Structure of sperm cell | Stages of fertilization | Embryology | First Aid lectures | Lec2
Channel: Dr. Jamil Lectures
Date: 2022-11-26

In this lecture we will discuss about structure of sperm cell,movement of sperm within the female reproductive tract and stages of fertilization (General embryology)


https://youtu.be/bvtXcYHRZl0
https://youtu.be/gXGK6F_vDJQ
https://youtu.be/6hTsDkFhRQ0


instagram acount   Dr_jamil56

Sperm cell consists of 3 portions
1) Head
2) Mid piece
3) Tail or Flagella
Head
● Head of the sperm cell contains
➢ Nucleus which is 23-chromosomes male haploid
➢ Acrosome which contains hydrolytic, proteolytic and glycolytic enzymes such
as acrosin
Mid Piece
● Midpiece of sperm cell contains mitochondria in spiral shape
● These mitochondria utilize the fructose to produce ATP which is used in the
movement of flagella or tail.
RECALL ⇒ Fructose → carbohydrate fuel source for sperm cells that is present in seminal
fluid and released from seminal vesicles → (semen also known as seminal fluid and contains
sperms,chemicals and nutrients secreted from seminal vesicles,prostate glands and
bulbourethral glands .These chemicals and nutrients are necessary for fertilization to occur)
Flagella or Tail
● Tail of a sperm cell has a 9+2 microtubule arrangement along its entire length.
● 9 microtubule pairs are formed in circular shape around the outer region of the
flagella while 2 microtubule segments or 1 microtubule pair are located in the middle
of the flagella.
● Within the microtubule there are further two motility proteins
➢ Dynein protein (motor protein) consists of outer and inner arms and plays role in
transport of sperm cell
➢ Tubulin (cytoskeleton protein) and also play role in movement or transport of sperm
cell
● This kind of arrangement of microtubules in the tail allows for powerful movement of
sperm cells along the reproductive system.So flagella is responsible for movement of
sperm cells in the reproductive tract by using ATP produced by mitochondria via
using fructose from seminal fluid

Movement of sperm within female reproductive tract
● After ejaculation of semen into the upper part of vagina,sperms can easily drain out
of the vagina → Vesiculase (a coagulase enzyme present in seminal fluid and
released from seminal vesicles) causes seminal and vaginal gluid to coagulate with
each other and sperm cells adhesion to the surface of vagina to avoid the drainage of
sperms out of vagina.
● During coagulation and adhesion of sperm cells with the vaginal surface,
Fibrinolysins (Enzyme present in seminal fluid and released from prostate glands)
breaks up coagulation and causes entry of sperm cells into the cervix
● Prostaglandins (Present in seminal fluid and released from seminal vesicles) induce
the peristaltic contractions in the smooth muscles of the uterus and causes
retropulsion of the uterus → This retropulsion and contraction of the uterus squeeze
the sperm cells further along the female reproductive tract.
● Seminal plasmins (present in seminal fluid and released from prostate glands) act as
an antibiotic and destroy bacterial cells and microbes present in the female
reproductive tract → In this way seminal plasmins ensure that the female
reproductive tract has a sterile environment for reproduction.
● Seminal relaxin (present in seminal fluid and released from prostate gland) enhances
the motility of sperm cells along the fallopian tube towards the ampulla of the female
reproductive tract.
● When many sperm cells reach the ampulla of fallopian tube, then fertilization occurs
in following stages


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