Spermatogenesis Flashcards
STAGES OF SPERMATOGENESIS:
- SPERMATOCYTOGENESIS
- SPERMATIDOGENESIS
- SPERMIOGENESIS
consists of a series of mitotic division of spermatogonia ending in production of primary spermatocytes
spermatogcytogenesis
The creation of spermatids from a
primary spermatocytes and eventually secondary spermatocytes after they undergo a series of meiosis
SPERMATIDOGENESIS
It is the differentiation or metamorphosis
stage of spermatids into mature
spermatozoa.
SPERMIOGENESIS
During SPERMIOGENESIS phase, the round spermatids undergo dramatic changes which includes?
formation of acrosomes, condensation and elongation of the nucleus, development of the flagellum or tail and the loss of redundant substances of the cytoplasm and its organelles
SPERMATOGENIC CELLS STAGES:
- SPERMATOGONIUM
- PRIMARY SPERMATOCYTES
- SECONDARY SPERMATOCYTES
- SPERMATIDS
- SPERMATOZOA
The primordial male germ cells that are the precursors of spermatozoa multiply by mitosis to become spermatocytes throughout adult life
SPERMATOGONIUM
The primordial male germ cells that are the precursors of spermatozoa multiply by mitosis to become?
Primary spermatocytes
are what arise after immature germ cells, spermatogonia, go through mitosis.
Primary spermatocytes
They are diploid cells which means that they have two sets of
chromosomes.
Primary spermatocytes
are haploid cells, Smaller than primary spermatocytes, and show coarse chromatin granules and abundant rough endoplasmic reticulum cisternae.
Secondary spermatocytes
Secondary spermatocytes rapidly undergo the
second?
meiotic division.
Is the haploid male sex cell formed after the completion of meiotic divisions, they give rise to the mature spermatozoa after undergoing differentiation
SPERMATIDS
the mature male sex cell capable of fertilizing the ovum characterized by having a compact head a long flagella for swimming
SPERMATOZOA
Becomes replacement cells that provides continuous
production of sperm cells
Spermatogonium
THE SEMINIFEROUS TUBULES located within the?
testis
it is the site the spermatozoa production
SEMINIFEROUS TUBULES
The seminiferous tubules are lined by?
Sertoli and spermatogenic cells arranged in layers
The seminiferous tubules are surrounded by a?
basement membrane consisting of an outer thin parietal epithelium overlying peritubular myoid cells, collagen, and an inner layer of extracellular matrix.
Includes the spermatogonia, primary and secondary spermatocytes, spermatids and spermatozoa.
GERM CELLS or SPERMATOGENIC CELLS
are larger and less numerous that nourishes the developing spermatozoa.
It produces both androgen binding protein and inhibin.
SERTOLI (NURSE) CELLS
are found in the parenchyma of the testes between the seminiferous tubules.
LEYDIG (INTERSTITIAL) CELLS
stimulates Leydig cells to produce testosterone and small quantities of other androgens
Luteinizing hormone
This space contains small blood vessels and interstitial cells or Leydig cells.
interstitial spaces
composed of extracellular matrix that serves to separate them from the interstitial compartment, provides structural integrity to the tubules, and regulates the function of cells in contact with it.
BASAL LAMINA
resides between the basement membrane and junctional complexes. It contains diploid spermatogonia that rest upon the basement membrane.
basal compartment
is the region from the junctional complexes to lumen of the seminiferous tubules. This compartment contains the spermatocytes, spermatids and the fully differentiated mature spermatozoa which migrated from the basal compartment.
adluminal compartment
THE BLOOD-TESTIS BARRIER Also called?
Sertoli Cell barrier
is a structural and physiologic barrier created by inter-Sertoli-cell tight junctions. It is one of the tightest blood-tissue barrier in the mammalian body. It divides the seminiferous tubules into the basal compartment and the adluminal compartment
blood-testis barrier
The primary function of the blood-testis barrier is to?
create a protected environment in adluminal compartment for the development of sperm.
