Male reproductive system Questions in English

(D) In most mammals,the testes are located outside the abdominal cavity within a pouch called the scrotum. This is necessary because the process of spermatogenesis requires a temperature lower than the normal internal body temperature. While some mammals like elephants and whales have abdominal testes,humans $(Man)$ possess scrotal testes.

(B) The inguinal canal is an anatomical passage in the lower abdominal wall. In males,it serves as a pathway for the spermatic cord,which contains the spermatic artery,pampiniform plexus of veins,nerves,and the vas deferens. Therefore,the spermatic artery is a structure found within the inguinal canal.

(A) Testosterone is produced by the Leydig cells in the testes under the influence of $ICSH$ (Interstitial Cell Stimulating Hormone),which is equivalent to $LH$ in males.
High levels of testosterone exert a negative feedback effect on the hypothalamus and the anterior pituitary gland.
This negative feedback specifically inhibits the secretion of $GnRH$ from the hypothalamus and $ICSH$ $(LH)$ from the anterior pituitary,thereby maintaining hormonal homeostasis.

(D) Testosterone is the primary male sex hormone. It is synthesized and secreted by the Leydig cells,also known as interstitial cells. These cells are located in the interstitial spaces,which are the regions situated between the seminiferous tubules in the testes. Therefore,the correct answer is the cells that lie between the seminiferous tubules.

(C) Leydig cells,also known as interstitial cells,are located in the connective tissue spaces between the seminiferous tubules of the testis.
These cells synthesize and secrete testicular hormones,primarily $Testosterone$,which is an androgen.
$Testosterone$ is responsible for the development of secondary sexual characteristics in males and the regulation of spermatogenesis.

(D) Testosterone is the primary male sex hormone. It is synthesized and secreted by the interstitial cells of the testes,also known as Leydig cells. These cells are located in the connective tissue spaces between the seminiferous tubules.

(B) $Cryptorchidism$ is a condition in which one or both of the testes fail to descend from the abdomen into the scrotum.
In mammals,the testes are located in the extra-abdominal scrotal sac to maintain a temperature $2-2.5^{\circ}C$ lower than the internal body temperature,which is necessary for spermatogenesis.
If the testes do not descend,the higher body temperature prevents normal sperm production,often leading to sterility.

(B) The bulbourethral gland,also known as $Cowper's$ gland,is a pair of small exocrine glands in the male reproductive system.
These glands are situated beneath the urinary bladder and behind the urethra.
They secrete a clear,alkaline fluid that neutralizes the acidity of the urethra before ejaculation.

(A) In male mammals,the accessory reproductive glands include the seminal vesicles,prostate gland,and bulbourethral glands (Cowper's glands).
These glands secrete fluids that form the seminal plasma,which is rich in fructose,calcium,and certain enzymes.
Among the given options,the prostate gland is a well-known accessory reproductive gland that contributes to the formation of semen.
Gastric glands are found in the stomach,mushroom-shaped glands are found in male cockroaches,and inguinal glands are not reproductive glands in mammals.

(B) Cowper's glands, also known as bulbourethral glands, are present in $Male$ mammals.
These glands open into the urethra before it enters the penis.
Their secretion acts as a lubricant for the glans penis and also neutralizes any residual acidic urine in the urethra.

(C) The seminiferous tubules are solid cords of cells during fetal development and childhood. They develop a central lumen only after the onset of puberty. This process is driven by hormonal changes,specifically the increase in testosterone levels,which initiates spermatogenesis and the maturation of the germinal epithelium,leading to the formation of the lumen.

(D) $Sertoli$ cells are specialized cells found within the seminiferous tubules of the testes.
They are also known as nurse cells because they provide structural and metabolic support to the developing germ cells (spermatids) during spermatogenesis.
Unlike germinal cells which undergo meiosis to form sperm,$Sertoli$ cells are somatic in nature and do not produce gametes themselves.

