What is the Difference Between Secretion and Excretion?

what is the difference between secretion and excretion

The main difference between secretion and excretion is that excretion involves the disposal of waste material that is no longer valuable to living creatures.

Whereas secretion involves the movement of materials from one region of the body to another.

Understanding the fundamental definition is necessary to better compare secretion and excretion.

So, let’s look at what each definition means.

Definition Of Excretion

definition of excretion

Excretion is the term for the biological process that involves removing toxic metabolic wastes from the body.

Excretion is the process of gathering water, filtering bodily fluids, and removing waste products from the body in the form of urine, stool, and moisture.

The kidneys are the main organs involved in excretion. 

The human excretory system consists of one kidney and one kidney pair.

Right and left kidneys, two ureters, a urinary bladder for a urethra, right dorita, and left ureter.

The kidneys are situated on either side of the spine in the abdomen.

Many chemical reactions occur in the body during living processes, including cellular respiration.

Waste products from these chemical processes include carbon dioxide, water, salts, urea, and uric acid.

The body is harmed if these wastes are allowed to build up inside it past a certain point.

They are eliminated via the excretory organs. This method by which metabolic waste is removed from the body is excretion.

Importance Of Excretion

importance of excretion

All living things produce waste as a normal by product of metabolic processes.

Waste products from these processes must be eliminated for cells to operate normally.

The process of eliminating waste from the body is called excretion.

Waste products include urine, sweat, ammonia, too much salt, water, and feces, which are both liquid and solid.

The elimination of waste is crucial. Without it, harmful waste products build up and harm living things.

Modes Of Excretion

There are three main modes of Excretion

1. Ammonotelism

Ammonotelism is the removal of ammonia from the body. The type of excretion in ammonotelism is ammonia.

This group includes the majority of fish, protozoans, echinoderms, poriferans.

Ammonia is immediately excreted into the environment by aquatic species.

2. Ureotelism

Urea is a metabolic waste product that several animals and amphibians excrete.

These creatures are known as ureotelic.

The ammonia is created in these organisms and discharged back into the blood.

Urea is filtered by the kidneys and then excreted outside the body.

3. Uricotelism

Uricotelic animals eliminate nitrogenous wastes as pellets or pastes of uric acid.

Although this procedure is the least toxic and most expensive metabolically, it also loses the least amount of water. 

Moreover, the excretions turn into pasty white discharges because uric acid is not readily soluble in water. 

Most birds, insects, and reptiles fall under the uricotelic order.

Because we eliminate urea through urine, humans are ureotelic. Additionally, urea is less harmful than ammonia in terms of comparison.

Definition Of Secretion

definition of secretion
Source: commons.wikimedia.org

Secretion is the process by which organisms actively transport chemicals produced inside cells to the area outside the cell.

Process Of Secretion

Food enters the mouth during digestion when it is chewed up and combined with saliva.

Saliva is produced by the salivary glands, which also create a lot of mucus.

They also include salivary amylase, the first digestive enzyme which breaks down carbohydrates.

Digesting carbohydrates starts in the mouth, where the meal is chewed up and formed into a bolus before being swallowed and entering the stomach, where several secretions occur.

1. The parietal cells are the source of the first order of secretions. 

You have proton pumps in your parietal cells, which generate hydrogen ions. Hydrogen ions aid in the production of hydrochloric acid.

Additionally, the parietal cells release intrinsic factors. For the absorption of vitamin B12, an intrinsic factor is crucial.

2. An alkaline mucus that the stomach secretes those aids in protecting it against its hydrochloric acid.

The G-cells secrete a hormone called gastrin, which is the hormone that encourages stomach discharges.

3. The enteroendocrine cells secrete ghrelin which is an important hormone.

It increases hunger, if you haven’t eaten for a while, ghrelin secretion increases.

4. The pancreatic duct, another exocrine gland that secretes chemicals for digestion, is a part of the digestive system.

The pancreas secretes various chemicals, including enzymes for proteins, fats and carbohydrates.

5. In the small intestine, additional enterocytes secrete enzymes, water, and electrolytes.

Peptidase is one of the enzymes that convert peptides into amino acids.

Sucrase, Maltese, and lactase, among other carbohydrate digestive enzymes, convert disaccharides into monosaccharides.

Difference Between Secretion and Excretion

difference between secretion and excretion

The differences between secretion and excretion are given below:

1. The primary difference between secretion and excretion is that secretion allows the exchange of material between two locations, each of which is significant.

 Excretion, as opposed to secretion, requires the discharge of a substance from a living entity.

2. In secretion, the secreting substance may serve a specific purpose, but the excretory substance is typically a waste and may not serve a specific purpose.

3. The liver, glands, and glandular cells are involved in the secretion process, while the lungs and kidneys are the primary excretory organs.

4. Excretion, as opposed to secretion, is crucial for maintaining a balance between the body’s salt and water levels.

5. In terms of the substances, the body excretes substances like water, CO2, feces, and urine while secreting substances like saliva, enzymes, and hormones.

6. Secreted substances contribute to the body’s metabolism. Conversely, excretion is mainly in charge of eliminating waste from the body.

7. The secretion mechanism is active, whereas the excretion mechanism is passive.

Secretion Vs Excretion

These two terms describe the body’s synthesis of biological compounds.

In comparison of secretion vs excretion, excretion results in waste materials. 

The body uses the secretion’s by products for lubrication and cleansing, among other purposes.

The difference between secretion and excretion is that secretion refers to any substance that is secreted by an organism or might be the act of concealing something.

Whereas excretion is the action of removing, or ejecting, anything that has no longer utility, especially from the body.

Excretion Vs Secretion: Comparison Table

Highlighting the comparison between excretion and secretion in the following table.

The process of excretion involves removing waste from the body.The process of secretion involves movement of materials in the body.
The body secretes substances, including hormones, enzymes, and saliva.The body excretes substances, including urine, faces and sweat.
Excretion is an active process.Secretion is a passive process.
The lungs and kidneys are main organs used for excretion.The liver, glands, and glandular cells are the main organs used for secretions.
Excretion helps in removing waste materials.Secretion helps in body metabolism.


The two mechanisms for moving and removing items inside the body are secretion and excretion. The difference between secretion and excretion is that the chemicals required for metabolism are produced and secreted by the body’s organs and glands.

While the wastes like urea and carbon dioxide are mostly released from the body through excretion.

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