REPRODUCTION IN LOWER AND HIGHER ANIMALS

REPRODUCTION IN ANIMALS

Reproduction: It is a process by which an organism produces young ones like themselves. It is an essential process for the continuity of generation.

Asexual reproduction: The reproduction which does not involve the fusion of two gametes or sex cells is called asexual reproduction.

Sexual reproduction: The reproductions which involve the fusion of two gametes or sex cells are called sexual reproduction.

Clones: Morphologically and genetically identical individuals are called clones or the organisms produce by asexual reproduction are called clones.

Offspring: An organism produced by means of sexual reproduction is called offspring.

Fragmentation: It is a type of asexual reproduction in which an organism simply breaks in individual pieces at maturity.

Budding: The form of an asexual reproduction in which a new individual develops from some generative anatomical point of the parent organism.

Binary fission: A form of asexual reproduction In which the parent body divide into two equal halves E.g.  Amoeba, Paramecium.

Gemmule formation: A form of asexual reproduction In which a type of internal bud (gemmule) is formed in sponges to overcome the unfavourable season.

Juvenile phase: The phase which mainly represents physical growth starting from birth is called juvenile phase.

Reproductive phase: Reproductive maturity phase is attained usually after physical growth is almost over. It involves growth and activity of the sex organs.

Seasonal breeders: The animals that mate only during certain time of the year is called seasonal breeders.

Continuous breeders: The animals that mate throughout the year is called continuous breeders.

Secondary sex organs: Organs other than testis and ovary are called secondary sex organs of the male and female.

Secondary sexual characters: The feature by which male and female can be externally differentiated are called secondary sexual characters.

Adam’s apple: The enlarged larynx in male is called Adam’s apple.

Amphimixis: Formation and fusion of gametes are called amphimixis.

Inguinal canal: The canal through which testis descends into the scrotum from the abdomen is called the inguinal canal.

Tunica albuginea: The collagenous connective tissue layer present on testis is called tunica albuginea.

Tunica vaginalis: The incomplete peritoneal covering on testis is called tunica vaginalis.

Seminiferous tubule: The seminiferous tubules are the site of spermatogenesis where germ cells develop into spermatozoa.

Sertoli cells: The large pyramidal cells present inside the seminiferous tubules are called Sertoli or sustentacular cells.

Gametogenesis: The process of formation f gametes is called gametogenesis.

Interstitial or Leydig’s cells: The cells which are located between the spaces of seminiferous tubules responsible for the secretion of testosterone is called interstitial cells.

Gubernaculum: The fibrous cord which connects the testis to the inner wall of the scrotum is called gubernaculum.

Rete testis: An anastomosing network of delicate tubules located in the hilum of the testicle that carries sperm from the seminiferous tubules to the efferent ducts.

Urinogenital duct: The common duct which carries both urine and a gamete is called urinogenital duct.

Glans penis: The swollen tip of the penis is called the glans penis.

Semen: Seminal fluid containing spermatozoa is called semen.

Scrotum: It is a loose pouch of pigmented skin lying behind the penis in which testis is located called scrotum.

Cowper’s gland / Bulbourethral gland: It is a small, pea-sized and paired gland situated  on  either  side of the urethra.

Cryptorchidism: A condition in which one or both of the testes fail to descend from the abdomen into the scrotum is called cryptorchidism.

Atresia: The primordial follicles during growth are called atresia.

Puberty: The process of physical changes through which a child's body matures into an adult body capable of sexual reproduction.

Graffian follicle: The mature follicle in the female is called graffian follicle.

Menarche: The first occurrence of menstrual bleeding is called menarche.

Ovulation: The process of release of the ovum into the fallopian tube is called ovulation.

Corpus leuteum: the remaining part of the follicle after the ovulation changes into a temporary endocrine gland called corpus leuteum.

Corpus Albicans: If fertilization does not occur then the corpus luteum degenerates into a white scar called corpus Albicans.

Antrum: The part of ovarian follicle filled with fluid is called antrum.

Ampulla: It is the middle, long and straight part of the oviduct is called the ampulla. Fertilization of the ovum takes place in this region.

Cervix: The cylindrical neck of the tissue which connects the vagina to the uterus is called the cervix.

Parturition: The act of giving birth to the young one is called parturition.

Hymen: A fold of mucus membrane by which vaginal opening is partially covered is called the hymen.

Mons pubis: The fleshy elevation above the labia majora is called the mons pubis.

Labia majora:  A pair of fleshy folds of skin forming the boundary of the vulva is called labia minora.

Clitoris: A small conical and sensitive projection lying at the anterior end of labia minora is called the clitoris.

Vestibule: It is a median vertical depression of vulva enclosing the urethral and vaginal opening called a vestibule.

Mammary glands: It is the modified sweat gland meant for the secretion of the milk is called mammary gland.

Areola: The dark brown coloured and circular area of the skin present on the breast is called the areola.

Weaning: The gradual replacement of Mother’s milk by solid food after some time is called weaning.

Menopause: The time that marks the end of the menstrual cycle or a childbearing period is called menopause.

Menstrual cycle: The monthly cyclic changes that occur in the ovary is called the menstrual cycle.

Spermiogenesis: The process of transformation of spermatid into functional spermatozoa are called spermiogenesis.

