Egestion: Definition, Function, Types, Examples

What Is Egestion?

Egestion is a behavior that is concerned with the removal of the solid wastes that remain undigested. This is important as digestion reduces food into nutrients, absorption moves nutrients into the bloodstream and egestion expels the undigested substances. It enables ridding the body of pathogenic and toxic agents, supports the functional efficiency of the gastrointestinal tract and serves as one of the factors maintaining the organism’s cleanliness.

The Process of Egestion in Humans

The process of egestion in humans:

Mouth to Stomach

• Food is taken through the mouth

• Broken down through chewing and subjected to the initial breakdown through saliva secretion

• From the mouth, it gets into the esophagus and then into the stomach

• Stomach acids and enzymes continue digestion

Small Intestine

• In the small intestine, nutrients are transported through villi and microvilli f

• Vitamins, minerals and other nutrients are absorbed in the blood.

Large Intestine

• The remaining indigestible content goes to the large intestine

• Water is again absorbed to form solid feces.

Rectum and Anus

• These faeces are temporarily accumulated in the rectum.

• They are passed out through the anus

Factors Affecting Egestion

Egestion is affected by the following factors:

Dietary Fibre

• Dietary fibre is involved in the regulation of egestion since it increases the size of faecal matter that can easily pass through the digestive system.

• Fruits, vegetables, whole grains, and legumes most of which are rich in fibre help enhance bowel movements/elimination.

Hydration

• Taking enough water ensures the stool softens

• This avoids cases of constipation.

• Water ensures proper texture and easy passage of stool through the colon.

Physical Activity

• Exercise helps to get blood circulations to the muscles of the Colon

• Stimulating bowel movements and reducing the occurrence of constipation.

Health Conditions

Some diseases will impact egestion, example:

• Constipation: Feces are seldom and difficult to expel

• Diarrhoea: Faeces are liquid

• IBS: Change the bowel aetiology either temporarily or permanently

Egestion In Other Organisms

Egestion is likely to differ with the diet and consequently the gastrointestinal system of the various animals in the ecosystem.

• It’s evident that animals, which feed on plants, for instance cows and rabbits, give plant fibrous feces.

• Discarded scats of lions and wolves for instance contain barely digested remains due to their carnivorous diet.

• Carnivores such as the human being and the bear showed a proportional combination of both vegetable and animal matter in their faecal samples.

Egestion In Plants

In plants, there is no known egestion because plants do not possess a digestive tract where the process should take place. The waste products are released through the stomata, lenticels or specific cells if they include oxygen resulting from the process of photosynthesis: water and minerals.

Egestion in Invertebrates

There is a direct comparison between the digestive system and the type of animals since invertebrates like insects and earthworms have different digestive systems from vertebrates. Most insects have a specific area for digestive and absorptive processes with the excretion of waste materials through the anal opening. In bio-physics, earthworms assist in getting nutrients from the soil and organic matter and then provide castings.

Egestion NEET MCQs (With Answers & Explanations)

Important questions asked in NEET from this topic are:

• Process of Egestion

• Factors affecting Egestion

Practice Questions for NEET

Q1. Absorbed substances finally reach the tissues which utilise them for their activities , this process is called

1. Assimilation

2. Absorption

3. Digestion

4. Mastication

Correct answer: 1) Assimilation

Explanation:

Assimilation is the process by which absorbed nutrients are delivered to the cells and tissues that need them for various functions. After digestion and absorption, nutrients such as glucose, amino acids, and fatty acids are transported through the bloodstream to different cells throughout the body. This process takes place at the cellular level in organs like the liver, muscles, adipose tissue, and other target cells.

Hence, the correct answer is option 1) Assimilation.

Q2. Which of the following statements is incorrect?

1. Faecal accumulation in the rectum initiates a neural reflex causing an urge for its removal.

2. Irregular bowel movements cause constipation.

3. In diarrhea absorption of food is increased.

4. All of the these

Correct answer: 3) In diarrhea absorption of food is increased.

Explanation:

The digestive wastes, solidified into coherent faeces in the rectum initiate a neural reflex causing an urge or desire for its removal. The egestion of faeces to the outside through the anal opening is called defecation. It is a voluntary process and is carried out by a mass peristaltic movement

Hence, the correct answer is option 3) In diarrhoea absorption of food is increased.

Q3. Removal of digestive wastes, solidified into coherent feces in the rectum initiates a neural reflex causing an urge or desire for its removal the process is known as:

1. Ingestion

2. Defaecation

3. Egestion

4. Assimilation

Correct answer: 2) Defaecation

Explanation:

The above process is termed the defecation reflex. Thus, when the rectum is filled with fecal matter, it activates the stretch receptors and sends information to the brain, initiating an urge to move it out. It is also, therefore, a process consisting of both involuntary and voluntary actions within the muscles that expel waste from the body.

Hence, the correct answer is option 2) Defaecation.

Also Read:

• MCQs on Assimilation and Egestion

• Digestive Glands

• Alimentary Canal

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