Podcast
Questions and Answers
During spermatogenesis, cellular bridges facilitate the asynchronous development of cells.
During spermatogenesis, cellular bridges facilitate the asynchronous development of cells.
False (B)
Genetic diversity is a primary goal of spermatogenesis.
Genetic diversity is a primary goal of spermatogenesis.
True (A)
Oestradiol directly stimulates FSH release from the AP.
Oestradiol directly stimulates FSH release from the AP.
False (B)
High concentrations of testosterone in systemic blood promote normal testis function.
High concentrations of testosterone in systemic blood promote normal testis function.
Spermatogonia undergo meiosis to form spermatids.
Spermatogonia undergo meiosis to form spermatids.
In the stallion, spermatogenesis takes approximately 65 days plus an additional 20 days for epididymal transit.
In the stallion, spermatogenesis takes approximately 65 days plus an additional 20 days for epididymal transit.
Spermatogenesis is solely regulated by the presence of FSH and LH from the anterior pituitary.
Spermatogenesis is solely regulated by the presence of FSH and LH from the anterior pituitary.
The blood-testis barrier isolates spermatozoa from the systemic immune system to prevent autoimmune reactions.
The blood-testis barrier isolates spermatozoa from the systemic immune system to prevent autoimmune reactions.
The Golgi phase in spermiogenesis involves the breakdown of the acrosome.
The Golgi phase in spermiogenesis involves the breakdown of the acrosome.
During spermatogenesis, Type B spermatogonia always revert back to Type A spermatogonia to maintain stem-cell numbers.
During spermatogenesis, Type B spermatogonia always revert back to Type A spermatogonia to maintain stem-cell numbers.
Spermiation refers to the final maturation processes spermatozoa undergo in the epididymis.
Spermiation refers to the final maturation processes spermatozoa undergo in the epididymis.
Spermatids undergo meiosis II to become spermatozoa.
Spermatids undergo meiosis II to become spermatozoa.
Spermatogenesis only occurs efficiently when the 'plant' is kept cold.
Spermatogenesis only occurs efficiently when the 'plant' is kept cold.
High sperm concentration in systemic blood, as opposed to within the seminiferous tubules, is advantageous for normal testis function.
High sperm concentration in systemic blood, as opposed to within the seminiferous tubules, is advantageous for normal testis function.
The 'Cauda' of the epididymis stores fertile, immotile sperm.
The 'Cauda' of the epididymis stores fertile, immotile sperm.
The process from spermatogonia to spermatozoa is called 'spermiation'.
The process from spermatogonia to spermatozoa is called 'spermiation'.
A 4-year cycle must occur for the stages of the seminiferous epithelium cycle to complete.
A 4-year cycle must occur for the stages of the seminiferous epithelium cycle to complete.
During spermatogenesis, a diploid spermatogonium will eventually produce two spermatids after undergoing meiosis I and meiosis II.
During spermatogenesis, a diploid spermatogonium will eventually produce two spermatids after undergoing meiosis I and meiosis II.
Pulsatile secretion of GnRH from the tonic center reduces the functionality of the Leydig cells.
Pulsatile secretion of GnRH from the tonic center reduces the functionality of the Leydig cells.
The location of the tight junctions creates a basal and adluminal compartment, but these are functionally identical.
The location of the tight junctions creates a basal and adluminal compartment, but these are functionally identical.
The main goal of spermatogenesis is to introduce genetic uniformity in gametes.
The main goal of spermatogenesis is to introduce genetic uniformity in gametes.
In spermatogenesis, some advanced spermatogonia types revert back to Type A to maintain stem-cell numbers.
In spermatogenesis, some advanced spermatogonia types revert back to Type A to maintain stem-cell numbers.
Spermatocytogenesis involves a maturation step of the spermatids.
Spermatocytogenesis involves a maturation step of the spermatids.
Spermatogenesis only occurs within the seminiferous tubule independent of the Sertoli cells.
Spermatogenesis only occurs within the seminiferous tubule independent of the Sertoli cells.
Spermatozoa does not require transtport through the epididymis to acquire fertilising capcity.
Spermatozoa does not require transtport through the epididymis to acquire fertilising capcity.
In the Maturation Phase of differientiation, the Spertmatid nucleus is capped by a newly formed acrosome.
In the Maturation Phase of differientiation, the Spertmatid nucleus is capped by a newly formed acrosome.
