Reproductive Biology Quiz

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Questions and Answers

What is the primary role of the blood-epididymis barrier?

To increase seminal fluid production

To enhance sperm motility

To regulate testosterone levels

To protect maturing sperm from the immune system (correct)

Which component is responsible for producing the majority of alkaline semen?

Epididymal epithelial cells

Prostate

Seminal vesicles (correct)

Ejaculatory duct

What function do prostaglandins serve in the female reproductive system?

Strengthening the uterine wall

Inhibiting sperm movement

Stimulating muscular contractions within reproductive organs (correct)

Increasing semen viscosity

Which substance from the seminal vesicles aids in the coagulation of semen after ejaculation?

Fibrinogen Signup and view all the answers

What is the main function of acid phosphatase in semen?

Activating sperm Signup and view all the answers

What role does zinc play in sperm function?

Maintaining sperm chromatin stability Signup and view all the answers

What initiates the process of semen liquefaction after ejaculation?

Activation of KLKs, including PSA Signup and view all the answers

Which of the following substances is primarily produced by the prostate?

Citric acid Signup and view all the answers

What is the main challenge in the direct measurement of reactive oxygen species (ROS)?

Their short half-lives Signup and view all the answers

Which antioxidant contributes the most to the total antioxidant capacity (TAC) of seminal plasma?

Non-enzymatic antioxidants Signup and view all the answers

What types of DNA damage can occur in spermatozoa?

Single and double strand breaks, and deletions Signup and view all the answers

What is the principle behind the Comet assay?

Migration of broken DNA strands in an electric field Signup and view all the answers

Which of the following is NOT considered an enzymatic antioxidant found in epididymal fluid?

Vitamin C Signup and view all the answers

What can potentially result from fertilization with sperm that have DNA damages?

Pregnancy loss or congenital malformations Signup and view all the answers

How do non-enzymatic antioxidants function in seminal plasma?

By scavenging excessive ROS Signup and view all the answers

What role does sperm DNA integrity play in fertilization?

It is crucial for transmitting genetic material Signup and view all the answers

What does the size and intensity of the comet tail in the comet assay indicate about spermatozoa?

The degree of DNA damage Signup and view all the answers

What color indicates good chromatin integrity in sperm when using toluidine blue staining?

Light blue Signup and view all the answers

How is DNA damage assessed using CMA3 staining?

By measuring the protamination state of sperm DNA Signup and view all the answers

What procedure follows the preparation of a thin smear for toluidine blue staining?

Fixation in 96% ethanol-acetone solution Signup and view all the answers

Which of the following statements about deep violet staining in toluidine blue is true?

It indicates abnormal chromatin structure. Signup and view all the answers

What is a significant implication of >30% DNA damage as determined by the CMA3 assay?

Reduction in fertilization rates during ICSI Signup and view all the answers

In the comet assay, where do the intact DNA fragments remain after separation?

In the comet’s head Signup and view all the answers

What is the primary purpose of the epididymis in sperm maturation?

Allowing sperm to acquire fertilization potential Signup and view all the answers

What stage must oocytes reach to be suitable for ICSI procedures?

Metaphase II Signup and view all the answers

What does the cumulus expansion indicate about the oocyte?

The oocyte has good quality. Signup and view all the answers

Which of the following structures is evaluated to determine oocyte quality?

Oocyte cytoplasm Signup and view all the answers

What is the role of cumulus cells surrounding the oocyte during maturation?

To form gap junctions and facilitate communication Signup and view all the answers

How are oocytes categorized as Metaphase II?

By the expansion of the cumulus and a 'sun-burst' appearance Signup and view all the answers

During which phase does the first polar body extrusion occur?

Metaphase II Signup and view all the answers

What type of cells differentiate into mural and cumulus cells during follicular development?

Granulosa cells Signup and view all the answers

What role do mitochondria play in human spermatozoa?

They regulate calcium levels and reactive oxygen species. Signup and view all the answers

Why are oocytes at Prophase I not suitable for ICSI?

They contain a diploid chromosomal set. Signup and view all the answers

What does a high mitochondrial membrane potential (MMP) indicate when using JC-1 dye?

Increased red fluorescence due to J-aggregates. Signup and view all the answers

Which fertilization event is NOT directly mentioned as part of sperm function testing?

Mitochondrial health. Signup and view all the answers

During in vitro fertilization (IVF), which barrier remains for sperm selection?

The zona pellucida. Signup and view all the answers

What is the JC-1 ratio used to evaluate?

Mitochondrial membrane potential. Signup and view all the answers

Which statement is true regarding sperm selection during intracytoplasmic sperm injection (ICSI)?

Only sperm morphology and viability are considered. Signup and view all the answers

Which factor can indicate dysfunctional sperm despite normal morphology and motility?

