Spermatogenesis Flashcards
What does the term semen refer to?
Spermatozoa and secretions from the accessory glands
What shape are fully formed spermatozoa heads and what do they contain?
Flattened shaped and contain the nucleus
What is the spermatatozoa covered by?
Plasma membrane
What three parts of the tail is the spermatozoa made up of?
middle, principal and end pieces
What is the double walled structure between the anterior portion of the sperm head and the plasma membrane?
Acrosomal cap
Where in the sperm is the DNA contained and in what form?
1N chromosome is in the nucleus in the head of the sperm resulting from meiotic cell division
The socket at the neck of the sperm is called?
implantation socket
What is the central core of the middle piece of the sperm tail called?
Axoneme
What is the axoneme composed of?
9 pairs of microtubules around 2 central filaments (In the middle piece this is also surrounded by 9 outer course fibers)
Describe Spermatogenesis.
Occurs in the Seminiferous tubules and consists of all cellular transformation in developing germ cells.
Describe Spermocytogenesis.
Mitotic divisions involving proliferation and maintenance of the spermatogonia
Meiosis is important for what?
Assuring genetic diversity
Spermiogenesis is what?
transformation of spherical spermatids into differentiated spermatozoa
What part of Spermatogenesis takes place in the Basal Area?
Proliferation
Where does Proliferation occur?
Basement membrane in the Basel Area
What stages are there in Proliferation?
Spermatogonia A1-A4, Spermatogonia I, Spermatogonia B
What stages of Spermatogenisis occur in the adluminal area?
Meiosis and Differentnition
What divisions do the Spermatogonia go through?
Mitotic
What process does the spermatocytes go through?
Meiosis
What set of the spermatocytes divides the meiosis and differetition parts of spermatogenisis
Secondary Spermatocytes
What are the most immature germ cells?
Spermatogonia (2N)
Which spermatocyte has the longest life?
Primary spermocyte
What phases does Speriogenesis consist of?
Golgi Phase, Cap phase, acrosomal phase and maturation phase
What devolps during the Golgi phase?
acrosomic vesicle is fused of many proacrosomic vesicles
What occurs in the cap phase?
Acrosome forms a cap over the anterior part of the nucleous
What happens in the acrosomal phase?
Acrosome spreads across the nucleous
What happens in the Maturation phase?
Mitochondria are arranged in a helical fashion to form middle pieces
Sperimation is what?
Release of the spermatozoa from the Sertoli cell into the ST lumen
Generation
A cohort group of cells that has a similar appearance and function
Referring to the Cycle of SE how many generations does Section I have?
4 generations (A-spermatogonia, 2 1 degree spermatocytes and an immature speratid
What is different about 1-7 cycle sections and 8?
Only section 8 can release spermatozoa
How many days does the SE cycle require for the bull?
13.5 days
How many days does the SE cycle require for the Ram
10.4 days
How many days does the SE cycle require for the Boar?
8.3 Days (shortest)
How many days does the SE cycle require for the stallion?
12.2 days
What is the equations to figure out the time for A-spermatogonia to become mature spermatids?
4.5 cycles X #days/cycle
How many days does it take in each species to go from A-Spermatogonia to mature spermatids?
Bull-61 days
Ram-4.7 days
Boar-39 days
Stallion-55 days
What does the spermatogenic wave refer to?
The distribution of stages along the length of the ST at a given time
T/F
During the spermatogenic wave each stage of the SE changes to a more advanced stage.
True
Where on the tubule does spermiation occur?
It is constantly changing along the tubule
How does Heat stress affect the male reproductive system?
It decreases the rate of spermatogenesis
Which cycle of sperm is first affected by heat stress?
Spermatids-most sensitive
Why are the spermatids considered the most sensitive?
They are undergoing morphological changes
Why is the Secondary spermatocyte the second to fail to heat stroke?
It is undergoing Meiosis
What is the third sperm type to be affected by heat stress?
Primary spermatocyte
Why does it take so long for heat stress issues to appear in the animal?
Because it must pass through (at least) the epididymis
What does BTB stand for?
Blood Testis Barrier
What is BTB made up of?
Partial barrier of myoid cells
What divides the ST into 2 compartments?
Sertoli-Sertoli junctions
What does the basal compartment contain?
Spermatogonia and immature spermatocytes
What does the adluminal compartment contain?
More advanced spermatocytes and spermatids
Fully formed spermatozoa tails contain what?
The tail contains the apparatus for motility
What does the acrosome cap contain?
Acrosin, Hyaluronidase and other enzymes for fertilization
What is another name for the sperm neck?
Capitulum
Describe the Basal plate.
Continues with the 9 outer course fibers that project throughout the tail.
What gives rise to the spermatids?
Primary and secondary spermatocytes
Which germ cell has the longest life span?
Primary spermatocyte
Which germ cell has the shortest life span?
Secondary spermatocyte
What is the cytoplasmic droplet composed of?
Residual cytoplasm
What are the 3 types of spermatogonia?
A spermatogonia
I spermatogonia
B spermatogonia
What do the A spermatogonia undergo and they progress from what stages?
Mitotic divisions and progress from A1 to A4
Describe the purpose of the Stem cells.
A pool of stem cells is always maintained and divide mitotically to always have a source of A spermatogonia
What is the last mitotic division?
When B spermatogonia form 1o spermatocytes
What compartment do all mitotic divisions occur?
Basal
