Male reproductive system Questions in English

(B) The condition where the testes fail to descend into the scrotum during development is known as $Cryptorchidism$. Since the temperature of the scrotum is lower than the body temperature,which is essential for spermatogenesis,the failure of descent leads to sterility in the individual.

(A) In rabbits,the testes are located outside the abdominal cavity in a pouch called the scrotal sac (testes sac). The structures associated with the testes that are also located outside the abdominal cavity include the epididymis and the penis. Therefore,the testes,penis,and epididymis are considered ex-abdominal reproductive organs.

(D) In most mammals,the testes descend into the scrotum outside the abdominal cavity to maintain a temperature lower than the body temperature,which is necessary for spermatogenesis. However,in some mammals like bats,elephants,and whales,the testes remain permanently within the abdominal cavity. This condition is known as intra-abdominal testes.

(A) Stereocilia are long, non-motile, branched microvilli-like projections found on the apical surface of certain epithelial cells. They are primarily found in the $Epididymis$ and the $Vas deferens$ of the male reproductive system, where they increase the surface area for the absorption of fluid and the maturation of sperm. Among the given options, $Epididymis$ is the most characteristic site for the presence of stereocilia.

(B) $Leydig$ cells,also known as interstitial cells,are located in the interstitial spaces outside the seminiferous tubules within the $Testis$.
These cells are responsible for the synthesis and secretion of testicular hormones called androgens,primarily $Testosterone$.

(A) Cryptorchidism is a medical condition where one or both testes fail to descend from the abdomen into the scrotum during development.
Since the scrotum provides a temperature slightly lower than the body temperature,which is essential for spermatogenesis,the failure of the testes to descend can lead to infertility and an increased risk of testicular cancer.

(C) The human penis is composed of three cylindrical masses of erectile tissue: two $Corpus cavernosum$ located dorsally and one $Corpus spongiosum$ located ventrally.
These tissues are responsible for the erection of the penis during sexual arousal.
Therefore, both $Corpus cavernosum$ and $Corpus spongiosum$ are masses of erectile tissue found in the human penis.

(D) The ejaculatory duct is a short duct that is formed by the union of the duct of the seminal vesicle and the vas deferens (ductus deferens).
These ducts pass through the prostate gland and open into the urethra.
Therefore,the correct option is $D$.

(NONE) The seminal vesicles are accessory glands in the male reproductive system.
They secrete a fluid that constitutes about $60-70\%$ of the volume of semen.
This fluid is rich in fructose, which serves as the primary energy source for sperm motility.
Among the given options, none explicitly list 'seminal vesicles'. However, in the context of male reproductive anatomy, the seminal vesicles are the primary source of fructose. If the question implies the source of seminal plasma, the seminal vesicles are the correct answer. Since the provided options are limited, please note that none of the listed options $(A, B, C, D)$ are the primary source of fructose. The correct answer should be 'Seminal Vesicles'.

(D) Sustentacular cells,also known as Sertoli cells,are located within the seminiferous tubules of the testes.
They provide nutrition to the developing spermatozoa.
They form the blood-testis barrier,which protects the developing sperm from the immune system.
They do not convert estrogen into testosterone; in fact,Leydig cells are responsible for the synthesis of testosterone.
Therefore,option $D$ is the incorrect statement.

(A) Human semen contains a high concentration of citric acid,which is primarily secreted by the prostate gland.
Citric acid helps in maintaining the pH of the semen and acts as a buffer.
It also plays a role in the liquefaction of semen after ejaculation.

(C) The male reproductive system includes a series of ducts that transport sperm from the testes to the exterior.
$1$. The intratesticular genital duct system consists of the $Rete testis$, $Tubuli recti$, and $Vasa efferentia$.
$2$. The $Vas deferens$ is an extratesticular duct that arises from the $Epididymis$ and transports sperm towards the $Ejaculatory duct$.
$3$. Therefore, the $Vas deferens$ is not part of the intratesticular genital duct system.

(C) The secretions of the male accessory glands,specifically the seminal vesicles,are rich in fructose,calcium,and certain enzymes.
These components provide nourishment and energy to the sperm,facilitate their motility,and help in the coagulation of semen after ejaculation.
Therefore,the correct answer is $C$ (Male accessory glands).