Spermatids are considered diploid cells following the second meiotic devision?
Spermatids are considered diploid cells following the second meiotic devision?
The final maturation process for sperm occurs once they reach the female reproductive tract?
The final maturation process for sperm occurs once they reach the female reproductive tract?
Testicular transport to acquire fertilizing capcity can be used in ICSI programs?
Testicular transport to acquire fertilizing capcity can be used in ICSI programs?
In the epididymis, spermatozoa are transcriptionally and translationally active, synthesizing new proteins for maturation?
In the epididymis, spermatozoa are transcriptionally and translationally active, synthesizing new proteins for maturation?
Because spermatogonia are stem cells, they cannot be induced to undergo apoptosis if damaged?
Because spermatogonia are stem cells, they cannot be induced to undergo apoptosis if damaged?
Given the fixed timing of spermatogenesis stages, the germinal epithelium sections contain a variable number of stages?
Given the fixed timing of spermatogenesis stages, the germinal epithelium sections contain a variable number of stages?
The testis must be kept hypoxic at all times for proper germ cell development?
The testis must be kept hypoxic at all times for proper germ cell development?
The Sertoli cells provide a microenvironment that promotes synchronous rather than asynchronous development.
The Sertoli cells provide a microenvironment that promotes synchronous rather than asynchronous development.
Once spermatazoa enters the epididymis, fertility is not dependent on exposure to final seminalplasma.
Once spermatazoa enters the epididymis, fertility is not dependent on exposure to final seminalplasma.
Spermtogenesis is only formation of spermatazoa from stems cells.
Spermtogenesis is only formation of spermatazoa from stems cells.
The corpus of the sperm is motile, more expression and acquire great potential for fertility
The corpus of the sperm is motile, more expression and acquire great potential for fertility
Phase 3 requires no further cell devisions but spermiigenesis also needs the golgi phase, cap phase, acorsomal phase and maturation phase.
Phase 3 requires no further cell devisions but spermiigenesis also needs the golgi phase, cap phase, acorsomal phase and maturation phase.
The cauda and tail of the sperm are not motile or ready for fertilisation.
The cauda and tail of the sperm are not motile or ready for fertilisation.
The epididymis supports the function and fertility for seminal plasma.
The epididymis supports the function and fertility for seminal plasma.
Spermatogenesis involves cytoplasmic division without differentiation.
Spermatogenesis involves cytoplasmic division without differentiation.
The primary goal of spermatogenesis is to ensure genetic uniformity in sperm cells.
The primary goal of spermatogenesis is to ensure genetic uniformity in sperm cells.
Air conditioning is not a critical factor for maintaining optimal sperm production in the testes.
Air conditioning is not a critical factor for maintaining optimal sperm production in the testes.
During spermatogenesis, cells develop independently without any intercellular connections.
During spermatogenesis, cells develop independently without any intercellular connections.
Spermatogonia transition directly into spermatids without undergoing meiosis.
Spermatogonia transition directly into spermatids without undergoing meiosis.
The systemic blood contains high concentrations of testosterone to support spermatogenesis.
The systemic blood contains high concentrations of testosterone to support spermatogenesis.
Leydig cells secrete GnRH, which directly stimulates spermatogenesis in the seminiferous tubules.
Leydig cells secrete GnRH, which directly stimulates spermatogenesis in the seminiferous tubules.
Oestradiol, produced by Leydig cells, inhibits GnRH release from the hypothalamus, creating a negative feedback loop.
Oestradiol, produced by Leydig cells, inhibits GnRH release from the hypothalamus, creating a negative feedback loop.
Inhibin, secreted by Sertoli cells, enhances FSH release from the anterior pituitary.
Inhibin, secreted by Sertoli cells, enhances FSH release from the anterior pituitary.
The adluminal compartment of the seminiferous tubule contains diploid spermatogonia and primary spermatocytes.
The adluminal compartment of the seminiferous tubule contains diploid spermatogonia and primary spermatocytes.
Spermatocytogenesis only consists of meiotic events.
Spermatocytogenesis only consists of meiotic events.
Type A spermatogonia are terminally differentiated and cannot revert to stem cells.
Type A spermatogonia are terminally differentiated and cannot revert to stem cells.
Genetic variation is not guaranteed during meiosis in primary spermatocytes.
Genetic variation is not guaranteed during meiosis in primary spermatocytes.
The duration of spermatogenesis is consistent across different mammalian species.
