Collegedunia Team Content Curator
Content Curator
The difference between Secretion and Excretion is that excretion is the process of eliminating or ejecting anything that is no longer useful, whereas secretion is any substance released by an organism or secretion can be the act of concealing something. The active process of secretion is different from the passive process of excretion.
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What is Secretion?
The production and discharge of material from a cell, gland, or organ is referred to as secretion. The secretory products of humans include hormones, enzymes, and saliva. Endocrine glands produce hormones, while gastric glands in the stomach's lining produce enzymes. Hormones are secreted into the bloodstream in order to reach their target.
Hormones and enzymes help to speed up and control biological reactions. Saliva moisturizes, lubricates, and protects the mouth. Within the cells, the Golgi apparatus is involved in secretory material creation and release. Depending on the cell type and the chemical being carried, secretion occurs via a variety of paths.
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Secretory Routes
- Lysosomes
Lysosomes are organelles that are commonly assumed to be primarily responsible for dehydration, although they also play a role in secretion. Certain specialized cell types, such as pigment cells and blood stem cells, use the lysosomal secretory route regularly. Lysosomes, like secretary vesicles, can fuse with the cell membrane to release their contents, but the fusion process requires a distinct type of protein.
- Porosomes and the ER-Golgi Pathway
Secretory products are first synthesized in the endoplasmic reticulum, then put into spherical containers like vesicles, known as transport vesicles, which are formed of a lipid bilayer. These products are subsequently changed in the Golgi apparatus before being packaged into specialized secretory vesicles.
Fig. Porosomes and the ER-Golgi Pathway
- Membrane Transports
Proteins in the cytosol can travel through the cell membrane via transporter proteins rather than exocytosis in some instances. The products are not packaged in vesicles in this situation, but rather are delivered separately by specific proteins in the cell membrane.
What is Excretion?
The process through which metabolic waste products such as urea and carbon dioxide are eliminated from the body is known as excretion. By balancing inorganic ions and water and maintaining acid-base balance, excretion aids in osmotic pressure regulation. The primary goal of excretion is to preserve homeostasis in an organism's internal environment. Diffusion is how protozoans like Amoeba get rid of their waste. Higher multicellular species, on the other hand, have specialized excretory organs.
In vertebrates, kidneys are the primary excretory organs that maintain water balance while excreting urine. In humans, the skin, lungs, and liver all play a role in excretion. Sweat excretes a little amount of urea, water, and salts from the skin. Cholesterol and bile are both excreted by the liver. Carbon dioxide, which is created as a byproduct of cellular respiration, is removed by the lungs. The most common form of sweat glands in the human body is eccrine sweat glands.
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Excretion in Organisms
Depending on the species and type of organism, each has a unique way of secretion. The following are some examples of excretion in various organisms:
- Animal Excretion
The smallest and thinnest species defecate through their skin, which diffuses away over time, whereas larger animals have specific organs and mechanisms for excretion.
Fig. Animal Excretion
- Plant Excretion
Plants, like animals, go through excretion. Small plants merely excrete wastes through the cells on their surfaces, whereas larger vascular plants have an excretion system in which the leaves play a key role.
- Unicellular Organisms' Excretion
Unicellular organisms' excretion is a simple process. Phagocytosis is the most common method of feeding. During this procedure, the cell membrane is folded inwards to form a food vesicle, which is then transported to the cell's cytoplasm, where digestive enzymes work. Exocytosis is a mechanism that removes the leftovers of the food, often known as waste, from the vesicle.
Fig. Unicellular Organisms' Excretion
Difference Between Secretion and Excretion
- Excretion releases waste materials that cannot be reused, whereas secretion releases undesirable materials that can be reused.
- The process of excretion is passive, whereas secretion is active.
- Carbon dioxide, perspiration, tears, faeces, and urine are excreted by the body, whereas hormones, enzymes, and saliva are secreted by the body.
- The lungs, skin, tear ducts, and rectum is engaged in excretion, whereas the Endocrine glands, digestive glands, salivary glands, liver, pancreas, and gallbladder are involved in secretion.
