Students can go through AP Inter 2nd Year Zoology Notes Lesson 5(a) Human Reproductive System will help students in revising the entire concepts quickly.
AP Inter 2nd Year Zoology Notes Lesson 5(a) Human Reproductive System
→ The sex organs of the Male Reproductive System in the pelvic region are a pair of testes, accessory ducts, glands and external genitalia.
→ Testes are suspended within a pouch called scrotum.
→ Scrotum maintains temperature of 2-2.5°C, necessary for spermatogenesis.
→ Scrotal sac is connected to abdominal cavity through ‘inguinal canal’.
→ Testis is held in position in the scrotum by the ‘gubernaculum’.
→ Testis is enclosed in a fibrous envelope called ‘tunica albuginea’.
→ A pouch of serous membrane ’tunica vaginalis’ covers testis.
→ Seminiferous tubules are present in the lobules of testis.
→ Spermatogonial mother cells of seminiferous tubules play an important role in spermatogenesis.
→ ‘Nourishing cells’ or ‘sertoli cells’ provide nutrition to spermatozoa.
→ Leydig cells produce ‘Testosterone’ hormone, that controls secondary sexual characters and spermatogenesis.
→ Epididymis is a storage organ of sperms and gives the sperms time to mature.
→ Urethra is the shared terminal duct of the reproductive arid urinary systems. It opens into penis through a opening called ‘urethral meatus’.
→ Penis is the copulatory organ of male and the enlarged, bulbous end of penis is called glans penis, and is covered by a foreskin or prepuce.
→ Seminal vesicles produce seminal fluid which contains nutrients for the nourishment of sperms.
→ Prostate gland’s secretion activates the spermotozoa and provides nutrition to them.
→ The secretion of bulbourethral glands acts as a flushing agent that washes out the acidic urinary residues that remain in urethra, before the semen is ejaculated.
→ The Female reproductive system consists of a pair of ovaries, a pair of oviducts, uterus, vagina and external genitalia.
→ Ovaries are enveloped by outer germinal epithelium and inner tunica albuginea.
→ The ovarian stroma is divided into an outer cortex and inner medulla. Cortex is more dense due to ovarian follicles and medulla is abundant with blood and lymphatic vessels and nerve fibres.
→ Fallopian tube is the site of fertilization which conducts ovum or zygote towards the uterus by peristalsis.
→ Uterus is a muscular pear-shaped structure and carries foetus, it is also known as womb.
→ Uterus opens into the vagina is called the cervix. The cavity of cervix is called cervical canal.
→ Bartholin’s glands lubricate vagina and are homologous to the bulbourethral glands of the male reproductive system.
→ Skene’s glands secrete a lubricating fluid when stimulated and are homologus to the prostate gland.
→ The nourishment of newborn baby is provided by milk produced from mother’s mammary glands.
→ Gametogenesis in. male is called Spermatogenesis and that in a female is called Oogenesis.
→ Spermatozoa is composed of head, neck middle piece and tail.
→ The cap like structure on the head of spermatozoa is called acrosome.
→ The middle piece of sperm contains mitochondria that produce energy for the movement of tail.
→ Ovum is produced from modified secondary follicle called Graafian follicle.
→ Ovum is sorrounded by a membrane called Zona Pellucida.
→ Corpus luteum secretes Progesterone for the maintenance of pregnancy.
→ The menstrual flow results due to breakdown of endometrial lining of the uterus and its blood vessels.
→ During follicular phase, primary follicles mature into Graafian follicles and produce gonadotropins LH & FSH.
→ Rupture of Graafian follicle by LH results in the release of ovum.
→ The enzyme hyaluronidase from acrosome of a sperm dissolves hyaluronic acid of the follicle cells thus making easy penetration of sperm into a ovum.
→ The nuclear union of sperm and ovum results in the formation of synkaryon or zygotic nucleus.
→ Implantation of blastocyte occurs on the 6th day of fertilization.
→ The extra embryonic or foetal membranes are chorion, amnion, allantois and yolk sac.
→ The sclerotome of enlbryo forms vertebral column.
The myotome fonns voluntary muscles.
The dermotome forms dermis of skin and other connective tissues.
→ The notochord and neural tube are formed by the converge and involution of chorda mesodermal cells through the Hensen’s node.
→ The placenta of human is called chorioallantoic placenta as allantois fuses with the chorion in the process of vascuralisation.
→ Placenta is deciduous, because during parturition placenta is Cast off causing extensive haemorrhage and there by bleeding.
→ Progesterone secreted by placenta is essential for the maintenance of preganancy after 4th month.
→ Human Chorionic Gonadotropin (HCG) presence is used as a test in the detection of pregnancy.
→ The gestation period in humans is 266 days or 38 weeks.
→ Most of the major organs are formed by the end of first trimester and by the end of nine months of pregnancy, the foetus is fully developed.
→ Oxytocin acts on the uterine muscle during parturition and causes stronger uterine contractions.
→ Mammary glands produce milk after the birth of pregnancy, called lactation.
→ Breast feeding is recommended by doctors for bringing up a healthy baby.