Embryonic Oogenesis Growth Quiz

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Questions and Answers

What is the estimated number of oogonia at 14–15 weeks' gestation?

43,000

7,000

140,000

7 million (correct)

What happens to the number of germ cells after the seventh month of embryonic development?

It doubles.

It remains constant.

It drops precipitously. (correct)

It increases rapidly.

What is the process called when the remaining oogonia enter the first meiotic division?

Folliculogenesis

Mitosis and growth

Gonadal changes during puberty

Primary oocytes (correct)

What is the first phenotypic change that occurs during puberty?

Breast development/testicular enlargement Signup and view all the answers

What triggers the anterior pituitary to release LH and FSH during puberty?

GnRH from the hypothalamus Signup and view all the answers

What is the process called when ovarian follicles grow and develop?

Folliculogenesis Signup and view all the answers

Which of the following is NOT a factor affecting the onset of puberty?

Socioeconomic status Signup and view all the answers

What is the role of the hormone leptin in puberty onset?

It determines the age of menarche in girls Signup and view all the answers

Which of the following is the correct sequence of events in the hormonal control of the male reproductive system?

Hypothalamus → Anterior pituitary → Interstitial cells → Sertoli cells Signup and view all the answers

What is the function of Androgen Binding Protein (ABP) in the male reproductive system?

It binds to testosterone and facilitates spermatogenesis Signup and view all the answers

During spermatogenesis, what is the result of the first meiotic division?

Two secondary spermatocytes with 23 double-stranded chromosomes Signup and view all the answers

What is the primary function of the seminal vesicle in the male reproductive system?

To produce seminal fluid Signup and view all the answers

What is the primary mechanism by which nitric oxide (NO) facilitates penile erection?

Dilation of cavernosal arteries and relaxation of trabecular smooth muscle Signup and view all the answers

Which of the following events occurs during the emission phase of the male sexual response cycle?

Closure of the sphincter at the base of the bladder to prevent retrograde flow of semen Signup and view all the answers

What is the primary role of the trabecular smooth muscle relaxation during penile erection?

Facilitating the entry of blood into the cavernous spaces Signup and view all the answers

Which of the following is the primary function of the sympathetic nervous system during the ejaculation phase of the male sexual response cycle?

Stimulating the contraction of the skeletal muscles to expel semen Signup and view all the answers

What is the primary mechanism by which the increase in blood volume and relaxation of the trabecular smooth muscle leads to penile erection?

Increased pressure in the cavernous spaces compresses the venules, obstructing venous outflow Signup and view all the answers

Which of the following is a key event that occurs during the emission phase of the male sexual response cycle?

Secretion of prostatic fluid into the urethra to mix with the seminal fluid Signup and view all the answers

Which hormone is responsible for the development of secondary sex characteristics in males during puberty?

Testosterone Signup and view all the answers

What is the process by which ovarian follicles grow and develop in the ovary?

Folliculogenesis Signup and view all the answers

How does the sensitivity of the hypothalamus and pituitary gland to negative feedback from testosterone and estrogen change during puberty?

The sensitivity decreases, allowing for an increase in hormone production. Signup and view all the answers

Which of the following is not a secondary sex characteristic that develops in males during puberty?

Enlargement of the breasts Signup and view all the answers

What is the primary function of the hypothalamus and pituitary gland during puberty?

To regulate the negative feedback from testosterone and estrogen Signup and view all the answers

Which of the following statements about spermatogenesis is correct?

Spermatids undergo spermiogenesis to produce mature spermatozoa with a haploid chromosome number of 23. Signup and view all the answers

Which of the following statements about the composition of semen is correct?

Seminal vesicles contribute approximately 60% of the seminal fluid, while the prostate contributes 30%. Signup and view all the answers

Which of the following statements about the function of Sertoli cells is incorrect?

Sertoli cells secrete inhibin, which increases sperm production. Signup and view all the answers

What is the primary role of the scrotum in relation to sperm survival?

The scrotum contains smooth muscle that contracts to elevate the testes during exposure to cold and arousal, maintaining a lower temperature for sperm survival. Signup and view all the answers

Which of the following statements about the composition of the scrotum is correct?

The scrotum is divided into two pouches by a septum, with each pouch containing a testis. Signup and view all the answers

What is considered a normal sperm count for a healthy male?

50-150 million spermatozoa per milliliter of semen. Signup and view all the answers

Study Notes

Oogonia and Germ Cells

Estimated number of oogonia at 14–15 weeks' gestation is around 6 to 7 million.
After the seventh month of embryonic development, the number of germ cells declines significantly as many oogonia undergo atresia.

Meiotic Division and Puberty Changes

Remaining oogonia enter the first meiotic division, a process called oogenesis.
The first phenotypic change during puberty is the development of breast tissue in females.

Hormonal Triggers and Follicular Development

Anterior pituitary releases LH (Luteinizing Hormone) and FSH (Follicle-Stimulating Hormone) during puberty due to increased gonadotropin-releasing hormone (GnRH) from the hypothalamus.
Ovarian follicles grow and develop through a process known as folliculogenesis.

Factors Affecting Puberty Onset

Genetics, nutrition, and overall health are key factors affecting the onset of puberty; however, environmental toxins are NOT a factor.

Leptin's Role in Puberty

Leptin plays a crucial role in signaling the body’s energy status, influencing the timing of puberty onset.

Male Reproductive System Hormonal Control

Correct sequence of events in the hormonal control of the male reproductive system involves hypothalamic release of GnRH, stimulating anterior pituitary to release LH and FSH, leading to testosterone production from Leydig cells.

Androgen Binding Protein Function

Androgen Binding Protein (ABP) binds to testosterone in the seminiferous tubules, increasing its concentration and promoting spermatogenesis.

Spermatogenesis

The first meiotic division during spermatogenesis results in two secondary spermatocytes, each with half the original chromosome number.
Sertoli cells support and nourish developing sperm cells.

Seminal Vesicle and Penile Erection

The primary function of the seminal vesicle is to produce a fluid that nourishes sperm and makes up a significant portion of semen.
Nitric oxide (NO) facilitates penile erection by causing vasodilation of blood vessels in the penis.

Male Sexual Response Cycle

During the emission phase, the sperm are transported from the epididymis to the ejaculatory duct, mixing with seminal fluid.
Trabecular smooth muscle relaxation is essential during penile erection, allowing increased blood flow into the erectile tissues.

Ejaculation and Sympathetic Nervous System

The primary role of the sympathetic nervous system during ejaculation is to trigger the contraction of seminal vesicles and prostate to expel semen.
Increased blood volume and trabecular muscle relaxation lead to penile erection through engorgement of erectile tissues.

Secondary Sex Characteristics and Hormonal Changes

Testosterone is responsible for the development of secondary sex characteristics in males during puberty.
Sensitivity of the hypothalamus and pituitary gland to negative feedback from testosterone and estrogen increases during puberty.

Scrotum Function and Sperm Count

The primary function of the scrotum is to maintain optimal temperature for sperm survival, crucial for fertility.
A normal sperm count for a healthy male is typically considered to be 15 million to over 200 million sperm per milliliter of semen.

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Description

Test your knowledge on the growth of oogonia during embryonic development, including the rapid increase in numbers up to the 9th week and the subsequent drop after the seventh month. Learn about the transition of oogonia into primary oocytes and their progression through the first meiotic prophase I stage.