Meiosis and Embryology of Reproductive System

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Questions and Answers

How many germ cells does the male produce after meiotic division?

Two

Three

One

Four (correct)

What is a bar body?

A condensed inactive X chromosome (correct)

A type of sperm cell

An active X chromosome

A feature of the Y chromosome

What happens to the cortex in a fetus with a 46 XY chromosome configuration?

It regresses (correct)

It forms the uterus

It develops into ovaries

It becomes the external genitalia

How do human chromosomes get studied in detail?

By growing them in tissue culture Signup and view all the answers

At what week do the gonads of both sexes begin to differentiate?

6 weeks Signup and view all the answers

What occurs in the absence of a functional testis?

Development of Mullerian ducts Signup and view all the answers

How many X chromosomes are active in female somatic cells?

One Signup and view all the answers

What substance do Sertoli cells produce in the presence of functional testis?

Mullerian inhibiting substances Signup and view all the answers

What is the definition of menopause?

A diagnosis made after one year without a period Signup and view all the answers

At what age range does menopause typically occur?

45-55 years Signup and view all the answers

What hormonal change occurs following menopause?

Elevated gonadotropins due to loss of ovarian feedback Signup and view all the answers

What is one of the psychological changes that may occur during menopause?

Increased risk of depression Signup and view all the answers

What is the term climacteric referring to?

The transition period of waning ovarian function Signup and view all the answers

What is the consequence of premature menopause?

Menstruation stops before 40 years of age Signup and view all the answers

What metabolic change is associated with changes during menopause?

Increased incidence of coronary artery disease Signup and view all the answers

Which hormone is primarily deficient in postmenopausal women?

Estradiol Signup and view all the answers

What is the primary role of the Sertoli fluids in sperm transport?

To aid in the movement of sperm Signup and view all the answers

During sperm storage in the epididymis, what characteristic do sperm acquire?

Motility characteristics without fertilization potential Signup and view all the answers

What processes occur when sperm reaches the female genital tract?

Capacitation and acrosomal reaction Signup and view all the answers

What is the main source of secretions in the semen?

Seminal vesicles (60%) Signup and view all the answers

Which part of the mature spermatozoon is responsible for penetrating power?

Head Signup and view all the answers

What is the role of the ejaculatory duct in the male reproductive system?

It connects the vas deferens to the prostatic urethra. Signup and view all the answers

What does spermatogenesis begin?

At puberty. Signup and view all the answers

What is produced from one primary spermatocyte after undergoing meiosis?

Four haploid spermatids. Signup and view all the answers

What is the process through which spermatids mature into spermatozoa called?

Spermiogenesis. Signup and view all the answers

What is one of the functions of Sertoli cells?

Production of Mullerian inhibitory factor. Signup and view all the answers

How long does the process of spermatogenesis typically take?

60-70 days. Signup and view all the answers

How many spermatids can be produced from one spermatogonium?

<ol start="64"> <li></li> </ol> Signup and view all the answers

What triggers first meiotic division in primary spermatocytes?

Pairing of homologous chromosomes. Signup and view all the answers

What phenomenon reduces the interoital opening by 50% in females, facilitating a firmer grip during intercourse?

Orgasmic platform Signup and view all the answers

Which of the following statements about orgasms is true?

Females can experience multiple orgasms in a single sexual act. Signup and view all the answers

What physiological effect is commonly associated with ejaculation in males?

Hyperventilation Signup and view all the answers

What distinguishes the refractory period in males from females?

Males have a variable refractory period that can last minutes to hours. Signup and view all the answers

Which muscles are involved in the mechanism of ejaculation in males?

Cavernous muscles and pelvic floor muscles Signup and view all the answers

What did Masters and Johnson discover about sexual ability in older adults?

Sexual ability persists with good health and an attractive partner. Signup and view all the answers

In females, what contributes to the pleasurable sensations experienced during orgasm?

Pelvic organ contractions and muscle spasms Signup and view all the answers

Which of the following occurs as a consequence of sympathetic stimulation during ejaculation?

Emission of semen into the internal urethra Signup and view all the answers

Study Notes

Meiosis and Germ Cell Formation

Females produce one ovum (23X) after meiosis, while males generate four spermatozoa (2 with 23X and 2 with 23Y).
Female development is neuter; the presence of the Y chromosome is crucial for male development.
In females, one X chromosome is active in somatic cells; the inactive X condenses into a Barr body.
Human chromosomes can be analyzed by culturing cells, arresting mitosis with colchicine, staining, and microscopy.

Embryology of the Reproductive System

Gonads are identical until the 6th week of intrauterine life, derived from the genital ridge on the posterior abdominal wall.
Germ cells migrate to the genital ridge by the 3rd week; 46XX chromosomes lead to ovary development, while 46XY results in testes.
Genital differentiation begins at 8 weeks, with distinguishable male and female structures identifiable by 10-12 weeks.
In absence of functional testes, Müllerian ducts develop into female reproductive structures; presence of testes leads to regression of these ducts.

Menstrual Cycle and Menopause

Menopause is the complete cessation of menstruation diagnosed after one year without a period, occurring between ages 45-55.
Female gonadal aging results in ovarian follicle atrophy and reduced estrogen levels, leading to elevated gonadotropins.
Climacteric denotes the transitional phase leading to menopause; includes psychological, vasomotor, and physical changes.
Hormone replacement therapy may alleviate post-menopausal symptoms; premature menopause occurs before age 40.

Physiology of Human Sexual Response

Masters and Johnson conducted foundational studies on human sexual responses, compiling data from numerous participants.
Females experience engorgement and lubrication; the interoital opening is reduced, forming an orgasmic platform.
Orgasm represents peak sexual tension, with coordinated muscular contractions; males experience ejaculation simultaneous with orgasm.
Females can have multiple orgasms, characterized by rapid muscle contractions and euphoric sensations.

Spermatogenesis

Spermatogenesis begins at puberty, producing 100-200 million sperm daily, occurring in the seminiferous tubules.
Mitosis starts with spermatogonia that divide into primary spermatocytes.
Meiosis occurs when primary spermatocytes divide into secondary spermatocytes, producing four haploid spermatids per primary spermatocyte.
Spermiogenesis involves maturation of spermatids into spermatozoa within Sertoli cells.

Structure and Function of Spermatozoa

Mature spermatozoa consist of a head (with acrosome), middle piece (energy storage), and tail (for propulsion).
Sertoli cells support sperm maturation and secretes hormones, including Müllerian inhibiting factor and inhibin.
Mature spermatozoa are stored in the epididymis for up to a month, gaining motility as they travel through the male reproductive tract.

Fertilization Process

Capacitation enhances sperm ability to fertilize; uterine fluids remove inhibitory factors.
The acrosomal reaction involves enzymatic release for penetrating the egg's protective layers during fertilization.

Composition of Semen

Semen consists of spermatozoa (10%), seminal vesicle secretions (60%), prostate secretions (30%), and additional glandular contributions.

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Description

Explore the intricate details of meiosis and the formation of germ cells in this quiz. Learn about the differences in reproductive cell production between males and females, as well as the embryological development of the reproductive system. Test your knowledge on chromosome behavior and the formation of reproductive structures.