Spermatogenesis and semen evaluation Flashcards

1
Q

What are the 3 goals of spermatogenesis?

A
  1. Produce spermatozoa (cells capable of fertilisation)
  2. Replenish supply of primordial stem cells
  3. Create genetic diversity
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2
Q

What are the 3 phases of spermatogenesis?

A
  1. Proliferation
  2. Meiotic phase
  3. Differentiation
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3
Q

What are the functions of sertoli cells?

A
  • Nerve cells
  • Provide nutrition to cells
  • Remove waste
  • Involved in hormonal regulation
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4
Q

The proliferation phase begins with what type of cell?

A

Spermatogonia

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5
Q

Describe the division and replication of cells in proliferation

A
  • Mitosis
  • Daughter cells are genetically identical to parent cells
  • Diploid
  • Some cells go back to the start to replenish stocks
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6
Q

In which compartment are spermatogonia present?

A

Basal compartment

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7
Q

The meiosis phase begins with which type of cell?

A

Primary spermatocytes

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8
Q

Describe the events of the meiosis phase

A
  • Cross over and random assortment of DNA creates genetic diversity
  • End up with haploid daughter cells which are genetically unique
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9
Q

In the bull how long is the primary spermatocyte lifespan?

A

18-19 days

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10
Q

What is the total length of spermatogenesis in the bull?

A

61 days

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11
Q

Which cells are produced at the end of the differentiation phase?

A

Spermatozoa

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12
Q

What is the function of the acrosome in the head of the spermatozoa?

A

Contains hydrolytic enzymes required for penetration of the zona pellucida

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13
Q

Name the 3 pieces that make up the tail of the spermatozoa

A
  • Middle piece
  • Principle piece
  • Terminal piece
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14
Q

How can fertility be assessed externally?

A
  • Scrotal circumference

- Palpation of testicle

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15
Q

Where do spermatozoa mature?

A

The head and body of epididymis

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16
Q

GnRH released from the hypothalamus has what effects?

A

Influences the anterior pituitary which releases LH and FSH

17
Q

What is the role of LH?

A
  • Acts on leydig cells which produce testosterone

- Testosterone has a negative feedback effect on Sertoli cells and the hypothalamus

18
Q

What is the role of FSH?

A
  • Acts on the Sertoli cells to regulate them
19
Q

Which hormone is produced from Sertoli cells, what is the function of this hormone?

A

Inhibin

- negatively feedbacks to the anterior pituitary inhibiting GnRH, FSH and LH

20
Q

How long does transport of spermatozoa through the epididymis take?

A

1-2 weeks

21
Q

What should be recorded when evaluating semen?

A

Volume, colour, appearance, motility, density, any head/tail abnormalities, live:dead

22
Q

A sperm score of 5 in a ram would have what appearance? Compare to a score of 0

A
5 = Thick and creamy 
0 = Clear and watery
23
Q

Describe 2 types of sperm defects

A

Primary vs secondary = classifying whether the defect occurred in the seminiferous tubule or after release into the lumen
Compensable vs non-compensable = will increasing the number of spermatozoa overcome the problem

24
Q

Give examples of what spermatozoa are sensitive to

A
  • Temperature
  • Water
  • Bright light
  • Blood
  • Cigarettes