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Reproduction > Chapter 10 > Flashcards

Chapter 10 Flashcards

1
Q

What endocrine requirements must be met so spermatozoa can be produced?

A

1) adequate secretion of GnRH from hypothalamus
2) FSH and LH secretion from the anterior lobe of the pituitary
3) secretion of gonadal steroids (testosterone and estradiol)

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2
Q

What does luteinizing hormone act on?

A

Leydig cells within the testes

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3
Q

What do leydig cells synthesize and what is this converted into?

A

progesterone into testosterone

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4
Q

What does successful testis function require?

A

pulsatile GnRH secretion, high concentrations of testosterone in the seminiferous tubule, low concentrations of testosterone in a systemic blood, and adequate LH receptors in Leydig cells

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5
Q

What do sertoli cells secrete?

A

inhibin

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6
Q

What else do the testes secrete?

A

estradiol

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7
Q

What is the female equivalent of leydig cells in the male?

A

follicular theca interna cells

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8
Q

What is the female equivalent of sertoli cells in the male?

A

follicular granulosal cells

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9
Q

What do sertoli cells convert?

A

testosterone to estradiol

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10
Q

What type of relationship does estradiol and testosterone have on the hypothalamus in the male?

A

negative feedback

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11
Q

What are the goals of spermatogenesis?

A

1) provide a continual supply of male gametes, genetic diversity, provide sperm for reproduction and an immunologically privileged site for developing germ cells.

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12
Q

What is the process of producing spermatozoa?

A

spermatogenesis

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13
Q

Where does spermatogenesis take place?

A

seminiferous tubules

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14
Q

How much more testosterone should be in testes than circulation for normal spermatogenesis?

A

100-500 x

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15
Q

Testosterone in circulation keeps what from happening?

A

negative feedback

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16
Q

What are the three phases of spermatogenesis?

A

Proliferation, meiosis, differentiation

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17
Q

What does the proliferation phase consist of?

A

mitotic divisions of spermatogonia and stem cell renewal

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18
Q

What does meiotic phase consist of?

A

2 meiotic divisions (meiosis 1 and 2) that are for genetic diversity and haploid spermatids

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19
Q

What does the differentiation phase consist of?

A

Head, mid piece, and flagellum

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20
Q

Where spermatogonia located in?

A

basal compartment of the seminiferous epithelium

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21
Q

What are the three types of spermetogina?

A

A1-A4,I, and B-spermatogonia

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22
Q

What is the last division of proliferation?

A

primary spermatocyctes

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23
Q

What is reduced in the meiotic phase?

A

chromosomes

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24
Q

What are chromosomes reduced too?

