Male reproductive system Questions in English

(B) During a single ejaculation,the human male releases approximately $200$ to $300$ million sperms.
For normal fertility,at least $60$ percent of sperms must have normal shape and size,and at least $40$ percent of them must show vigorous motility.

(A) The semen is composed of secretions from the accessory glands and sperm.
$1$. The seminal vesicles contribute about $60-70\%$ of the total volume of semen.
$2$. The prostate gland contributes about $20-30\%$.
$3$. The bulbourethral glands (Cowper's glands) contribute a very small amount of mucus.
Therefore,the seminal vesicles contribute the largest volume to the semen.

(D) The seminiferous tubules are the structural and functional units of the human testis.
They are the site where spermatogenesis (the process of sperm production) occurs,making them the functional units.
Additionally,the interstitial spaces between these tubules contain Leydig cells (interstitial cells),which are responsible for the production of androgens (testosterone),making them associated with hormone production.
Therefore,all the given options are correct.

(D) The seminiferous tubules are lined by a germinal epithelium which consists of two types of cells: $1$. Male germ cells (spermatogonia) and $2$. Sertoli cells (nurse cells).
- The germinal epithelium is primarily composed of cuboidal cells that undergo spermatogenesis.
- Sertoli cells are tall,columnar cells that provide nutrition and support to the developing spermatozoa.
- Therefore,the germinal epithelium consists of cuboidal cells,and the Sertoli cells are columnar in shape.

(C) The inguinal canal is a passage in the anterior abdominal wall that allows structures to pass between the abdominal cavity and the scrotum. During fetal development,the testes descend from the abdominal cavity into the scrotum through this canal. Therefore,it serves as a pathway connecting the scrotum to the abdominal cavity.

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

(C) The $vas$ $deferens$ is a duct that transports sperm from the epididymis to the urethra.
Cutting or ligating the $vas$ $deferens$ is a surgical procedure known as a $vasectomy$.
This procedure prevents sperm from reaching the urethra,meaning the semen ejaculated will not contain any sperm.
However,the production of semen by accessory glands (seminal vesicles,prostate,and bulbourethral glands) continues,so the volume of the ejaculate remains largely unchanged,but it is $azoospermic$ (sperm-free).

(A) The testis is covered by a dense connective tissue capsule called the $Tunica \ albuginea$.
Extensions of this capsule,known as septa,project inward into the testis and divide it into about $200-250$ compartments called testicular lobules.
Therefore,the $Tunica \ albuginea$ is responsible for dividing the testis into lobules.

(D) The condition in which one or both testes fail to descend from the abdominal cavity into the scrotum during development is known as $Cryptorchidism$.
Normally,the testes descend into the scrotum before birth because the temperature of the scrotum is $2-2.5^{\circ}C$ lower than the internal body temperature,which is essential for spermatogenesis.
If the testes remain in the abdominal cavity,the higher body temperature can lead to infertility or an increased risk of testicular cancer.

(D) In the human male reproductive system,the accessory glands include the seminal vesicles,the prostate gland,and the bulbourethral glands (also known as Cowper's glands).
$1$. The seminal vesicles are a pair of glands.
$2$. The bulbourethral glands (Cowper's glands) are also a pair of glands.
$3$. The prostate gland is a single,unpaired gland that surrounds the urethra.
Therefore,the prostate gland is the only gland among the options that is not present in pairs.

(B) Sperm cells are produced in the $Seminiferous \text{ tubules}$ of the testes. After production, they move to the $Epididymis$, where they undergo physiological maturation, gaining motility and the ability to fertilize an egg. Therefore, the $Epididymis$ is the site of sperm maturation.

(D) The erection of the penis is a vascular phenomenon primarily controlled by the $Parasympathetic$ nervous system.
When sexual stimulation occurs, the $Parasympathetic$ nerves release neurotransmitters like nitric oxide $(NO)$, which cause the smooth muscles of the penile arteries and the erectile tissues (corpora cavernosa) to relax.
This relaxation leads to vasodilation, increasing blood flow into the erectile tissues, which results in the erection of the penis.
Conversely, the $Sympathetic$ nervous system is primarily responsible for ejaculation.

(A) The process of ejaculation is a reflex action that involves the coordination of the autonomic nervous system.
Specifically,the sympathetic nervous system is responsible for the emission and ejaculation of semen.
During sexual arousal,the parasympathetic nervous system is primarily responsible for penile erection,while the sympathetic nervous system triggers the contraction of the smooth muscles in the vas deferens,seminal vesicles,and prostate gland,leading to the expulsion of semen (ejaculation).