- Tears, perspiration, and urine are materials released during the excretion process, whereas saliva and hormones are materials released during the secretion process.
| Excretion | Secretion |
|---|---|
| It is the process of removing materials from a living organism. | It's the transportation of material from one region to another. |
| In nature, excretion is a passive process. | In nature, secretion is active. |
| Tears, urine, carbon dioxide, and sweat are all excreted by humans. | Enzymes, saliva, and hormones are all examples of human secretions. |
| Body waste makes up the majority of excretion. | Secretion is a vital substance that our bodies can metabolize. |
| Plants excrete through their roots into their surroundings, as well as through the leaves and bark of their leaves and bark. | Latex, resin, gums, and other secretions are found in the plant body. |
Things to Remember
- Excretion is a biological process by which the body gets rid of waste materials that can no longer be utilized.
- Excretion is also necessary for a variety of other functions, such as osmoregulation, which is responsible for supplying the cells with an appropriate environment in which to perform the requisite reactions.
- Secretion is a biological process by which the body discharges undesirable substances that can be reused.
- Functional proteins and several non-protein, such as steroids, are among the compounds released.
- Both are necessary for biological homeostasis to be maintained.
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Sample Questions
Ques. What are examples of excretion and secretion? (2 Marks)
Ans. The body secretes substances such as saliva, enzymes, and hormones. The body excretes substances such as tears, sweat, carbon dioxide, urine, and faeces. Plants excrete through their roots into the environment, as well as through the leaves and bark of their leaves and bark.
Latex, resin, gums, and other plant secretions are found in the body of the plant.
Ques. In the kidneys, what is secretion? (3 Marks)
Ans. The glomerular filtrate passes via the renal tubule, where nutrients and water are reabsorbed into the capillaries. Waste ions and hydrogen ions flow through the capillaries and into the renal tubule at the same time. This is known as secretion.
Hydrogen, creatinine, ions, and other waste products, such as medicines, are among the most commonly secreted compounds. Tubular secretion is the process of transferring materials from peritubular capillaries to the renal tubular lumen, which is mostly accomplished through active transport and passive diffusion.
Ques. In the human body, what is secretion? (3 Marks)
Ans. Secretion refers to the production and release of a beneficial substance by a gland or cell; it can also refer to the substance itself. Body tissues release a multitude of chemicals that provide lubrication and moisture, in addition to the enzymes and hormones that assist and regulate complex biochemical processes.
Hormone secretion; milk secretion by the mammary glands. A secreted substance such as saliva, mucus, tears, bile, or a hormone. The process of a cell or gland secreting a material. A secreted substance such as saliva, mucus, tears, bile, or a hormone.
Ques. What is the substance that the skin produces? (3 Marks)
Ans. The dermal layer of the epidermis contains glands that produce skin secretions. Eccrine glands secrete sweat, which is physiological assistance in regulating body temperature. The lubricant sebum is produced by sebaceous glands.
Sebum is a natural oil that is secreted by the hair shaft to keep it from splitting. It is a yellowish, oily material produced by the sebaceous glands, which can be found on almost every surface of the body. Sebum seals in moisture and keeps skin from becoming too dry because of its particular composition.
Ques. What is the definition of secretion in the digestive system? (2 Marks)
Ans. The digestive tract secretes about 7 litres of fluid per day. Saliva, mucus, hydrochloric acid, enzymes, and bile are examples of these fluids. Saliva moistens dry foods and contains salivary amylase, a digestive enzyme that starts carbohydrate digestion. Gastric secretions will continue their digestive operations for a short period in the small intestine after the chyme is emptied into the duodenum. The pancreas, a huge gland that generates both digestive enzymes and hormones, is one of the most important sources of digestive output.
Ques. What is the name of the liver secretion? (2 Marks)
Ans. Bile is an essential aqueous secretion of the liver that is generated by the hepatocyte and changed downstream by the bile duct epithelium's absorptive and secretory characteristics. Organic and inorganic solutes of great complexity make up approximately 5% of bile.
Ques. Is sweat a form of excretion? (3 Marks)
Ans. The process of excretion is the removal of wastes and excess water from the body. Sweat glands produce sweat on the skin, which aids in excretion. Sweating removes extra water, ions, and a tiny quantity of urea, a result of protein catabolism.
Under physical stress, sweat acts as an "excretion machine" in the skin (schematic). Sweat released by apocrine and eccrine sweat glands plays a critical role in maintaining body temperature and physiology. Sweat includes antimicrobial peptides that help to strengthen the skin's defensive mechanism.
Ques. What are the similarities between secretion and excretion? (2 Marks)
Ans.
- In the movement or passage of materials in the body, both secretion and excretion are involved.
- In animals, organs are engaged in both secretion and excretion.
- Both are necessary for maintaining the body's homeostasis.
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