Excretory System

What is the Excretory System?

The excretory system is a vital biological system that removes excess and waste products from the body to maintain homeostasis.

The excretory system primarily involves:

• A pair of kidneys, which filter blood to remove waste and excess water
• The waste is turned into urine, which is stored in the bladder until it is time to be released
• This system also includes the skin, which removes sweat
• The lungs help us get rid of carbon dioxide when we breathe out

Thus, without the excretory system, we would become ill from accumulated waste. It is very important to keep our excretory system healthy by drinking enough water and keeping active!

The Excretory System Diagram:

Major Organs of the Excretory System

The human excretory system is made up of a few key organs that function together to remove waste and extra fluids from our bodies.

Here is a quick look at how it is all structured:

• A pair of Kidneys
• Ureters
• Bladder
• Urethra

Each of these excretory system organs has a specific function and they function together to ensure our bodies stay clean and healthy by eliminating the wastes and other toxic materials from our body which are no longer required.

Additional Excretory Organs

While the kidneys do most of the heavy lifting in the excretory system, there are a few other excretory organs that help get rid of waste and keep our body in balance.

These accessory excretory system organs include:

Lungs:

• The lungs are a pair of spongy organs in the chest which function as a built-in air filter
• We usually think of lungs for breathing, but they also help with excretion!
• The lungs remove carbon dioxide (a waste gas) from our body every time we breathe out

Skin:

• The skin is the body's largest external organ, which is also considered an excretory organ
• The skin functions by secreting excess water, salt, and urea from the body through sweat

Liver:

• The liver is the largest internal organ in the body and is also considered a very important organ for excretion
• The liver functions by breaking down toxins and other waste products from our food, drinks, and other things we consume. It then sends these waste products to the kidneys to be removed from the body

These accessory excretory organs work together with the kidneys to ensure our body stays clean and healthy by removing unwanted waste.

Structure of the Human Excretory System

The excretory system has a few important organs that work together to remove waste and keep our bodies healthy.

Here is a quick rundown of the main ones:

Kidneys :

A pair of kidneys - the primary excretory system organs are considered as the "filters" of the body.

This excretory organ functions by filtering the blood, eliminating the wastes and extra water and fluid, in the form of urine. We have two kidneys, and they are vital for keeping everything in balance

Ureter:

After the kidneys filter the blood, urine travels through two tubes called ureters to get to the bladder. It functions as a delivery system.

Urinary Bladder:

It is a subperitoneal, hollow, muscular excretory organ that acts as a reservoir for urine. The bladder holds the urine until we are ready to release it from our body.

Urethra:

This is the tube through which urine is carried out of the body from the bladder. The Urethra carries out the final step of excretion by getting rid of waste.

Lungs:

Lungs, the primary part of the respiratory system, also play a role in the excretory system

It is an important excretory organ, which functions by eliminating gaseous waste like carbon dioxide which is useless and harmful to our bodies.

Liver: 

The liver plays a crucial role in the excretory system by filtering blood, removing toxins and waste products, converting ammonia to urea, which is then excreted in urine, and producing and secreting bile.

Skin:

The skin plays a vital role in the excretory system by releasing sweat, which helps get rid of extra water and salts

The Human Excretory System Diagram:

Structure of the Kidney

The kidneys work nonstop to keep our bodies clean by filtering out waste and excess water. It is like a little filter system that helps keep everything in balance!

The Structure of the Kidney:

Kidneys - The Body's Filtration System!

The kidney is one of the most important organs in the excretory system, and it is two bean-shaped organs that are roughly the size of a fist. It plays a vital role in filtering waste.

Here is a detailed structure of the kidney:

Renal Cortex:

• This is the outer part of the kidney
• It looks like a soft, reddish-brown layer
• It is where the first part of filtration happens

Renal Medulla:

• Inside the cortex is the renal medulla
• It looks like a bunch of little triangles
• It helps process the waste by moving it into the next stage

Nephrons:

• The tiny, microscopic structures are the real workhorses of the kidney
• Each kidney has around a million nephrons
• The primary filter for blood in the human body is the kidneys, which remove waste and create urine
• The nephron has two main parts:
  • Glomerulus: A tiny ball of capillaries where blood is filtered
  • Bowman’s Capsule: A cup-shaped structure that collects the filtered liquid

Renal Pelvis:

• It is the area present at the centre of the kidney
• The renal pelvis acts like a funnel, leading the urine to the ureter
• Once the waste is filtered and turned into urine, it flows into the renal pelvis

Ureter:

• The ureters are bilateral, muscular tubes, which are approximately 25-30 cm long and are situated bilaterally, with each ureter draining one kidney
• The ureter has 3 layers: the mucosa (innermost layer), muscularis (middle layer), and adventitia (outer layer)
• The ureters function like a carrier. This muscular tube carries urine from the kidney to the urinary bladder

Mechanism of Excretion in Humans

Excretion is the process of elimination or removal of wastes and extra substances from our body that is no longer required. This process of excretion helps our body to stay healthy and balanced.

Here is a detailed explanation of how the excretion process works in our body:

Filtration in the Kidneys:

A pair of kidneys is the main organ for excretion. Blood flows into the kidneys, where tiny filters called nephrons remove waste and extra water. This waste turns into urine.

Reabsorption:

Not everything in the filtered blood is waste. The body retains the necessary things which are still required, such as water, glucose, and salts, by reabsorbing them back into the bloodstream.

Urine Formation:

The waste products that do not get reabsorbed (like urea and extra salts) combine with excess water to form urine

Urine Storage:

The formed urine moves from the kidneys through the ureters down to the bladder until it is released.

Excretion:

During urination, urine is released from the bladder through the urethra and exits the body.

Other Excretory Processes:

• Skin: It helps in getting rid of waste through sweat
• Lungs: It helps in removing carbon dioxide when we breathe out

Thus, all these steps work together to make sure our body stays clean and free of waste!

Importance of the Excretory System

The excretory system is vital for the existence of an organism. The food that we take needs to be removed as well, and it would be possible only with the help of the excretory system.

Here are some of the important functions of the Excretory System

Keeps Us Healthy:

The excretory system removes waste like urea, salts, and extra water that our body does not need. If waste builds up, it can cause problems like kidney stones or urinary infections.

Maintains Balance:

The system helps keep the right balance of water, salts, and other important substances in our body.

Regulates Blood Pressure:

The kidneys also help control our blood pressure by adjusting the amount of water in our body. Too much or too little water can cause our blood pressure to go up or down.

Detoxifies:

The liver and kidneys help filter out toxins and harmful substances from food, drinks, and even the air we breathe. This prevents harmful chemicals from building up in our bodies.

Waste would accumulate without the excretory system, leaving us feeling ill or frail. That is why it is important to drink plenty of water, stay active, and take care of our kidneys and skin.

Keeping this system healthy helps us feel our best!