Mitochondrial membrane potential. Signup and view all the answers

What is a common misconception about sperm selection barriers in IVF?

Defective sperm cannot bypass the zona pellucida. Signup and view all the answers

What is the primary function of prostate-specific antigen (PSA) in semen?

To facilitate the swimming movement of sperm into the uterus Signup and view all the answers

Which gland contributes 20% to the volume of semen and provides mucoid alkaline fluid?

Cowper's gland Signup and view all the answers

What is a significant cause of male infertility linked to swelling of veins above the testicle?

Varicocele Signup and view all the answers

Which hormonal factor can negatively influence spermatogenesis in males?

Fluctuations in LH levels Signup and view all the answers

What does semen analysis predominantly evaluate regarding male fertility?

Testicular and epididymal function Signup and view all the answers

What color change in semen could indicate inflammation of the prostate?

Red Signup and view all the answers

Which anatomical abnormality is characterized by the failure of the testes to descend into the scrotum?

Cryptorchidism Signup and view all the answers

What contributes to the liquefaction of semen post-ejaculation?

PSA activity Signup and view all the answers

Study Notes

Fertility Analysis - Male Reproductive System

The male reproductive system includes the following structures: urinary bladder, ureter, seminal vesicle, bulbourethral gland, prostate gland, ductus deferens, epididymis, testis, urethra, and glans of penis.
Sperm is produced in the seminiferous tubules within the testes.
The hypothalamic-pituitary-testicular axis regulates testosterone production, spermatogenesis, LH and FSH.
GnRH (gonadotropin-releasing hormone) is synthesized by the hypothalamus and stimulates the anterior pituitary to release FSH and LH.
FSH stimulates Sertoli cells which support spermatogenesis.

Fertility Analysis - Male Reproduction & Endocrinopathies

Prolactin is a polypeptide hormone secreted from the anterior pituitary gland.
Prolactin inhibits GnRH release, leading to decreased spermatogenesis and infertility in males, but this is considered pathologic.
Normal prolactin levels in males are 2-18 ng/mL; 2-30 ng/mL in females; 10-210 ng/mL during pregnancy third trimester
Inhibin B is a glycoprotein from the TGF-β family produced by Sertoli cells in response to FSH stimulation.
Inhibin B controls FSH function via negative feedback and is a marker of Sertoli cell function.
Inhibin suppresses GnRH-stimulated release of FSH.

Fertility Analysis - Male Infertility

Varicocele: swelling of the testicular veins, contributing to 38% of male infertility cases. It results in decreased sperm count, motility, and abnormal morphology.
Undescended testicle (Cryptorchidism): Inability of testicles to descend into the scrotum, occurring in 2-6% of newborns.
Hormonal imbalance: Genetic conditions, gland malfunctions (hypothalamus, pituitary, thyroid, adrenal glands) and unhealthy weight can have impacts on sperm production and male fertility. Changes in LH, FSH, and testosterone levels can impact spermatogenesis.

Fertility Analysis - Evaluation of Male Infertility

Important aspects of male infertility evaluation include: reproductive history, medical history, physical examination, semen analysis, endocrine evaluation, and advanced analysis.

Fertility Analysis - Semen Analysis

Semen analysis is critical for assessing male fertility potential, providing a global measure of testicular/epididymal function, vasal patency and accessory sexual gland function.
A normal semen volume is 2–6 mL after 2–7 days of abstinence.
Color variations in semen can indicate potential issues.
Greyish white color is considered normal, while red semen may point to prostate inflammation, and yellow/green to infections, jaundice, or vitamin/medication presence
Aspermia: no ejaculate after orgasm; Hypospermia: under 0.5 mL of semen; Hyperspermia: over 6 mL of semen.

Fertility Analysis - Semen pH

Normal semen pH is 7.2 - 8.2, increasing slightly after ejaculation.
Variations in pH are typically due to prostate or seminal vesicle inflammation.
A low semen volume and pH below 7.0 usually signals ejaculatory duct obstruction.

Fertility Analysis - Sperm Count & Morphology

Sperm counts are reported as millions of sperm per milliliter (e.g., 15 million per mL). Total sperm count is the product of sperm concentration and semen volume.
Conditions like normozoospermia (completely normal semen sample), oligozoospermia/oligospermia (<15 million/mL), and azoospermia (absence of sperm) are diagnosed based on total sperm count.
Azoospermia can be obstructive or non-obstructive.
Obstruction may be in the epididymis, vas deferens, or reproductive tract
Non-obstruction suggests problems with sperm production or testicle structure/function.