(A) Leydig cells,also known as interstitial cells,are located in the interstitial spaces of the testes.
These cells are responsible for the synthesis and secretion of testicular hormones called androgens,primarily testosterone.
Leydig cells remain inactive during childhood and become mature and functional at the onset of puberty due to the stimulation by Luteinizing Hormone $(LH)$ from the anterior pituitary gland.

(A) The seminal plasma in humans is secreted by the accessory glands, which include the seminal vesicles, prostate gland, and bulbourethral glands.
Seminal vesicles contribute about $60-70\%$ of the total volume of semen.
This fluid is rich in fructose, which provides energy to the sperm for motility.
It also contains calcium and certain enzymes that are essential for the survival and activation of sperm.
Therefore, seminal plasma is rich in fructose and calcium.

(D) The male reproductive system consists of structures like $Sertoli$ cells,germ cells,and $Leydig$ cells,which are all components found within the testes.
$Sertoli$ cells provide nourishment to developing sperm.
Germ cells are the precursors to sperm.
$Leydig$ cells produce androgens (testosterone).
In contrast,a follicle is a structure found in the female reproductive system (ovary) involved in oogenesis.
Therefore,the follicle is the odd one out.

(C) The seminiferous tubules of the testis open into the vasa efferentia through a network of tubules called the rete testis. The vasa efferentia leave the testis and open into the epididymis located along the posterior surface of each testis. Therefore,the network connecting the seminiferous tubules to the vasa efferentia is the rete testis.

(A) Human semen contains a high concentration of citric acid,which is primarily secreted by the prostate gland. This citric acid plays a crucial role in maintaining the $pH$ of the semen and is involved in the liquefaction process of the ejaculate after it enters the female reproductive tract.

(C) The correct matches are as follows:
$(1)$ Seminal vesicle: It is a male accessory reproductive gland that contributes about $60-70\%$ of the total volume of semen.
$(2)$ Prostate: It is a male accessory reproductive gland that secretes fluid into the urethra.
$(3)$ Mammary gland: These are modified sweat glands that undergo differentiation during pregnancy to produce milk.
$(4)$ Penis: It is the male external genitalia or male accessory reproductive organ.
Therefore,the correct matching is: $(1-a, 2-c, 3-d, 4-b)$.

(A) In the provided diagram of the human male reproductive system:
$a$ represents the Vas deferens,which transports sperm from the epididymis to the ejaculatory duct.
$b$ represents the Prostate gland,an accessory gland that contributes to seminal fluid.
$c$ represents the Glans penis,the enlarged end of the penis.
$d$ represents the Epididymis,where sperm mature and are stored.
Therefore,the correct identification is $a-$ Vas deferens,$b-$ Prostate,$c-$ Glans penis,$d-$ Epididymis.

(C) Circumcision is a surgical procedure in which the foreskin,also known as the prepuce,is removed from the glans penis. This procedure is often performed for religious,cultural,or medical reasons. It does not involve the removal of the glans itself or the entire skin of the penis.

(B) The surgical removal of one or both testes is known as $Orchidectomy$ (or $Orchiectomy$).
$Cryptorchidism$ refers to the condition where the testes fail to descend into the scrotum.
$Vasectomy$ is a surgical procedure for male sterilization where the $vas$ $deferens$ are cut or tied.
$Tubectomy$ is a surgical procedure for female sterilization where the fallopian tubes are blocked or cut.

(A) $Cryptorchidism$ is a condition where one or both testes fail to descend into the scrotum during development.
The surgical procedure performed to move an undescended testis into the scrotum and permanently fix it there is known as $Orchiopexy$.
$Vasectomy$ is a method of male sterilization where the $vas$ $deferens$ are cut or blocked.
Therefore,the correct answer is $Orchiopexy$.

(B) bull is an intact male bovine,while a bullock (steer) is a castrated male bovine.
Castration involves the removal of the testes,which are the primary source of the male sex hormone,$Testosterone$.
Since the bullock lacks functional testes,its $Testosterone$ levels are significantly lower than those of an intact bull.
$Testosterone$ is responsible for the development of secondary sexual characteristics,increased muscle mass,and aggressive behavior in bulls.
Therefore,a bull has higher levels of $Testosterone$ compared to a bullock.

(C) The correct option is $(C).$
In the given diagram:
$A$ represents the Testis,which contains about $250$ testicular lobules.
$B$ represents the Urinary bladder (not the seminal vesicle).
$C$ represents the Vas deferens,which transports sperms from the epididymis towards the urethra.
$D$ represents the Seminal vesicle.
Therefore,the statement '$C$ - Vas deferens - helps in the transport of sperms' is scientifically correct.

