To understand the basic components of the sperm and their

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Learning Objectives
To understand the basic components of the sperm
and their functions. To understand
the overall characteristics and functions of
sperm.
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Head Structure of Bovine Spermatozoa
Outer Acrosomal Membrane
Apical Ridge
Upper 2/3 of sperm head
L X W X Thick 9 X 4 X 1 mm Ovum - 200-250 mm
Acrosome
Inner Acrosomal Membrane
Equatorial Segment
Plasma Membrane
Covers outside of sperm head
Mid piece of head
Head
Nucleus
Mid-Piece
Post-Acrosomal Region
Principle Piece
Implantation Socket
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Sperm Tail
Sperm Head
Capitulum
Hooks tail into head
Nine Two Inner Double Tubules
Contractile portion of tail which causes it to
bend
Mid Piece
Nine Outer Coarse Fibers
Mitochondrial Helix (ATP Production)
Fibrous sheath surrounds tail except at end of
tail
Energy for tail movement
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Parts of Sperm - Function Nucleus Acrosome
Plasma Membrane Apical Ridge Post
Acrosomal Region
Haploid - Condensed DNA stabilized by disulfide
bonds until fertilization occurs. Inactive - no
synthetic activity
(Similar to a modified Lysosome) Enzymes
facilitate sperm penetration of
oocyte Hyaluronidase, Acrosin, Corona Penetrating
Enzyme
Contains the very little cytoplasm remaining in
sperm. Surrounds entire tail
Can be used as indicator of viability When gone
indicates sperm death
Position where sperm attaches head to vitelline
membrane of oocyte during fertilization
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Implantation Socket Capitulum Mitochondrial
Helix 9 Course Outer Fibers 9 Inner Double
Tubules

Tail Attachment
Energy for tail motility - ATP production
Structural support (i.e. give tail
rigidity) Peculiar to vertebrate and invertebrate
spermatozoa DO NOT CONTRACT
Involved with tail movement - similar to cilia
and flagella of bacteria. Contract through
fibers of b and a-tubulin (Similar to actin and
myosin of muscle)
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Evaluation of Sperm Integrity Stained with
Fluorescent Dyes
Dead Sperm Stained with PI
Live Stained with SYBR
Active Mitochondrial Activity Stained with JC-1
Pictures provided by Dr. Duane L. Garner,
University of Nevada
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Events of a sperm's life 1. Fertilize the
oocyte 2. Degeneration Fertilization -
True acrosome reaction
- Fate of majority of sperm
With Permission Cross et al. 1988 Biol. Reprod
38235
Occurs as capacitated sperm approaches and
attaches to oocyte
Acrosome
Plasma membrane
Pores within Acrosome
ZP
Post- Acrosome Region
Inner acrosomal membrane covers sperm nucleus
with an intact post- acrosomal region
Fusion of outer plasma membrane with
outer acrosomal membrane forming pores
-release of enzymes
Sperm attachment to Zona pellucida at
its acrosomal region
Intact Sperm-head
Degeneration - False acrosome reaction
Sperm postacrosomal region also breaks-down
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Metabolic characteristics of sperm General
types of metabolism Catabolic
Anabolic Catabolic Properties of Sperm
Sperm DNA is inactive - breakdown of substrates
into chemical energy
Sperm are not anabolic - Formation of compounds
from substrates. Sperm cannot repair themselves
Limited life span It is difficult for sperm to
repair and maintain its metabolic components
i.e. sperm wear out as it metabolizes. Therefore,
to stop or slow metabolism to preserve sperm
Cool with extenders which control CO2, K, pH at
5OC Freeze in liquid nitrogen (Glycerol)
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Species Comparison of Spermatozoa
Bull
Ram
Man
Cock
Boar
Rat
Stallion
Head 10 mm
Tail 60 mm
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Learning Objectives
Understand the process of spermatogenesis
-How mitosis and meiosis fit in.
-How spermatocytogenesis and spermiogenesis
differ. -What happens during
spermiogenesis.
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Sperm Producing
Capacity
Bull Boar Ram
Stallion Sperm X 106/gram of testis/day
16 27 25 20
Testis weight (grams) 350 360
275 200 Total sperm produced/day
11 19 14 8
( x 109 sperm) Length of Spermatogenesis 61
34 49 49 (Days)
Takes less time to produce sperm in boar
compared to bull
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Bovine Spermatogenesis
Develops at the onset of Puberty
Initial cells -provides base cell to start cell
divisions
Renews base cells
20 Days Mitotic Division
Takes 43 Days
Spermatocytogenesis
All chromosomes duplicate Reduction Division
21 Days Meiosis I
2 Days Meiosis II
Equational Division
Morphological change in Shape
Second Phase 17 Days
When release by the sertoli cells into
seminiferous tubule
Total 60-63 Days
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Spermatogenesis
Every 13.5 Days sperm are released from this
point
Spermatid
Round Spermatid
Secondary Spermatocyte
Sertoli Cells
Primary Spermatocyte
Spermatogonia
Every 13.5 Days a new group of cells initiate the
cycle
Myoid Cells
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Spermiogenesis Spermatids to Spermatozoa
Round Spermatid
Golgi Vesicle
Granules fuse and flatten over nucleus
Nucleus
Centrioles
Move opposite pole to golgi
Forms the acrosome contains enzymes
Spermatids are connected in groups throughout
development
92 doublets develop from tubules of this
centriole
Sperm head takes shape
Chromatin Condenses
Residual Body
Cytoplasmic droplet
Mitochondria locate in neck
Mitochondria spiral around the tail
Micro- tubules
Excess cytoplasm
Tail develops
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Learning Objective
To understand how heat stress impairs
spermatogenesis and reproductive capacity
Stress can be caused by environmental
temperature fever, and psychological events
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Effect of Thermal Stress in Boars
6 Weeks

Control Heat
Stress Percentage of Gilts Pregnant
41 29 Number of Embryos
8.6
6.1 Embryo Survival
71 49 Sperm
Motility (6 wks) 85
45 Testis Weight (grams)
939 901 Total
Testis Sperm (x109) 104
52 Total Caput Corpus Sperm
(x109) 127 66 Total
Cauda Sperm (x109) 234
95 Abnormal Sperm
No Change 5 to
10 A-Spermatogonia
1.1 1.1 Primary
Spermatocytes 29
28 Round Spermatids
115 63
Reduces pigs pregnant and embryo survival
Reduces sperm production
Heat stress does not kill sperm!
Decreases spermatogenesis
Cells in seminiferous tubule
Data from Wettemann et al. 1976, J.Anim. Sci.
42664-669 Wettemann and Desjardins 1979, Biol.
Reprod. 20235-241
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Order of Sperm Damage During Heat Stress
1. Spermatids - Most sensitive Why
Undergoing Morphological Change 2. Secondary
Spermatocyte 3. Primary Spermatocyte
Undergoing Meiosis
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Response to stress can be quite varied between
animals Once sperm becomes a spermatocyte they
undergo different level of activity
Meiosis and Spermiogenesis When and how long
will stress effect sperm production in Bulls
Example Long term stress - Two weeks of heat
stress Damages spermatids, secondary and
primary spermatocytes Takes 11 days to appear
WHY? Will last for 14 Days of stress
21 Days of Meiosis I
2 Days of Meiosis II
17 Days Spermiogenesis
11 Days Sperm passage
through epididymis 65
Days
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Thermal Effects on Bulls
June July Aug Sept
Poor Quality Semen