Animal Science 434

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Animal Science 434

• Lecture 13 Epididymis, Ejaculation and Semen

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Head
Sperm Structure
Acrosome
Neck
Middle Piece
Annulus
Principal Piece
End Piece
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Sperm From Different Species
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Sperm Head
(Equatorial Segment)
Nucleus
Nucleus
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Acrosome
Plasma Membrane
Nucleus
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• Acrosin
• Hyaluronidase

Acrosome
Nucleus
Plasma Membrane
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Posterior head
Capitulum
Laminated columns(flexibility)
Mitochondrial helix (energy)
Middle piece
Axoneme (9 9 2)
Course outer fibers
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Annulus
Midpiece
Principal Piece
Fibrous Sheath or helix
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Axoneme
Principal Piece
Middle Piece
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Axoneme
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Microtubule Sliding in Sperm Tail
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Sperm Metabolism
Hexokinase
Glucose
Glucose-6-phosphate
Phosphohexoisomerase
Anerobic Metabolism (Glycolysis)
Fructose-6-phosphate
Fructose
Hexokinase
Lactate 2 ATP 2 H2O
Fatty Acids
Aerobic Metabolism
Tricarboxcylic Acid Cycle
36 ATP/Glucose 36 ATP/Fructose
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ATP Utilization in Sperm

• motility (60)
• substrate cycling (40)
• wasted
• maintenance of ionic gradients
• very small amount
• transcription and translation
• none after condensation of nucleus and loss of
  residual body

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Sperm Metabolism

• Temperature dependent
• ATP production increases as temperature increases
• ATP dependent processes are temperature dependent
• motility increases with increasing temperature

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Effect of Temperature on Motility
Velocity (µm/s)
Temperature (C)
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Transport of Sperm
Vas Efferentia

• fluid flow
• cilia

Caput

• contractions

Vas Deferens
Rete Testis

• contractions

• fluid flow
• RT secretion

Corpus

• contractions

Seminiferous Tubule

• bulk fluid flow
• contractions ofof myoid cells

Cauda

• contractions

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Epididymal Function

• Maturation
• change in fertility
• develop motility
• nuclear condensation
• cytoplasmic droplet
• Concentration
• remove water

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Epididymal Function

• Secretion
• T DHT
• energy substrates (GPC, carnitine)
• glycoproteins, lipids, enzymes
• Transport
• smooth muscle contraction
• Storage
• cauda

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Hormonal Control of Epididymis

• Caput
• tubal testosterone
• Corpus
• tubal dihydrotestosterone (DHT)
• vascular testosterone
• Cauda
• tubal DHT
• vascular testosterone

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Erection
Sensory
Psychic
Sympathetic
relaxation of penile retractor muscle
Parasympathetic
contraction of ischiocavernosus muscle
dilation of vessels
Inhibit vasoconstriction
engorgement of corpus cavernosum
decreased venous outflow
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Emission and Ejaculation
Sensory
Psychic
Parasympathetic
Sympathetic
smooth muscle contraction of prostate, seminal
vesicles, vas deferens, cauda epididymis, closure
of the sphincter to the bladder
striated muscle contraction of ischiocavernosus, b
ulbospongiosus, pelvic urethral
emission
ejaculation
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Ejaculate Characteristics
Species Time lapse for Composition of Bull 1
second single fraction Ram 1 second single
fraction Boar 5 - 25 minutes fractionated sperm-
free sperm-rich coagulum Stallion 30 - 60
seconds fractionated sperm-free sperm-rich m
ucus Human 10 - 30 seconds single fraction but
coagulated
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Components of Semen

• water
• sperm
• substrates
• fructose
• sorbitol
• inositol
• glycerol phosphatidyl choline (GPC)
• citric acid
• inorganic salts
• sodium, potassium, calcium, magnesium, chloride
• proteins

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Initial Semen Evaluation

• color
• volume
• concentration
• motility
• viability
• morphology

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Ejaculate Characteristics
Species Ejaculate Sperm Total Sperm Volume Co
nc. (x109) Motile Normal (x109/ml)
/Ejaculate Bull 8.0 1.5 12 75 95 Ram 1.0 3.0 3 95
95 Boar 200 .25 50 70 90 Stallion 80 .15 12 70 40-
90 Man 2-6 .15 .9 65 30-70