Male Reproductive System

Question 1

Spermatogenesis steps.

Answer 1

PGC➡️Spermatogonia➡️ Primary spermatocyte➡️Secondary spermatocyte➡️Spermatids➡️Spermatozoa

Question 2

Acrosome of sperm and it’s features

Answer 2

Acrosome of sperm is formed from Golgi Apparatus and it contains enzymes like hyaluronidase & powerful proteolytic enzymes.

Question 3

Describe tail/Flagella of Sperm

Answer 3

It has 3 components which are axoneme, cell membrane covering axoneme and mitochondria surrounding base of axoneme.

Back and forth flagellar movement and with energy from ATP.

Normal speed is 1 to 4mm/minute.

Question 4

Hormones stimulating spermatogenesis.

Answer 4

Testosterone, LH , FSH , estrogen, growth hormone

Question 5

Testosterone role in spermatogenesis

Answer 5

Secreted by Leydig cells in interstitial spaces.
Essential for growth and division of testicular germinal cells.

Question 6

Lutenising hormone role in spermatogenesis.

Answer 6

Secreted by anterior pituitary gland.
Stimulate Leydig cells to secrete testosterone.

Question 7

Follicle-stimulating hormone role in spermatogenesis

Answer 7

Secreted by anterior pituitary gland.
Stimulate sertoli cells.
Conversion of Spermatids to sperm / spermiogenesis.

Question 8

Growth hormone role in spermatogenesis.

Answer 8

Necessary for controlling background
metabolic functions of the testes.

Question 9

Estrogen role in spermatogenesis

Answer 9

Essential for spermiogenesis

Question 10

Sperm storage

Answer 10

Both testis forms 120 million sperms per day and are stored in epididymis.
Suppressed in inactive state by inhibitory substances.
After ejaculation, the sperm become motile and capable of fertilizing the ovum, a process called maturation

Question 11

Physiology of the Mature Sperm

Answer 11

activity of sperm is greatly enhanced in a neutral and slightly alkaline medium.
strong acidic medium can cause the rapid death of sperm.
activity of sperm increases markedly with increasing temperature, but so does the rate of metabolism,
causing the life of the sperm to be considerably shortened

Question 12

Function of seminal vesicles.

Answer 12

secretes an abundance of fructose, citric acid, and other nutrient substances, as well as large quantities of prostaglandins and fibrinogen.

Prostaglandins are believed to aid fertilization in two
ways:
(1) by reacting with the female cervical mucus to make it more receptive to sperm movement and
(2) by possibly causing backward, reverse peristaltic contractions in the uterus and fallopian tubes to move the ejaculated sperm toward the ovaries

Question 13

FUNCTION OF THE PROSTATE GLAND

Answer 13

secretes a thin, milky fluid that
contains calcium, citrate ion, phosphate ion, a clotting enzyme, and a profibrinolysin.
slightly alkaline characteristic of the prostatic fluid may be quite important for successful fertilization.

Question 14

Describe semen

Answer 14

composed of the fluid and sperm from the vas deferens
(about 10 percent of the total), fluid from the seminal
vesicles (almost 60 percent), fluid from the prostate gland (about 30 percent), and small amounts from the mucous
glands, especially the bulbourethral glands.
pH of semen is 7.5
a clotting
enzyme from the prostatic fluid causes the fibrinogen of
the seminal vesicle fluid to form a weak fibrin coagulum
that holds the semen in the deeper regions of the vagina

Question 15

Capacitation of sperms and changes occuring

Answer 15

Although spermatozoa are said to be “mature” when they
leave the epididymis, their activity is held in check by multiple inhibitory factors secreted by the genital duct
epithelia. Therefore, when they are first expelled in the semen, they are unable to fertilize the ovum. However, on coming in contact with the fluids of the female genital tract, multiple changes occur that activate the sperm for the final processes of fertilization. These collective changes are called capacitation of the spermatozoa,

1)membrane of the sperm also becomes much more permeable to calcium ions, so calcium now
enters the sperm in abundance and changes the activity of the flagellum.
2)The uterine and fallopian tube fluids wash away the various inhibitory factors that suppress sperm activity in the male genital ducts
3) Loss of cholesterol causing head of sperm becoming weaker.

Question 16

Acrosome Enzymes, the “Acrosome
Reaction,” and Penetration of the Ovum

Answer 16

Stored in the acrosome of the sperm are large quantities of hyaluronidase and proteolytic enzymes.Hyaluronidase depolymerizes the hyaluronic acid polymers in the intercellular cement that holds the ovarian granulosa cells
together. The proteolytic enzymes digest proteins in the structural elements of tissue cells that still adhere to the ovum.

Question 17

Why Does Only One Sperm Enter the Oocyte?

Answer 17

within a few minutes after the first sperm penetrates the zona pellucida of the ovum, calcium ions diffuse inward through the oocyte membrane and cause multiple cortical granules to be released by exocytosis from the oocyte into the perivitelline space. These granules contain substances
that permeate all portions of the zona pellucida and prevent binding of additional sperm, and they even cause any sperm that have already begun to bind to fall off. Thus, almost never does more than one sperm enter the
oocyte during fertilization