(C) The $Vasa$ $efferentia$ are the ductules that lead from the $Rete$ $testis$ to the $Epididymis$.
These ductules are lined with ciliated columnar epithelium.
The cilia help in the movement of spermatozoa from the $Rete$ $testis$ towards the $Epididymis$.

(B) In the human male fetus, the testes develop in the $Abdominal \text{ cavity}$.
During the later stages of fetal development (usually around the $7^{th}$ to $8^{th}$ month of gestation), the testes descend into the $Scrotum$ through the $Inguinal \text{ canal}$.
In most premature infants, this descent has not yet been completed, and therefore, the testes are still located within the $Abdominal \text{ cavity}$.

(B) The $Tunica \text{ } albuginea$ is a tough, fibrous connective tissue capsule that surrounds and encloses the $Testis$.
It provides structural support and protection to the seminiferous tubules located within the $Testis$.

(A) The seminiferous tubules are the structural and functional units of the testes. Each seminiferous tubule is lined by a germinal epithelium and is surrounded by a thin layer of fibrous connective tissue known as the tunica propria. This layer provides structural support to the tubules.

(C) The $vas$ $deferens$ is the duct that transports sperm from the epididymis to the ejaculatory duct. If the $vas$ $deferens$ is cut or blocked (a procedure known as a vasectomy),the sperm produced in the testes cannot reach the urethra. Consequently,the semen ejaculated will be devoid of sperm,although it will still contain secretions from the accessory glands like the seminal vesicles and prostate gland.

(C) The human testis is oval in shape,with a length of about $4$ to $5 \ cm$ and a width of about $2$ to $3 \ cm$.
Each testis is covered by a dense covering.
Inside each testis,there are about $250$ compartments called testicular lobules.
These lobules contain $1$ to $3$ highly coiled seminiferous tubules in which sperms are produced.

(B) The glans penis is the sensitive,bulbous end of the penis. In uncircumcised males,it is covered by a loose fold of skin known as the foreskin or prepuce. Therefore,the correct option is $B$.

(C) The primary sex organ in males is the $Testis$.
Primary sex organs are defined as those organs that produce gametes (sperms in males) and secrete sex hormones (androgens like testosterone).
The $Testis$ performs both these functions.
Other organs like the $Scrotum$,$Penis$,and $Prostate$ are considered accessory reproductive organs or secondary sex organs because they assist in the transport or maturation of gametes but do not produce them.

(C) Seminal plasma is the fluid secreted by the accessory glands (seminal vesicles,prostate gland,and bulbourethral glands).
It is rich in fructose,calcium,and certain enzymes.
The primary function of seminal plasma is to provide a nutrient-rich,alkaline medium that facilitates sperm motility and protects them from the acidic environment of the female reproductive tract.

(D) The male accessory glands in humans consist of the paired seminal vesicles,a single prostate gland,and paired bulbourethral glands.
These glands secrete fluids that form the seminal plasma,which is rich in fructose,calcium,and certain enzymes.
Therefore,all the options provided are correct components of the male accessory glands.

(B) The prostate gland is an accessory reproductive gland in males that secretes a milky,slightly acidic fluid containing citric acid,acid phosphatase,and proteolytic enzymes.
This secretion forms a significant part of the seminal plasma.
Its primary function is to nourish the sperms and stimulate their motility (activity) to facilitate fertilization.

(A) In the human male reproductive system,the testes contain seminiferous tubules and interstitial spaces.
Leydig cells (also known as interstitial cells) are located in the interstitial spaces outside the seminiferous tubules.
These cells synthesize and secrete testicular hormones called androgens,primarily testosterone,under the influence of Luteinizing Hormone $(LH)$.
Therefore,the correct option is $A$.

(C) Testosterone is the primary male sex hormone.
It is secreted by the Leydig cells,also known as interstitial cells,which are located in the interstitial spaces outside the seminiferous tubules in the testes.
Sertoli cells provide nutrition to the developing germ cells and are not responsible for the secretion of testosterone.
Sustentacular cells is another name for Sertoli cells.
Therefore,the correct answer is Leydig cells or interstitial cells.

