Spermatogenesis and semen evaluation Flashcards

1
Q

Describe the order of cells produced in spermatogenesis

A
Stem cells
Spermatogonia
Primary spermatocytes
Secondary spermatocytes
Spermatids
Spermatozoa
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2
Q

What are the 3 aims of spermatogenesis?

A

Create genetic diversity
Produce spermatozoa capable of fertilisation
Replenish supply of primordial stem cells

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3
Q

What are the 3 phases of spermatogenesis?

A

Spermatocytogenesis (proliferation)
Spermatidogenesis (meiotic phase)
Spermiogenesis (differentiation)

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4
Q

What is the 1st phase of spermatogenesis and what happens?

A

Spermatocytogenesis - formation of primary spermatocytes from spermatogonia

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5
Q

What is the 2nd phase of spermatogenesis and what happens?

A

Spermatidogenesis - formation of spermatids from primary spermatocytes
(Create genetic diversity)

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6
Q

What is the 3rd phase of spermatogenesis and what happens?

A

Spermiogenesis - forming spherical shaped spermatids with enzymes and DNA

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7
Q

What is the blood testis barrier? What is its purpose?

A

Physical barrier between blood vessels and seminiferous tubules
Prevent sperm entering blood stream

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8
Q

What does the sperm-testis barrier do? Which stage of germ cells does it separate?

A

Separate basal and adlumenal compartments of seminiferous tubules
Separates spermatogonia and spermatocytes

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9
Q

What is the function of Leydig cells and Sertoli cells?

A

Leydig cells produce testosterone

Sertoli cells aid spermatogenesis

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10
Q

Which germ cell in the testes has the longest lifespan?

A

Primary spermatocyte

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11
Q

Are spermatids diploid or haploid? Are they genetically unique or identical?

A

Haploid

Genetically unique

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12
Q

What is the spermatogenic wave?

A

The differences at any given time across the seminiferous tubule
Each section of tubule contains different stage of sperm development

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13
Q

How long does spermatogenesis roughly take?

A

1-2 months

depending on species

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14
Q

Briefly describe the endocrinology leading to the production of FSH and LH

A

Hypothalamus produces GnRH
GnRH travels in blood to anterior pituitary
GnRH stimulates anterior pituitary gland to produce FSH and LH

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15
Q

Spermatazoa are produced in the testes. How long does it take for them to pass through the epididymis?
What happens to them throughout the epididymis?

A

1-2 weeks
Mature and develop motility in head and body of epididymis
Stored in the tail

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16
Q

The tail of the epididymis stores enough spermatozoa for multiple ejaculations. Does copulation frequency impact on time taken for spermatogenesis?

A

No

Increased copulation decreases spermatozoa density

17
Q

Describe the structure of the head of a spermatozoa

A

Head has nucleus
Acrosome
Post nuclear cap
Varies between species

18
Q

What does the acrosome contain?

A

Hydrolytic enzymes to penetrate zona pellucida

19
Q

The tail is a self powered flagellum. What 3 pieces does it consist of?

A

Principle piece
Middle piece
Terminal piece

20
Q

What is semen?

A

Fluid released at ejaculation

21
Q

What are the 3 seminal fractions and describe their consistency?

A

Pre-spermatazoal fraction = watery
Spermatozoa rich fraction = creamy
Post-spermatozoal fraction = gelatinous

22
Q

What contaminants may be found in a sperm sample?

A
Blood 
Bacteria
Pus 
Urine
Dirt
23
Q

What should be evaluated when looking at a semen sample? How are they scored?

A
Volume
Colour 
Appearance
Live:dead ratio
Mass motility/wave motion
1-5
24
Q

What is the difference between an electroejaculation sample and a natural insemination sample?

A

EEJ sample are more dilute as more accessory gland secretion

25
What should mass/motility wave motion of semen resemble?
Clouds
26
A live:dead ratio can be calculated from a semen sample. Spermatozoa are very sensitive to timing, handling and staining. What can damage them?
Cold temperatures - keep all collecting equipment warm Water Bright light Etc
27
What instrument is used to calculate spermatozoa density?
Haemocytometer
28
How can sperm defects be categorised?
Primary or secondary Compensable or non-compensable Head or tail
29
Give some examples of spermatozoa head abnormalities
Crater defect (vacuoles) Tapered heads Ruffled/knobbed acrosome
30
Give some examples of spermatozoa tail abnormalities?
Coiled/folded tail Detached tail Double midpiece