(D) The correct answer is $D$. The spermatic cord is a bundle of nerves,ducts,and blood vessels connecting the testicles to the abdominal cavity. It passes through the inguinal canal. While the gubernaculum is a fibrous cord that helps in the descent of the testis,the structure extending between the testis and the abdominal wall containing the vas deferens,blood vessels,and nerves is the spermatic cord.

(A) $Gubernaculum$ is the ligamentous connective $(elastic)$ cord that connects the testes to the scrotal sac posteriorly.
This cord represents the original $mesorchium$.

(A, C) The germinal epithelium of the seminiferous tubules consists of two types of cells: $1$. Male germ cells (spermatogonia) which undergo meiotic divisions to form sperms. $2$. Sertoli cells which provide nutrition to the developing germ cells.

(C) The testes are held in the scrotal sac by the gubernaculum,which is a fibrous cord that anchors the testis to the floor of the scrotum.
Additionally,the inguinal canal,through which the spermatic cord passes,is relatively narrow,which restricts the movement of the testes back into the abdominal cavity.
Therefore,both the anatomical attachment provided by the gubernaculum and the structural limitation of the inguinal canal prevent the testes from being pulled into the abdomen during the contraction of the spermatic cord.

(A) The $Leydig$ cells,also known as interstitial cells,are located in the interstitial spaces of the testis.
These cells are stimulated to secrete the male sex hormone,testosterone,by the Interstitial Cell Stimulating Hormone $(ICSH)$,which is released from the anterior lobe of the pituitary gland.

(B) The $vas$ $deferens$ is a duct that transports sperm from the epididymis to the ejaculatory duct.
If the $vas$ $deferens$ is surgically disconnected (a procedure known as a vasectomy),the sperm produced in the testes cannot reach the urethra.
Consequently,the semen ejaculated will contain seminal plasma (secretions from accessory glands like the prostate and seminal vesicles) but will be devoid of sperm cells.
Therefore,the correct option is $B$.

(A) Each testis is externally covered by a dense white fibrous connective tissue capsule known as the $Tunica \ albuginea$.
This capsule extends inwards to form fibrous septa that divide the testis into testicular lobules.

(C) The correct answer is $C$.
In mammals, the testes are located outside the abdominal cavity within a pouch called the scrotum.
The $Inguinal canal$ is the anatomical passage that connects the abdominal cavity to the scrotal sac.
During fetal development, the testes descend from the abdomen into the scrotum through this $Inguinal canal$.

(B) The secretion of Cowper's glands (also known as bulbourethral glands) serves two primary functions:
$1$. It lubricates the urethra to facilitate the passage of semen during ejaculation.
$2$. It neutralizes the residual acidity in the urethra caused by urine,creating an alkaline environment that protects the sperms and keeps them viable.
Therefore,if these glands are removed,the survival and transport of sperms will be negatively affected.

(D) The $Gubernaculum$ is a fibrous cord of mesodermal tissue that connects the testis to the scrotal wall.
Its primary function is to anchor the testis and keep it in its proper position within the scrotal sac.
Therefore, the correct option is $(d)$.

(C) In the human male reproductive system,the $vas$ $deferens$ (plural: $vasa$ $deferentia$) emerges from the epididymis and travels into the abdominal cavity.
It loops over the urinary bladder and joins with the duct from the seminal vesicle to form the ejaculatory duct.
The ejaculatory ducts from both sides then open into the $urethra$,which serves as a common passage for both urine and semen.

(D) Vitamin $E$ is known as the anti-sterility vitamin. Its deficiency leads to the degeneration of the germinal epithelium of the testes in males,resulting in sterility. In females,it can cause reproductive failure and fetal resorption. Therefore,the correct option is $D$.

(C) The correct answer is $C$.
In the testes,the seminiferous tubules are embedded in a connective tissue stroma.
This interstitial space contains groups of polyhedral endocrine cells known as interstitial cells or Leydig's cells.
These cells synthesize and secrete the male sex hormone known as testosterone.