(B) In mammals, the male reproductive system includes accessory glands that secrete fluids to nourish and transport sperm.
$1$. The $Prostate$ $gland$ is a major accessory gland in the male reproductive system of mammals, which secretes a milky, slightly acidic fluid that forms a significant part of the semen.
$2$. The $Phallic$ $gland$ and $Mushroom$ $gland$ are found in the male reproductive system of insects like cockroaches.
$3$. The $Bartholin's$ $gland$ is found in the female reproductive system of mammals, homologous to the $Bulbourethral$ $gland$ in males.
Therefore, the correct option is $B$.

(A) The human penis consists of three cylindrical masses of erectile tissue: two dorsal $corpus \ cavernosum$ and one ventral $corpus \ spongiosum$.
The $corpus \ spongiosum$ expands at its distal end to form a bulbous structure known as the $glans \ penis$.
Therefore,the $glans \ penis$ is formed primarily by the distal enlargement of the $corpus \ spongiosum$.

(A) The vas deferens is a muscular tube that transports sperm from the epididymis to the ejaculatory duct.
It originates from the cauda epididymis (tail of the epididymis),which is the distal part of the epididymis where mature sperm are stored before ejaculation.

(A) The Cowper's glands,also known as the bulbourethral glands,are a pair of small exocrine glands present in the male reproductive system of mammals.
These glands are located posterior to the prostate gland at the base of the penis.
Their primary function is to secrete a clear,alkaline fluid that neutralizes the acidity of the urine in the urethra and acts as a lubricant during sexual intercourse.
Therefore,they are characteristic of male mammals.

(B) The testis is located outside the abdominal cavity within a pouch called the scrotum.
This position is essential for maintaining a low temperature ($2-2.5^{\circ}C$ lower than the normal internal body temperature) required for spermatogenesis.
The testis is connected to the abdominal cavity through the inguinal canal,which allows for the passage of blood vessels,nerves,and the spermatic cord.

(C) The seminal vesicles are a pair of tubular glands located behind the urinary bladder in the male reproductive system.
They are situated above the prostate gland and the Cowper's (bulbourethral) glands.
They secrete a significant portion of the seminal fluid,which contains fructose,prostaglandins,and clotting proteins.

(A) Somatic cells are diploid $(2n)$ in nature. Given that the number of somatic chromosomes is $40$,it implies $2n = 40$.
Seminiferous tubules are the structural components of the testes,which are composed of somatic cells (such as Sertoli cells and spermatogonia).
Since the cells forming the wall of the seminiferous tubule are somatic cells,they contain the diploid number of chromosomes.
Therefore,the number of chromosomes in the cells of the seminiferous tubule is $40$.

(A) Cryptorchidism is a medical condition where one or both testes fail to descend from the abdomen into the scrotum during fetal development.
Normally,the testes descend into the scrotum before birth.
If they remain in the abdominal cavity or inguinal canal,the higher body temperature prevents normal spermatogenesis,which can lead to infertility.

(B) The $Tunica \text{ } vaginalis$ is the serous covering of the testis. It is a pouch of serous membrane that covers the testis and is located within the scrotal sac (scrotal cavity). Therefore, it is associated with the male testis.

(A) In humans and rabbits,the testes are located outside the abdominal cavity within a pouch called the scrotum.
This arrangement is essential for maintaining the temperature of the testes $2-2.5^{\circ}C$ lower than the normal internal body temperature,which is necessary for spermatogenesis.
The scrotum is connected to the abdominal cavity through a passage known as the $Inguinal \ canal$.

(D) In the rabbit's reproductive system, the $Vasa \text{ } deferentia$ (singular: $Vas \text{ } deferens$) are the ducts that transport sperm from the testes to the urethra. These structures are specific to the male reproductive system. In contrast, the $Oviduct$ and $Vagina$ are parts of the female reproductive system. The $Urethra$ is present in both sexes, although its function and anatomical path differ slightly.