Acrosome: A cap-like structure present at the tip of the sperm is called acrosome.

Oogenesis: The process of formation of haploid egg or ova is called oogenesis.

Ooplasm: The cytoplasm of the egg is also called ooplasm.

Germinal vesicle: The nucleus of the egg appears large and is called a germinal vesicle.

Animal pole: The side having germinal vesicle and first the polar body is called the animal pole.

Vegetal pole: The side opposite to the animal pole is called a vegetal pole.

Capacitation: The process of functional maturation of spermatozoa are called capacitation.

Synkaryon: A somatic hybrid cell in which chromosomes from two different parental cells are enveloped in a single nucleus.

Syngamy or karyogamy: The fusion of two cell or their nuclei during the sexual mode of reproduction is called syngamy or karyogamy.

Insemination: The deposition of semen into the vagina of the female during sexual intercourse is called insemination.

Cleavage: It is the process of early mitotic division of the zygote into a hollow multicellular blastula. It does not involve the growth of the daughter cells.

Holoblastic: The whole zygote gets divided into the blastomeres are called holoblastic cleavage.

Blastomeres: The cells formed by cleavage are called blastomeres.

Morula: A solid mass of cells that formed by the division and re-division of the fertilized egg is called a morula.

Fertilization: The process of fusion of male and female gametes to form zygote is called fertilization.

Placenta: The structure which connects the mother to the foetus is called placenta.

Blastulation: The process of formation of hollow and multicellular blastocyst (blastula) from morula is called blastulation.

Trophoblast: The outer layer of cells seen in the morula form the outer layer on blastula called the trophoblast.

Embryoblast: The inner cell mass which participates in the formation of the embryo is called embryoblast.

Cells of Rauber: The embryonal knob or the cells of trophoblast which remains in contact with the inner cell mass of a blastocyst is called cells of Rauber.

Implantation: Establishment of the blastocyst into the endometrium of the uterus is called implantation.

Syncytiotrophoblast: Trophoblast cells with many nuclei are called syncytiotrophoblast.

Cytotrophoblast: The trophoblastic cells with defined membrane or with their cell boundaries are called cytotrophoblast.

Organogenesis: The process of formation of various body organs from gastrula is called organogenesis.

Stem cells: The undifferentiated somatic cells of a multicellular organism are called stem cells.

Gestation: The condition of carrying one or more embryos in the uterus is called gestation.

Foetus: An unborn human offspring more than eight weeks after conception is called a foetus.

Morning sickness: during pregnancy, the mother experiences nausea, vomiting, mood swings etc. in the morning is called ‘morning sickness’.

Foetal placenta: The Part of the placenta contributed by the foetus is called the foetal placenta.

Maternal placenta: The part which is rich in blood supply shared by the mother is termed as maternal placenta.

Labour pains: Labour is accompanied by a localized sensation of discomfort or agony called labour pains.

Lactation: The mammary glands of the female start producing milk at the end of pregnancy by the process called lactation.

Colostrum: The fluid secreted by the mammary glands soon after childbirth is called colostrum.

STD’s: Sexually transmitted diseases.

Contraceptives: The birth control measures which deliberately prevent fertilization are referred to as contraceptives.

Coitus Interruption or withdrawal: The withdrawal of penis by the male partner from the vagina just before ejaculation is called coitus interruption.

Lactational amenorrhea: The temporary postnatal infertility in female after giving birth to the bay is called lactational amenorrhea (absence of menstruation).

Spermicides: The chemical which kills the sperm is called spermicides.

Condom: It is a thin rubber sheath that  is used to cover the penis of the male during copulation.

Vasectomy: The process of cutting a small part of the vas deferens and tied is called vasectomy.

Tubectomy: The process in which a small part of the fallopian tube is tied and cut.

Amniocentesis: Amniocentesis is a procedure in which amniotic fluid is removed from the uterus for testing or treatment. Sometimes this procedure is also used to detect the sex of the developing foetus illegally.

Infertility: The inability  to conceive naturally even after the one year of regular unprotected intercourse is called infertility.

IVF (In Vitro Fertilization): The process of fertilization where an egg is united with sperm outside the body in a test tube or glass plate to form a zygote under simulated conditions in the laboratory.

ZIFT (Zygote Intrafallopian Transfer): ZIFT is an infertility treatment used when there is a blockage in the fallopian tubes which prevents the fertilization of egg by the sperm.

GIFT (Gamete Intrafallopian Transfer): GIFT is an infertility treatment in which eggs are removed from a woman's ovaries, and placed in one of the Fallopian tubes, along with the man's sperm.

ICSI (Intra Cytoplasmic Sperm Injection): ICSI is an in vitro fertilization procedure in which a single sperm cell is injected directly into the cytoplasm of an ovum in the laboratory.

Artificial Insemination (AI): Artificial introduction of sperm into a female's cervix or vagina to achieve a pregnancy through in vivo fertilization without any sexual intercourse.

IUI (Intra Uterine Insemination): In this technique, the sperm are placed directly into the uterus of the female to achieve the pregnancy.

Adoption: Adoption  is  a  legal  process  by  which   a  couple  or  a  single  parent  gets  legal  rights,  privileges  and  responsibilities that are associated with a biological child for the upbringing of the adopted child.