RBSE Class 12 Biology Notes Chapter 3 Human Reproduction

These comprehensive RBSE Class 12 Biology Notes Chapter 3 Human Reproduction will give a brief overview of all the concepts.

RBSE Class 12 Biology Chapter 3 Notes Human Reproduction

→ Human is sexually reproducing and viviparous organism. Human has internal fertilization and internal development.

→ In human the process of sexual reproduction involves the events in a sequences are-Gametogenesis, Insemination, Fertilization, Cleavage, Implantation, Gestation and Parturition.

→ Men and women are visibly different from each other in physical appearance, external genital organs and accessory sex characters. This is called sexual dimorphism.

→ Both male and female reproductive organ comprise Primary sex organ and Secondary or accessory sex organs.

→ The male reproductive system is located in the pelvic region. It includes:

• Primary Sex Organs r One pair of testes.
• Accessory Ducts: Rate testes, vasa efferentia, epididymis, vasa deferentia.
• Accessory Sex Organs t Seminal vesicles, cowper’s glands, prostate glands, urethra and penis.

→ Testes are the primary male sex organs. They are extra-abdominal and suspended in the scrotal sac by spermatic cord.

→ Each testis is divided into 250 compartments called testicular lobules. Each lobule contain 1-3 highly coiled tubules known as seminiferous tubule in which sperms are produced.

→ Each seminiferous tubule is lined on its inside by two type of cells called germ cells (spermatogonia; produce sperms) and sertoli cells (provide, nutrition to developing sperms).

→ The seminiferous tubules open into the vasa efferentia, which open into epididymis and carry sperms outside the testes.

→ Epididymis stores non-motile and immature sperms temporarily.

→ The duct- from seminal vesicle and vasa deferens together form the ejaculatory duct.

→ Urethra originates from the urinary bladder and extends through the penis to its external opening called urethral meatus.

→ The accessary glands of man include a prostate gland (produces a milky secretion), seminal vesicles (releases a watery alkaline fluid) and cowper’s gland (releases mucus).

→ Penis is the male copulatory organ having erectile tissues and vascular space. The man ejaculates sperms into vagina of woman by penis.

→ The female reproductive system of man is consists of the primary sex organs (one pair ovary), secondary sex organs (A pair of oviduct, uterus, cervix and vagina) dnd external genetalia (vulva).

→ Ovaries are located one on each side of the lower abdomen and remain attached to the pelvic wall and uterus by ovarion ligaments.

→ Ovaries are the primary female reproductive organs that produce the female gametes (ovum) and several 'steroid hormones.

→ Oviducts are two small tube lying on either sides of uterus. It is also called fallopian tube. It is the site where fertilization takes place.

→ Uterus is a single hallow, muscular pear-shaped structure supported by ligaments and attached to the pelvic wall. Here implanted embryo is developed to produce factus and finally; a baby.

→ Human female has a pair of mammary glands that contain glandular tissues and fatty tissues. These function the production of milk.

→ The external genitalia of female are collectively called vulva and consists of mons pubis, labia majora, labia minora, clitoris, hymen and external orifice.

→ Gametogenesis is the process of gamete formation in the gonads (tests and ovaries) is sexually reproducing animals.

→ The two process of gametogenesis are: Spermato-genesis and Oogenesis.

→ The process of formation of spermatozoa (sperms) from diploid spermatogonia is called spermatogenesis, it includes multiplication phase, growth phase, maturation phase and differentiation phase.

→ A sperm is called male gamete which consists of head, neck, middle piece and tail. It carries half number of chromosomes (i.e, 23).

→ The process of formation of a mature gamete (ovum) is called oogenesis. It occurs in ovaries. It also has four phase like spermatogenesis.

→ The rhythmic series of changes that occur in the reproductive organs of female primates is called menstrual cycle. It is repeated it an average interval of about 28/29 days.

→ Male discharges semen in the female’s vagina close to the cervix during sexual intercourse. This is, called insemination.

→ The process of fusion of a sperm (male gamete) with an ovum (female gamete) is called fertilization. This process occurs in fallopian tube of female.

→ Ultimately diploid zygote is produced by the fusion of sperm and an ovum. Zygote divides rapidly by mitotic divisions as it moves through isthmus of oviduct towards uterus. This is called cleavage. As a result 2, 4, 8 and 16 daughter cells are produced which are termed as blastomeres.