(A) Testosterone is the primary male sex hormone.
It is synthesized and secreted by the Leydig cells (also known as interstitial cells) located in the interstitial spaces of the testis.
These cells are stimulated by the Luteinizing Hormone $(LH)$ released from the anterior pituitary gland.

(D) The seminal plasma in humans is composed of secretions from the seminal vesicles,the prostate gland,and the bulbourethral glands (also known as Cowper's glands).
These secretions provide nutrients (like fructose),enzymes,and a buffering environment for the sperm to survive and remain motile.
The seminiferous tubules are the site of sperm production,not a source of seminal plasma secretion.
Therefore,the correct combination of glands contributing to seminal plasma is the seminal vesicles,prostate gland,and bulbourethral glands.

(A) The epididymis is a coiled tube located on the posterior surface of the testis. It is divided into three main regions:
$1$. $Caput$ (head) epididymis: This is the superior,enlarged portion located on the anterior/superior part of the testis.
$2$. $Corpus$ (body) epididymis: This is the middle portion.
$3$. $Cauda$ (tail) epididymis: This is the inferior portion that continues as the $vas$ $deferens$.
Therefore,the head of the epididymis is called the $Caput$ $epididymis$.

(D) The seminiferous tubules are the structural and functional units of the testes.
They are lined internally by a specialized layer of cells known as the germinal epithelium.
This epithelium consists of two main types of cells: $1$. Male germ cells (spermatogonia),which undergo meiosis to produce sperm,and $2$. Sertoli cells,which provide nutrition to the developing germ cells.
Therefore,the correct answer is germinal epithelium.

(A) The testes are situated outside the abdominal cavity within a pouch called the scrotum.
This arrangement is essential because the process of spermatogenesis requires a temperature that is $2-2.5^\circ C$ lower than the normal internal body temperature.
This lower temperature is necessary for the proper development and survival of sperm cells.

(C) The human testis is composed of numerous compartments called testicular lobules. Each lobule contains $1$ to $3$ highly coiled structures known as seminiferous tubules. These tubules are the sites where spermatogenesis (the production of sperm) occurs,making them the structural and functional units of the testis.

(D) The Cowper's gland,also known as the bulbourethral gland,secretes a clear,alkaline fluid that neutralizes the acidity of the urethra caused by urine.
This secretion also acts as a lubricant for the urethra and the tip of the penis during sexual intercourse (copulation).
If the gland is removed,the lubrication process is impaired,which makes the process of copulation difficult or painful.
Therefore,the primary function affected by the removal of this gland is copulation.

(C) The $prostate$ $gland$ is an accessory reproductive gland that is exclusively found in male mammals.
$Bartholin's$ $glands$ are homologous to the $bulbourethral$ $glands$ in males but are found in females.
$Perineal$ $glands$ are found in both sexes in many mammals.
Therefore, the $prostate$ $gland$ is the correct answer as it is a male-specific accessory gland.

(C) Circumcision is a surgical procedure in which the foreskin (prepuce),which is the fold of skin covering the glans penis,is removed. This procedure is often performed for religious,cultural,or medical reasons.

(D) The seminiferous tubules in the testes join to form the vasa efferentia. These vasa efferentia then lead into the epididymis. However,in the context of the male reproductive system anatomy,the duct formed by the union of the vasa efferentia (which carry sperm from the rete testis) and the epididymis leads to the vas deferens. If the question refers to the pathway of sperm,the vasa efferentia leave the testis and open into the epididymis. Among the given options,the structure that acts as the primary duct for sperm transport exiting the testis is the vasa deferentia (vas deferens).

(C) The human male reproductive system includes accessory glands such as the seminal vesicles,prostate gland,and bulbourethral glands (also known as Cowper's glands).
$A$. Cowper's glands are present in pairs.
$B$. Vas deferens is a duct,not a gland.
$C$. The prostate gland is a single gland,not a pair.
Therefore,the prostate gland is not present as a pair in the human male reproductive system.

(C) $Leydig$ cells,also known as interstitial cells,are located in the interstitial spaces outside the seminiferous tubules within the $Testis$.
These cells are responsible for the synthesis and secretion of testicular hormones called androgens,primarily $Testosterone$.