• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Reproduction, Gamete formation and fertilisation

Extracts from this document...


Biology Assignment 8 Reproduction, Gamete formation and fertilisation Katie Bennett Reproductive system Male Reproductive System The Male system produces sex cells (Gametes) called Sperm. Sperm production is continuous and reduces with age. The main reproductive organs in males include the Testes and Penis. http://www.drstandley.com/images/male.gif The testes lie outside the body in a pouch of skin called the Scrotum, where they can maintain the optimum temperature for sperm production- approximately 3 0C (50F) lower then body temperature. Testes are responsible for sperm production and the sex-hormone Testosterone. From each testis, sperm pass into a coiled tube - The Epididymis - for the final stages of maturation. They are stored in the Epididymides until they are either broken down or reabsorbed, or ejaculated - forced by movement of seminal fluid from the accessory glands down a duct called the Vas deferens. Inside the Male Scrotum http://www.zianet.com/nlynch/scrotum/testicle1.gif Scrotal Layers http://www.phyto-2000.co.uk/images/reproductive-system2.jpg Each testis is covered by a thin tissue layer, the Tunica vaginalis around which is a layer of connective tissue called Fascia. ...read more.


The follicle enlarges as its cell proliferates, and begins to fill with fluid, becoming a Secondary Follicle that moves to the ovary's surface. It also increases its production of the hormone oestrogen. A surge of Luteinizing Hormone (LH) causes the follicle to rupture and release the ripe egg - this is Ovulation. The lining of the empty follicle thickens into a Corpus- Luteum. http://cache-media.britannica.com.cdnetworks.net//eb-media/36/99236-004-770A8041.jpg Fertilisation Fertilisation is the term used to describe the exact moment when the Nuclei of the male and female gametes fuse. Each gamete contains half the full number of chromosomes, fertilisation creates a new cell with the full number of chromosomes this cell is called a Zygote. The Zygote contains two sets of chromosomes - one set from the male parent and the other from the female parent. Combining the genetic materiel from the two individuals makes offspring that are genetically Unique. http://members.optushome.com.au/karens/fertilisation.gif In humans, sperm are deposited high up in the female vagina close to the entrance of the cervix. ...read more.


This process is known as cleavage. http://sprott.physics.wisc.edu/pickover/zygote.jpg Morula The zygote divides several times to form a solid blackberry- like cluster of 16-32 cells, the morula (derived from the Latin for "Mulberry"). At 3-4 days after fertilisation the morula leaves the fallopian tube and enters the uterine cavity. http://blogs.discovermagazine.com/loom/files/prevsite/morula.gif Blastocyst About six days after fertilisation, the cell cluster forms a hollow cavity and is known as a Blastocyst. It floats within the uterus for around 48 hours before landing on the thick uterus lining (Endometrium), which softens to aid implantation (Burrowing of the Blastocyst into the Endometrium). The inner group of cells become the embryo itself. http://www.molecularstation.com/molecular-biology-images/data//504/thumbs/Blastocyst.jpg Embryonic disc Within the inner cell mass, an Embryonic disc forms. This separates the cell cluster into the amniotic cavity, which develops a sac that fills with fluid and fold around to cover the embryo, and the yolk sac, which helps to transport nutrients to the embryo during the second and third weeks. The disc develops three circular sheets called the primary germ layers-ectoderm, mesoderm and endoderm - from which all body structures will derive. http://www.citruscollege.edu/pic/46/0795l.gif http://cache-media.britannica.com.cdnetworks.net//eb-media/79/1079-004-38FAAFCC.gif ?? ?? ?? ?? Page 1 of 9 ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Exchange, Transport & Reproduction section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Here's what a teacher thought of this essay

4 star(s)

A well structured and comprehensive report on the stages and process of reproduction. Good use of images to illustrate and sub-headings to structure. However, some key A-level detail is omitted (i.e. the role of Meiosis)
To improve:
1)Explain the role of Meiosis in generating haploid gametes. This is essential fro reproduction to occur
2)Include biological terms such as haploid and diploid where relevant
3)Include brief detail about the role of stem cell differentiation in the development of the embryo
3)Include a reference list at the end

Marked by teacher kerry jackson 19/02/2012

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Exchange, Transport & Reproduction essays

  1. Marked by a teacher

    Describe the molecular structure of starch (amylase), glycogen and cellulose, and relate these structures ...

    4 star(s)

    This diagram shows two molecules of ? glucose forming a disaccharide: This shows two glucose molecules joining together to form the disaccharide maltose. Because this bond is between carbon 1 of one molecule and carbon 4 of the other molecule it is called a 1-4 glycosidic bond.

  2. Marked by a teacher

    The Effect Of Temperature On The Permeability Of The Cell Membrane

    3 star(s)

    So they are the same length and surface area for each experiment.] * Boiling tubes [What? This is used to place the suited number of beetroot discs and distilled water during the experiment. A boiling tube is used instead of a test tube as a test tube can break in extreme temperatures.

  1. Effects of exercise on cardiovascular system

    - experimenter places the index and middle finger over the underside of the wrist of the subject below the base of the thumb and presses firmly with flat fingers until they feel the pulse in the radial artery. Here the artery passes over a bone near to the surface of the skin and pulse can be easily felt.

  2. Osmosis in Potato cells

    The reason for my prediction is based on my definition of osmosis and the fact that water will move from a higher concentration of water to a lower concentration of water, thus I predict that for a high concentration of sugar (and low concentration of water)

  1. To find out the factors affecting the refractive index of liquid by using different ...

    This can be due to experimental error. Another reason of this can be because the light source that I used is red; the wavelength of red light is longer than the wavelength of white light. Since I know that red light is less refracted than blue light, this is demonstrated when white light is shown on prisms.

  2. Internal and External Fertilisation

    This type of fertilisation enables animals to reproduce in a terrestrial environment because it enables sperm to swim to the egg and it prevents gametes from drying out. The male often has a copulatory organ (a penis) for transferring sperm.

  1. P6Explain how these dietary nutrients are processed through the digestive system

    The enzyme in the lining of the small intestine splits the molecule down and absorbs the glucose into the blood.

  2. Describe the structure and purpose of the lymphatic system .

    The lymphatic system also works with the circulatory system in order to deliver, nutrients and oxygen from the blood to the cell?s in the same way it also delivers hormones from the blood to the cells in order to make up the different tissues of the body.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work