• It acts as physical barrier between the blood vessels and the seminiferous tubules to isolate the cellular events of spermatogenesis and provide an ideal environment during the process
• It separates the developing sperm from the immune system so the immune system does not attack and destroy the sperms because they are genetically different from the male
THE BLOOD-TESTIS BARRIER
• Maintain the environment necessary for development and maturation of the spermatogenic cells segrete substances initiating meiosis
• Secrete supporting testicular fluid
• Secrete androgen-binding protein (ABP), which concentrates testosterone in close proximity to the developing gametes
• Testosterone is needed in very high quantities for maintenance of the reproductive tract, and ABP allows a much higher level of fertility
• Secrete hormones affecting pituitary gland control of spermatogenesis, particularly the polypeptide hormone, Inhibin Phagocy to senesidual cytoplasm left over from spermiogenesis
• Secretion of anti-Milerian hormone causes deterioration of the Müllerian duct
• Protect spermatids from the immune system of the male, via the blood-testis barrier
• Contribute to the spermatogonial stem cell niche
SERTOLI OR NURSE CELLS
SPERMIOGENESIS also called?
SPERMATELEOSIS
• The final stage of spermatogenesis where the spermatids undergoes morphologic changes or differentiation into the streamline spermatozoa adapted for fertilization
• Occurs while the spermatids are embedded in small hollows in the free luminal surface of the Sertoli Cells in the seminiferous tubules within the testis
Spermiogenesis
STAGES OF SPERMIOGENESIS
- Golgi phase
- Cap phase
- Acrosomal phase
- Maturation phase
- This is the phase where spermatids begin to develop polarity
- Midpiece forms
- Mitochondria gathers towards the midpiece
- Distal Centriole begins to form an Axoneme
- DNA undergoes packaging and becomes tightly condensed
GOLGI PHASE
attached to the Sertoli Cell
ANTERIOR POLE
points towards the lumen
POSTERIOR POLE
creates enzymes that will become the acrosome at the anterior pole
Golgi apparatus
- The Golgi apparatus surrounds the condensed nucleus, becoming the acrosomal cap
- The distal centriole forms the axoneme and continue to project away from the nucleus towards the lumen of the seminiferous tubule forming the flagallum
CAP PHASE
The Golgi apparatus surrounds the condensed nucleus, becoming the?
acrosomal cap
forms the axoneme and continue to project away from the nucleus towards the lumen of the seminiferous tubule forming the flagallum
distal centriole
- The nucleus begins to elongate
- The acrosome eventually covers the majority of the anterior nucleus
- The Manchette forms in the region of the caudal half of the nucleus and extends down toward the developing flagellum The neck and the annulus are formed
- The plasma membrane completely surrounds the developing spermatid
ACROSOMAL PHASE
- Mitochondria form a spiral assembly around the flagellum that defines the Middle Piece
- The Postnuclear Cap is formed from the manchette microtubules
- The annulus forms the juncture between the middle piece and principal piece
- The excess cytoplasm is released as residual bodies and will be phagocytosed by the Sertoli Cells
MATURATION PHASE
form a spiral assembly around the flagellum that defines the Middle Piece
Mitochondria
is formed from the manchette microtubules
Postnuclear Cap
forms the juncture between the middle piece and principal piece
annulus
• The process by which fully differentiated spermatozoa are released from the supporting somatic Sertoli cells into the lumen of the seminiferous tubules.
• It is the critical determinant of the number of sperm entering the epididymis and thus the sperm content of the ejaculate
• The resulting spermatozoa are now. mature but lack motility, rendering them
sterile
SPERMIATION
SPERMIATION is the process by which fully differentiated spermatozoa are released from the supporting somatic Sertoli cells into the?
lumen of the seminiferous tubules
Factors Affecting The Rate And Quality Of Spermatogeneis:
• Hormones
• Temperature
• Dietary Deficiencies
• Radiation
• Infectious Diseases
• Exposure to certain metals and drugs
What are the characteristics of normal sperm?
