Spermatogenesis and oogenesis are the methodologies of building male and female gametes. Spermatogenesis leads to the formation of sperm, while oogenesis supports the figure of eggs. Fertilization of sperm and eggs leads to the formation of a zygote, which further develops into an embryo.
What Is Spermatogenesis?
Table of Contents
Spermatogenesis is the formation of spermatids (sperm) in male testicles. The process starts from spermatogonium, which is genetically diploid. Spermatogonia produces primary spermatocytes (diploid) through mitosis.
The resulting primary spermatocyte experiences meiosis I to deliver two identical haploid cells that reached secondary spermatocytes.
What Is Oogenesis?
Oogenesis is the formation of eggs in females. Usually, the initial stages of oogenesis start in the early embryonic stages and end after puberty. The production of eggs has a cyclical pattern; this usually occurs once a month.
What Is The Major Difference Between Spermatogenesis And Oogenesis Quizlet?
The fundamental difference between spermatogenesis and oogenesis is that: one mature egg is produced by oogenesis and four mature sperm are produced by spermatogenesis. one mature egg is produced by oogenesis and four mature sperm are produced by spermatogenesis.
What Is Oogenesis Explaining?
Oogenesis, in the human female reproductive method, growth process in which the primary egg cell (or egg) becomes a mature egg. … These cells, known as the primary egg, number about 400,000. The primary egg remains dormant until just before ovulation when an egg is released from the ovary.
Why Do Spermatogenesis And Oogenesis Produce A Different Number Of Gametes?
Spermatogenesis and oogenesis differ in the number of gametes they produce because spermatogenesis produces four functioning gametes and oogenesis produces a large gamete with three polar bodies.
What Are 3 Differences Between Spermatogenesis And Oogenesis?
Spermatogenesis and oogenesis lead to the build of sperm, while oogenesis helps with the build of eggs. Fertilization of sperm and eggs leads to the formation of a zygote, which further develops into an embryo.
Spermatogenesis Vs Oogenesis.
Spermatogenesis Oogenesis
Produces moving gametes Produces non-motile germ cells
What Causes Oocytes To Mature?
Eggs. At the time of ovulation, and outside is released from the follicle. … In the fallopian line, if pregnancy ensues, the ootid is fertilized by a sperm. When this fertilization takes place, the ootid undergoes its final stage of maturation and becomes an egg, a fully mature human egg cell.
How Long Is The Process Of Spermatogenesis In Humans?
For humans, the entire spermatogenesis and oogenesis process is estimated differently to take 74 days (according to tritium-labeled biopsies) and approx. 120 days (according to DNA clock measurements). Including transport on the ductal system, it takes 3 months. Testicles produce 200 to 300 million spermatozoa daily.
Is Spermogenesis Part Of Spermatogenesis?
Spermiogenesis is the last stage of spermatogenesis, which sees the maturation of spermatids in mature spermatozoa. The sperm is a more or less circular cell containing a heart, Golgi machine, centriole, and mitochondria. All these components participate in the formation of sperm.
What Are The Stages Of Spermatogenesis?
Spermatogenesis can be divided into three phases:
(1) proliferation and differentiation of spermatogonia,
(2) meiosis, and
(3) spermiogenesis, a complex procedure that converts rounded spermatids after meiosis into a complex system called a spermatozoon
What Are The 3 Phases Of Oogenesis?
Oogenesis involves three key phases: proliferation, growth, and maturation, in which PGCs develop into primary oocytes, secondary oocytes, and then into mature tides.
Why Is Oogenesis Important?
Oogenesis – the differentiation of eggs – differs from spermatogenesis in several ways. While the gamete formed by spermatogenesis is essentially a motile nucleus, the gamete formed by oogenesis contains all the materials necessary to initiate and maintain metabolism and development.
How Many Eggs Does Oogenesis Produce?
In human women, the process that produces mature eggs is called oogenesis. Only one egg is produced from the four haploid cells due to meiosis. The individual egg is a very large cell that you can see from the human egg in the figure below.
How Are Sperm Formed? – Phases Of Spermatogenesis
Spermatogenesis is a procedure whose main position is the production of sperm. It consists of different phases and is carried out inside the testicles, in rounded structures called seminiferous tubules.
Once formed, the sperm are expelled to the center of the tubule and transported to the epididymis (upper part of the testicle), where the final maturation of the same takes place. The mature sperm are expelled in the ejaculate and, after training, they are capable of fertilizing the ovum.
1. What Is Spermatogenesis?
Spermatogenesis is the process by which sperm are formed. It occurs continuously in adult males, and a full cycle of spermatogenesis takes approximately 75-90 days in the human species.