(D) Leydig cells (interstitial cells) are present in the interstitial spaces of the testes.
$1$. They are abundant during early foetal life to support the development of male reproductive organs.
$2$. Their number decreases significantly during childhood.
$3$. They increase again at the onset of puberty due to the influence of Luteinizing Hormone $(LH)$.
$4$. They persist throughout the life of a male and do not disappear completely in old age,although their activity may decline. Therefore,the statement that they are 'Absent in old age' is incorrect.

(C) The seminal fluid coagulates upon ejaculation due to the presence of fibrinogen and calcium ions in the prostatic secretion.
Specifically,the clotting enzyme (vesiculase) present in the prostatic fluid acts on the fibrinogen secreted by the seminal vesicles.
This enzymatic reaction converts fibrinogen into a fibrin clot,which causes the semen to coagulate within the vagina,thereby ensuring it remains near the cervix.

(B) The epididymis is a long,highly coiled,narrow tubule that is approximately $4-6\,m$ (about $13-20\,feet$) in length.
It is located along the posterior surface of each testis.
Since the options provided do not contain the correct length in meters,and $20\,feet$ is often cited as an approximate upper limit or common reference in some textbooks for the total length of the coiled duct system,option $B$ is the intended answer in many contexts.
However,strictly speaking,the length is $4-6\,m$.

(C) The epididymis is a coiled tube located on the posterior surface of each testis. It is anatomically divided into three distinct regions:
$1$. $Caput$ epididymis: The upper,wider head region.
$2$. $Corpus$ epididymis: The narrow,middle body region.
$3$. $Cauda$ epididymis: The lower,tail region.
Therefore,the narrow middle part is known as the $Corpus$ epididymis.

(C) The tip of the penis is covered by a loose,retractile fold of skin known as the prepuce or foreskin.

(D) Seminal fluid is secreted by the accessory glands (seminal vesicles,prostate gland,and bulbourethral glands).
It provides a nutrient-rich medium (fructose) that maintains the viability of sperms.
It contains various secretions that provide an alkaline $pH$ to neutralize the acidity of the female reproductive tract,thereby protecting the sperms.
It also provides the necessary ionic strength and fluid medium that facilitates the motility of sperms.
Therefore,all the listed functions are performed by the seminal fluid.

(B) In humans $(Men)$,the testes develop in the abdominal cavity during embryonic development.
Just before birth,they descend into the scrotal sac through the inguinal canal.
This descent is essential because the temperature of the scrotum is $2-2.5^{\circ}C$ lower than the internal body temperature,which is necessary for spermatogenesis.

(B) The scrotal sacs of a male mammal are homologous to the labia majora of a female.
Both structures develop from the same embryonic tissue (genital swellings).
In contrast,the clitoris is homologous to the penis.

(A) Cowper's gland (also known as the bulbourethral gland) in males secretes a fluid that neutralizes the acidity of the urethra and provides lubrication.
Bartholin's gland in females is homologous to the Cowper's gland in males.
Both glands perform a similar function of secreting lubricating fluid to facilitate reproductive processes.

(B) The germinal epithelium lining of the seminiferous tubules consists of two types of cells: spermatogonia (germ cells) and Sertoli cells. Sertoli cells are large,columnar supporting cells that provide nutrition and structural support to the developing germ cells. They are also known as sustentacular cells or nurse cells.

(D) The correct answer is $D$. The seminiferous tubules of the testis open into the $Rete testis$ through the $Tubuli recti$. From the $Rete testis$, the spermatozoa are transported into the $Vasa efferentia$, which then lead to the $Epididymis$.

(A) The human testis is divided into about $250$ testicular lobules. Each testicular lobule contains $1$ to $3$ highly coiled seminiferous tubules.
These tubules are the site of spermatogenesis,where sperm production occurs.
The wall of each seminiferous tubule is lined by a single-layered germinal epithelium.

(D) Leydig cells,also known as interstitial cells,are located in the interstitial spaces outside the seminiferous tubules within the testes of mammals,including rabbits.
These cells are responsible for the synthesis and secretion of male sex hormones,primarily testosterone,which is essential for the development of secondary sexual characteristics and spermatogenesis.

