Human Reproductive System Definition and Diagram

Introduction:

• Humans are dioecious or unisexual or exhibit sexual dimorphism, i.e., male and female individuals are differentiated externally.
• Humans reproduce sexually by the fusion of male and female gametes produced in their respective reproductive system.
• The steps involved in the human reproductive system are:
  - Gametogenesis
  - Insemination
  - Internal fertilization
  - Zygote formation
  - Embryogenesis
  - Gestation
  - Parturition
• The gametes in male and female are sperm and egg that are formed in the primary sex organs called testes and ovaries, respectively.
• Organs other than the primary sex organs are called secondary sex organs such as reproductive glands, external genitalia, accessory glands, etc.
• Males and females are externally differentiated through secondary sexual characters or sexual dimorphic characters.
• Few differentiating secondary sexual characters of males are beard, moustache, hair on the chest, muscular body, enlarged larynx (Adam's apple).
• Whereas in females the secondary sexual characters are developed breast, broader pelvis and high pitched voice.

Topics covered:

• Puberty
• Male reproductive system
• Female reproductive system
• Gametogenesis
• Menstrual cycle
• Fertilization
• Placentation
• Pregnancy
• Lactation
• Disorders of reproductive system

Quiz

1. Sertoli cells are regulated by the pituitary hormone known as -
(1) FSH
(2) GH
(3) Prolactin
(4) LH

2. Withdrawal of which of the following hormones is the immediate cause of menstruation?
(1) Estrogen
(2) FSH
(3) FSH-RH
(4) Progesterone

3. In the human female, menstruation can be deferred by the administration of -
(1) FSH only
(2) LH only
(3) Combination of FSH and LH
(4) Combination of estrogen and progesterone

4. Which part of the ovary in mammals acts as an endocrine gland after ovulation?
(1) Vitelline membrane
(2) Graffian follicle
(3) Stroma
(4) Germinal epithelium

5. Which one of the following statements is incorrect about menstruation?
(1) At menopause in the female, there is especially abrupt increase in gonadotropic hormones
(2) The beginning of the cycle of menstruation is called menarche
(3) During normal menstruation about 40 ml blood is lost
(4) The menstrual fluid can easily clot

6. Which extraembryonic membrane in humans prevents desiccation of the embryo inside the uterus?
(1) Yolk sac
(2) Amnion
(3) Chorion
(4) Allantois

7. In human adult females oxytocin -
(1) Stimulates pituitary to secrete vasopressin
(2) Causes strong uterine contractions during parturition
(3) is secreted by anterior pituitary
(4) stimulates growth of mammary glands

8. In humans, at the end of the first meiotic division, the male germ cells differentiate into the -
(1) Spermatids
(2) Spermatogonia
(3) Primary spermatocytes
(4) Secondary spermatocytes

9. Seminal plasma in humans is rich in -
(1) Fructose and certain enzymes but poor in calcium
(2) Fructose, calcium and certain enzymes
(3) Fructose and calcium but has no enzymes
(4) Glucose and certain enzymes but has no calcium

10. The correct sequence of spermatogenetic stages leading to the formation of sperms in a mature human testis is -
(1) Spermatogonia - Spermatid - Spermatocyte - Sperms
(2) Spermatocyte - Spermatogonia - Spermatid - Sperms
(3) Spermatogonia - Spermatocyte - Spermatid - Sperms
(4) Spermatid - Spermatocyte - Spermatogonia - Sperms

Answer Key:

1.  (1)
2.  (4)
3.  (4)
4.  (2)
5.  (4)
6.  (2)
7.  (2)
8.  (4)
9.  (2)
10.  (3)