The duration of spermatogenesis is consistent across different mammalian species.
Spermiation is the process where spermatids differentiate into spermatozoa.
Spermiation is the process where spermatids differentiate into spermatozoa.
Testicular spermatozoa are mature and fully capable of fertilization upon release from the seminiferous tubules.
Testicular spermatozoa are mature and fully capable of fertilization upon release from the seminiferous tubules.
Spermatozoa store in the caput section of the epididymis have acquired the potential for fertilization.
Spermatozoa store in the caput section of the epididymis have acquired the potential for fertilization.
Sperm are transcriptionally and translationally active at all stages of development.
Sperm are transcriptionally and translationally active at all stages of development.
In a semen evaluation, a lower percentage of normal sperm automatically implies lower fertility.
In a semen evaluation, a lower percentage of normal sperm automatically implies lower fertility.
A vital stain is unable to detect whether the sperm membrane has been compromised.
A vital stain is unable to detect whether the sperm membrane has been compromised.
The main purpose of Diff Quick staining is to assess the sperm's viability.
The main purpose of Diff Quick staining is to assess the sperm's viability.
Glutaraldehyde/formalin requires a counter stain for assessment.
Glutaraldehyde/formalin requires a counter stain for assessment.
Compensable sperm abnormalities will inhibit normal sperm from fertilizing an egg.
Compensable sperm abnormalities will inhibit normal sperm from fertilizing an egg.
A cycle, in the context of spermatogenesis, refers to a specific cellular association in the seminiferous epithelium.
A cycle, in the context of spermatogenesis, refers to a specific cellular association in the seminiferous epithelium.
Maturation of sertoli cells into spermatozoa is known as Spermiogenesis.
Maturation of sertoli cells into spermatozoa is known as Spermiogenesis.
Flashcards
Spermatogenesis
Spermatogenesis
The process of sperm production, starting from spermatogonia and developing into spermatozoa.
Meiosis
Meiosis
Cell division that results in four daughter cells each with half the number of chromosomes of the parent cell, as in the production of gametes.
Spermatogenesis Goals
Spermatogenesis Goals
The continuous supply of male gametes, ensuring genetic diversity and reproductive efficiency.
Pulsatile GnRH Secretion
Pulsatile GnRH Secretion
Signup and view all the flashcards
Proliferation (Phase 1)
Proliferation (Phase 1)
Signup and view all the flashcards
Meiotic Phase (Phase 2)
Meiotic Phase (Phase 2)
Signup and view all the flashcards
Differentiation (Phase 3)
Differentiation (Phase 3)
Signup and view all the flashcards
Spermiogenesis
Spermiogenesis
Signup and view all the flashcards
Spermiation
Spermiation
Signup and view all the flashcards
Epididymal Maturation
Epididymal Maturation
Signup and view all the flashcards
Caput (Epididymal Head)
Caput (Epididymal Head)
Signup and view all the flashcards
Corpus (Epididymal Body)
Corpus (Epididymal Body)
Signup and view all the flashcards
Cauda (Epididymal Tail)
Cauda (Epididymal Tail)
Signup and view all the flashcards
Epididymal Events
Epididymal Events
Signup and view all the flashcards
Semen Morphology Assessment
Semen Morphology Assessment
Signup and view all the flashcards
Sperm Abnormality: Primary and Secondary
Sperm Abnormality: Primary and Secondary
Signup and view all the flashcards
Sperm Abnormality: Major and Minor
Sperm Abnormality: Major and Minor
Signup and view all the flashcards
Sperm Abnormality: Compensable and Uncompensable
Sperm Abnormality: Compensable and Uncompensable
Signup and view all the flashcards
Study Notes
- Sperm is seed, and 'Zoa mean little animals
- Learning goals include describing spermatogenesis in detail, testicular anatomy, normal spermatozoan anatomy, and spermiogram assessment
Meiosis
- Meiosis is not a cycle
- Formation of the zygote happens when (c + c = 2c, n + n = 2n)
Sperm Development
- The sperm factory includes high-speed manufacturing, finishing shops, warehousing and shipping, delivery system, and final alterations/packaging
- 1 Trillion sperm are produced per day
- 10,000 spermatozoa are produced per second
- The "plant" must be airconditioned
- High-speed manufacturing occurs in the testis
- <1-25x109 spermatozoa are made per day (35,000-200,000 per second)
- Fluid absorption, membrane changes, and nuclear & flagellar stabilization occur in finishing shops