Fertility Analysis - Sperm Motility

Sperm motility is classified as rapid progressive, slow progressive, nonprogressive, and immotile.
Rapid progressive motility (>25 μm/s at 37°C and >20 μm/s at 20°C) is essential for successful fertilization.
For proper semen analysis at least 32% of sperm must be graded A and B (rapidly progressive motile spermatozoa).
Reduced sperm motility may be a symptom of issues related to male accessory sex gland secretion or emptying.
Asthenozoospermia describes the condition of reduced sperm motility due to various factors such as poor nutrition, varicocele, toxins, smoking, age, cancer treatments, and febrile episodes, among others.

Fertility Analysis - Sperm Viability & Necrosis

Vitality is assessed through staining methods when sperm motility is less than 40%.
Necrozoospermia refers to dead/necrotic sperm in a semen sample.
Normal semen samples contain less than 30% necrotic sperm. Moderate necrozoospermia is 50-80% and Severe necrozoospermia is over 80%. Complete necrozoospermia involves almost all cells being dead/necrotic.

Fertility Analysis - Sperm Morphology

Sperm morphology quantitatively evaluates normal and abnormal sperm forms in an ejaculate using WHO classification.
Abnormalities are based on head, tail, and mid-piece characteristics from postcoital cervical mucus or zona pellucida surface.
Teratozoospermia describes an increased percentage of abnormal sperm morphology in the semen exceeding 96%.

Fertility Analysis - Biochemical Markers (Semen)

Fructose test assesses seminal vesicle function and is used to identify obstructive azoospermia in males with low ejaculate volume.
Low levels of fructose (WHO defined lower limit 13 µmol per ejaculate) with low semen volume and low pH supports obstructive azoospermia diagnosis.
Endtz test detects peroxidase within the neutrophils in a semen sample. This supports screening for granulocytes in unusual conditions.

Fertility Analysis - Biochemical Markers (Blood)

Testosterone levels (300-1000 ng/dL) vary daily (best measured 8 AM-10 AM) and decline approximately 1% per year after age 35.
Hypogonadism is defined as a serum testosterone level under 300 ng/dL, exhibiting various physical signs like increased body fat, reduced strength and muscle bulk, low bone mineral density, decreased energy/motivation and libido among other symptoms.
Prolactin levels in males range from 2-18 ng/mL. Mild elevations don't typically cause infertility, while significant elevations can inhibit FSH & LH release from the pituitary gland, decreasing testosterone levels.

Fertility Analysis - Oxidative Stress & Antioxidant Capacity

ROS (reactive oxygen species) refers to oxygen metabolism by-products.
Free radicals, including superoxide and hydroxyl radicals, indicate potential oxidative stress due to unpaired electrons.
Antioxidant capacity of seminal plasma includes enzymatic antioxidants and non-enzymatic antioxidants such as vitamin C, E and zinc, with non-enzymatic antioxidants contributing to about 65% of the total antioxidant capacity (TAC)

Fertility Analysis - Sperm DNA Damage

Sperm DNA integrity is crucial for fertilization and transmitting genetic material.
DNA Damage includes single or double stranded breaks, interstrand and intrastrand cross-linkage, DNA base modifications and protamine mispackaging. Often termed as DNA fragmentation
Procedures like the Comet assay (a single-cell gel electrophoresis) can be used to measure DNA breaks in sperm.

Fertility Analysis - Oocyte & Sperm Assessment

Oocyte maturation includes nuclear and cytoplasmic maturation.
Mature eggs arrest in metaphase II until fertilization.
Oocyte quality can be assessed through OCCC structure (measuring cumulus expansion for potential fertilization success), zona pellucida and polar body morphology.
The hypo-osmotic swelling test (HOST) detects sperm viability issues, especially in samples with testicular or epididymal aspiration. PVP (Polyvinylpyrrolidone) is a common immobilization medium for ICSI, but may damage mitochondria

Fertility Analysis - Physical Exams

Breast evaluation for symmetry, noting any evidence of galactorrhea (abnormal secretion from the breasts) which could point to pituitary lesions, in a fertility evaluation. Galactorrhea commonly involves bilateral multiple duct discharges in appearance.
Hysterosalpingogram (HSG) checks fallopian tube patency and uterine cavity for normal function.
Antral Follicle Count (AFC) evaluates the number or recruited follicles from both ovaries in the earlier phase of the cycle via ultrasound. It serves as a marker for ovarian reserve. Folliculometry tracks follicle growth and ovulation timing for 9-20 days into the cycle, to confirm that ovulation has occurred.
Chlamydia antibody testing checks for previous infection as a cause of potential salpingitis (inflammation of the fallopian tubes.) This accounts for over 50% of tubal factor infertility.

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Description

Test your knowledge on the key functions and components of male reproductive biology. This quiz covers crucial topics such as the blood-epididymis barrier, seminal fluid components, and oxidative stress in sperm. Perfect for students and enthusiasts of reproductive science.