(C) Sertoli cells are located in the seminiferous tubules within the testes of mammals,such as the rabbit. Their primary function is to provide nutrition and support to the developing spermatozoa.

(D) The epididymis is a coiled tube located along the posterior surface of the testis. It is anatomically divided into three regions:
$1$. $Caput$ $epididymis$ (head): This is the anterior part located at the head of the testis.
$2$. $Corpus$ $epididymis$ (body): This is the middle part.
$3$. $Cauda$ $epididymis$ (tail): This is the posterior part which continues as the vas deferens.
Therefore,the head of the epididymis is known as the $Caput$ $epididymis$.

(C) The $Leydig$ cells (also known as interstitial cells) are located in the interstitial spaces outside the seminiferous tubules.
These cells are endocrine in nature and synthesize and secrete testicular hormones called androgens,primarily testosterone.

(D) In many seasonal breeders,such as certain mammals like bats and rodents,the testes are not permanently located in the scrotum.
During the non-breeding season,the testes retract into the abdominal cavity to protect them from external environmental conditions.
As the breeding season approaches,the testes descend into the scrotum to facilitate spermatogenesis at a temperature lower than the core body temperature.
Among the given options,bats $(Chiroptera)$ exhibit this seasonal migration of the testes.

(A) The testes are located in the scrotum because it provides a temperature $2-2.5^{\circ}C$ lower than the normal internal body temperature. This lower temperature is essential for the maintenance of spermatogenic tissue and the successful process of spermatogenesis (formation of sperms).

(C) $ICSH$ (Interstitial Cell Stimulating Hormone) is the male equivalent of $LH$ (Luteinizing Hormone).
It acts on the Leydig cells (also known as interstitial cells) present in the testes.
Upon stimulation by $ICSH$,these cells synthesize and secrete androgens,primarily testosterone,which are essential for spermatogenesis and the development of secondary sexual characteristics in males.

(B) The $Cauda$ $epididymis$ (tail of the epididymis) is the posterior part of the epididymis.
It continues as the $Vas$ $deferens$,which is a long,muscular tube that transports sperm from the epididymis toward the urethra.
Therefore,the correct option is $(b)$.

(B) The prostate gland secretes a milky,slightly acidic fluid that forms a significant portion of the semen volume. This secretion contains substances such as citric acid,acid phosphatase,calcium,and various proteolytic enzymes like fibrinolysin. These components are essential for the activation,nourishment,and motility of sperms within the female reproductive tract.

(A) The correct answer is $A$.
Seminal fluid,secreted by the seminal vesicles,has a $pH$ of approximately $7.4$.
It contains fructose,citrate,ascorbic acid,prostaglandins,and various enzymes.
Fructose serves as the primary energy source for the spermatozoa,providing the necessary nutrition for their motility and survival after ejaculation.

(A) The testis is the primary male reproductive organ. Its main function is the production of male gametes,known as sperms,through a process called spermatogenesis. Additionally,it secretes the male sex hormone,testosterone.

(C) The testes in mammals are located outside the abdominal cavity within the scrotum.
This is because the process of spermatogenesis (maturation of sperm) requires a temperature that is $2$ to $2.5^{\circ}C$ lower than the normal internal body temperature.
The scrotum provides this lower temperature environment,which is essential for the survival and functional maturity of the sperm.

(B) The pathway of sperm transport in the male reproductive system starts from the seminiferous tubules of the testis.
$1$. The sperm produced in the seminiferous tubules pass into the $Rete \ testis$.
$2$. From the $Rete \ testis$,they move into the $Vasa \ efferentia$.
$3$. The $Vasa \ efferentia$ then lead to the $Epididymis$,where sperm are stored and matured.
$4$. Finally,the sperm travel through the $Vas \ deferens$ and the $Urethra$ to exit the body.
Therefore,the correct sequence is: $Rete \ testis \rightarrow Vasa \ efferentia \rightarrow Epididymis \rightarrow Urethra$.