Sperm are the male gametes, that is, the sex cells of man. Therefore, they are haploid (they contain half of the genetic information) and during spermatogenesis, they must pass from somatic cells with 46 chromosomes (diploid) to sex cells with 23 chromosomes (haploid). This is achieved thanks to meiosis.
The biological function of this reduction in the number of chromosomes in gametes is that once the fusion of the two gametes occurs, fertilization, the resulting zygote has the correct number of chromosomes: 46.
For this process to be possible, specific hormonal control of the hypothalamic-pituitary-testicular axis is necessary, which favors the production of sperm. This occurs for the first time with the onset of puberty in men. From that moment on, the testes will continuously produce sperm thanks to the initiation of the hormonal cascade.
2. Phases Of Spermatogenesis
As we will see below, there are three basic stages during sperm formation: proliferative phase, meiotic phase, and spermiogenesis.
2.1. Proliferative Phase
It is also called the spermatogonia phase. From a germ stem cell, type A spermatogonia are formed. These, by mitosis (cell division), will give rise to type A and B spermatogonia:
Type A: will continue to replicate and can give rise to type A and B spermatogonia.
Type B: it will give rise to a primary spermatocyte which, in turn, will give rise to four mature spermatozoa once spermatogenesis has finished.
Once a man’s reproductive age (puberty or adolescence) reaches, these cells will divide multiple times to form a type of cell called a primary spermatocyte. Throughout these divisions, some cellular changes take place.
It is known as the proliferative phase because of the multitude of mitoses that occur. The main objective is to form many sperm precursor cells, that is, many spermatocytes.
2.2. Meiotic Phase
Also known as spermatocytogenesis, it is the stage in which a new type of cell division begins, meiosis, which cuts genetic information in half. Thanks to it, haploid cells called spermatids are produced.
We can divide meiosis into two substages:
Meiosis I
Each primary spermatocyte gives rise to two haploid secondary spermatocytes.
Meiosis II
From each secondary spermatocyte, two spermatids are produced, so that, in total, from each primary (diploid) spermatocyte, we obtain four (haploid) spermatids.
These cells are already very similar to sperm: we can already see in them the formation of a small flagellum.
2.3. Spermiogenesis
In the last stage of sperm formation, the final maturation of spermatids occurs to give rise to mature sperm.
Its tail increases in size and gives rise to the flagellum, which will allow its development. The sperm head decreases and acquires the pointed shape that characterizes it by the reduction of the cytoplasm, the elongation of the nucleus, and the formation of the acrosome.
Finally, the mature sperm are released into the center of the seminiferous tubule. Although at this time the sperm is already ready to be ejaculated, it will need to go through the training process to be able to fertilize the egg.
Naturally, the training occurs in the path that the sperm travels in the female reproductive tract until it reaches the egg. However, it is also possible to carry it out in the laboratory if it is necessary to resort to in vitro fertilization ( IVF ).
3. Hormonal Regulation Of Spermatogenesis
Spermatogenesis is hormonally regulated by negative feedback (negative feedback) involving the hypothalamus, pituitary, and testes. The hormones involved in controlling the sperm formation process are:
Testosterone: It is secreted by cells located in the testicle called Leydig or interstitial cells. Among many other functions in the body, testosterone is responsible for activating genes that promote the differentiation of spermatogonia.
FSH (follicle-stimulating hormone): It is secreted by the pituitary and acts on the testicle. Specifically, it exerts its function on testicular cells known as Sertoli or nurse cells, responsible for nourishing sperm and promoting their development and maturation.
LH (luteinizing hormone): it is also secreted by the pituitary. Its main function is to activate the release of testosterone by the Leydig cells.
Inhibin: it is released by Sertoli cells. It exerts its function on the pituitary gland, inhibiting the release of FSH and, therefore, stopping spermatogenesis.
4. Questions From Users
4.1. How Long Does It Take For Sperm To Ejaculate Once They Have Been Produced?
Spermatogenesis is the process of formation of male sex cells, from the most immature, the spermatogonia, to the most mature, the sperm. All this complicated process takes place inside the seminiferous tubules in the testicle and lasts between 64 and 72 days.
Once the sperm have been produced, they leave the testicle to go to the epididymis, where they will acquire the necessary mobility in a process that lasts about 10 days. Here they will be stored until the moment of ejaculation, in which they will be transported through the vas deferens, to mix with the seminal fluid that comes from the secretory glands, forming semen, to finally be expelled through the urethra.
4.2. Is Sperm Production Daily?
Yes, sperm are continuously formed in the seminiferous tubules.
4.3. How Many Sperm Does Each Spermatogonia Form?
Each type A spermatogonia can give rise to:
Type A spermatogonia, which will continue to replicate.
Type B spermatogonia, which will be from which a primary spermatocyte will be formed, will continue its development until it is sperm.
