PRESENTATION ON

SEXUAL REPRODUCTIONIN

HUMANS

FERTILISATION

For fertilization to occur, sperm must be deposited in the vagina within a few (5) days before or on the day of ovulation. Sperm transfer is accomplished by copulation. Sexual excitation dilates the arterioles supplying blood to the penis. Blood accumulates in three cylindrical spongy sinuses that run lengthwise through the penis. The resulting pressure causes the penis to enlarge and erect and thus able to penetrate the vagina. Movement of the penis back and forth within the vagina causes sexual tension

to increase to the point of ejaculation. Contraction of the walls of each vas deferens propels the sperm along. Fluid is added to the sperm by the seminal vesicles, Cowper's glands, and the prostate gland.

These fluids provide a source of energy (fructose) an alkaline environment to activate the sperm, and Perhaps in other ways provide an optimum chemical environment for them.

The mixture of sperm and accessory fluids is called semen. It passes through the urethra and is expelled into the vagina.

TYPES OF FERTILISATION

EXTERNAL FERTILISATION-In external fertilisation the fusion of male and female gametes takes place outside the body of the female.

Eg-frogs , fish etc.

INTERNAL FERTILISATION-In internal fertilisation the fusion of male gamete with the female gamete takes place inside the body of the female.

Eg-cats , dogs etc.

SEXUAL REPRODUCTION

Sexual reproduction is a process that creates a new organism by combining the genetic material of two organisms. It occurs both in eukaryotes[1][2] and prokaryotes:[3] in multicellular eukaryote organisms, an individual is created anew; in prokaryotes, the initial cell has additional or transformed genetic material. In a process called genetic recombination, genetic material (DNA) originating from two different individuals (parents) join up so that homologous sequences are aligned with each other, and this is followed by exchange of genetic information. After the new recombinant chromosome is formed, it is passed on to progeny.

Sexual reproduction is the primary method of reproduction for the vast majority of macroscopic organisms, including almost all animals and plants. The evolution of sexual reproduction is a major puzzle. The first fossilized evidence of sexual reproduction in organisms such as eukaryotes is in the Steinem period, about 1 to 1.2 billion years ago.[4] There are two main processes during sexual reproduction in eukaryotes: meiosis, involving the halving of the number of chromosomes; and fertilization, involving the fusion of two gametes and the restoration of the original number of chromosomes. During meiosis, the chromosomes of each pair usually cross over to achieve homologous recombination

MALE REPRODUCTIVE SYSTEM

FEMALE REPRODUCTIVE SYSTEM

TESTES-There is a pair of testes which lie outside the body within the scrotum.They produce a million of sperms.

VAS DEFERENS-Vas deferens are 2 in no.this duct connects each testes to the urethra.It carries sperms to the urethra along with the secretion of reproductive glands .

URETHRA-The 2 vas deferens open into the urethra and pass through penis.

PENIS-Urethra leads to a muscular organ called penis.It is used to deliver semen into the vagina of the female during mating.

SPERMS-Sperms are produced in millions by the testes.They are very small in size

PARTS OF MALE REPRODUCTIVE SYSTEM

PARTS OF FEMALE REPRODUCTIVE SYSTEM

OVARIES-There are 2 ovaries which are situated in the abdominal cavity.Each ovary produces one mature ovum every month.

OVIDUCT-It joins the uterus with the ovary .It carries the ovum into the uterus.

UTERUS-The developmemt of the baby takes place inside it.The lower narrow part of the uterus is called cervix.

VAGINA-The vagina receives the penis during sexual intercourse.The sperms are discharged into the vagina.

DEVELOPMENT OF EMBRYO

During development cells and tissues undergo changes in pattern and form that employ a wider range of physical mechanisms than at any other time in an organism's life. This book demonstrates how physics can be used to analyze these biological phenomena. Written to be accessible to both biologists and physicists, major stages and components of the biological development process are introduced and then analyzed from the viewpoint of physics. The presentation of physical models requires no mathematics beyond basic calculus.

Demonstration of the power of a physics-based approach to the life sciences, accessible to both biologists and physicists Extensively illustrated in full-colour throughout Describes more than two dozen physical models of developmental biological processes

Thanks……………………NAME: Mukul

CLASS:10-BROLL NO.:41