraction
of Smooth
Muscle
Collagenase (inactive)
Follicular Wall
Weakens
Plasmin
Collagenase (active)
Protein Synthesis
in and around Follicle
Plasminogen
Activator
Progesterone Prostaglandin
Synthesis
PGE and PGF
29. Follicular dynamics in buffaloes
Buffaloes evidence 1-, 2- or 3- wave cycles with
the 2-wave cycle being the most common pattern
of follicular growth Size of ovulatory follicle above
8.5mm
In some breeds one wave cycle is common for
example the Surti breed
During hot summer months there is variable degree of
ovarian follicular turnover in one or both ovaries
without expression of estrus signs and regression of
dominant follicles instead of their ovulation.
30. The types of follicular waves that develop in mares are
major waves (characterized by dominant and subordinate
follicles) and minor waves (largest follicle does not attain
the diameter of a dominant follicle).
Follicular dynamics in mares
In the mare ovary there are approximately
40,000 primordial follicles and 100 growing follicles
Atresia (regression) of follicles is rare until
they reach 1 mm
31. In some breeds (e.g. Quarter-Horses, Ponies), usually only
one major wave develops in late diestrus and culminates in the
estrous ovulation. In other breeds (e.g. Thoroughbreds), a
secondary major wave frequently develops in early diestrus,
and the dominant follicle may be anovulatory (more common),
or occasionally ovulatory (diestrous ovulation).
Minor follicular waves have been demonstrated in mares in
variable patterns. In all horse breeds, however, a major
ovulatory wave begins at mid-cycle and one follicle
(occasionally two, rarely three) becomes dominant and
ovulates.
32. • The ovulatory waves, as well as major
anovulatory waves and minor waves,
originate from the stimulation of an FSH
surge, which reaches a peak when the
largest follicle is about 13 mm.
• The physiologically selected dominant
follicle grows to a large diameter (≥ 28
mm) and then either regresses
(anovulatory major wave) or ovulates
(ovulatory wave).
33. • Maximum diameter of the dominant follicle is
smaller for major anovulatory waves than for
ovulatory waves (e.g., means of 37 and 46
mm
• A paradox in mares is the occurrence of
ovulation from the dominant follicle of what
was expected to be an anovulatory wave.
These ovulations have been called
secondary or diestrus ovulations and occur
during high progesterone concentrations.
34. Follicular dynamics in sheep
• In sheep follicles ≥5mm in diameter would
exhibit a wave-like pattern while follicles
smaller than 4mm would grow randomly. Both
patterns of growth are classified as primary
and secondary follicular waves, respectively.
• Two to 3 follicular waves per cycle are
common in sheep, and 3 or 4 follicular waves
per cycle are most common in goats
35. • During estrous cycles, the dominant and
largest subordinate follicles reach maximum
diameters of 5 to 7 mm and 3 to 5 mm
respectively in sheep. In most cases the
ovulatory follicles develop from the cohort of
follicles from the last follicular wave. However,
the ovulatory follicles can also derive from the
penultimate follicular wave with the result
that follicles can ovulate both from the last
and the second last follicular waves of the
cycle.
36. Follicular dynamics in goats
• In goats on any one day of the estrous cycle
there are 5 to 10 follicles > 3 mm in diameter
in the ovaries and follicles ovulate at or
between 6 and 9 mm in diameter. As in sheep
double ovulations can derive from follicles of
the last and the second last wave.
37. • The above lectures are also explained in video
lectures at my YouTube Channel Govind
Narayan Purohit
• Kindly share the videos and subscribe to my
channel if you like them
• Thanks
