B115 Male Reproductive

Anatomy & Physiology

Lesson Outline

Male Reproductive Terms

Male Reproduction Process

Glands

Semen Evaluation

Abnormalities

Fertilization

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Male Reproductive Terms

Testicle: The male sex gland that produces sperm. Spermatozoa: The male’s sex cell that is responsible for

fertilization. Seminiferous Tubules: Small structures in the testicles that are

responsible for spermatogenesis (sperm production). Semen: Sperm and additional fluids produced by several

accessory glands.

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Male Reproductive Terms

Epididymis: Cord attached to the testicle that is responsible for sperm maturing and final development.

Vas Deferens: Tube that connects the epididymis with the urethra. Sperm cells move through here to the urethra.

Urethra: Tube that carries urine from the bladder Seminal Vesicles: Organs which contain fluids necessary for

sperm survival. Prostate Gland: Gland that contributes seminal fluid necessary for

healthy sperm.

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Male Reproductive Terms

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Male Reproductive Terms

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Male Reproductive Terms

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Male Reproduction Process

Gonadotrophin production by the hypothalamus causes the pituitary to produce FSH and LH.

These stimulate the cells of the testicle to produce testosterone, and spermatozoa or sperm.

In the tiny seminiferous tubules of the testicle, immature sperm are produced.

These sperm move to the epididymis where they fully mature and are stored prior to ejaculation.

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Male Reproduction Process

During ejaculation, the sperm travel through the vas deferens, and into the urethra.

In the vas deferens and urethra, additional fluid from the secondary sex glands (seminal vesicles, prostate, bulbourethral glands) is added which helps keep the sperm alive.

Sperm are very sensitive to extremes in heat or cold.

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Male Reproduction Process

The scrotum is sack like structure designed to regulate the optimal temperature for sperm production by drawing the testicles closer to the body or away from the body.

Animals that are sick, have a fever, or are fat (causing insulation for the sperm) often have lower numbers of healthy sperm. Severe cold, and stress, can also cause decreased numbers of normal sperm.

It takes 60 days for sperm to completely mature so many reproductive problems in bulls may not show up for several months.

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Male Reproductive Tract Glands

Seminal Vesicles: Produce a fluid that protects and transports the sperm.

Prostrate Gland: Located near the urethra and the bladder. Produces fluid that is mixed with seminal fluid.

Cowper’s Gland: Produces fluid that cleans and neutralizes the urethra.

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Semen Evaluation

Semen is evaluated on three things: Concentration Morphology Motility

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Concentration

Number of sperm cells per milliliter Most important fertility Indicator Average ejaculate ranges from 4 to 6 milliliters and contains 6 to

8 billion sperm cells.

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Mobility

Microscope at 400X 70% or more mobile cells at 40 degrees centigrade (104 F)

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Mobility

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Morphology

Proportion of abnormal sperm Should not exceed 20% Most bulls produce some abnormalities

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Sperm Morphology

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Double Head

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Abnormal Head

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Abnormal Head

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Elongated Head

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Swollen Neck & Tail

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Detached Head

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Broken Tail

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Coiled Tail

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Sperm Abnormalities

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Sperm Abnormalities

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Sperm Abnormalities

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Sperm Abnormalities

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Fertilization

Fertilization is the union of the sperm and the egg. Conditions for fertilization:

Male and female compatibility Female in Heat Egg is mature

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Sperm on an Egg

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Embryos

The result of fertilization, early stage of development of the fetus.