- 8-25x109 spermatozoa are processed in finishing shops
- Accessory sex glands are part of the finishing shops
- Spermatozoa is Warehouse and Shipped
- Storage is 10-50x109 spermatozoa, enough spermatozoa for 5 to 10 ejaculations
Sperm Production Capacity Varies by Animal Type
- Comparative production in Bull, Boar, Ram, and Stallion is detailed
- Sperm X 10^6 /g testis/day is 16, 27, 25, 20 respectively
- Testis Weight (g) is 350, 360, 275, 200 respectively
- Total sperm produced/day (billion) is 11, 19, 14, 8 respectively
- Duration of spermatogenesis (days) is 61, 34, 49, 57 respectively
Normal Testis Function
- Pulsatile secretion of GnRH occurs in the tonic centre
- High concentrations of Testosterone are in the seminiferous tubule
- Low concentrations of Testosterone are in the systemic blood
- Adequate LH receptors are found in the Leydig cells
Hormones and Testis Function
- The Leydig cells release testosterone (T)
- Testosterone in blood is 500x diluted
- Oestradiol is produced by the Sertoli cells
- Oestradiol is produced in combination with T and DHT feedback
- Inhibin is also produced by the sertoli cells
- Inhibin has a negative feedback mechanism on FSH release from the AP(Anterior Pituitary)
- FSH induces ABP (Androgen Binding Protein)
- FSH is required to convert testosterone to oestradiol
- Sertoli cells support germ cell development, create the blood-testis barrier, and secrete hormones such as inhibin and estradiol
Anatomy
- SEM of Testicular Parenchyma details the anatomy
- Seminiferous tubules = ST
- Connective tissue = CT
- Leydig cells = LC
- Basement membrane = BM
- Germ cells = GC
- Flagella = F
- Blood vessel = BV
- Details of Seminiferous Tubule include:
- Tight cell junction
- Sertoli cell
- Adluminal compartment with double 2n, 2n, n spermatids & spermatazoa
- Putative shape extent of a Sertoli cell
- Basal compartment with diploid spermatogonia
- Schematic Diagram of Seminiferous tubule details:
- Peripheral adluminal compartment
- Deep Adluminal compartment
- Basal compartment
- Interstitial compartment
- Lamina propria is the layer of connective tissue surrounding the seminiferous tubules
Spermatogenesis Phases: an Overview
- Consists of spermatocytogenesis and spermiogenesis
- Spermatocytogenesis is Phase 1 (proliferation) and Phase 2 (meiosis)
- Spermiogenesis is Phase 3 (differentiation)
- Cellular bridges allow cells to develop as cohorts
Spermatogenesis - Goals
- Provides a continual supply of male gametes
- Provides genetic diversity
- Maximizes efficiency through billions of spermatozoa
- Provides an immunologically privileged site for production
Phase 1 - Proliferation
- Generates spermatogonia
- Committed to becoming more advanced cell types, and maintenance of stem-cell numbers
- Spermatogonia are primitive cell types = Stem cells
- There is a progression from Type A1 spermatogonia to A2, A3, A4, Type I, and Type B through mitosis
- Most are committed to becoming spermatocytes, but some revert back to Type A spermatogonia to maintain stem-cell numbers
Phase 2 – Meiotic phase
- Involves primary spermatocytes
- Genetic variation guaranteed
- Meiosis I – DNA replication and crossing over
- Results in secondary spermatocytes
- No two sperm cells are the same
At any cross section, there are different stages of cycle- seminiferous epithelium
- Each Sperm Cycle: Each vertical line represents one cycle of germ cells in the seminiferous tubule
- In Stallions this is 12.2 days, in Bulls it is 14.5, cycles are approximately 4.5
- Total cycle is c.55 days, plus approximately 10 days epididymal transit
Spermatogenesis in Sertoli Cells
- Involves spermatogonia, starts the process of Trudging Relentlessly and Upwards
- Moves towards the spermatic tube lumen, turning into spermatocytes
- Reaches the zenith of the spermatic tubule, and becomes a spermatocyte
- Unfolds to become a spermatid
- Is the process of Golgi, Cap, and Acrosomal phases
- Completes within the Sertoli cell reaching Immature spermatozoa to starts journey
- Begins the journey in the Convoluted tubule to Straight tubule Rete then the testis, tail of the epididymis, and so on
Spermatozoa maturation occurs in Epididymis
- Involves Maturation, Herm flying, attaining motility and packaging DNA
- IncludesSecretions and absorption of fluids
- Depends on HCO3 absorption (Decrease pH), with helps Testosterone
- Maturation within the epididymis; Herm flies via his own assistance. Sperm then joins his mates in the quest, and in the sperm reservoir
- Herm is the sperm, and goes on to meet Olivia, the oocyte, to form a zygote...
