Development

Development and Cell Biology

Development

• Development involves the formation of sex cells, zygote formation, and subsequent stages in one's life span.

Haploid Condition

• Haploid Condition: A cell with only half the chromosome number or one set of chromosomes.

Diploid Condition

• Diploid Condition: A cell with the full chromosome number or two sets of chromosomes.

Totipotent Cell

• Totipotent Cell: Capable of differentiating into any kind of cell.

Stages of Animal Development

• Gametogenesis: Stage yielding haploid gametes.

• Fertilization: Results in a unicellular diploid zygote.

• Cleavage: Series of mitotic divisions producing a multicellular blastula.

• Gastrulation: Morphogenetic movements producing a gastrula with germ cell layers.

• Organogenesis: Differentiation of germ layers into organ systems.

• Growth: Characterized by an increase in individual size.

Monozygotic Twins

• Monozygotic Twins: Result from a single zygote splitting during cleavage.

Dizygotic Twins

• Dizygotic Twins: Result from separate fertilization events developing almost simultaneously.

Male Reproductive System

• Testis

  • Where Sperms are produced

• Epididymis

  • Where sperms are temporarily stored

• Scrotal Sac

  • Supports the testis and epididymis

• Urethra

  • serves as passageway of both sperm and urine

• Seminal Vesicle

  • Secretes fluid that forms part of the semen

• Prostate gland

  • Secretes fluid that also provides alkalinity to the semen

• Bulbourethral Glands

  • produceclear, viscous secretion known aspre-ejaculate that helps to lubricate the urethra for sperm topass through

Female Reproductive System

• Clitoris

  • The homologue of the penis in females.

• Vagina

  • Main entrance to thefemale reproductive tract

• Cervix

  • Where the vagina ends

• Uterus

  • where the embryo develops

• Endometrium

  • Innermost lining of theuterus where the embryoimplants and develop.

• Fallopian Tubes

  • This is where fertilization takes place

• Ovaries

  • Female gonads that releasethe oocytes during ovulation

Human Development

• Fertilization

  • occurs in the fallopiantube’ results in a unicellular zygote

• Cleavage

• Morula

  • A human blastula madeup of a solid ball of cells

• Blastocyst

  • human blastula composed of the inner cell mass

• Implantation

  • Process where the blastocyst implants itself in the endometrium

• Gestation

  • Carrying of the embryo insidethe female reproductive tract

• Human Embryo

  • Corresponds to the first two months of gestation

• Human Fetus

  • Corresponds to the months 3-9 of human gestation

Menstrual Cycle

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• Ovarian Cycle:

• Follicular Phase

  • where the follicles begin to mature

  • Secretions of the follicle-stimulating hormone (FSH) and the leutinizing hormone (LH) by the anterior pituitary gland

• Ovulation

  • is the release of eggs fromthe ovaries

• Luteal Phase.

  • Part of the menstrual cycle of the ovary after the oocyte sare released from the follicles

• Uterine Cycle:

• Menstrual Phase

  • Part of the menstrual cycle of the uterus; also known asthe “period

• Proliferative Phase

  • Corresponds to the latter partof the follicular phase of theovaries (days 8-14

• Secretory Phase

  • The endometrium undergoes final changes before it receives the embryo during implantation

Contraception

• Contraception stages: release and transport of gametes, fertilization, implantation, embryo/fetus development.

• Oral Contraceptives

  • Type of contraception taken in by women to prevent them from ovulating

• Barrier Methods

  • Type of contraception thatprevents fertilization

• Condom

  • Type of barrier method that is inserted on the malepenis to prevent release of sperm

• Diaphragm

  • Type of barrier method that blocks the cervix

• Cervical Cap

  • blocks passage of the sperm into the uterus

Chemical

• Spermicidal jelly or foam

  • Type of barrier method that kills sperm on contact.

  • Placed inside the vaginal canal.

• Surgical methods

  • Special type of contraception preventing fertilization.

  • Involves surgery.

• Vasectomy

  • Type of surgical method for men.

  • Involves cutting the vas deferens.

• Tubal Ligation

  • Type of surgical method for women.

  • Involves cutting the fallopian tubes.

• Implantation-suppressing methods

  • Contraception preventing blastocyst implantation in the endometrium.

• Intra-uterine devise (IUD)

  • Type of implantation-suppressing method.

  • Physically blocks blastocyst from implanting.

• Morning-after pill

  • Implantation-suppressing method.

  • Blocks the action of hormones preparing the uterus for the embryo.

• Coitus interruptus

  • Contraception requiring the man to withdraw before ejaculation.

• Abstinence

  • Contraception where no sexual intercourse occurs.

• Abortion

  • Contraception involving the deliberate removal of the embryo/fetus before