- Oval-shaped head
- Intact midpiece
- Uncoiled single tail
- Able to swim well and in a straight line
- Contains healthy genetic information with the correct number of chromosomes
Disorders of Spermatogenesis:
• OLIGOZOOSPERMIA
• ASTHENOZOOSPERMIA
• TERATOZOOSPERMIA
• OAT SYNDROME
• AZOOSPERMIA
Reduced sperm count
OLIGOZOOSPERMIA
sperm motility
ASTHENOZOOSPERMIA
Reduced percentage of sperms with normal morphology
TERATOZOOSPERMIA
• Oligoasthenoteratozoospermia
• combination of the first three conditions
• A Common finding in sperm analysis
OAT SYNDROME
The most severe clinical phenotype where no sperm is found in the ejaculate
AZOOSPERMIA
refers to when the sperm has a GIANT HEAD. These types of sperm often carry extra chromosomes and have problems fertilizing the ovum.
Macrocephaly
Macrocephalic sperm may be caused by?
homozygous mutation of the aurora kinase C gene. This means that because this kind of sperm abnormality may be genetic, fathers may be able to pass the condition on to their sons.
is when the sperm’s head is smaller than normal
Microcephaly
Microcephaly is when the sperm’s head is smaller than normal, also known as
SMALL-HEAD SPERM
Small-head sperm may have?
defective acrosome (a pocket of enzymes in the sperm head used to enter the egg) or reduced genetic material.
a variation of the small-head sperm, is when the head appears as a pin with minimal to no paternal DNA content.
Pinhead sperm
The presence of pinhead sperm may point to a
diabetic condition
are sperm with “cigar-shaped” heads that may indicate the presence of varicocele in the male or constant exposure of the scrotum to high temperature locations such as daily hot Sauna.
Tapered head sperm
These tapered head sperm often contain?
abnormal chromatin or packaging of the paternal DNA genetic material
Abnormal number of sperm chromosomes called?
aneuploidy
Abnormal number of sperm chromosomes called aneuploidy has been shown in?
tapered head sperm
An extreme variation of the tapered head sperm is the “ ? “ with pathologies seemingly different from the tapered head sperm.
thin narrow head sperm
Thin head sperm are?
seldom identified and they may be due to broken DNA, varicocele or disrupted head formation.
is an abnormal sperm morphology that indicates either there is an absence of the acrosome or the sperm is missing inner parts of its head responsible for “activating” or turning on the egg and starting the fertilization process.
Globozoospermia, or round headed sperm condition
is an abnormal sperm morphology that indicates either there is an absence of the acrosome or the sperm is missing inner parts of its head responsible for “activating” or turning on the egg and starting the fertilization process.
Globozoospermia, or round headed sperm condition
when the sperm prematurely starts to break down its nucleus and the unraveling DNA material fills the entire sperm head.
Decondensing head sperm seen
HEADLESS SPERM have no head at all and are called? They do not have genetic material or chromosomes. This type of sperm may look like a pinhead sperm but upon close examination, one can see that there is no tiny sperm head giving the sperm the appearance of a loose piece of string.
acephalic sperm or
DECAPITATED SPERM SYNDROME
TAIL-LESS SPERM are called ? and these sperm are often seen during necrosis, the death of most or all of the cells in an organ.
acaudate sperm
have two or more large vacuoles (cyst-like bubbles) or multiple small vacuoles in the sperm head. Some studies show this type of sperm has low fertilization potential, other studies have shown no effect. Studies are still in progress.
Nuclear vacuoles sperm
can have multiple heads or tails.
Multiple parts sperm
When the sperm has two heads, it is called a?
DUPLICATE SPERM
a condition linked to exposure to toxic chemicals, heavy metals like cesium, smoke or high prolactin hormone in the male.
DUPLICATE SPERM
may be related to defective mitochondria, the energy-making parts of the sperm cell. It may also be a sign that the centrioles, the guidance system for moving chromosomes stored at the sperm neck, may be missing or broken.
