Module 4

How is the large intestine different from the small intestine?

The large intestine is wider but shorter than the small intestine, measuring about ¼ of the length of the small intestine.

What are the main functions of the large intestine?

A: The large intestine is responsible for:

• Movement of contents via peristalsis.

• Further digestion of proteins by bacteria.

• Water absorption.

• Formation of feces and defecation.

What are the main parts of the large intestine?

The large intestine consists of the ascending, transverse, descending, and sigmoid colons, along with the rectum and anal canal.

What is haustral churning in the large intestine?

Haustral churning is the uncoordinated contraction of bands of longitudinal muscle in the large intestine that churns food for further mechanical digestion.

What role do bacteria play in the large intestine?

Bacteria in the large intestine help digest proteins, produce vitamins, and aid in the fermentation of certain carbohydrates.

What happens if the large intestine becomes dysfunctional?

Dysfunction of the large intestine can lead to issues such as constipation, diarrhea, or malabsorption of water and nutrients.

How long is the small intestine?

The small intestine is about 3 meters long in a living person and 6.5 meters in a cadaver.

What are the three regions of the small intestine?

A: The three regions are:

1. Duodenum – the shortest section.

2. Jejunum – the middle section.

3. Ileum – the longest section.

What structural features of the small intestine enhance digestion and absorption?

The small intestine has circular folds, villi, and microvilli, which increase surface area for digestion and absorption.

What are villi and their role in digestion?

Villi are fingerlike projections that increase the surface area for absorption. Each villus contains capillaries and a lacteal to transport nutrients.

How is the small intestine histologically structured?

The small intestine has four main layers:

What is the upper GI tract composed of?

The upper GI tract includes the mouth, pharynx, oesophagus, and stomach.

What are the roles of the teeth in digestion?

The teeth tear and crush food, increasing the surface area for enzyme action.

What does the tongue do in digestion?

The tongue manipulates food into a bolus and directs it to the back of the throat for swallowing. It also produces lingual lipase, which breaks down triglycerides (fats).

What is the function of the salivary glands in digestion?

The salivary glands produce salivary amylase, which starts the breakdown of carbohydrates.

What is digestion?

Digestion is the process by which the body breaks down food into nutrients that can be absorbed into the bloodstream and used by cells for energy, growth, and repair.

What are the main macronutrients that must be digested?

The main macronutrients are carbohydrates, proteins, and fats.

What are the main components of the digestive system?

The digestive system consists of the digestive tract (GI tract) and accessory organs.

What are the parts of the digestive tract (GI tract)?

The digestive tract includes the mouth, pharynx, oesophagus, stomach, small intestine, and large intestine.

What is the role of the salivary glands in digestion?

The salivary glands produce saliva containing the enzyme salivary amylase, which begins breaking down carbohydrates.

What is the function of the liver in digestion?

The liver produces bile, which helps in the digestion and absorption of fats.

What does the pancreas secrete to aid digestion?

The pancreas secretes digestive enzymes and bicarbonate to neutralize stomach acid and break down carbohydrates, proteins, and fats.

What is the process of ingestion?

Ingestion is the process of taking food and liquid into the mouth

What is secretion in the digestive process?

Secretion is the release of digestive enzymes, acids, buffers, and water into the digestive tract to help break down food.

What is absorption?

Absorption is the uptake of digested nutrients, water, and electrolytes into the bloodstream or lymphatic system.

What is defecation?

Defecation is the elimination of undigested and unabsorbed materials from the body in the form of feces.