(C) The development,maturation,and functional regulation of male accessory sex organs,including the epididymis,vas deferens,seminal vesicles,prostate gland,and urethra,are primarily controlled by androgens (such as testosterone). These hormones are essential for the maintenance of the male reproductive system.

(D) The testis performs a dual function in humans.
First,it acts as a primary sex organ because it produces male gametes (sperms) through the process of spermatogenesis.
Second,it acts as an endocrine gland because the Leydig cells (interstitial cells) present in the interstitial space produce androgens,primarily testosterone,which are released directly into the blood.
Therefore,the testis functions as both a primary sex organ and an endocrine gland.

(B) Leydig's cells,also known as interstitial cells,are characteristic of the testes of mammals.
These cells secrete the male sex hormone testosterone,which influences secondary sexual characters in males.

(A) Gynaecomastia is the abnormal development or enlargement of mammary glands in males.
In later life,hormonal imbalances,such as a decrease in testosterone levels,can occur.
This leads to a perturbation in the estrogen-to-androgen ratio,where the relative influence of estrogen increases,promoting the development of breast tissue in males.
Therefore,both the assertion and the reason are correct,and the reason provides the correct explanation for the assertion.

(A) Cryptorchidism is a medical condition in which one or both of the testes fail to descend from the abdomen into the scrotal sac during development. This condition is significant because the temperature in the scrotal sac is lower than the body temperature,which is essential for normal spermatogenesis.

(B) In the human male reproductive system,the prostate gland is a single,unpaired,and large gland.
It is situated around the first part of the urethra.
It secretes a thin,milky fluid that contains calcium,citrate ions,phosphate ions,a clotting enzyme,and a profibrinolysin.
In contrast,seminal vesicles,bulbourethral glands,and testes are all present in pairs.

(B) Leydig's cells,also known as interstitial cells,are located in the connective tissue surrounding the seminiferous tubules in the testes.
These cells are endocrine in nature and are responsible for the synthesis and secretion of male sex hormones,collectively known as androgens,primarily $Testosterone$.
$Testosterone$ plays a crucial role in the development of male secondary sexual characteristics and the process of spermatogenesis.
In contrast,$Oestrogen$ and $Progesterone$ are female sex hormones,while $Corticosterone$ is a glucocorticoid secreted by the adrenal cortex.

(C) The $vas$ $deferens$ loops over the urinary bladder,where it is joined by the duct from the seminal vesicle to form the ejaculatory duct. The ejaculatory duct stores and transports sperm from the testes to the urethra.

(A) Primary sex organs (gonads like testes or ovaries) are responsible for the production of gametes and the secretion of sex hormones.
Secondary sex organs (such as the vas deferens,epididymis,fallopian tubes,uterus,etc.) are involved in the transport and storage of gametes or the development of the fetus,but they do not produce gametes or sex hormones themselves.
Therefore,$A$ represents primary sex organs and $B$ represents secondary sex organs.

(C) The glans penis is the enlarged,sensitive end of the penis.
It is covered by a loose,retractable fold of skin.
This fold of skin is known as the foreskin or prepuce.
Therefore,both terms refer to the same anatomical structure.

(C) Seminal plasma is the combined secretion of three glands: $(a)$ seminal vesicles,$(b)$ prostate gland,and $(c)$ bulbourethral (Cowper's) gland.
When these secretions are mixed with sperm,they collectively form semen.

(C) The primary sex organs are those that are responsible for the production of gametes and the secretion of sex hormones. In males,the testes are the primary sex organs because they produce sperms (male gametes) and secrete the male sex hormone,testosterone. Secondary sex organs are involved in the transport and maturation of gametes but do not produce them. The differences are summarized below:

Primary sex organs	Secondary sex organs
They produce gametes.	They do not produce gametes. They are concerned with the conduction of gametes.
They secrete sex hormones.	They do not secrete sex hormones.
Testes in males and ovaries in females are examples of primary sex organs.	Epididymis,vasa deferentia,penis,etc.,are secondary sex organs in males and oviducts,uterus,etc.,are examples of secondary sex organs in females.

(B) The $Vas$ $deferens$ is a large duct that arises from the $Cauda$ $epididymis$ and ascends into the abdomen,looping over the urinary bladder to reach the seminal vesicles.

