Human Reproduction

Flashcards on Human Reproduction

Reproduction

The process by which living organisms produce young ones of their own type.

Primary sex organs

These are also called gonads which form gametes like - testis in males and ovary in females. Testis produces sperms and secretes testosterone. Ovary produces ova and secrete estrogen.

Secondary sex organs

Sex organs, glands and ducts which do not produce gametes but are otherwise essential for sexual reproduction.

Accessory sex characters

Traits which do not have any direct role in reproduction but provide specific features and structures to both the sexes.

Puberty

Beginning of sexual maturity or ability to reproduce.

Male Reproductive System

Located in the pelvis region and consists of a pair of testis, a paired duct system consisting epididymis, vasa efferentia, vas deferens, ejaculatory duct & urethra.

Scrotum

A pouch outside the abdominal cavity that allows sperms to develop at the optimum temperature (temperature of testes which is 2–2.5°C lower than the normal internal body temperature).

Testicular lobules

Each testis has about 250 compartments.

Seminiferous tubules

Highly coiled tubules in which sperms are produced.

Seminiferous tubule

Lined by germinal epithelium which is formed of two types of cells -male germ cells (spermatogonia) and sertoli cells.

Spermatogonia

Male germ cells.

Germ cells

Undergoes spermatogenesis to form spermatozoa.

Sertoli cell

Functions as nurse cells for differentiating spermatozoa.

Leydig cells

Synthesize and secrete testicular hormones called androgens.

Epididymis

Involved in temporary storage, nutrition & physiological maturation and motility of sperms.

Ejaculation

Discharge of semen due to powerful rhythmic contraction of urethra.

Glans penis

Tip of the penis which is highly sensitive to stimulation.

Prepuce

Loose retractile foreskin which covers glans penis.

Seminal vesicles

Secretions of these, a prostate and paired bulbourethral glands constitute the seminal plasma which is rich in fructose, calcium and certain enzymes.

Testosterone

Hormone secreted by leydig cells of testis controls growth, maintenance and functions of secondary sex organs.

Follicular stimulating hormone(FSH)

Controls seminiferous tubules and leydig's cells.

Female reproductive system

Consists of a pair of ovaries, a pair of oviducts, a uterus, a vagina, external genitalia, and a pair of mammary glands.

Ovaries

Produces the female gamete (ovum) and some steroid hormones (ovarian hormones).

Graafian folicule

Mature follicles which occupy a single cavity called antrum & contains a secondary oocyte ready for ovulation.

Corpus luteum

Ruptured graafian follicle is called corpus luteum which secretes progesterone hormone for the maintenance of pregnancy.

Oviduct

Conveys the egg from the ovary to the uterus, and provides the appropriate environment for its fertilization.

Fimbriae

Helps in collection of ovum after ovulation.

Tubectomy

Cutting of oviduct & tying its two ends separately.

Uterus

Site of implantation of the pre-embryo and for the subsequent embryonic & fetal development

Hysterectomy

Surgical removal of uterus

Female external genitalia

Includes mons pubis, labia majora, labia minora, hymen and clitoris.

Vagina

Tubular female copulatory organ and passageway for menstrual flow as well as birth canal and is of about 10 cm length.

Bartholin's glands

Pair of small glands which open in the vestibule lateral to vaginal orifice. The secretion of this gland is thick, viscous and alkaline for lubrication and counteracting urinary acidity.

Mammary gland

Essential function is milk production which has nutritional and immunologic functions.

Ovary

Regulated by pituitary gonadotropins or GnRH.

Follicle stimulating hormone (FSH)

Controls the transformation of young primary follicle into graafian follicle, maturation of ovum and secretion of estrogen by its follicular cells.

Luteinizing hormone (LH)

The Luteinizing hormone (LH) of anterior pituitary regulates the ovulation from the graafian follicle, transformation of empty graafian follicle into yellowish, conical corpus luteum and secretion of progesterone hormone from the corpus luteum.

Estrogen and progesterone

Growth and function of secondary sex organs are regulated by this.

