| Structure | Characteristics/Function | |
| Placenta | The placenta is connected to the embryo through an umbilical cord which helps in the transport of substances to and fro from the embryo. Placenta also acts as an endocrine tissue and produces several hormone-like human chorionic gonadotropin (hCG), placental lactogen (hPL), estrogens, progestogens, etc. | |
| Zona pellucida | The secondary oocyte has a new membrane called Zona pellucida surrounding it. This thick coat of zona pellucida is composed of glycoproteins and synthesized by the oocyte. Later, the granulosa cells lying in close vicinity of the ovum and zona pellucida become elongated to form the corona radiata. | |
| Bulbourethral glands | The bulbourethral glands also called Cowper’s glands located in the membranous urethra, also opens into the urethra and secrete clear mucus for lubrication and alkaline fluid that neutralizes the traces of acidic urine in the urethra. | |
| Leydig cells | The regions outside the seminiferous tubules called interstitial spaces contain small blood vessels and interstitial cells or Leydig’s cells. Leydig cells constitute the endocrine tissue of testis. Leydig cells synthesize and secrete testicular hormones called androgen. Androgens are a group of male sex hormones mainly testosterone. |