→ Embryo with 8-16 blastomeres is called morula. The morula continues to divide and transforms into a large mass of cells called blastocyst which passes further into the uterus.

→ The process of the attachment of the blastocyst to the uterine wall is called implantation, which takes place about seven days after fertilization.

→ The period from fertilization to parturition is called gestation period. The gestation period of human is 280 days.

→ Placenta is a temporary intimate mechanical and physiological connection between foetal and maternal tissue for nutrition, respiration, excretion etc., of the foetus.

→ The act of expelling the full term foetus from mother’s uterus at ‘the end of gestation period is ‘called parturition. It is induced by a complex neuroendocrine mechanism.

→ Mammary glands of female undergo differentiation and start producing milk at the end of pregnancy. This is called lactation. This help the mothers in feeding the newborn.

→ Reproduction: A biological process by which an organism produces another organism similar to itself.

→ Gametogenesis: The process of formation of gametes (sperm or ovum) from germ cells,

→ Testes: Primary reproductive organs in man which produce sperm.

→ Scrotum s A pouch like structure which has testes inside it and lies outside the abdominal cavity between legs.

→ Seminiferous tubules: Thin and coiled tubules present in testes. Their germinal cells produces sperms.

→ Germ cells: The cells present in primary reproductive organs and produce gametes.

→ Rete testes: A network of wider, irregular tubul S at the end of seminiferous tubul S is called rete testes.

→ Epididymis: A glandular structure present on the posterolateral side of each testes.

→ Vos deferens: A tube arises from the tail of epididymis and ascends into the abdominal cavity finally meets with ejaculatory duct.

→ Ejaculatory ducts: Thin walled tubes which passing through prostate glands open into urethra.

→ Urethra s A nerrow tube that transport urine from the bladder to outside the body. In males it also conducts sperm and semen to the outside.

→ Penis ; A cylindrical, erectile and copulatory organ found in men.

→ Seminal vesicle: A elongated, coiled sac present at the base of the bladder which releases seminal fluid.

→ Prostate gland: A large, chestnutshaped, spongy and lobulated gland which surrounds the first portion of urethra.

→ Sperms s Male gametes produced by seminiferous tubules in testes.

→ Acrosome: A caplike structure present enteriorly on sperm head.

→ Spermatogenesis: The process of formation of sperms is called spermatogenesis.
 
→ Ovary: The primary reproductive organs of female human.  

→ Oviduct: Small tubes lying on either sides of uterus near the kidney.

→ Infundibulum: The opening of the fallopian tube towards ovary and is expanded into funnel-shaped structure called infundibulum.

→ Ampulla: The infundibulum leads to a wider part at the oviduct is called ampulla.

→ Isthmus: It is the last part of the oviduct having a narrow lumen which joins the uterus.

→ Uterus (Womb) s A single hollow, pear-shaped structure in female which bears foetus for development.

→ Cervix: Lower narrow part of uterus that projects into the vagina is called cervix.

→ Vagina: Elastic and fibro-muscular tube-like structure extends from cervix to vulv of the female. It is copulation chamber of female.

→ Vestibule s The area between the two labia minoro is called vestibule.

→ Clitoris: A small erectile body of the size of a pea, located at anterior union of the vulva in female. Analogous to the penis in male.

→ Vulva: The external female genetalia that surround the opening to the vagina, collectively these consists at the labia majora, labia minora, clitoris, vestibule of the vagina and the glands of bartholin.

→ Puberty: The time when a child’s body is changing and becoming physically like that of an adult.

→ Oogenesis: The process of formation of 6vum in ovary is called oogenesis.

→ Menstrual cycle: The rythmic series of changes that occur in the reproductive organs of female primates is called menstrual cycle.

→ Fertilization s The process of fusion of male and female gamete to produce zygote.

→ Ovum: Female garnet having half number of chromosome.

→ Insemination: Ejaculation of sperms in female genital tract.

→ Zygote: A diploid structure produced by the fusion of sperm and ovum.

→ Embryogenesis s The process of development of embryo from zygote.

→ implantation: The process of the attachment of the blastocyst to the uterine wall is called implantation.

→ Cleavage: Series of rapid mitotic divisions of the zygote to form multicellular structure called morula and finally blastula. 

→ Gastrulation: Transformation of the blastula into the gastrula.

→ Gastation period: Time period from fertilization to parturition.

→ Parturition: Expelling the full term foetus from mothers’ uterus at the end of gestation.

→ Lactation: Production of milk by mammary glands.