Semen Examination and Composition Overview

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Questions and Answers

What is the primary function of seminal fluid?

To provide nutrients for spermatozoa (correct)

To serve as a lubricant during sexual intercourse

To create a barrier against infections

To transport waste from the body

Which gland contributes the largest volume to the semen composition?

Bulbourethral glands

Prostate gland

Testes

Seminal vesicles (correct)

What controls the process of ejaculation?

Autonomic nervous system

Digestive system

Hormonal system

Central nervous system (correct)

Which of the following components is NOT typically found in semen?

Insulin Signup and view all the answers

What percentage of sperm is typically released during ejaculation?

2-5% Signup and view all the answers

What is the role of the bulbourethral glands in semen composition?

To secrete a clear fluid that helps sperm mobility Signup and view all the answers

Which of these substances is a significant nutrient found in semen?

Calcium Signup and view all the answers

How do the seminal vesicles affect the semen's appearance?

Add a viscous texture due to fructose-rich fluid Signup and view all the answers

What term describes the condition where a male has a high percentage of abnormally shaped sperm?

Tetratozoospermia Signup and view all the answers

Which part of the sperm is primarily responsible for penetrating the outer surface of the egg?

Head Signup and view all the answers

What is the condition characterized by no spermatozoa in a male's seminal fluid?

Aspermia Signup and view all the answers

Which of the following factors can lead to abnormally shaped sperm?

Exposure to toxic chemicals Signup and view all the answers

What is required to assess sperm morphology during a semen analysis?

Microscopic examination Signup and view all the answers

Which of the following is NOT a location where semen can be found as evidence?

Blood stream Signup and view all the answers

What precaution should be taken when packaging specimens to avoid contamination?

There should be no friction between the apparel and the stain Signup and view all the answers

During hot weather, how should liquid semen be preserved?

By adding a few drops of 10% solution of formalin Signup and view all the answers

Study Notes

Semen and Stains

Semen examination is crucial in sexual offense investigations (rape, adultery, sodomy, bestiality, and homicide).
Semen is a greyish-white fluid containing spermatozoa (sperm).
Semen is secreted by male animal gonads.
It contains sperm, fructose, and enzymes aiding fertilization.
Semen's opalescence is due to high protein content and slight turbidity from sperm.

Process of Ejaculation

Semen release occurs during ejaculation.
Semen is processed in seminal vesicles in the pelvis.
Ejaculation is controlled by the central nervous system.
Ejaculation triggers impulses from friction or sexual stimulation up the spinal cord to the brain.

Semen Composition

Semen travels through ejaculatory ducts, mixing with fluids from seminal vesicles, prostate, and bulbourethral glands.
Seminal vesicles produce 65-70% of semen, a viscous, fructose-rich fluid.
Prostate glands contribute 25-30% of semen, containing enzymes, citric acid, lipids, and acid phosphatase.
Testes release 200-500 million sperm per ejaculation (2-5% of semen volume).
Bulbourethral glands produce a clear fluid (less than 1% of semen).

Sperm Morphology

Sperm morphology refers to sperm shape (head size/DNA content, midpiece, tail) critical for fertilization.
Morphology assessment is part of routine semen analysis.
Analysis also checks sperm motility (movement ability) and concentration.
Abnormal sperm shapes (microcephaly, pinhead, tapered, thin, globozoospermia, headless, tail-less, nuclear vacuole) can result from various causes (temperature, chemicals, infections, genetics).
Tetratozoospermia or tetratospermia means a large number of abnormally shaped sperm.

Types of Sperm Morphology

Normal sperm: Oval head, intact midpiece, single tail.
Microcephaly (small head): Smaller than normal head size.
Pinhead: Head resembling a pin; minimal to no paternal DNA.
Tapered head: "Cigar-shaped" head, possible cause of varicocele.
Thin head: Extreme variation of tapered head, possibly due to broken DNA, varicocele, or disrupted development.
Decondensing head: Sperm prematurely breaking down.
Headless: Missing sperm head, also termed acephalic or decapitated sperm syndrome.
Tail-less: Missing sperm tail, sometimes during necrosis.
Nuclear vacuoles: Presence of large or multiple vacuoles within the sperm head.

Multiple Parts Sperm

Multi-head: Exposure to toxins, chemicals, heavy metals, high prolactin might cause this.
Thick/swollen neck: Could relate to faulty mitochondria (powerhouse of sperm)
Coiled-tail: Exposure to bacteria or poor seminal fluid quality or heavy smoking.
Stump-tail: Immotile, short tails and lower motility.

Semen as Evidence

Semen collection, preservation, and transit are significant for evidence purposes.
Methods like the Florence test and Barberio's test help to determine if a stain is semen.
Further analysis, like microscopy, is necessary.
Different stain types (Vaginal content, Rectal content, Oral content, Wet or dried conditions, Underclothing, Bed clothing) need to be collected and analysed per the circumstances.

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Description

This quiz covers essential information about semen, including its role in sexual offense investigations, composition, and the process of ejaculation. Gain insights into the biological and forensic significance of semen in various contexts. Perfect for students studying biology, forensic science, or criminal justice.