Therefore, from a type, A spermatogonia, infinite spermatozoa can be formed.
In contrast, of each type B, only four sperm will form at the end of the spermatogenesis process.
4.4. How Many Sperm Are Generated From One Primary Sperm Cell?
From a primary spermatocyte, four sperm are obtained.
4.5. How Many Sperm Result From A Secondary Sperm?
From each secondary spermatocyte, two sperm are formed.
5. Recommended Reading
As we have seen, spermatogenesis is strongly regulated by a hormonal cascade. If you want to know more about the role of these hormones in male fertility, we recommend that you read the following article: What male hormones are involved in reproductive function?
On the other hand, if you want to know the stages that the sperm has to go through before reaching the egg, you will find more information here: Path of the sperm to the egg.
Gametogenesis (Spermatogenesis And Oogenesis)
gametogenesis The process of formation of the male and female gamete, that is the cell with a haploid chromosomal set which joining a couple ( gamia ) in the act of fertilization gives rise to a new individual.
The two gametes can be the same ( isogametes ), as in many unicellular organisms, or different ( isogametes ), as in most organisms. In higher animals the female gamete or macrogamete is the egg, the male gamete or microgamete is the sperm or spermatozoon.
In plants, the most differentiated gametes, that is oospheres and sperms, have a different appearance in the various systematic groups and are produced in single or multicellular systems called gametangium. There are different types: iso-, micro-, macrogametangi, spermatangi, oangi.
It is said gametangiogamia is the fusion of two gametangia, with subsequent conjugation of various cores and the consequent formation of zygotes or more of a polizigote; it is observed, for example, in the Mucoraceae.
Spermatogenesis:
Spermatogenesis takes place in the testes, it begins at puberty
lasts until the end of life.
At the start of each spermatogenesis, Spermatogonia A activate into Spermatogonia B.
B (2n) spermatogonia divide by mitosis to give diploid cells = Spermatocytes I (2n)
Spermatocytes I (2n) start the first phase of meiosis (reduction phase) to give haploid cells = Spermatocytes II (n).
Spermatocyte II (n) completes the second phase of meiosis (equational phase) to give haploid cells = Spermatids.
Haploid spermatids have a rounded shape while the shape of the spermatozoa is elongated, for this, the spermatids will undergo a morphological transformation, this process is called SPERMIOGENESIS.
Oogenesis takes place in the female gonads = Ovaries, in mammals the female has 2 ovaries.
Oogenesis:
Oogenesis begins very early in a woman’s fetal life, it is a limited phenomenon that begins in the fetal stage and ends at a specific period = menopause.
During this period, it goes through two major phases, phase I and phase II, these two phases are separated by puberty.
1. Phase I Of Oogenesis: it lasts from fetal life to puberty: during this phase, the oogonia multiply (about 7 million) then their number is reduced (degeneration) (about 400,000), these oogonia begin the first phase of meiosis (reduction phase) but they remain blocked in Prophase I in the form of Oocyte I blocked in Prophase I, in this form they are surrounded by a layer of flattened follicular cells to form follicles = primordial follicles. At this stage, meiosis as well as the development of follicles remain blocked until puberty.
2. Phase II Of Ovogenesis: It begins at puberty and ends at menopause, during this phase and under the action of the hormones FSH (follicle-stimulating hormone) and LH (Lutenil Hormone), the primordial follicles begin their development at the rate of one follicle/cycle, it is the follicular cycle.
The primordial follicle develops into a larger follicle = Primary follicle (I ary ),
The Primary follicle develops into a larger follicle = secondary follicle (II area ), it is composed of an oocyte I blocked in Prophase I surrounded by two layers of cubic follicular cells.
The secondary follicle is transformed into a larger follicle = Tertiary follicle (III area ) or cavity, this follicle is characterized by the presence of a cavity (empty) = ANTRUM
The Tertiary follicle develops into a larger follicle = DEGRAAF wall follicle, this follicle is made up of the same constituents as the tertiary follicle but it is larger, this formation marks the end of the development of the follicles (follicular cycle).
At this stage, a hormonal signal is given to the oocyte I blocked in Prophase I to resume its Meiosis, the OVI (2n) ends the first phase of meiosis (reduction phase) and gives two haploid cells; a large cell = Oocyte II (n) and a small cell = Polar Globule GP (n).
Oocyte II (n) begins the second phase of meiosis (equational phase) but it remains blocked in Metaphase II, in this form, the oocyte II blocked in metaphase II is expelled out of the DEGRAAF follicle, it is OVULATION.
After ovulation, OV (II) (n)
After ovulation, the DEGRAAF follicle transforms into a structure called the Yellow Body, this is the start of the luteal cycle, this structure is responsible for the synthesis of a hormone = Progesterone which plays an important role during the first weeks of pregnancy. gestation (pregnancy).