(D) The scrotal sac maintains the temperature of the testes at $2-2.5^{\circ}C$ lower than the internal body temperature.
This lower temperature is essential for spermatogenesis (sperm formation).
Therefore,the primary function of the scrotal sac is temperature regulation,which subsequently enables sperm production.

(A) Sertoli cells are specialized somatic cells found within the seminiferous tubules of the testes. They provide structural and nutritional support to developing germ cells,which is why they are also known as subtentacular cells.

(C) The human testis is primarily composed of two major structural and functional components:
$1$. Seminiferous tubules: These are the highly coiled structures where spermatogenesis occurs.
$2$. Interstitial space: The region outside the seminiferous tubules,which contains Leydig cells (interstitial cells) that secrete androgens.
Sertoli cells and developing spermatozoa are located within the seminiferous tubules themselves,not as separate major entities of the testis structure as a whole.

(A) Based on the anatomical structure of the male reproductive system:
$A$ represents the Vas deferens,which carries sperm from the epididymis.
$B$ represents the Seminal vesicle,which secretes a fluid containing fructose.
$C$ represents the Urinary bladder,which stores urine.
$D$ represents the Prostate gland,which surrounds the urethra and secretes a milky fluid.

(B) The seminiferous tubules of the testis open into the vasa efferentia through the rete testis.
$1$. The seminiferous tubules are the structural and functional units of the testis where sperm production occurs.
$2$. These tubules join together to form a network of tubules known as the rete testis.
$3$. From the rete testis,fine ciliated ductules called vasa efferentia arise,which carry the sperm out of the testis to the epididymis.

(C) The prostate gland is located around the urethra.
Its secretion is milky and slightly alkaline, contributing approximately $25\%$ to the total volume of semen.
The secretion is rich in citric acid, acid phosphatases, amylase, pepsinogen, and prostaglandins.
Therefore, $A = \text{urethra}$, $B = 25\%$, and $C = \text{citric}$.

(B) The seminal vesicles are accessory glands in the male reproductive system.
They secrete a fluid that constitutes about $60-70\%$ of the total volume of semen.
This fluid is rich in fructose,which provides energy to the sperm,and prostaglandins,which help in the movement of sperm within the female reproductive tract.

(B) During early and middle fetal life,the testes develop in the abdominal cavity.
They descend into the scrotal sacs during the late fetal development stage.
Failure of the testes to descend into the scrotum is a condition known as $Cryptorchidism$.

(C) Epididymis is a mass of coiled tubules attached to the posterior surface of the testes.
It stores the sperms temporarily.
Sperms achieve maturity and motility in the epididymis by the reabsorption of fluid originally secreted by the seminiferous tubules and by chemicals produced by the lining of the epididymal tube.

(C) $A-$Testosterone,$B-$Sertoli cell,$C-$Inhibin.
Hormonal Control of Spermatogenesis:
Spermatogenesis is initiated due to the increase in Gonadotropin Releasing Hormone $(GnRH)$ by the hypothalamus.
$GnRH$ acts on the anterior lobe of the pituitary gland to secrete Luteinising Hormone $(LH)$ and Follicle Stimulating Hormone $(FSH)$.
$LH$ acts on the Leydig cells of the testis to secrete testosterone.
$FSH$ acts on the Sertoli cells of the seminiferous tubules of the testis to secrete an androgen-binding protein $(ABP)$ and inhibin.
$ABP$ concentrates testosterone in the seminiferous tubules.
Inhibin suppresses $FSH$ synthesis.
$FSH$ acts on spermatogonia to stimulate sperm production.

(C) Ejaculation is a sympathetic response,which involves the contraction of smooth muscles in the reproductive tract to expel semen.
Erection is a parasympathetic response,which involves the dilation of blood vessels in the penis to allow blood flow into the erectile tissues.
Both sympathetic and parasympathetic nervous systems are divisions of the autonomic nervous system.

Somatic Nervous System	Autonomic Nervous System
Conscious or voluntary regulation. Fibres do not synapse after they leave the $CNS$ (single neuron from $CNS$ to effector organ). Innervates skeletal muscle fibres,always stimulatory.	Functions without conscious awareness (involuntary). Fibres synapse once at a ganglion after they leave the $CNS$ (two neuron chain motor control). Innervates smooth muscle,cardiac muscle,and glands; either stimulates or inhibits.

(C) The epididymis leads to the $vas \ deferens$ (vas deferens) that ascends to the abdomen and loops over the $urinary \ bladder$.
Therefore,$A$ refers to the $vas \ deferens$ and $B$ refers to the $urinary \ bladder$.
Thus,the correct option is $C$.