Large swollen midpiece or sperm neck
have been exposed to either incorrect seminal fluid conditions or the presence of bacteria. These sperm cannot swim, as their tails are damaged. Heavy smoking has been linked to the presence of coiled-tail sperm.
Coiled-tail sperm
Sperm cells with short tails often have low or no motility and are called?
STUMP TAIL or Dysplasia of Fibrous Sheath (DFS) sperm.
What are sperm cells with short tails called, and what issue do they often face?
Sperm cells with short tails are called stump tail sperm or Dysplasia of Fibrous Sheath sperm. They often have low or no movement.
When does the defect in sperm tail development typically occur?
The defect in sperm tail development typically occurs during the late stages of sperm formation in the testis.
What additional health issue might patients with Dysplasia of Fibrous Sheath experience?
Patients with Dysplasia of Fibrous Sheath might also experience chronic respiratory problems due to a condition associated with immotile cilia syndrome.
How is Dysplasia of Fibrous Sheath inherited?
Dysplasia of Fibrous Sheath is inherited in an autosomal recessive manner, meaning both parents must carry the gene for the condition to affect the child.
What specific protein is associated with the genetic defect in Dysplasia of Fibrous Sheath?
The specific protein associated with the genetic defect in Dysplasia of Fibrous Sheath is the sperm neck centrin 1 protein.
What reproductive issues are linked to Dysplasia of Fibrous Sheath, including problems in seminal fluid?
Dysplasia of Fibrous Sheath is linked to a higher percentage of sperm having abnormal chromosomes and may also be associated with incorrect conditions in the seminal fluid.
What is spermatogenesis and what does it produce?
Spermatogenesis is a type of gametogenesis that results in the production of male gametes, known as spermatozoa. These spermatozoa are capable of fertilizing the female gamete, which is the ovum.
Where does spermatogenesis take place?
Spermatogenesis occurs in the seminiferous tubules of the testis.
What structures are found in the head of a mammalian sperm cell?
The head of a mammalian sperm cell has the nucleus and acrosome. It also contains some cytoskeletal components and a small amount of cytoplasm.
What is the shape of the head of a mammalian sperm cell, and how are the nucleus and acrosome arranged?
The head of a mammalian sperm cell is spatulate. The nucleus and acrosome are flattened along the length of the sperm cell and are symmetrical.
What are the main components of the sperm plasma membrane?
The sperm plasma membrane is composed of a complex mixture of lipids, including phospholipids, glycolipids, and sterols.
What is one of the primary functions of the sperm plasma membrane?
One primary function of the sperm plasma membrane is to protect sperm from extracellular injuries.
How does the sperm plasma membrane contribute to fertilization?
The sperm plasma membrane plays a crucial role during sperm capacitation, sperm-egg interaction, and fertilization.
What role does the sperm plasma membrane play in responding to physiological challenges?
The sperm plasma membrane helps respond to physiological challenges by maintaining sperm integrity and function.
What are nuclear vacuoles in sperm cells, and how do they develop?
Nuclear vacuoles are membrane-bound spaces within the nucleus of sperm cells. They develop due to incomplete chromatin condensation during spermatogenesis.
How common are nuclear vacuoles in sperm cells, and what variation can they have?
Nuclear vacuoles are observed in 90% of structurally and functionally normal sperm cells. They can vary in number, size, and location within the sperm cell.
What does the presence of nuclear vacuoles indicate about sperm cells?
The presence of nuclear vacuoles generally indicates that the sperm cells are structurally and functionally normal, despite the variation in vacuole characteristics.
What does the nucleus of a sperm cell contain?
The nucleus of a sperm cell contains genetic material, specifically DNA.
How much genetic material does the sperm’s nucleus have compared to somatic cells?
The sperm’s nucleus contains half the genetic material of somatic cells.
How many chromosomes are present in the nucleus of a sperm cell?
The nucleus of a sperm cell contains one chromosome.
