Gametes: Definition, Formation & Fusion - Video & Lesson Transcript | santemontreal.info
Human reproduction is any form of sexual reproduction resulting in human fertilization, typically involving sexual intercourse between a man and a woman. During sexual intercourse, the interaction between the male and female reproductive systems results in fertilization of the woman's These are specialized reproductive cells called gametes, created in a. These two gametes meet within the female's uterine tubes located one on each side of Similarities between male and female reproductive systems .. The myoepithelial cells can contract, similar to muscle cells, and thereby push the milk. We're updating subjects as fast as we can. Visit In females, the two sex chromosomes are the same. They are XX. Gametes are sex cells. The male Fertilisation is the joining or fusion of a male gamete and a female gamete. The new cell.
Organisms that reproduce sexually are usually fairly complex, and the individuals involved are usually either male or female, with the sex of each being separate.
BBC Bitesize - National 5 Biology - Reproduction - Revision 1
Males and females have different types of gonads or sex organs in which the gametes develop. The males produce sperm in gonads called testes, and the females produce egg, or ova, in gonads called the ovaries. Sperm are generally smaller than the egg and must swim through a liquid to get to the egg in order to fertilize it. Fertilization or the union of a male sex cell and a female sex cell can occur inside the female internal fertilization or outside external fertilization. Both methods have advantages and disadvantages.
Aquatic organisms those that live in water more commonly use external fertilization. The sperm and eggs are released into the water where they meet, and fertilization occurs. Actually, the sex cells are scattered into the environment and the rest is left to chance.
To increase the odds for fertilization, gametes are released in large numbers. For example, oysters release millions of sperm and eggs into the water. Although there may be great waste in this process, there is little cost to the parents who do not have to care for the offspring produced.
Animals that use external fertilization, like fish and frogs, have generally short lives and do not reproduce many times.
Process[ edit ] "Coition of a Hemisected Man and Woman" c. Human reproduction normally begins with copulation, followed by nine months of pregnancy before childbirth, though it may be achieved through artificial insemination.
Many years of parental care are required before a human child becomes independent, typically between twelve and eighteen or more. Pregnancy can be avoided with the use of contraceptives such as condoms and Intrauterine devices. Sexual intercourse Human reproduction naturally takes place as internal fertilization by sexual intercourse. During this process, the male inserts his penis, which needs to be erectinto the female's vaginaand then either partner initiates rhythmic pelvic thrusts until the male ejaculates semen, which contains sperm, into the vaginal canal.
This process is also known as "coitus", "mating", "having sex", or, euphemistically"making love". The sperm and the ovum are known as gametes each containing half the genetic information of the parent, created through meiosis. The sperm being one of approximately million sperm in a typical male ejaculation travels through the vagina and cervix into the uterus or Fallopian tubes.
Only 1 in 14 million of the ejaculated sperm will reach the Fallopian tube. The egg simultaneously moves through the Fallopian tube away from the ovary. Doctors have different names for this developing baby. When the ovum was fertilised and became your first cells, these 'plans' or genes helped to decide lots of things about you, eg.
Genes are made of DNA 'de-ox-y-ri-bo-nu-cle-ic acid', if you want the full name. If you could see your genes they would look like beads on a necklace of DNA. Each cell in a human body has 46 chromosomes. That first single cell has 23 chromosomes from mum and 23 from dad, which is why you might look like mum or dad or grandparents and have similar traits, eg.
Isn't it annoying when people who haven't seen you for a while say things like, "He's got his dad's chin", or "she's got grandma's eyes! Twins and more Remember, any one sperm can only fertilise one ovum, so if 2 ova eggs leave the ovaries at the same time and are both fertilised then 'non-identical' twins are born.
They may look alike or they may not, just like any brothers or sisters. If an ovum splits after it has been fertilised, then you get identical twins because they have the same set of genes. It is called a multiple birth if two or more babies are born at the same birth. Do you know what we call a set of three babies who are born at the same time? What sex you are What sex a baby will be is decided when the egg and sperm unite.
Each egg and each sperm have one sex chromosome.
Can you see why they are called x and y chromosomes? Hint - look at the picture of a male chromosome.
You may look a bit like someone in your family, but there is only one of you!