Biology Notes on Human Excretory System

By Rahul Chadha|Updated : December 13th, 2019

The excretory system is one of the most important topics of Biology for General Awareness Section of Railways & SSC Exams. Every year 1-2 questions are expected from this section. Thus, this post is very helpful for the upcoming SSC CHSL, NTPC, Group D & other government Exams.

Excretion system: an excretory system is a process by which an organism gets rid of waste products of its metabolism. The three terms excretion, secretion, and egestion all describe the passing out of substances from organisms or cells. Removal of nitrogenous substances like urea, ammonia, uric acid, etc. formed during metabolism from the body of the human is called excretion.

Various animals and their excretory organs

Animals 

Excretory organs

Unicellular animals

Diffusion/Osmosis

Coelenterates

Direct by cells

Platyhelminthes

Flame cells

Ascehehelminthes

Renette cells

Annelida

Nephridia

Porifera

Canal system

The main excretory organs of human are as follows –

(i) Kidneys: kidneys are the most vital and prominent organ in the excretory system. The excretory process is mostly done by kidneys.

  • In the human being, there exists a pair of the kidney which is dark-red, bean-shaped.
  • Its weight is 140 grams.
  • There are two parts to it. The outer part is called cortex and the inner part is called medulla.
  • A kidney has about ten lakh structural and functional units, called nephrons.
  • Bowman's capsule is a cup-like structure in every nephron called.
  • Glomerulus of thin blood vessels is found in the Bowman's capsule which is made up of two types of arterioles.

(a) Afferent arteriole: An afferent arteriole connects the renal artery to the glomerular capillary network in kidney's nephron, Which carries the blood to the glomerulus, starting the filtering process.

(b) Efferent arteriole: it has less diameter than afferent arteriole and takes blood out of the glomerulus.

Functions of the kidney:

  • It maintains the PH of blood.
  • Ultra filtration – it is the process of filtration of liquids into the cavity of Bowman's capsule.
  • It maintains salt contents of the body.
  • It eliminates toxic substances of the body.
  • Homeostasis – kidney removes various unwanted materials from the blood, it helps in keeping the internal environment of the body constant.
  • Kidney secrets an enzyme Renin which change the plasma protein, the angiotensinogen.

(ii) Skin: Oil gland and sweat glands secrete sebum and sweat respectively. Along with sebum and sweat some other excretory substance to enhance the excretory process.

(iii) Liver: the cells of the liver transform the excessive amino acids and ammonia of the blood into urea which is the main excretory substance. And spleen split the damaged blood cells and separate them from the blood flow.

(iv) Lungs: in general Lungs are associated with the respiratory system but it also plays an important role in the excretory system. Lungs do the excretion of the gaseous substance. CO2 and water vapours and some substances like garlic, onion, and some species are also excreted by lungs.

Different excretory Products

List of various excretory products are as follow-

  • Nitrogenous waste material
  • Mineral Salts
  • Co2
  • Water
  • Pigments
  • Creatine and creatinine
  • Vitamins and Hormones 

RRB NTPC FREE Test based on the recent pattern: Attempt Now

Want to clear RRB NTPC Exam? Gradeup has something in stock for you...

Lakhs of candidates will appear for the upcoming RRB NTPC Exam which will eventually hike the competition level. What is your strategy to deal with the soared up competition level? Have you made any plans? To help you crack RRB NTPC Exam, Gradeup has come with an advanced course for RRB NTPC Exam with a 50-Day Study Plan. This course is exam-focused with a structured study plan to enhance speed and accuracy in both NTPC Stage I & II.

Comments

write a comment

SSC & Railway

CGLSSC GDDFCCILCHSLCPONTPCMTSStenoGroup DDelhi PoliceOthersCoursesMock Test

Follow us for latest updates