Progesterone

Suspends ovulation during pregnancy, promotes implantation of foetus on the endometrium and development of foetus in the uterus

Relaxin

Broadens the pelvis for easy parturition.

Gametogenesis

Process of gamete (sperm or egg) formation which include spermatogenesis & oogenesis.

Spermatogenesis

Results in the formation of sperms that are transported by the male sex accessory ducts.

Spermiogenesis or spermateleosis

the process of formation of flagellated spermatozoa from spermatids.

Spermiation

Sperm heads become embedded in the sertoli cells, and are finally released from the seminiferous tubules

Sperm

Microscopic structure composed of a head, neck, a middle piece and a tail.

Sperm head

Contains an elongated haploid nucleus, the anterior portion of which is covered by a cap-like structure

Acrosome

Cap-like structure filled with enzymes that help in fertilization of the ovum

Middle piece

Possesses numerous mitochondria, which produce energy for the movement of tail that facilitate sperm motility essential for fertilization

Oligospermia

Deficiency in the number of sperms result in sterility

Oogenesis

Process of formation of a mature female gamete.

Oogenesis

The process of formation of a mature female gamete is called

Menarche

The first menstruation begins at puberty in females is known as

Menstrual cycle

Four phases which are follicular, ovulatory, luteal and menstrual

Fertilization

The fusion of a sperm with an ovum to form a diploid cell is called.

Cleavage

The mitotic division of the zygote unit moving through the isthmus of the oviduct towards the uterus and forms 2, 4, 8, 16 daughter cells called blastomeres.

Morula

Solid ball of 32 cell stage without a cavity which is formed after 5th cleavage and 31 cell division

Blastocyst

The blastomeres in the blastocyst are arranged into an outer layer and an inner group of cells attached to trophoblast called the inner cell mass.

Implantation

The blastocyst becomes embedded in the endometrium of the uterus

Placenta

Placenta is an intimate mechanical connection between foetus and uterus of mother for nutrition, respiration and excretion

the supply of oxygen and nutrients

Placenta facilitates this to the embryo and also removal of carbon dioxide and excretory /waste materials produced by the embryo.

Parturition

Process of childbirth

Colostrum

The milk produced during the initial few days of lactation is called this which contains several antibodies absolutely essential to develop resistance for the new-born babies.

Reproductive health

According to the World Health Organisation (WHO), reproductive health means a total well-being in all aspects of reproduction, i.e., physical, emotional, behavioural and social.

audio-visual and print media

Reproductive health programmes create awareness in both males and females about various reproduction related aspects with the help of this

Human population explosion

Increase in human population size over a relatively short period

Birth control

The process, regulation of conception by preventive methods or devices to limit the number of offsprings

Contraception

Deliberately prevents fertilization

Natural methods of contraception

Avoidance of ovum and sperm meeting which includes safe period, abstinence, coitus interruptus and lactational amenorrhea.

Mechanical methods of contraception

Prevents ovum and sperm from physically meeting with the help of barriers such methods are available for both males and females.

Physiological (oral) devices (hormonal) includes birth control pills

Administered orally to check ovulation by inhibiting the secretion of FSH and LH that are necessary for ovulation.

Surgical methods

Intervention blocks gamete transport and thereby prevent conception. Sterilization procedures in the male and female are called ‘vasectomy’ and ‘tubectomy’

Amniocentesis

For prenatal diagnostic technique to determine sex of the developing baby, Genetically controlled congenital diseases and Metabolic disorders in foetus.

Chorionic Villus Sampling (CVS)

Prenatal procedure which provides rapidly dividing foetal cells, thus facilitating the examination of chromosomal disorders.

Medical Termination of Pregnancy (MTP)

Intentional or voluntary termination of pregnancy before full term

Sexually Transmitted Diseases (STD)

Transmitted through sexual intercourse

Infertility

Inability to conceive or produce children even after 2 years of unprotected sexual cohabitation

Assisted reproductive technology (ART)

Includes all fertility treatment in which both sperms and eggs are handled.

Surrogate Motherhood

Woman allows a fertilized ovum of another couple to be infected into her womb. Then she carries to its full term for other couple.