A

haploid state

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25
What do primary spermatocytes do?
Immediately enter meiosis 1
26
What takes place in meiosis 1?
crossing over results that are in a random assortment of different segments of each chromosome
27
How much time does prophase of meiotic division take up of entire spermatogenic process
30% (long process)
28
What germ cell type has the longest lifespan?
primary spermatocyte
29
What happens after the first meiotic division?
secondary spermatocyte rapidly undergoes the second meiotic division
30
What does the second meiotic division result in?
haploid spherical spermatids
31
What is the role of spermatozoon?
deliver male's genetic material to an oocyte during fertilization and forms cells capable of fertilization
32
What happens to these haploid spermatids?
their nucleus becomes highly condensed, the acrosome forms, and the cells become motile
33
What develops on the spermatids?
flagellum and mitochondrial helix
34
What ability is unlocked in differentiation?
ability to fertillize
35
What are the four phases of differentiation?
Golgi phase, cap phase, acrosomal phase, maturation phase
36
What do the four steps of differentiation do?
make gamete capable of moving independently with change in head shape and tail feature added
37
Spermatozoa =
head + tail
38
What does the head of the spermatozoa consist of?
nucleus + acrosome + post-nuclear cap
39
What does the tail of the spermatozoa consist of?
middle piece + principal piece + terminal piece
40
Where is the spermatozoa released from and where does it go?
sertoli into seminiferous epithelium
41
Characteristic of Spermatozoa? 4 of them
1) Head shapes are characteristic of each species 2) DNA transcription and translation stop until fertilization 3) The anterior two thirds of the nucleus is covered in acrosome 4) the tail forms,
42
What does the acrosome contain?
hydrolytic enzymes
43
What does the acrosome undergo?
acrosome reaction
44
What is the tail of spermatozoa?
self-powered flagellum
45
The cycle of seminiferous epithelium?
yes
46
What are germ cell generations?
cells of the same type located at one site within the seminiferous epithelium
47
What should we think of the cycle of seminiferous epithelium as?
A university (freshman, Sophmore, Junior, Senior) Spermatagonia -> Primary spermatocytes -> Secondary Spermatocytes -> Spermatids
48
Do lifespan of cells and duration of the cycles vary among species?
yes
49
How long is the complete process of spermatogenesis?
61 days
50
How many cycles do these cells of the seminiferous epithelium proceed through?
4.5 x
51
How long are these individual cycles?
13.5
52
What is analogous to graduation?
spermiation (fully differentiated spermatozoon)
53
Do the individual germinal elements have different lifespans though?
yes, 21 days for primary spermatocyte and 1.7 days for secondary spermtocyte
54
Is the pace of spermatogensis affected by environment?
no
55
What should we think of spermiation like?
A wave in a stadium where when you stand up you mimic spermiation (VIII) and the rest is the sitting phase (1-VII) so that the spermatogenic wave is relatively constant in its supply of spermatozoa to the epididymis for pool of ejaculation
56
What is a good estimator of sperm producing ability?
testicular size
57
How much of every ejaculate contain abnormal sperm?
5-15% abnormal sperm
58
Where do morphological abnormalities originate?
testes or epididymis
59
What are the two classifications of morphologically abnormal sperm?
head or tail abnormalitites
60
T/F Female gametes are complete prior to birth?
True
61
Spermiation process versus ovulation process?
uniformly v pulsatile
62
What is the exception of the regular spermiation process?
seasonal breeders
63
How long after restoration from an event that impacted spermatogensis is needed?
6-12 weeks
64
What is the fertility of the male determined by:
assuming that he can copulate, sperm producing ability, viability (motility) of his spermatozoa, # of morphologically abnormal spermatozoa, and number of normal spermatozoa from ejaculation
65
Two tail and head abnormalitites for spermatozoa?
Coiled and folded tail / tapered and knobbed heads
66
What is the most important physiologic technology ever devised for accelerating genetic improvement?
Artificial Insemination
67
What is the criteria for artificial insemination?
collection of semen from the male, preservation and extension of sperm, and insemination of the female
68
What information is needed after collection of sperm?
ejaculate volume, concentration of spermatozoa, and percentage of motile sperm
69
Ejaculation volume * Spermatozoa concentration =
total sperm in ejaculation
70
What does the total number of sperm lets us know?
how many insemination doses are available (good is over 60% and bad is below 50%)
71
total number of sperm / desired number of sperm in each does =
number of doses
72
What is the main thing that AI provides?
accelerated genetic improvement to use only the best male genetics that removes need for males on farms and decreases inbreeding
73
What happens after it is determined that the ejaculate is of sufficient quantity?
it must be diluted in an extender solution
74
Is ejaculated semen sterile?
no
75
A good seminal extender must have?
be isotinic, good buffers, cryoprotectants, appropaite nutrients, viability. low in cost and prevention against microbial growth
76
What is the sex of the conceptus determined by?
sperm due to each spermatozoa containing either an X or Y chromosome
77
Why is there a desire to seperate the X and Y bearing sperm?
one sex is significantly more valuable (dairy -> female -> lactation)
78
How much more bearing is the X sperm than the Y bearing sperm?
2.8 - 4.2% more DNA
79
Manipulation of the sex ratio under controlled conditions does what?
Impacts the efficiency of food animal production
80
How are X and Y seperated?
using a DNA stain or dye called flourochrome where X absorbs more dye and thus becomes more intense light when excited by a laser in a flow cytometer
81
What are ejaculated in doublets?
American opossum
82
What does production of normal numbers of fertile spermatozoa (normal spermatogenesis) require?
endocrine regulation of testis, mitotic divisions of spermatogonia and meiotic divisions resulting in haploid spermatids and morphological transformation of spermatids to spermatozoa

Reproduction (11 decks)

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