What are the possible types of sexual chromosomes in the sperm’s nucleus?
The sexual chromosome in the sperm’s nucleus can be either X or Y.
What is the tail of a sperm cell called?
The tail of a sperm cell is called the flagellum.
How is the sperm tail structured?
The sperm tail is divided into four parts: the connecting piece (or neck), the mid-piece, the principal piece, and the end piece.
How many proteins are involved in the structure of the sperm tail?
The sperm tail involves more than 1000 proteins in its structure.
What is the function of the proteins in the sperm tail?
The proteins in the sperm tail help in its complex structure and function, aiding in the movement of the sperm.
What is the role of the proximal centriole in sperm development?
The proximal centriole is involved in the first division of the zygote after fertilization.
What is the function of the distal centriole in a sperm cell?
The distal centriole helps form the axial filament of the sperm, which is important for tail movement.
Where is the proximal centriole located in the sperm cell?
The proximal centriole is located towards the nucleus in the neck of the sperm cell.
What does the distal centriole give rise to in the sperm cell?
The distal centriole gives rise to the axial filament of the sperm.
What is the structure of the midpiece of a sperm cell?
The midpiece of a sperm cell is a long cylinder about the same length as the head. It consists of an axoneme, which is a bundle of microtubules surrounded by nine dense outer microtubules.
What is the role of the helical sheath in the sperm midpiece?
The helical sheath surrounding the midpiece is made of tightly packed, elongated mitochondria. This sheath provides the energy needed for tail movement.
Where are mitochondria located in a sperm cell, and what is their function?
Mitochondria are located within the midpiece of the sperm cell. They produce energy needed for the sperm’s movement.
How do the mitochondria in sperm cells compare to those in other cells?
The mitochondria in sperm cells are similar in structure and function to mitochondria in other cells.
What happens to the mitochondria in mammalian sperm after fertilization?
In mammalian sperm, the mitochondria are usually destroyed by the egg cell after fertilization.
What is the axoneme in the context of sperm cell structure?
The axoneme, also known as an axial filament, is the microtubule-based structure that forms the core of the sperm cell’s flagellum.
Where does the axoneme extend within the sperm cell?
The axoneme extends from the connecting piece along the full length of the sperm cell’s flagellum.
What is the main function of the axoneme in sperm cells?
The main function of the axoneme is to generate the propulsive force that allows the sperm cell to move.
What is the annulus, and where is it located in the sperm tail?
The annulus is a higher order septin cytoskeletal structure located between the midpiece and principal piece regions of the sperm tail.
What is the function of the annulus in the sperm tail?
The annulus is believed to create a diffusion barrier between the midpiece and principal piece membrane domains of the sperm tail.
What is the principal piece of the sperm tail, and what is it made of?
The principal piece is the longest part of the sperm tail. It is made of a central axoneme core surrounded by nine coarse fibers that extend from the middle piece to form the axonemal complex.
How does the principal piece affect sperm movement?
The movement of sperm is closely related to the quality of the beating of the principal piece, which depends on the normal shape and structural integrity of the principal piece.
What structure is formed by the coarse fibers around the central core in the principal piece?
The coarse fibers around the central core in the principal piece form the axonemal complex.
What is the end piece of the sperm tail, and what does it contain?
The end piece of the sperm tail is a short, narrowing segment that contains only the axoneme.
What is the acrosome, and where is it located?
The acrosome is a unique membranous organelle located over the front part of the sperm nucleus.
What is the main function of the acrosome in sperm cells?
The main function of the acrosome is to help the sperm penetrate the egg’s coats by releasing hydrolytic enzymes.
What does the acrosome contain, and what role do these contents play during fertilization?
The acrosome contains hydrolytic enzymes, which are essential for breaking down the egg’s outer layers during fertilization.
How has the acrosome been conserved throughout evolution, and why is this important?
The acrosome has been highly conserved throughout evolution, meaning its structure and function have remained largely unchanged because of its crucial role in fertilization.
