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

Excretion is the biological process by which an organism chemically separates waste products from its body. The waste products are then usually expelled from the body by elimination.

Extracts from this document...

Introduction

��ࡱ�>�� /1����.�������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������5@ ��0�bjbj�2�2 (*�X�XF�������������������8� ���vVXXXXXX$MR�^|�|���$$$��V$V$$6��6 p���~���6V�0�6� � 6������� �6 $||$Excretion is the biological process by which an organism chemically separates waste products from its body. The waste products are then usually expelled from the body by elimination. In mammals, for example, the two major excretory processes are the formation of urine in the kidneys and the formation of carbon dioxide (a human's most abundant metabolic waste) in the lungs. The waste products are eliminated by urination and respiration respectively. In urination, Hormone control over excretion occurs in the distal tubules of the kidneys as directed by the hypothalamus. Perspiration is another excretory process which removes salts and water, although the primary purpose is cooling. Urine formation begins with the process of filtration, which goes on continually in the renal corpuscles (Figure 3). As blood courses through the glomeruli, much of its fluid, containing both useful chemicals and dissolved waste materials, soaks out of the blood through the membranes (by osmosis and diffusion) ...read more.

Middle

is entirely reabsorbed back into the blood from the proximal tubules. In fact, it is actively transported out of the tubules and into the peritubular capillary blood. None of this valuable nutrient is wasted by being lost in the urine. However, even when the kidneys are operating at peak efficiency, the nephrons can reabsorb only so much sugar and water. Their limitations are dramatically illustrated in cases of diabetes mellitus, a disease which causes the amount of sugar in the blood to rise far above normal. As already mentioned, in ordinary cases all the glucose that seeps out through the glomeruli into the tubules is reabsorbed into the blood Sodium ions (Na+) and other ions are only partially reabsorbed from the renal tubules back into the blood. For the most part, however, sodium ions are actively transported back into blood from the tubular fluid. The amount of sodium reabsorbed varies from time to time; it depends largely on how much salt we take in from the foods that we eat. ...read more.

Conclusion

� � � � � ����rstu:;<=������������������������������gd[>F�������LMNOF����'()*���� ��������������������������$a$gd�S�$a$gd�S�gd[> }~�������������������gd[>$a$gd�S�$a$gd�S� &1�h:p[>��/ ��=!�'"�'#��$��%��D@�D NormalCJ_H aJmH nHsH tHDA@�D Default Paragraph FontRi�R Table Normal�4� l4�a� (k�(No ListDZ@�D [> Plain TextCJOJQJ^JaJ4@4 �S�Header ���!4 @4 �S�Footer ���!`�o"` �S�watermark header$a$CJOJQJfHq� ����N�o2N �S�watermark footer$a$ CJOJQJ�*����r�V�:���� �����alex�[>�S��@Fp ��P@��Unknown������������G��z ��Times New Roman5V��Symbol3&� �z ��Arial7&�� �VerdanaG5�� �����h�MS Mincho-�3� fg?5� �z ��Courier New"1���hH8�&H8�&H8�&$J e$J e$�������4bb3�� H�?������������������[>��jExcretion is the biological process by which an organism chemically separates waste products from its bodyTCoursework.Info Coursework - http://www.coursework.info/ - Redistribution ProhibitedTCoursework.Info Coursework - http://www.coursework.info/ - Redistribution Prohibitedalexalex�� ��Oh��+'��0���t��,@ P\ x � � ������kExcretion is the biological process by which an organism chemically separates waste products from its bodyUCoursework.Info Coursework - http://www.coursework.info/ - Redistribution ProhibitedrodalexewoUCoursework.Info Coursework - http://www.coursework.info/ - Redistribution Prohibitedrod>Downloaded from Coursework.Info - http://www.coursework.info/is Normal.dotfalexl.d2exMicrosoft Word 10.0@@��~��@��~��@��~��$J�� ��Õ.��+,��D��Õ.��+,�������H����� ���� � g�UCoursework.Info Coursework - http://www.coursework.info/ - Redistribution Prohibited UCoursework.Info Coursework - http://www.coursework.info/ - Redistribution Prohibited UCoursework.Info Coursework - http://www.coursework.info/ - Redistribution Prohibited oe bA kExcretion is the biological process by which an organism chemically separates waste products from its body Titled@���+K_PID_LINKBASE CopyrightDownloaded FromCan RedistributeOwner�A4http://www.coursework.comcoursework.comehttp://www.coursework.comocNo, do not redistributecoursework.com/ �������� !"#$%����'()*+,-��������0��������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������Root Entry�������� �F� ��~��2�1Table��������WordDocument��������(*SummaryInformation(����DocumentSummaryInformation8������������&CompObj������������j������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������ ���� �FMicrosoft Word Document MSWordDocWord.Document.8�9�q ...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

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

    Sand Dune Succession Coursework

    5 star(s)

    As you travel away from the sea you will go from young to old dunes. A transect is the best technique to use for the study of dune succession. By using a quadrat, vegetation and soil can be sampled at intervals along the line.

  2. Marked by a teacher

    Biology coursework planning - the effect of lead chloride on the growth of cress ...

    5 star(s)

    Do not mix up the syringes for lead chloride and distilled water. Put the solutions in the syringes into the test tubes as done previously. Concentration of lead chloride solution desired (mol dm-3) Volume of 0.02moldm-3 lead chloride solution required (ml)

  1. Marked by a teacher

    What is Type 1 diabetes

    3 star(s)

    in the blood (especially triglyceride). If you have had a blood clot in the arteries supplying the heart (coronary thrombosis), or a stroke. If you're on certain types of medications, especially corticosteroids or diuretics. What can I do to avoid Type 2 diabetes? Try not to get overweight. Exercise regularly.

  2. Peer reviewed

    The comparison of antibacterial properties of herbal products and standard antibiotics

    5 star(s)

    Due to their simplistic nature, they are also very small an inhibit places such as water, air and human bodies. The majority of bacteria are harmless, however various bacteria that inhibit the body are known as pathogens and can cause disease and infection.

  1. Rate of Respiration

    40 �C 7 40 �C Lactose 0 0 0 0 0 0.1 0.1 0.1 0.1 0.2 7 40 �C 7 40 �C 0 0 0 0 0.2 0.2 0.2 0.2 0.2 0.3 7 40 �C 7 40 �C Average 0 0 0 0 0.1 0.2 0.2 0.2 0.2 0.3 7

  2. The formation of urine.

    As the bladder expands this membrane flattens out to maintain its barrier. viii. Ureters: These are two long tubes that collect the urine from the pelvis and run it down the back of the abdomen and feed into the bladder via two small flap like openings ix.

  1. the role of the microbiology department

    If these contaminate the water supply, or infected people handle food or cooking utensils without washing their hands, then bacteria are transmitted to uninfected people. Almost all people with cholera who are treated make a quick recovery. A death from cholera is an avoidable death.

  2. Homeostasis and excretion.

    Body warm = vasodilatation, body cold = vasoconstriction. 3. Convection heat lost due to normal air circulation: wind=cold. The skin has hairs on it that are controlled by hair erector muscles. When in state of relaxation the hair remain down close to the skin, thus no air is trapped between

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