Human Reproduction Class 12 Notes Biology Chapter 3 - CBSE

Chapter:3

What are Human Reproduction?

    Fields marked with a ◉ are mandatory, so please fill them in carefully.
    To download the PDF file, kindly fill out and submit the form below.

    The Male Reproductive System

    It consists of the primary sex organs (a pair of testes):

    • Scrotum – a pouch in which testes are situated
    • Testicular lobules
    • Seminiferous tubules – contains Spermatogonia and Sertoli cells- contains Leydig cells

    Accessory Ducts

    • ➥ Rete testis
    • ➥ Vasa efferentia
    • ➥ Epididymis
    • ➥ Vas deferens
    • ➥ Urethra

    Accessory Glands

    • ➥ A pair of seminal vesicles
    • ➥ Prostate gland
    • ➥ Bulbourethral gland

    These glands secrete seminal plasma rich in fructose, calcium and certain enzymes. Secretions of bulbourethral glands also help in lubrication of penis.

    External Genitalia

    • The penis is the external genitalia in human males.
    • It is made up of special erectile tissue that helps in erection of the penis to facilitate insemination.
    • The enlarged tip of the penis is called glans penis covered by foreskin.

    The Female Reproductive System

    It consists of the primary sex organ that is a pair of ovaries.

    • Secondary sex organs- the duct system consisting of a pair of fallopian tube , a uterus , cervix and vagina
    • External genitalia
    • Mammary glands

    Ovaries

    • ➥ Produce female gametes called ova.
    • ➥ Covered by a thin epithelium, enclosing the ovarian stroma.
    • ➥ Stroma is divided into 2 regions i.e. Cortex (outer) and Medulla (inner).

    Gametogenesis

    The process of formation of gametes is called gametogenesis. It is of two types:

    Spermatogenesis in males Oogenesis in females
    The process of formation of sperms in males is called spermatogenesis The process of formation of a mature female gamete is called oogenesis

    Structure of sperm composed of head, neck, middle piece and a tail.

    Menstrual Cycle

    The cyclic changes that occur in the reproductive organs of primate females is called menstrual cycle

    The events in a menstrual cycle can be studied under four phases:

    • Menstrual Phase
    • Follicular Phase
    • Ovulatory Phase
    • Luteal Phase

    Fertilization

    The process of fusion of a sperm with an ovum is called fertilization.

    Implantation

    • Zygote moves towards uterus → Blastomeres (2, 4, 8,16 daughter cells) → morula (8-16 blastomeres) → Blastocyst
    • Blastocyst gets embedded in ndometrium of uterus.

    Pregnancy And Embryonic Development

    • Placenta secretes hormones like hCG, hPL, estrogens, progesterones (to maintain pregnancy).
    • Inner cell mass differentiates into an outer layer called ectoderm, middle mesoderm and an inner layer endoderm.

    Parturition

    • Gestation period – 9 months.
    • Parturition – the process of delivery of the foetus (childbirth).

    Lactation

    • Production of milk towards the end of pregnancy is called lactation.
    • The milk produced during the initial few days is called colostrum that is rich in IgG antibody.

    Share page on

    Chapterwise Notes Class 12 Biology
    CBSE CLASS 12 Notes
    CBSE CLASS 12 SYLLABUS
    CBSE CLASS 12 BOOKS