Theory:

Male reproductive organ:
As we have already seen, in sexual reproduction, there is the involvement of the male and female gamete, i.e., the fusion of the sperm and the ovum or egg, respectively.
 
The male reproductive organ includes,
  • A pair of testes (testis in singular form)
  • Two sperm ducts
  • A penis
  • Glands
The testes are oval-shaped organs present outside the abdominal cavity and produce millions of sperm.
Screenshot_9.jpg
Male reproductive system
 
The other parts include the,
  • Scrotum - Testes arepaired, and each of them are enclosed in a sac made of skin called thescrotum.
  • Epididymis - Sperms produced in the testes are stored and released from the tube called the epididymis.
  • Seminal vesicles - It starts from the epididymis, and the sperms are carried by the sperm duct into the seminal vesicle. The seminal vesicle joins with the urethra that comes from the bladder.
  • Urethra - The urethra then carries sperm to the penis.
Sperm:
  • The sperm has \(3\) components - a head, a middle piece, and a tail. It is about \(0.05\)mm in length.
  • It is a single cell with cell components like the cell membrane, nucleus, and cell membrane.
  • The nucleus is present in the head of the sperm.
  • The amount of cytoplasm in a sperm cell is very less, while the tail functions or aids in the movement of the sperm.
  • Sperm moves side to side by the waving action of sperm.
512px-Sperm_Anatomy.png
Structure of sperm
Female reproductive organ:
The female reproductive organ contains a pair of ovaries, fallopian tubes or the oviducts, and the uterus.
  • A pair of ovaries - The ovary is oval-shaped inside the abdominal cavity and produces the female gametes called the ova or the eggs.
  • A pair of fallopian tube - Fallopian tubes are not connected directly to the ovaries, but connected by the funnel-shaped opening.
  • The uterus - The oviducts connect to the uterus, which is a bag-like organ. The uterus is the female part where the development of the zygote takes place.
  • A vagina - Uterus is connected to a narrow opening called cervix to another tube called the vagina.
Important!
Like sperm, an egg is also a single cell.
Screenshot_10.jpg
Female reproductive system
 
Ovum or Egg:
  
Ova are much larger than the sperm and is about \(0.15\)mm in diameter. Egg has a thin layer called the jelly coat that allows only one sperm to enter into it during the process of fertilisation.
 
kzr5_098h_200825.jpg
Structure of ovum
 
In the humans, a matured egg is released into the fallopian tubes by one of the ovaries during every month called as ovulation.
The sperm and the egg have nuclei that contain chromosomes that carry genes which carry genes and transmit the characteristic of parent to the offspring. 
Important!
In some animals like reptiles, birds the eggs are large.
Reference:
https://upload.wikimedia.org/wikipedia/commons/c/cf/Male_genital_system_-_Front_view.svg
https://upload.wikimedia.org/wikipedia/commons/e/ea/Human_male_reproductive_system_en.svg
https://upload.wikimedia.org/wikipedia/commons/thumb/2/2b/Sperm_Anatomy.png/512px-Sperm_Anatomy.png
https://upload.wikimedia.org/wikipedia/commons/c/ca/Female_genital_system_-_Front_view_1.svg
https://www.vecteezy.com/vector-art/1432702-human-egg-or-ovum-structure-for-health-education-infographic