Spermatogenesis Flashcards

1
Q

Know how GnRH, LH, and FSH work together to cause spermatogenesis (including the cell types that secrete the, the cell types that have receptors for them and where feedback occurs).

A

-GnRH: Secreted from tonic center, Target the gonadotropic cells in the anterior pituitary, Feedback occurs in Hypothalamus
-LH: Secreted from the anterior pituitary, Acts on Leydig cells in the testes, Feedback occurs in Anterior lobe and Hypothalamus
-FSH: Secreted from the anterior lobe, Acts on sertoli cells, Feedback occurs in Anterior pituitary and Hypothalamus

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2
Q

GnRH

A

-Frequent, intermittent bursts: Lasts a couple of minutes
-Cause release of LH: Lasts 10-20 mins, Occurs 4-8 times a day

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3
Q

FSH

A

-Lower concentrations & longer durations: Constant secretion of inhibin and Longer half-life of FSH
-Received by Leydig cells: Progesterone is synthesized (Most is converted to testosterone)

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4
Q

LH

A

-Prevents Leydig cells from becoming unresponsive (reduced receptors)
~low testosterone levels occur
~LH pulses cannot be too long: Excess of testosterone, Intense negative feedback, Reduced testosterone (in long run)
-Too much testosterone
~FSH reduction: From negative feedback
~Sertoli cell function compromised

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5
Q

Know the different forms of the male germ cell.

A

-Spermatogonia
-Primary Spermatocytes
-Secondary Spermatocytes
-Spermatids
-Spermatozoa

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6
Q

Spermatogonia

A

-A1-A4, I, & B
-Specialized diploid cells
-Can revert back to less mature space
-Basal seminiferous epithelium

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7
Q

Primary Spermatocytes

A

-Haploid cells
-Adluminal seminiferous epithelium

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8
Q

Secondary Spermatocytes

A

-Haploid cells: “Crossed Over” chromosomes
-Adluminal seminiferous epithelium

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9
Q

Spermatids

A

-Haploid
-Spherical
-Adluminal compartment

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10
Q

Spermatozoa

A

-Highly condensed nucleus
-Acrosome is formed
-Motility achieved: Development of a flagellum and development of mitochondrial helix
-Lumen

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11
Q

What are between cytoplasmic bridges?

A

Daughter cells

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12
Q

Know how the divisions of Spermatogenesis progress.

A

-Spermatocytogenesis: Mitosis, A1-A4, I, & B Spermatogonia, Stem cells left over, and Last division produces Primary Spermatocytes
-First Meiosis: Produces Secondary Spermatocytes
-Second Meiosis: Produces Round Spermatids
-Spermiogenesis: Transformation into sperm-like shape (Golgi phase, Cap phase, Acrosomal phase, and Maturation phase)
-Spermiation: Separation of formed Spermatozoa from seminiferous epithelium

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13
Q

What is the order of the maturation phases of sperm development.

A

-Golgi
-Cap
-Acrosomal
-Maturation

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14
Q

Golgi phase

A

-Development of acrosome
-Migration of centrioles

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15
Q

Cap phase

A

-Acrosome development continues
-Flagellum elongates

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16
Q

Acrosomal phase

A

-Acrosome development finishes
-Manchette development: Series of microtubules, Associated with nuclear elongation
-Elongation progression

17
Q

Maturation phase

A

-Manchette disappears
-Mitochondria migrate
-Dense fibers form

18
Q

Spermatogenesis

A

The whole process of sperm production

19
Q

Spermiogenesis

A

Differentiation of Spermatids

20
Q

Spermiation

A

Separation of formed Spermatozoa from seminiferous epithelium

21
Q

Know why stem cell renewal is important.

A

-Stem cell renewal
-Replenish testis: Injury, Trauma, and High heat
-Keep Spermatogenesis going indefinitely

22
Q

Stem cell renewal

A

-process of renewing early mitotic cells to always have cells that are dividing to produce sperm.
-A2, A3, A4: Can revert back to less mature space, Can be maintained as a stem cell (Produce more sperm)

23
Q

Stage of spermatogenesis

A

-Designation applied to a given cross section of a seminiferous tubule.
-Each seminiferous tubule can be at a different stage in any given cross section.
-Based on the degree of maturation of the cells closest to the lumen.

24
Q

Cycle of spermatogenesis

A

-Time it takes the same cross section to complete all established stages
-Species dependent
-Multiple cycles needed for the whole development process
-All about TIME.

25
Q

Wave of spermatogenesis

A

-Spermiation only occurs at certain sites.
-During a wave seminiferous epithelium progresses through stages.
-Causes spermiation to occur at different sites along the seminiferous tubule: creates a wave of sperm cell release.
-Provides a relatively constant rate of spermatozoa to the epididymis.
-Distance between the same stage is a wave.
-Think DISTANCE.

26
Q

Know relative cycle length and duration of spermatogenesis for the boar, bull, and stallion.

A

Boar
~Cycle: 8.3 days
~Spermatogenesis: 39 days
Bull:
~Cycle: 13.5 days
~Spermatogenesis: 61 days
Stallion:
~Cycle: 12.2 days
~Spermatogenesis: 57 days

27
Q

Know relative cycle length and duration of spermatogenesis for the ram and man.

A

Ram:
~Cycle: 10.4 days
~Spermatogenesis: 47 days
Human:
~Cycle:16 days
~Spermatogenesis: 75 days

28
Q

Know what factors cause variation in sperm production.

A

-Testis size
-Efficiency of spermatogenesis: Mitotic division and Degeneration of germ cells
-Length of spermatogenesis

29
Q

Know how many germ cells are present in the sertoli cells of stallions.

A

-Primary spermatocytes: 3.0 +/- 0.2
-Round spermatids: 10.9 +/- 0.9
-Max. Potential spermatids: 64

30
Q

Know how many germ cells are present in the sertoli cells of bulls.

A

-Primary spermatocytes: 1.2 +/- 0.1
-Round spermatids: 5.2 +/- 0.6
-Max potential spermatids: 64

31
Q

Know how many germ cells are present in the sertoli cells of men.

A

-Primary spermatocytes: 1.3 +/- 0.1
-Round spermatids: 4.2 +/- 0.2
-Max potential spermatids: 16

32
Q

Know what factors might increase apoptosis.

A

-Normal: Typical part of spermatogenesis
-Abnormal:
~Seasonal factors
~Disease
~Trauma
~Heat
~Hormone levels
~Age