After a few days, there is no fertilization, the yellow body transforms into a structure = Corpus Albicans then it degenerates. This structure marks the end of the luteal cycle and the start of a new follicular cycle.
After a few years, the follicles of the ovary undergo a strong degeneration which results in the complete stop of all the cycles, is Menopause. This process is gradual and lasts several years.
Maturation Of The Oocyte In Amphibians
The Maturation of the oocyte in amphibians lasts about one and a half to two months and is divided into six stages characterized by the following events:
Stage I : The oogonia have ceased all mitotic activity and each of them gives a translucent oocyte a few microns in diameter, in which the first division of meiosis is initiated.
Stage II: the cytoplasm becomes opacified at the same time as the cell diameter increases. This is the sign of the accumulation of the first nutrient reserves which will not cease until the end of growth.
Stage III: The cytoplasm is loaded with pigment granules which, initially, line the entire surface of the oocyte.
Stage IV: The pigment regionalizes in one-half of the oocyte and generates an apparent anisotropy that defines the animal hemisphere. The other non-pigmented half is called the vegetative hemisphere.
Stage V and VI: The oocyte reaches the end of its growth. In stage VI, its diameter is of the order of 1 to 1.4 mm depending on the individual.
At this final stage of its growth, the primary oocyte remains stored in the ovary. It is not fertile. It will take a hormonal stimulus from the pituitary gland to trigger maturation and ovulation. The resulting secondary oocyte will be fertilizable.
The amphibian ovary is organized in the form of a bag, the structure of which is particularly visible in the juvenile state. We distinguish the peripheral cortex which constitutes the wall of the ovary and the central stroma formed of few and spaced cells. Young oocytes lodge in the ovarian cortex. The ovary is connected to the dorsal mesentery by the ovarian pedicle.
At this final stage of its growth, the primary oocyte remains stored in the ovary. It is not fertile. It will take a hormonal stimulus from the pituitary gland to trigger maturation and ovulation. The resulting secondary oocyte will be fertilizable.
The amphibian ovary is organized in the form of a bag, the structure of which is particularly visible in the juvenile state. We distinguish the peripheral cortex which constitutes the wall of the ovary and the central stroma formed of few and spaced cells. Young oocytes lodge in the ovarian cortex. The ovary is connected to the dorsal mesentery by the ovarian pedicle.
The growth of the ovary naturally follows the growth of the oocytes, and an adult female can carry up to 1,500 to 2,000 oocytes. The volume of the ovaries in the general cavity is then considerable.
The nucleus of the oocyte or germinal vesicle is found eccentric in the animal hemisphere. In stage VI, it can reach 250-300 mm in diameter.
The structure of the amphibian oocyte envelopes is relatively simple and recognizable on histology. Next to the plasma membrane is the vitelline membrane secreted by follicular cells organized into a single layer. Two epithelial layers surround the follicular cells. These are the richly vascularized thèques in direct continuity with the ovarian epithelium.
The whole of the oocyte with its envelopes forms a follicle, the distal region of which constitutes the site of ovulation.
Difference Between Meiosis And Gametogenesis
Main difference – Meiosi vs gametogenesis
Meiosis is a type of cell division that occurs during sexual reproduction for sex cell formation. During meiosis, the chromosome number is reduced by half to maintain the chromosome number in the zygote. Male and female chromosomes segregate and then divide into the next generation. There are two main phases of meiosis, namely meiosis I and meiosis II.
Like mitosis, meiosis also consists of the steps known as prophase, metaphase, anaphase, and telophase. At the end of the meiotic cell division, four daughter cells are formed with a haploid number of chromosomes. Gametogenesis is the process that forms gametes for sexual reproduction.
Meiosis is necessary for gametogenesis. The key difference between meiosis and gametogenesis is, meiosis is a cell division process while gametogenesis is a process of gamete formation.
What Are The Similarities Between Meiosis And Gametogenesis?
Both meiosis and gametogenesis result in haploid cells.
Both processes occur during sexual reproduction.
In both processes, the initial cell is diploid, and the resulting cell is haploid.
What Is The Difference Between Meiosis And Gametogenesis?
Meiosis: Meiosis is a type of cell division that results in four haploid cells from a diploid parent cell.
Gametogenesis: Gametogenesis is the process of gamete formation.
Summary – Meios Vs Gametogenesis
Meiosis is a type of cell division that occurs during sex cell formation. Meiosis produces haploid cells from diploid cells. The process of gamete formation is called gametogenesis. Gametogenesis involves spermatogenesis and oogenesis and results in the formation of haploid (n) sperm and eggs. Meiosis is necessary for gametogenesis. This is the difference between meiosis and gametogenesis.