Phase 3 - Differentiation
- No further cell divisions occur in spermiogenesis
- Consists of the Golgi, Cap, Acrosomal, and Maturation phases
- Golgi apparatus develops into the acrosome
- Acrosomic vesicle is shown in this image
Spermiation
- The release of the spermatozoa from the Sertoli cells into the seminiferous tubules
- Analogous to Ovulation in the female
- Includes continual release of spermatozoa, and continual and uniform gamete production throughout male reproductive life
Epididymal Maturation
- Testicular spermatozoa are infertile and requires epididymal transport to acquire fertilising capacity
- Can be used in ICSI programs
- Epididymal spermatozoa can be used in Al programs
- Function and fertility is substantially improved when exposed to seminal plasma
- The epididymis is under the control of androgens
- Epididymal fluid is highly complex, with proteins, hormones, and enzymes
- Epididymal Events include: acquisition of fertility and motility,, final maturation and translocation of the proximal droplet, disulphide crosslinking, and being a spermatozoa reservoir
The Epididymis Anatomy
- Caput (Head): Sperm are NOT motile and fertile
- Corpus (Body): Maturation of sperm begins and shows some motility; Sperm begin to acquire 'potential' for fertility
- Cauda (Tail): Sperm is stored. motile sperm are (once removed from epididymal fluid). Sperm have acquired the potential for fertilisation
Sperm Genes and Proteins
- Sperm are transcriptionally & translationally silent: they can't make any new proteins
- DNA is compacted
- Transit time varies from head, to body, to tail and differs per species
- It ranges from ~4 days Camel, to Ram to a little over 12 days
Spermatogenic Terms
- Cycles: Progression through a complete series of cellular associations/stages
- Cycle duration: Time required to complete one cycle
- Stages: Specific cellular association - 8
- Stage duration: Time required for completion of one stage (cell association)
- Spermatocytogenesis: Mitosis events and Spermatogonia
- Spermiogenesis: Maturation of the spermatids into spermatozoa - Spermiation
- Spermatogenesis: Formation of spermatozoa from stems cells
- Daily Sperm Production (DSP)
- Daily Sperm Output (DSO)
- Extragonadal Reserves
- Epididymal Transit Time
Spermatozoa Details
- Spermatozoa classifications include: Individual abnormality description,Primary and secondary (tertiary), Major or minor, and Compensable or non compensable
- It is important to identify sperm defects to understand effects on fertility and what is causing the issues
- Normal forms are 72% and defects are calculated in the image
Classifying Sperm
- There are various classes of spermatozoa and here are some important points
- Morphological assessment is likened to taking a biopsy, with a delay in getting the sample read up to 60 days later Use a stained smear or a sample preserved in formol buffered saline, examined at 1000X under oil. with a minimum of 100 cells
- The specimen sample must have thick and thin areas when stained
- Examination requires at least examining FBS sample under phase contrast
- Divide into normal sperm to categorize the abnormalities -minimum 70% for Tick, 50 to 70 for Pass
- Other cells in the ejaculate can be WBCs, RBCs, Bacteria and some somatic cells
- Staining assists in examining the sperm
- The Commonly used stain helps to look at penetration of sperm membranes but the cell is compromised and the Vital stain has no light interference with contrast
- The Diff quick method Provides contrast, is quick, easy, and allows for easy identification
- Glutaraldehyde/formalin helps to Preserves samples
Sperm Defects
- Primary defects develop during spermatogenesis
- Secondary defects develop during epididymal transport
- Compensable abnormalities can be compensated for by increasing the insemination dose and not inhibit normal sperm but do not have the ability to compensate
- In contrast, Uncompensable abnormalities do not compensate for for by increasing the insemination dose, as they do not inhibit normal sperm
- Sperm require a specific amount of sperm to reach their maximum fertilisation rate
- The threshold for minimum sperm numbers varies from individual to individual
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
