Human reproduction

• Sperm cells are produced by spermatogenesis in the seminiferous tubules within the testes.
• Testosterone is secreted by Leydig's cells to stimulate spermatogenesis.
• The male reproductive system consists of the testes, epididymis, vas deferens, seminal vesicles, prostate gland, bulbourethral glands, penis, scrotum, and accessory ducts.
• Seminal vesicles secrete fructose-rich fluid that nourishes sperm during ejaculation.
• The prostate gland secretes alkaline fluid that neutralizes acidic urine and provides nutrients for sperm survival.
• The epididymis stores, matures, and transports sperm from the testes into the vas deferens.
• Mature sperm cells have an acrosome at one end that contains enzymes to digest the egg's protective coat during fertilization.
• Bulbourethral glands produce mucus that lubricates the urethra during sexual intercourse.
• Ejaculated semen contains spermatozoa, fructose from the seminal vesicles, citric acid from the prostate gland, enzymes from the prostate gland, and proteins from the seminal vesicles.
• Fertilization occurs when a sperm cell penetrates an ovum (egg) in the fallopian tube.
• The vas deferens carries mature sperm from the epididymis to the urethra.
• Semen is composed of spermatozoa (male gametes) and semen plasma (accessory sex gland secretions).
• The scrotum holds the testes outside the abdominal cavity to maintain optimal temperature for spermatogenesis.
• Testosterone stimulates the growth of secondary male characteristics such as facial hair, deepening voice, broad shoulders, and increased muscle mass.
• Leydig cells secrete testosterone into the bloodstream through the hypothalamus-pituitary axis.
• Urethra in males is used to transport urine and sperms out of the body
• sertoli cells found in the seminiferous tubules secrete nutrients used in the production of sperms
• ovaries are used to produce egg cells and they also produce hormones oogestrone and progesterone
• fallopian tubes are used to transport the ovum and it is the sight of fertilisation
• uterus it is responsible for carrying the foetus and embryo and placenta implants
• Vagina receives the penis and sperms, it is also known as the birth canal
• vulva is the external opening which allows urine and faeces to be expelled and also allows penetration of the penis inside the vagina
• spermatogenesis

  under the influence of testosterone, diploid cells found in the seminiferous tubules will undergo meiosis to form 4 spermatids, the spermatids will mature to form spermatozoan
• oogenesis

  under the influence of the FSH(Follicle stimulating hormone), the diploid cell found in ovaries will undergo mitosis to form numerous follicles, one cell inside he follicle enlarges and undergo meiosis, of the four cells that are formed only one will survive to form a mature ovum(Haploid)
• pituitary gland secretes LH( luteinising hormone) which stimulates the cells of leydig to produce testosterone
• functions of testosterone

  development of male secondary sexual characteristics such as beard, pubic hair, deep voice and a muscular body

  stimulates the maturation of sperm cells
• gametogenesis is the process of the formation of gametes

  Male gametes are formed by spermatogenesis and female gametes are formed by oogenesis
• structure of a sperm cell

  • it has an acrosome which has enzymes that digest the walls of the egg cells for fertilisation
  • nucleus contains genetic material for inheritance
  • mid piece is full of mitochondrion which produces energy for the movement of the sperm
• structure of the egg

  if has the layer of jelly which protects the egg and nucleus which has genetic material for inheritance and cytoplasm where resource sources of nutrients are found
• accessory glands are not endocrine glands as they do not secrete hormones and they secrete their secretions in ducts not in the blood stream